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HomeMy WebLinkAboutHydrogeologic Investigation ReportI I 1 I I I I I I I I PART 360 AND PHASE II HYDROGEOLOGIC INVESTIGATION REPORT Southold Landfill Town of Southold Suffolk County, New York I I I I Dvirka and Bartilucci Consulting Engineers OCTOBER 1991 I I I I I I I I I I I I I I I I I i $ PART 360 AND PHASE H HYDROGEOLOGIC I]qVF__.STIGATION REPORT SOUTHOLD LANDFH.L PRF-I)AI{RD FOR TOWN OF SOUTHOLD SUFFOLK COUI',fI'Y, ~ YORK PR.Ep,~J~ m BY DV]RKA A_ND BARTII..UCC~ CONSULTING ENGINEERS syOSSEF, NEW YORK Section 1.0 2.0 3.0 4.0 TABLE OF CONTENTS Titl~ SUMMARY PURPOSE SCOPE OF WORK 3.1 3.2 General Investigation Procedures 3.1.1 Health and Safety Program 3.1.2 Quality Assurance/Quality Control Program 3.1.3 Data Validation 3.1.4 Air Monitoring 3.1.5 Decontamination Subsurface Investigation 3.2.1 Soil Gas Survey 3.2.2 Geophysical Program 3.2.3 Monitoring Well Program 3.2.3.1 Monitoring Well Locations 3.2.3.2 Monitoring Well Depths 3.2.3.3 Monitoring Well Construction and Installation 3.2.3.4 Monitoring Well Development 3.2.3.5 Borehole Abandonment 3.2.3.6 Borehole and Monitoring Well Logging 3.2.3.7 Groundwater Level Measurements 3.2.4 Selection of Sampling Locations 3.2.5 Surveying 3.2.6 Analytical Procedures 3.2.7 Sampling Procedures 3.2.7.1 Subsurface Soil (Split Spoon) 3.2.7.2 Groundwater $~-r~ ASSK~SI~r 4.1 Background and History 4.1.1 Site Location and Background Information 4.1.2 Site History and Previous Investigations 4.1.3 Site Reconnaissance 4.1.4 Literature Search 4.1.5 Water Well Survey 4.2 Geology 4.2.1 Regional Geology 4.2.2 Local Geology 4.2.2.1 Soils 4.2.3 Site Geology 4.2.3.1 Soil Gas Survey Results 4.2.3.2 Geophysical Survey Results 4.2.3.3 Site Topography 4.3 Groundwater Hydrogeology 4.3.1 Regional Hydrogeology 4.3.2 Local Hydrogeology Page 1-1 2-1 3-1 3-1 3-1 3-2 3-2 3-2 3-3 3-4 3-4 3-4 3-6 3-6 3-9 3-10 3-11 3-13 3-13 3-13 3-14 3-15 3-15 3 -23 3 -23 3-23 4-1 4-1 4-I 4-4 4-6 4-6 4-6 4-10 4-10 4-15 4-20 4-21 4-23 4-27 4-27 4-27 4-27 4-28 S 1466~ i I TABLE OF CON'i'I~FS 5.0 6.0 Title 4.4 4.5 4.3.3 Site Hydrogeology 4.3.3.1 Permeability 4.3.3.2 Groundwater Flow Patterns 4.3.3.2.1 Shallow Water Table 4.3.3.2.2 Deep Groundwater Surface Water Sampling Program Results 4.5.1 Introduction 4.5.2 Data Validation Results 4.5.3 Soil Sampling 4.5.3.1 Organic Sampling Results 4.5.3.2 Inorganic Sampling Results 4.5.4 Groundwater Sampling 4.5.4.1 Organic Sampling Results 4.5.4.2 Inorganic Sampling Results 4.5.4.3 Leachate Parameter Sampling Results CONCLUSIONS RBCY)MM]~NDATIONS Page 4-31 4-31 4-35 4-35 4-35 4-40 4-40 4-40 4-40 4-40 4-40 4-44 4-51 4-51 4-69 4-76 5-1 6-1 Appendices APPENDIX A APPENDIX B APPENDIX C APPENDIX D APPENDIX E APPENDIX F APPENDIX G APPENDIX H APPENDIX ! APPENDIX $ APPENDIX K Field Forms Data Validation Report Soil Gas Survey Results Geophysical Report (Vol. Il) Well Construction Diagrams (Vol. II) Boring Logs (Vol. Il) Previous Investigation Results (Vol. II) Aerial Photographs (Vol. Il) Well Completion/Construction Logs - Wells in Vicinity of Landfill (Vol. I1) Boring Logs - Wells in Vicinity of Landfill (Vol. II) Slug Test Results (Vol. II) Number 1-1 1-2 3-1 3-2 3-3 4-1 4-2 4-3 4-4 4-5 4-6 4-7 4-8 4-9 4-10 4-11 4-12 4-13 4-14 4-15 4-16 4-17 4-18 4-19 4-20 4-21 4-22 4-23 4-24 LIST OF FIGURES Title Site Location Map Site Plan Soil Gas Monitoring Locations Monitoring Well Cluster Locations Plan for Construction of Monitoring Wells Zoning Map Landfill Operations Map Previous Groundwater, Water Supply and Soil Sampling Locations Monitoring Wells Located in Vicinity of Landfill Generalized Isometric Geologic Cross Section of the Southold Peninsula Longitudinal Geologic Cross Section of North Fork Cross Section Locations Geologic Cross Section in Vicinity of Site Hydrogeologic Cross Section in Vicinity of Site Hydrogeologic Cross Section Through the Landfill Soil Map Location of Landf'fll Site Cross Sections Cross Section A-A' Cross Section B-B' Regional Water Table Contour Map Groundwater Flow Patterns in Vicinity of Site Groundwater Flow Direction in Vicinity of Site Special Groundwater Protection Areas in the Town of Southold Water Table Contour Map Potentiometric Surface Map 3-D Clay Surface Elevation Map Organic Compounds Exceeding Class GA Groundwater Standards in Groundwater Conductivity Logs and Screen Intervals Inorganic Constituents Exceeding Class GA Groundwater Standards/ Guidelines in Groundwater Page 1-2 1-3 3-5 3-7 3-12 4-2 4-3 4-7 4-8 4-12 4-14 4-16 4-17 4-18 4-19 4-22 4-24 4-25 4-26 4-29 4-30 4-32 4-33 4-37 4-38 4-41 4-68 4-72 4-75 s ~4~ iii I I I I I I I I I I I I I I I I I I 3-1 3-4 4-2 4-5 4-]I 4-12 4-13 4-14 4-15 4-16 4-17 4-18 4-19 6-1 6-2 $14~ LIST OF TABLES Title Description of Monitoring Wells Parameters and Detection Limits of Volatile Organic Compounds Methods 8240, 601/602 Parameters and Detection Limits of Semivolatile Organic Compounds Methods 8270, 601/602 Parameters and Detection Limits of Pesticides/PCBs Parameters and Detection Limits of Inorganic Constituents Method 200.7 EP Toxicity - Parameters and Detection Limits Leachate Parameters and Detection Lhnits Monitoring Parameters - Method of Analysis, Preservation and Holding Times Leachate Parameters - Method of Analysis, Preservation and Holding Times Well Construction Data Geologic and Hydrogeologic Units in the Town of Southold Slug Test Results Groundwater Elevations - July 22, 1991 Vertical Hydraulic Gradients at Each Well Cluster Soil Sampling - Volatile Organics Soil Sampling - Method 601/602 - Volatile Organics Soil Sampling - Semivolatile Organics Soil Sampling - Pesficides/PCBs Soil Sampling - Inorganic Constituents Results of Organic Analyses from USEPA Soil Sampling Results of Inorganic Analyses from USEPA Soil Sampling Groundwater Sampling - Volatile Organics Groundwater Sampling - Method 601/602 - Volatile Organics Groundwater Sampling - Semivolatile Organics Groundwater Sampling - Pesticides/PCBs Organic Compounds Detected in Groundwater - Part 360 and Phase II Investigation and USEPA Site Inspection Results Groundwater Sampling - Inorganic Constituents Metals Exceeding Standards/Guidelines in Groundwater - Part 360 and Phase 11 Investigation and USEPA Site Inspection Results Baseline and Routine Parameters to be Analyzed Compounds/Analytes Detected Above NYSDEC Class GA Standards/ Guidelines and/or NYSDOH Drinking Water Standards iv Page 3-8 3-16 3-17 3-19 3-20 3-21 3 -22 3-24 3-32 4-9 4-13 4-34 4-36 4-39 4-42 443 4-45 4-47 4-48 4-49 4-50 4-52 4-54 4-57 4-65 4-67 4-70 4-74 6-2 6-5 Section I ! m mm mm m mm m m m mm mm m m m m m m m m m I I I I ! I I I I I I I I I I I i I I 1.0 S~Y The Town of Southold operates a municipal solid waste landfill for the disposal of approxhnately 150 tons per day (winter months) to 300 tons per day (summer months) of municipal waste. The existing Southold landfill comprises approximately 45 acres (excluding the 17 acres on Town property and north of the landfill area which was previously used as a borrow area for landfill cover material). The landfill site is situated between Oregon Road and North of Middle Road (County Road 48) to the north and south, respectively, and Cox Lane and Depot Lane to the east and west, respectively, in Cutchogue, Suffolk County, New York. A site location lnap is shown in Figure 1-1. A site plan is presented in Figure 1-2. The Town of Southold plans to close the existing Southold (Cutchogue) landfill and construct a new landfill in the future. In order to implement these actions, the New York State Department of Environmental Conservation (NYSDEC) required that a hydrogeologic investigation be conducted as part of a Part 360 landf'fll permit application for both closure and construction. The purpose of this Part 360 Hydrogeologic Investigation as defined in the NYSDEC, Division of Solid Waste Regulations (6NYCRR Part 360), is to define the site geology and hydrogeology, and groundwater and surface water (if present) flow at the site, and to establish an environmental monitoring system capable of detecting a contaminant release from the landfill which will form the basis for facility design and a remedial contingency plan. The objective of this Part 360 investigation, as requested by the Town of Southold, is to obtain additional information in the vicinity of the site to document the nature and extent of contamination (if present) caused by possible releases from the landfill. Specifically, the investigation is to determine the presence of chemical compounds specified on the New York State Target Compound List (+30) in samples obtained from soil, groundwater and leachate (if present) in the area of the landfill, as well as landfill leachate indicator parameters in groundwater and leachate (ff present). In addition, this study is intended to clarify site-specific hydrogeologic conditions, obtain background (baseline) groundwater quality data upgradient and downgradlent of the landfill prior to closure and construction, and relate this data to regional and local hydrogeologic pattems. This investigation was conducted in accordance with a Work Plan approved by NYSDEC. 1-1 I ! I ! I I I I I I i I I I I I I , ~ .. ~ ~ ~ -..~ ~ LANDFILL ~ ... ') :"5--.', '~. ., - SOURCE: U~, MATTITU~K HILL~ ~ ~O~THOL~ QUA~AN~LE~ TOWN 0~ 80UTHOLD 80UTHOLD LANDFILL ~ ~ SITE LOCATION MAP ~ ~IGU~E I-I ~0~0 DRUM STAGING APPROXIMATE ( LOCATION OF DECONTAMINATION PAD APPROXIMATE LOCATION OF ~7 687 TRAILER \ EXISTING M~II~tNG AREA E~(ISTING ..: L A NDrlL~ ?, ~E~A \ STORAGE GARAGE OVERHEAD ELECTRIC LINES-- ~STE OIL STORAGE COLLECTION CENTER STATION LEGEND EXISTING BUILDING ON LANDFILL 81TE ~--* ...... EXISTING FENCE LINE $-69761· EXISTING GROUND WATER MONITORING WELL TOWN OF SOUTHOLD SOUTHOLD LANDFILL SITE PLAN FIGURE I-2 Under the New York State Superfund Program, a Phase II Investigation at a potential inactive hazardous waste site may be required by NYSDEC based on the findings of a Phase I study, or from other information or determinations arising from within the Department, or from requests from other agencies or governmental entities, such as the Town of Southold, subject to the Department's evaluation. Since the objectives of both the Pan 360 Hydrogeologic Investigation and Phase II Investigation are similar, and since the Southold landfill is a Class 2a site (potential hazardous waste site) which will need to be addressed as required by Part 360 prior to future use of the site or land adjacent to the site, the purpose of this document is to provide a report that will jointly address the regulatory requirements of both the Solid Waste Management Facility/landfill and New York State Superfund programs. The hydrogeologic investigation consisted of a soil gas survey, installation of 14 new monitoring wells at 7 well cluster locations, subsurface soil sampling and logging, groundwater sample collection, downhole geophysical logging and permeability testing. The locations of the site trailer, decontamination pad and dram staging area used during this investigation are shown in Figure i-2. Split spoon samples collected during borehole construction were screened in the field for the presence of volatile organic compounds (VOCs). A a result, one subsurface soil sample was collected during the investigation for laboratory analysis. All samples were analyzed for TCL+30 parameters utilizing EPA SW846 Methods 601/602, 8240, 8270 and 8080 for TCL organics and NYSDEC 1989 Analytical Services Protocol (ASP) for TAL inorganics. These parameters include volatile and semivolatile organic compounds, base neutrals, acid extractables, pesticides/PCBs, metals and cyanide. As a result of groundwater sample data collected during the Pan 360 and Phase II investigation, it appears, based primarily on leachate indicators and a few metals, that there is a weak, limited plume emanating from the Southold landfill. The TCL list parameters exceeding either NYSDEC Class GA groundwater standards/guidelines or New York State Department of Health (NYSDOH) drinking water standards were 1,2-dichloropropene and 1,2-dichloroethane in low concentrations, and iron, magnesium, manganese and sodium in concentrations not substantially above ambient conditions. The leachate parameters, ammonia, nitrate, and phenols were also found at levels exceeding standards, but not at significant levels. All of these parameters were found at levels exceeding standards at upgradient well locations except for 1,2-dichloroethane, which was found above standards in only two wells located just downgradient sl203o 1-4 I I I I ! I I I I I I I ! I I I I I ! of former scavenger waste lagoons. Previous private well sampling conducted off-site and downgradient of the landfill, including a recent (December 1990) site inspection by the United States Environmental Protection Agency (USEPA), show results indicative of background (upgradient) groundwater quality conditions. Based on soil samples obtained during this investigation and the recent USEPA sampling, only a few organic contaminants in low concentrations (toluene, 4-chloroanaline, aldrin and 4,4'DDE) and some inorganic contaminants at elevated levels (aluminum, barium, copper, iron and zinc) were found on-site in the former scavenger waste lagoons. However, none of the organics and relatively low concentrations of inorganics were found in the groundwater underlying and downgradient of the landfffi. As a result of these f'mdings, which found only a very limited number of contaminants which exceeded standards/guidelines in relatively low concentrations, it is recommended that the Southold landfill be removed from the list of potential hazardous waste sites, as a Class 2a site, and that the landfill be delisted entirely. Also, as a result of the trmdings of this Part 360/Phase II investigation, it is recormnended that sample analysis, as part of the long-term monitoring program for the landfill as part of closure, be limited to the select list of parameters found to exceed groundwater standards/guidelines during this investigation, and that the sample frequency be on an annual basis. sl2o3o 1-5 Section 2 ,-, m m mm mm m ,,m mm m m mm ~, mm m mm m m m I I I I I I I I I I ! I I I I I I I I 2.0 PURPOSE The purpose of this investigation, which was conducted in accordance with the Part 360 and Phase II Hydfogeologic Investigation Work Plan approved by the New York State Department of Env~onrnental Conservation (NYSDEC), was to obtain detailed hydrogeologic information at the Southold landfill located in the Town of Southold, Long Island, New York, as well as to determine if the landfzll is a source of groundwater contamination. The Part 360 portion of the investigation was to characterize subsurface soil and groundwater conditions for the purposes of closure of the existing landfill and development of a new landf'fll, while the Phase II part of the investigation was to determine the presence of chemical compounds specified on the New York State Target Compound List, as well as leachate parameters. The results of this investigation were reviewed and compared to information obtained from previous investigations in the area to determine what impact, ff any, landf'fll leachate has had on groundwater quality in the vicinity of the Southold landfill. Based on this review, a long-term monitoring program was developed in order to meet the Part 360 requirements for landfill closure and development of a new landfill and recommendations provided to classify the site. I I I I I I I I I I I I I I I I I I ,I 3.0 SCOPE OF WORK 3. I General Investigation Procedures 3.1. i Health and Safety Program The Health and Safety Plan, as de£med in the Work Plan for the Southold landf~ll site and approved by NYSDEC, was implemented during the Part 360 and Phase II field investigation. Since the principal chemical hazards of concem consisted of volatile organic chemicals (VOCs), and since the potential hazards were restricted to specific work areas where drilling and sampling activities occurred, routine monitoring was required only at the drilling/sampling sites. All monitoring and surveillance equipment (Century OVA, Photovac MicroTip, Miniram Particulate Dust Monitor, and EXOTOX portable combustible gas/oxygen detector) was operated, maintained and calibrated each work day in accordance with the manufacturer's manual and Dvirka & Bartilucci (D&B) Consulting Engineer's Quality Assurance (QA) procedures. Organic vapor monitoring and particulate monitoring was undertaken prior to and following sampling at the site, as well as throughout the soil gas survey and drilling operations. During the field investigation, total VOC vapors exceeded background levels (less than 1 ppm) in the breatlfing zone at two locations. During drilling of wells MW-3S and MW-3D, levels in the area were encountered in excess of 50 ppm as measured by the OVA. Background readings as measured by the MicroTip remained at "zero" throughout the drilling. Since this portion of the site is a methane gas venting area, and the MicroTip is not capable of detecting methane, it was determined that these elevated VOC levels were due to methane. Data obtained during the drilling program showed methane levels lower in the borehole and soil samples than in the ambient air. Since methane is a simple asphyxiant and ambient oxygen levels were normal, level C personnel protection measures were not implemented while drilling at this location. Level C protection was used during the drilling of abandoned soil boring MW-6SA due to elevated OVA and slightly elevated MicroTip readings, both in and immediately around the borehole while drilling. Methane was encountered at abandoned soil borings MW-6SA, MW-6SB and MW-6SC at concentrations of 100% of the Lower Explosive Limit (LEL) These borings were eventually sealed with bentonite grout and abandoned. s]2o~ 3-1 3.1.2 Ouali _ty Assurance/Quality Control Program The Quality Assmance/Quality Control (QA/QC) Plan, as defined in the Work Plan for the Southold landfdl site and approved by NYSDEC, was implemented during the Part 360 and Phase II field investigation. All environmental samples collected as part of the field investigation were obtained in accordance with the decontamination procedures outlined in Section 3.1.5 of this report and the sampling procedures outlined in Section 5.7 of the QA/QC Plan contained in the Work Plan. Field management procedures included preparation of Sample Information Record Forms, Chain of Custody Record Forms, Daily Field Activity Reports and maintenance of a Daily Field Log Book. These records are contained in Appendix A of this report. QA/QC checks, including utilization of trip blanks, field blanks, matrix spikes, matrix spike duplicates, laboratory method blanks and spike blanks, were performed as described in the QA/QC Plan and in conformance with the NYSDEC September 1989 Analytical Services Protocol (ASP). The analytical laboratory which was utilized as pan of this investigation (NY'rest Envixonmental, Inc.) is New York State Department of Health approved (Environmemal Laboratory Approval Program [ELAP]) and approved by NYSDEC to meet the requirements of the 1989 ASP. 3.1.3 Data Validation All Pan 360 and Phase II investigation analytical sample data was validated to ensure laboratory compliance with the 1989 NYSDEC ASP. In general, all data was found to be within NYSDEC requirements and included evaluation with regard to holding times. A more detailed discussion of data validation is contained in Section 4.5.2. The data validation report prepared as pan of this investigation is provided in Appendix B. 3.1.4 Air monitoring with a portable organic vapor analyzer, either a Century OVA, and/or Photovac MicroTip, was conducted at each sample location, as well as throughout the soil gas survey, and the well drilling and installation program. In addition, monitoring with an EXOTOX portable combustible gas/oxygen detector was performed during borehole construction at all monitoring well locations for detection of methane in the breathing zone and within the borehole st2om 3-2 and elevated dust levels, respectively. No significant levels of methane gas were detected within the borehole at six of the seven of the monitoring well locations. As previously discussed, elevated levels of methane were detected only at well location MW-6 during the drilling program. At no time during sampling/drilling activities did total volatile organic chemical vapor concentrations, as measured by the MicroTip, exceed I ppm in the breathing zone, nor did dust levels exceed 0.01 Ug/ln3. LELs of 100 percent were encountered during the soil gas survey but were limited to areas underlain by fill. Elevated MicroTip readings were also encountered in soil gas in these areas, but breathing zone readings remained at background throughout the soil gas investigation. 3. 1.5 Decontamination Prior to sample collection, all reusable field sampling equipment was decontaminated according to NYSDEC approved protocol as follows and in the following sequence: 1. Equipment was washed thoroughly with nonresidual detergent (alconox) and tap water using a brash to remove any particulate matter or surface film. 2. Rinsed thoroughly with tap water. 3. Rinsed thoroughly with distilled water. 4. Rinsed with hexane (pesticide grade) or methanol (pesticide grade) and air dried. 5. Rinsed thoroughly with distilled water and air dried. 6. Wrapped completely with aluminum foil (shiny side out) to prevent contamination during storage and/or transport to or in the field. 7. Rinsed thoroughly with tap water in the field as soon as possible aher use. Submersible pumps, used to develop the monitoring wells, were decontaminated by steam cleaning or alconox washing the external surface of the pump and placing the pump in a clean plastic bucket and pumping ten volumes of potable water through the unit, including all appurtenances. New robing was dedicated to each well and discarded after each use. Care was taken to observe safety precautions since the pump was connected to a power source. 3-3 Drilling rig and split spoon decontamination procedures were as follows: Equipment was washed thoroughly with nonresidual detergent (alconox) and tap water ushag a brush to remove particulate material or surface film. Steam cleaned at 212°F. Sampling and drilling equipment was decontaminated at the "decon" pad located on the landfill site. Split spoon samplers were decontaminated directly over a 55-gallon drum at the drilling location. 3.2 Subsurface Investigation 3.2.1 Soil Gas Survey Individual soil gas samples were not collected as part of the investigation; however, total organic vapors were field-recorded using a flame ionization detector (Century Foxboro OVA), photoionization detector (Photovac MicroTip) and a methane meter. A soil gas sun, ey was conducted in areas of the site where waste was known to have been disposed based upon a 100-foot grid network. The spacing between the soil gas sampling stations was reduced'from a 100-foot to 50-foot grid network downgradient of former scavenger waste lagoons, waste oil storage tanks and an old automobile storage area. A total of 120 grid node/survey points were sampled during the soil gas investigation. At each grid node/survey point, a stainless steel probe, with a removable inner rod, was driven into the ground to a depth of approximately 3-1/2 feet. The inner metal rod was removed and immediately replaced with a stainless steel cap covering the top of the steel probe. After allowing gas to collect within the probe for a period of approximately five minutes, the stainless steel cap was removed and total organic volatile organic compound (TVOC) readings were taken. Soil gas survey locations are shown on Figure 3-1. The results of the soil gas survey are presented in Appendix C and discussed in Section 4.2.3.1 of this report. 3.2.2 A downhole geophysical survey was performed on all of the deep monitoring wells installed as part of this investigation. The logging was performed by Hager-Richter Geoscience, Inc. with oversight provided by D&B personnel. Natural gamma ray and conductivity (EM39) logs were s~2o5o 3-4 DESIGNATION DESCRIPTION · SOIL GAS MONITORING LOCATION DIRECTORY: C:~1027 FII.E NAME: SOItDAS DALE: SEPT. 1991 SCALE: $:1 DESIGNER: S.P.B. Dvirka and ~.~.'~l~'rti"'"'"i..s S OIL m A S TOWN OF SOUTHOLD CUTCHOGUE LANDFILL MONITORING LOCATIONS 0 400 800 FIGURE 5-1 I I I I I I I I I I I I I I I I I I I obtained for each well and incorporated into a report. The Hager-Richter August 1991 report is included in Appendix D. The results of the geophysical survey are discussed in Section 4.2.3.2 of this report. 3.2.3 Monitoring Well Program The primary purpose of the installation of monitoring wells at the landfill site was to obtain and evaluate subsurface data. Subsurface data includes groundwater quality and soil information which will assist in establishing current/background conditions, identifying in greater detail the geology and hydrogeology of the site, and determining if there has been a release of contamination, as well as to support a closure plan and landfill construction permit application, and fulfill the requirements of a Phase II Investigation. As part of this investigation, 14 new monitoring wells were constructed at seven locations and grouped as pairs. Although there are several existing monitoring wells on the landfdl site, it is not known whether these wells were constructed in conformance with current NYSDEC policy. The NYSDEC requirements for Part 360 and Phase II investigations require that PVC-cased wells be constructed without adhesives and contain seals above the well screen. In addition, there was the need for additional wells downgradient from the landfall. Therefore, new monitoring wells were constructed in accordance with NYSDEC requirements; however, the existing wells were used to supplement information obtained from the new wells. 3.2.3.1 - Monitoring Well Locations This section of the report provides a brief discussion of the rationale for the selection of the monitoring well locations. One well cluster (MW-I) was placed upgradient of the landffil, four well dusters were installed immediately downgradient of the existing landfill (MW-2, MW-3, MW-6 and MW-7), and two well clusters were installed downgradiem of the planned landfill area (MW-4 and MW-5). The well locations and sampling intervals are shown in Figure 3-2, and the depths are summarized in Table 3-I. The rationale for the well cluster locations was based on the Part 360 requirements for a hydrogeologic investigation in preparation of a landfill permit application, requirements for a Phase II Investigation and data obtained from prior investigations. st2o~o 3-6 m mmm m m mm m m mi mm mm m mm m mm m m, m m STORAGE GARAGE MW-4 MW-5 , ', MW-3 LAND/FI/L, AREA , % 'x MW-7 WASTIr OIL STORAGE OVERHEAD ELECTRIC LINES COLLECTION CENTER WEIGHING STATION LEGEND 8-697610 EXISTING BUILDING ON LANDFILL SITE EXISTING FENCE LINE EXISTING GROUND WATER MONITORING WELL MW- 1 ('~ GROUND WATER MONITORING WELL CLUSTER TOWN OF SOUTHOLD SOUTHOLD LANDFILL MONITORING WELL CLUSTER LOCATIONS FIGURE 3-2 I I I I I I I I I I I I I I I I I I Well No. MW-IS MW-ID MW-2S MW-2D MW-3S MW-3D MW-4S MW-4D MW-5S MW-5D MW-6D MW-7D Table 3-1 DESCRIFrlON OF MON1TORIlqG WELLS Shallow (glacial) Deep (glacial) Shallow (glacial) Deep (glacial) Depth Groundwater (feet)* Sampling Point 52 Water Table 152 Clay Interface 27 Water Table 85 Clay Interface Shallow (glacial) Deep (glacial) Shallow (glacial) Deep (glacial) Shallow (glacial) Deep (glacial) Shallow (glacial) Deep (glacial) Shallow (glacial) Deep (glacial) Soft Sampling *Approximate depth below ground surface. $120~O Continuous Every 5' Every 5' Every 5' starting at 32' 3-8 55 Water Table Every 5' 125 Clay Interface Every 5' starting at 60' 73 Water Table Every 5' starting at 45' 150 Clay Interface Every 5' starting at 75' 77 Water Table Every 5' starting at 56' 136 Clay Interface Every 5' starting at 80' 56 Water Table Continuous to 42' 145 Clay Interface Every 5' starting at 45' 50 Water Table Every 5' 125 Clay Interface Every 5' starting at 55' I I I I I I I I I i I I Well cluster MW-I (wells MW-IS and MW-ID) is upgradient of the existing landfill and is located in an area where groundwater quality is expected to be representative of ambient conditions in the vicinity of the site. This well cluster is also important in locating the divide between groundwater that flows north-northwest beneath the landfill and the special groundwater protection zone that lies southwest of the facility. Monitoring well clusters MW-2 (wells MW-2S and MW-2D), MW-3 (wells MW-3S and MW-3D) and MW-7 (wells MW-7S and MW-7D) are located approximately 500 feet apart downgradient along the northern and eastern boundaries of the existing landfill. Existing monitoring wells (S-68916 and S-68831) (see Figure 3-1) may be used to supplement these new wells maintaining a 500-foot spacing between well locations. Monitoring well cluster MW-7 is also located downgradient of the existing waste oil storage tanks. Monitor'mg well cluster MW-6 is located approximately 300 feet upgradient (south-southeast) of existing monitoring well S-68916 and immediately downgradient of the former scavenger waste lagoons and the old automobile storage area along the western boundary of the existing landfill. These monitoring wells will also serve as the upgradient wells for the planned landfill. Monitoring well clusters MW-4 (wells MW-4S and MW-4D) and MW-5 (wells MW-5S and MW-5D) are situated approximately 500 feet apart downgradient (north-northwest) of the planned landfill area. With regard to fulfilling the requirements of a Phase II Investigation, the monitoring wells described above should more than meet the intent of such an investigation which typically requixes the installation of four wall clusters: one upgradient of the site and three downgradient. In addition, the 14 new monitoring wells installed as part of fids investigation should also satisfy the requirements for closure of the existing landffil and construction of a new landfill under the Part 360 regulations. 3.2.3.2- ~ Wll t~ Each monitoring well cluster consists of two individual monitoring wells screened at different depths at the same location. The purpose of the monitoring well clusters in this investigation is to de£me the three-dimensional flow system within the water-bearing unit of the critical stxatigraphic section, which in the area of the Southold landfill is the upper glacial aquifer (above the North Fork glacial clay layer), as well as the quality of groundwater in this formation in the immediate area of the landfill. s I2ox~ 3 -9 The shallow/water table wells were installed at each cluster location at an average depth of approximately 55 feet below ground surface in the surficial glacial deposits. The water table at the site lies an average of approximately 40-45 feet below ground surface. The deep glacial aquifer wells were installed at each cluster location at an average depth of approximately 130 feet below ground surface in the Pleistocene glacial deposits, and were placed at the lithologic interface with the underlying clay layer in the area of the landfill. These borings were advanced to the North Fork glacial clay to demonstrate the continuity of the clay. Presence of the clay was established upon initial contact with one additional split spoon sample advanced into the clay. 3.2.3.3 - Monitoring Well Construction and Installation Six of the seven shallow wells were constructed using the hollow stem auger method. At the six clusters, borings were advanced for the shallow wells to a depth approximately 15 feet into the water table. Sampling at 1VIW-4S and MW-5S began at approximately 50 feet due to the fact that they were both constructed on the clifftop (northern side) of the mining area of the landfill. Borings were advanced to a depth equal to the elevation of the bottom of the mined pit prior to sampling. Since the stratigraphy of the cliff side was exposed to visible observation, no geologic logging was considered necessary in the upper visible layers at MW-4 and MW-5. This procedure was approved by the NYSDEC on-site supervisor. Six of the seven deep wells were constructed using the cable tool method. These deep boreholes were advanced to the clay layer. The clay layer contact was established by split spoon sampling approximately eveN five feet with more frequent sampling, as necessary. Monitoring well cluster MW-6 was constructed using the mud rotary method. The change in drilling method was required because of excessive levels of methane gas encountered during the drilling of soil borings MW-6SA, MW-6SB and MW-6SC. The levels of methane exceeded 100% of the Lower Explosive Limit (LEL) at these soil boring locations. Because of these explosive levels, mud was used to suppress the methane to safe levels. 3-10 Well construction consisted of a 2-inch diameter stainless steel screen and threaded, flush joint PVC casing. Ten feet of stainless steel wire wrapped screens with 0.02 inch openings were installed in each deep borehole and 20-foot screens were installed in each shallow borehole (5 feet above the water table and 15 feet below) except for MW-6S, which, in order to mitigate methane from entering the screen zone, the screen length was modified to 15 feet, most of which was installed in the saturated zone, in order to minimize the amount of screen exposed to the vadose zone. A 2-inch diameter PVC riser extends from the top of the screen to 2-1/2 feet above ground surface and is contained in a steel protective casing with a locking cover, except for MW-IS and MW-1 D, which were installed with flush mount protective casings. I I I The annulus of the borehole in the area of the screen was sand-packed to a height of 2 feet above the screened interval with clean silica sand in conformance with Part 360 requirements. A finer grained sand pack material (100% passing the No. 30 sieve and less than 2% passing the No. 200 sieve) 6 inches in thickness was placed on top of the sand pack between the sand and the bentonite seal. A 3-foot seal of thick PUREGOLD bentonite slurry was placed immediately above the filter material using a tremie pipe. The remaining annulus was grouted to the surface with a PUREGOLD bentonite slurry. PUREGOLD bentonite is tested and warranteed to be free of organic and inorganic contaminants. ! I I I I I ;I A 4-inch diameter protective outer steel surface casing with locking cover and a surface cement pad was installed around each well casing/riser pipe. Figure 3-3 provides an illustration of well construction. More detailed well construction and installation diagrams are contained in Appendix E. 3.2.3.4 - Monitoring Well Development All monitoring wells were developed using a 2-inch diameter Gmndfos Redi-flo 2 submersible pump. Surging of the wells was performed periodically by lowering and raising the pump rapidly similar to a surge block. Monitoring wells were pumped at a rate of approximately 5 gallons per minute (gpm). AH wells were developed until a turbidity of 50 NTUs (nephelometric turbidity units) was attained. Well development was supplemented by measurement of temperature, pH and specific conductance, and continued until stabilization of these parameters was achieved. Extensive development occurred at MW-6S and MW-6D to ensure that all excess mud was removed from the screen interval. s[20m 3-11 5"I.D. STEEL CAP MINIMUM 9 VENTED PVCC NEAT CEMENT S'O.ED $'- 6 ---- 2" I.D. SCHEDULE 40 PVC THREADED FLUSH JOINT RISER CEMENT' BENTONITE GROUT ~ENTONITE SEAL ~ 6"-FINER GRAINED S~ND SAND PACK -~f-ii PACK~ 6" ~ICK~ PLACED AT EXTEndING 2 F[ABOVE 2~0 TOP OF SAND PACK BE~EEN AND 2'-BELOW WELL ~ BENTONITE SEAL AND SAND SCREEN ~ PACK ~ ~ 20~X 2"STAINLESS STEEL ~ SLOTTED SCREEN WITH BOTTOM PLUG FOR DEEP WELL , TOWN OF SOUTHOLD SOUTHOLD LANDFILL PLAN FOR CONSTRUCTION ~~ OF MONITORING WELLS 3.2.3.5 - Borehole Abandonment All soil borings which were not completed as monitoring wells were fully sealed to prevent contaminant migration through the borehole. A total of three boreholes were abandoned during this investigation. Three borings were attempted in the vicinity of proposed monitoring well cluster MW-6 downgradient of the former scavenger waste lagoons. The fkst was located adjacent to the lagoon and was advanced to a depth of 29 feet. The second location was approximately 100 feet north paralleling the landfill perimeter fence and was advanced to a depth of 15 feet. The third location was adjacent to the two existing Suffolk County wells (S-68831 and S-68916), and was advanced to a depth of 20 feet. As previously discussed, all three boreholes had to be abandoned due to Lower Explosive Limits (LELs) exceeding 100% at each location. A decision was made to al/ow the third boring to vent over a weekend in the hope that LELs would subside to a safe level. Although LELs were found to be zero within the augers on the following Monday morning, turning the augers caused the LELs to climb quickly to 100%. All three locations were abandoned by grouting with PUREGOLD bentonite grout utilizing a tremie pipe as approved by the NYSDEC on-site representative. 3.2.3.6 - Borehole and Monitoring Well Logging All boreholes and monitoring wells were logged and documented by a geologist. Notes were kept in both bound field books and on a Boring Log and Well Construction Log. Boring Logs are included in Appendix F and Well Construction Diagrams are provided in Appendix E. The Modified Burmeister Classification System or Unified Soil Classification System (USCS) was used to describe soil samples recovered from the borings. A Daily Field Activity Report was completed whenever there were drilling activities (or any other field activities) undertaken as part of this investigation. 3.2.3.7 - Groundwater Level Measurement Stabilized groundwater level measurements were obtained from each of the 14 wells installed as part of this investigation and all readily accessible existing wells in the vicinity of the landfill. Measurements from wells installed during this investigation were obtained prior to well purging and sample collection. The static water level was measured to the nearest one-hundredth (0.01) foot using a Hunter-Keck electronic water level indicator. Groundwater level data was used to construct groundwater contour maps to determine local flow conditions. 3-13 I I I I I I I I I I I I 3.2.4 Selection of Sampling Locations Groundwater samples were obtained for chemical analysis from all 14 monitoring wells installed as part of the investigation. One subsurface soil sample was collected at monitoring well cluster MW-6 for chemical analysis. All other soil samples were collected for geologic logging and organic vapor screening. Monitoring well locations are shown in Figure 3-2. Subsurface Sampling At a minimum, 5-foot soil sampling was performed at all well cluster locations to the clay layer. At six of the seven clusters, the shallow well borings were sampled f'u'st with sampling continuing at each associated deep well boring. Exceptions to this were MW-IS, which was sampled continuously, MW-4S and MW-SS, where sampling commenced at approximately 50 feet, and MW-6D, which was sampled continuously to a depth of 42 feet and at 5-foot intervals thereafter. These samples were collected to provide detailed stratigraphic information on the landf'dl site. Soil samples obtained from the split spoons were observed for geologic characteristics and screened with a Century OVA and a Photovac MicroTip. As a result of this screening, one soil smnple was collected from MW-6S from a depth of 11 to 13 feet. This soil sample was analyzed for Target Compound List (TCL) +30 parameters and was retained for EP Toxicity analysis if the EP Toxicity parameters were detected in significant concentrations. Selection of this soil sample for chemical analysis was made with the approval of the NYSDEC on-site representative based on elevated levels of total organic vapors and visual staining. Each of the 14 wells installed as part of this investigation were sampled and analyzed for TCL +30 and landfill leachate indicator parameters which are described in Section 3.2.6. Prior to sampling, a minimum of four well volumes were removed or until pH, specific conductance and temperature stabilized. Wells were sampled only when the turbidity was less than 50 NTUs. Although provisions were made for the collection of up to four leachate samples, no samples were collected due to the absence of any visible leachate seeps. The absence of leachate was confirmed by inspections performed by NYSDEC personnel. 3-14 3.2.5 Surveying The location and elevations of all existing monitoring wells were surveyed to obtain the exact location and plotted on a map. The elevation of the ground surface and the top of the monitoring well riser pipe was accurately measured to the nearest one-hundredth (0.01) of a foot. 3.2.6 Analytical Procedures Samples collected as part of this investigation were initially analyzed for TCL+30 parameters utilizing USEPA Methods 601/602 and USEPA SW846 Methods 8240, 8270 and 8080 for TCL organics, and NYSDEC 1989 Analytical Services Protocol (ASP) for Target Analyte List (TAL) inorganics (Method 200.7) and Method 335.2 for cyanide. These parameters include: volatile and semivolatile organic compounds (base neutrals and acid extractables) pesticides and PCBs, metals and cyanide. In addition, groundwater samples from all monitoring wells were analyzed for NYSDEC field and leachate parameters (indicators) as specified in the NYSDEC Part 360 List of Expanded Parameters. Because there is no suspected hazardous waste disposal at the landfill, no samples were analyzed for dioxin or furans. Due to the different analytical requiremems for a Phase II Investigation and Part 360 Hydrogeologic Investigation, analysis for volatile organic compounds required two separate methods. The Phase II Investigation requires Method 8240 to be used for volatile organics, while the Part 360 requires Method 601/602. As a result, all volatile organic samples were analyzed by both methods. Parameter lists and detection limits for Methods 8240, 601/602, 8270, 8080, 200.7 and EP Toxicity extraction are shown in Tables 3-2, 3-3, 3-4, 3-5 and 3-6, respectively. A list of leachate parameters and detection limits are shown in Table 3-7. It should be noted that the Expanded Parameter List includes approximately 85 organic compounds listed in Appendix 33 of Pan 373-2 that are not analyzed for in TCL+30 analyses. However, there is provision in TCL+30 for analysis of 30 additional compounds provided that these compounds are detected in significant concentrations. TCL+30 includes analysis of compounds that coincide with the 30 highest peaks (10 volatile and 20 semivolatile), which may include some of the 85 Appendix 33 parameters not formally analyzed for in TCL+30. The extra 3-15 Table 3-2 PARAMIxI'P_,RS AND DETECTION LIMITS OF VOLATILE ORGANIC COMPOUNDS MEci'HODS 8240, 601/602 TCL* (Method 8240) Method 601 Method 602 (Detection (Delection (Detection Part 373-2* Parameters Limits..vpb~** Limits_~.b~**~** __AgL~endix Acetone X (10) Benzene X (5) X (0.2) XX Bromodichloromethane X (5) X (0. I) Bromoform X (5) X (0.2) XX Bromomethane X (10) X (1.18) Carbon disulfide X (5) Carbon tetrachloride X (5) X (0.12) Chlorobenzene X (5) X (0.25) X (0.2) Ch oro thane X (10) X (0.52) Xx Chloroform X (5) X (0.05) Chloromethane X (10) X (0.08) XX Dibromochloromethane X (5) X (0.09) 1,1-Dichloroethane X (5) X (0.07) 1,1-Dichloroethene X (5) X (0.13) i ,2-Dichloroethane X (5) X (0.03) XX 1,2-Dichloroethene (total) X (5) X (0.10) 1,2-Dichloropropane X (5) X (0.04) XX Cis-l,3-Dichloropropene X (5) X (0.34) Trans-l,3-Dichloropropene X (5) X (0.20) XX Ethylbenzene X (5) X (0.2) 2-Hexanone X (10) XX Methylene chloride X (5) X (0.25) 4-Methyl-2-pentanone X (10) Styrene X (5) 1 ,l,2,2-Tetrachloroethane X (5) X (0.03) Tetrachloroethene X (5) X (0.03) X Toluene X (5) X (0.2) X I I ! I I ! 1,1,1-Trichloroethane X (5) 1 ,l,2-Trichloroethane X (5) Trichloroethene X (5) Vinyl acetate X (5) Vinyl chloride X (10) Xylene (total) X (5) 2,-Chloroethyl vinyl ether X (10). Trichlorofluoromethane X (5) x (0.03) x X (0.02) X X (0.12) X X X (0.18) X X X (0.13) x (ND) Note that there are approximately 85 additional parameters (not listed in this table) that are included in the Part 373-2 Appendix 33 list of parameters that axe not analyzed for in TCL (Method 8240) analyses. ** Detection limits are the same for both water and soil. 3-16 Table 3-3 PARAMETERS AND DETECFION LIMITS OF SEMIVOLATILE ORGANIC COMPOUNDS M~IHODS 8270, 601/602 Parameters TCL* (Method 8270) Method Method (Detection 601 602 Limits ppb) (Detection (Detection ~ ~** Limits Acenaphthene X (10,330) Acenaphthylene X (10,330) Anthracene X (10,330) Benzo(a)anthracene X (10,330) Benzo(b)fluoranthene X (10,330) Benzo(k)fluoranthene X (10,330) Benzoic acid X (50,1600) Benzo(g,h,i)perylene X (10,330) Benzo(a)pyrene X (10,330) Benzyl alcohol X (10,330) 4-Bromophenyl-phenylether X (10,330) Butylbenzylphthalate X (10,330) 4-Chloroanaline X (10,330) Bis(2-chloroethoxy)methane X (10,330) Bis(2-Chloroethyl)ether X (10,330) Bis(2-Chloroisopropyl)ether X (10,330) 4-Chloro-3-methylphenol X (! 0,330) 2-Chloronaphthalene X (10,330) 2-Chlorophenol X (10,330) 4-Chlorophenyl-phenylether X (10,330) Chrysene X (10,330) Dibenzo( a,h)anthracene X (10,330) Dibenzofuran X (10,330) Di-n-butylphthalate X (10,330) 1,2-Dichlorobenzene X (10,330) 1,3-Dichlorobenzene X (10,330) 1,4-Dichlorobenzene X (10,330) 3,3-Dichlorobenzidine X (20,660) 2,4-Dichlorophenol X (10,330) Diethylphthalate X (10,330) 2,4-Dimcthylphenol X (10,330) Dimethylphthalate X (10,330) 4,6-Dinitro-2-methylphenol X (50,1600) 2,4-Dinitrophenol X (50,1600) 2,4-Dinitrotoluene X (10,330) 2,6-Dinitrotoluene X (10,330) Bis(2-ethylhexyl)phthalate X (10,330) Fluoranthene X (10,330) Fluorene X (10,330) Hexachlorobenzene X (10,330) Hexachlorobutadiene X (10,330) Hexachlorocyclopent adiene X (10,330) Hexachloroethane X (10,330) Indeno(!,2,3-cd)pyrene X (10,330) Isophorone X (10,330) s~2o~o 3-17 X (0.15) X (0.4) X (0.32) X (0.4) X (0.24) X (0.3) Part 373-2* X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Table 3~3 (continued) PARAMETERS AND Dt~I't~CTION LIMITS OF SEMIVOLATILE ORGANIC COMPOUNDS TCL* (Method 8270) (Detection Limits ppb) ~Wamr. Soft) Pa~ 373-2* ~ 33 2-Methylnaphthalene X (10,330) X 2-Methylphenol . X (10,330) X 4-Methylphenol X (10,330) X Naphthalene X (10,330) X 2-Nitroaniline X (50,1600) X 3 -Nitroaniline X (50,1600) X 4-Nitroanftine X (50,1600) X Nitrobenzene X (10,330) X 2-Nitrophenol X ( 10,330) X 4-Nitrophenol X (50,1600) X N-Nitrosodiphenytamine X (10,330) X N-Nitroso-di-n-propylamine X (10,330) X Di-n-octylphthalate X (10,330) X Pentachlorophenol X (50,1600) X Phenanthrene X (10,330) X Phenol X (10,330) X Pyrene X (10,330) X 1,2,4-Trichlorobenzene X (10,330) X 2,4,5 -Trichlorophenol X (10,330) X 2,4,6-Trichlorophenol X ( 10,330) X Note that there are approximately 85 additional parameters (not listed in this table) that are included in the Part 373-2 Appendix 33 list of parameters that are not analyzed for in TCL (method 8270) analyses. ** Detection limits are the same for water and soft. 3-18 I I I I 1 I I I I 1 I I 1 I I I i i I Table 3-4 PARAMEFERS AND DETECTION LIMITS OF PESTICIDES/PCBs Parame~rs TCL* (Method 8080) (Detection Limits ppb) Part 373-2* Aldrin X (0.05,8.0) X AROCLOR-1016 X (0.5,80) AROCLOR- 1221 X (0.5,80) AROCLOR- 1232 X (0.5,80) AROCLOR- 1242 X (0.5,80) AROCLOR-1248 X (0.5,80) AROCLOR- 1254 X (1.0,160) AROCLOR-1260 X (1.0,160) Alpha-BHC X (0.05,8.0) X Beta-BHC X (0.05,8.0) X Delta-BHC X (0.05,8.0) X Gamma-BHC X (0.05,8.0) X Alpha-chlordane X (0.5,80) X Gamma-chlordane X (0.5,80) 4,4'-DDD X (0.10,16) X 4,4'-DDE X (0.10,16) X 4,4'-DDT X (0.10,16) X Dieldrin X (0.10,16) X Endosulfan I X (0.10,16) X Endosulfan II X (0.10,16) X Endosulfan Sulfate X (0.10,16) X Endrin X (0.10,16) X Endrin-Ketone X (0.10,16) Heptachlor X (0.05,8.0) X Heptachlor Epoxide X (0.05,8.0) X Methoxychlor X (0.05,8.0) X Toxaphene X (1.0,160) X Total PCBs X (1.0,160) X Note that there are approximately 85 additional parameters (not listed in this table) that are included in the Part 373-2 Appendix 33 list of parameters that are not analyzed for in TCL (method 8080) analyses. S 12050 3-19 Antimony Arsenic Barium Beryllium Cadmium Calcium Chromium (total) Cobalt Copper Cyanide Iron Lead Magnesium Manganese Mercury Nickel Potassium Selenium Silver Sodium Thallium Vanadium Zinc S 1205(t Table 3-5 PARAM~f~I, tS AND D~J'v,:CTION LIMITS OF INORGANIC CONSTITUENTS METHOD 200.7 TCL* (Method 200.7) De--on Limit~ X (200, 20,000) X (60, 6,000) X (10, 1,000) X (200, 20,000) X (5,500) X (5,500) X (5,000, 500,000) X (10, 1,000) X (50, 5,000) X (25, 2,500) X (100, 10,000) X (5,500) X (5,000, 500,000) X (15, 1,500) X (0.2, 20) X (40, 4,000) X (5,000, 500,000) X (5, 50O) X (10, 1,000) X (5,000, 500,00O) X (10, 1,000) X (50, 5,000) X (20, 2,000) X (10, 1,000) Part 363-2 X X X X X X X X X X X X X X X X X 3-20 Part 360 Metals* X X X X X X X X X X X X X X X X X X X X X X I I I I i i I I i I I I I I I I I Table 3-6 EP TOXICTI~- PARAMETERS AND Dt~I'EL-~ON LIMITS 1. Arsenic 2. Barium 3. Cadmium 4. Total Chromium 5. Lead 6. Mercury 7. Selenium 8. Silver 9. gamma-BHC (Lindane) 10. 2,4-Dichlorophenoxyacetic acid; (2,4-D) 11. Endrin 12. Methoxychlor 13. 2,4,5 -Trichlorophenoxypropionic acidi (2,4,5-TP; Silvex) 14. Toxaphene 1,0~ i0,000 100 1,000 1,~0 50 1,0~ 100 1,000 5 1,0~ * Extraction Procedure Toxicity (concentrations in extract) S 12050 3-21 1 I I i I I I I I ! I I ! ! Table 3-7 LEACHATE PARAMETERS AND D~ON LIMITS Parmn~t~r~ Biochemical Oxygen Demand (BOD5) Chemical Oxygen Demand (COD) Total Dissolved Solids (TDS) Ammonia, as N Total Kjeldahl Nitrogen, as N Nitrate-Nitrite Sulfate Total Organic Carbon Chloride Alkalanity Specific Conductance Chromium (Hexavalent) MBAS Color Odor Hardness Total Volatile Solids Turbidity Boron Dissolved Oxygen 2,000 1,000 10,000 50 100 100 5,000 2,000 5,000 NA NA NA NA NA NA NA NA NA NA NA NA - Not applicable S 1205(/ 3-22 compounds in Appendix 33 are the less common contaminants that are not likely to be found during this investigation. Therefore, it was determined that the library search (+30) would be significant enough to include any of the Appendix 33 compounds that could be present at the site. The rationale for selection of the analytical procedures was contained in the Work Plan approved by NYSDEC. 3.2.7 Sampling Procedures Procedures that were used to collect the subsurface soil (split spoon) and groundwater samples are discussed below. Descriptions of sample containers, preservative techniques and maximum holding times can be found in Tables 3-8 and 3-9. 3.2.7.1 - Subsurface Soil (Split Spoon) Sample procedures for subsurface soil (split spoon) were implemented according to Section 5.6.1 of the Work Plan QA/QC procedures. Each split spoon was decontaminated according to the procedure outlined in Section 3.1.5 of this report. Chain of Custody Records, Sample Information Records and Boring Log Forms were prepared for each sample. 3.2.7.2 - Groundwater Sample procedures for groundwater were implemented according to Section 5.6.2 of the Work Plan QA/QC procedures. Teflon bailers were decontaminated at the laboratory as per the procedure outlined in Section 3.1.5 of this report and dedicated to each well. Nylon cord was dedicated to each well sampled and used only once. Location Sketches, Chain of Custody Forms and Sample Information Records were prepared for each sample. s ~20~o 3-23 Table 3-8 I~lITORI~ PARAMETERS HETflOD OF AI~LYSIS, PRESERVATZON AND MOLDING TIMES Number Sum~le Location Samole Typ~ Samole Metr~x Sample Fraction of Samples Frequency Monitoring Well Grab Soil Volatile Organics 1 1 Boreholes Container Sample Tvoe/Size/No. Preservation Glass, clear/ Cool to 4°C 40 mL/2 Volatile Organics 1' 1 Glass, clear/ Cool to 4°C 40 mL/2 Grab Soil Sase Neutral 1 1 and Acid Extractable Organics Glass, amber/ Cool to 4°C 150 mL/1 Grab Soil Pesticides/PCBs 1 1 Glass, amber/ Cool to 40C 150 mL/1 Grab Soil Metals 1 1 Glass, amber/ Cool to 4°C 1SO mL/1 Grab Soil Cyanide 1 1 EPTOX Metals Pesticides/ Herbicides 'Analysis depends on Method 8240 results. Glass, amber/ Cool to 4°C 1S0 mL/1 Glass, amber/ Cool to 4°C 150 mL/1 Glass, amber/ Cool to 40C 150 mL/1 **and SW-84G Methods for: Selenium (7740), Lead (7421), Thallium (7841), Mercury (7470), Arsenic (7060). ***Analysis depends on TCL+30 results. VTSR - Verified Time of Sample Receipt at the laboratory S1205G HQldlng Time 7 days after VTSR for extraction and analysis 7 days after VTSR for extraction and analysis 5 days after VTSR for extraction, 40 days after VTSR for analysis 5 days after VTSR for extraction, 40 days after VTSR for aealysls 26 days after VTSR for Hg analysis, 6 months after VTSR for analysis of others 12 days after VTSR for anal ysi s N/A N/A Analvtlcal Method 1986 USEPA SW846 Method 8240 1986 USEPA SW846 Method 601/602 1986 USEPA SW846 Method 8270 1986 USEPA SW846 Method 8080 1989 NYSDEC ASP, Method 200.7** 1989 NYSBEC ASP, Method 335.2 1986 USEFA SW846 Method 1310 1986 USEPA SW846 Method 1310 Samole Location Sample Tvoe Monitoring Grab ~ells Grab Table 3-8 (continued) HONITORING PAR~ETERS METHO0 OF ANALYSIS, PRESERVATION AHO HOLDING TIMES Samole Matrix Samole Fraction Groundwater Volatile Organics 14 Nmaber Container Sample of Samoles Frequency Type/Size/No. Preservation Glass, clear/ Cool to 4°C 40 mL/3 Volatile Organics 14' 1 Glass, clear/ Cool to 4°C 40 eL/3 Groundwater Base Neutral 14 1 Glass, amber/ Cool to 4°C and Acid 1L/2 Extractable Organics Grab Groundwater Pesticides/PCBs 14 1 Glass, amber/ Cool to 4°C 1L/2 Grab Groundwater Metals 14 1 Plastlc/1L/1 Cool to 4°C Grab Groundwater Cyanide 14 1 Plastic/IL/1 Cool to 4°C Grab Groundwater Leachate 14 1 See Table See Table Parameters No. 5-2 No. 5-2 H91dlnq Time 7 days after VTSR for extraction and analysis 7 days after VTSR for extraction and analysls 5 days after VTSR for extraction, 40 days after VTSR for analysis 5 days after VTSR for extraction, 40 days after VTSR for extraction 26 days after VTSR for Hg analysis, 6 months after VTSR for analysis of others 12 days after VTSR for analysis See Table No. 5-2 Analytical Method 1986 USEPA $W846 Method 8240 1986 US£PA SW846 Method 601/602 1986 USEPA SW846 Method 8270 1986 USEPA S~846 Method 8080 1989 NYSOEC ASP, Method 200.7"" 1989 NYSOEC ASP, Method 335.2 See Table No. 5-2 *Analysis depends on Method 8240 results. "and S~846 Methods for Selenium (7740), Lead (7421), Thallium (7841), Mercury (7470), and Arsenic (7060). VTSR - Verified Time of Sample Receipt at the laboratory S1205G Samole Location Samle Type Samole ~atrix Site/Study Area Field Blank Water Table 3-8 (continued) MONITORING PARAMETERS METHO0 OF ANALYSIS, PRESERVATION ~ HOLDING TIMES Samole Fraction Number Container Sample of S~les Frequency Type/Size/Me. Preservatlon Volatile Organics 2' 1 Glass, clear/ Cool to 4°C 40 mL/3 Volatile Organics 2" 1 Glass, clear/ Cool to 4°C 40 mL/3 Field Blank Water Base Neutral 2' 1 Glass, amber/ Cool to 4°C and Acid 1L/2 Extractable Organics Field Blank * Water Pesticide/PCBs 2" 1 Glass, amber/ Cool to 4°C 1L/2 Field Blank Water Metals 2* 1 Plastic/IL/1 Field Blank Water HNO3 to pH <2, Cool to 4°C Field Blank Water Cyanide 2' 1 Plastic/IL/1 NaOH to pH >12, Cool to 4°C Leachate 2* 1 See Table See Table Parameters No. 5-2 No. 5-2 'One for each of the sample matrices (soil [7 samples], groundwater [14 samples] and leachate [3 samples]). '*Analysis depends on Method 8240 results. '**and SW846 Methods for Selenium (7740), Lead (7421), Thallium (7841), Hercury (7470), Arsenic (7060). VTSR - Verified Time of Sample Receipt at the laboratory S1205G Maximum HQldinq Time 7 days after VTSR for extraction and analysis 7 days after VTSR for extraction and analysis 5 days after VTSR for extraction, 40 days after VTSR for analysis 5 days after VTSR for extraction, 40 days after VTSR for analysis 26 days after VTSR for Hg analysis, 6 months after VTSR for analysis of others 12 days after VTSR for analysis See Table No. 5-2 Analytical Method 1986 USEPA SW846 Method 8240 1986 USEPA SW846 Method 601/602 1986 USEPA SW84§ Method 8270 1986 USEPA SW84§ Method 8080 1989 NYS§EC ASP, Method 1989 NYSDEC ASP, Method 335.2 See Table No. 5-2 Table 3-8 (continued) HONITORXNG PARAMETERS HETHOD OF AJ~LYSIS, PRESERVATX(~I AND HOLDING TINES Sample Location Semele Tyne S~le Site/Study Area Trip Blank Water Number Container Sample Semele Fraction of Sameles Freauoncv Tyne/Size/No. Prq~ervatlon Volatile Organics 3 1 Glass, clear/ Cool to 4°C 40 mL/i ~ximum Holdlng Time 7 days after VTSR for extraction and analysis Analytical Hethed 1986 USEPA S~846 Hethod 8240 *One for every 48-hour sampling period for liquid samples only (anticipate about one [1] week for sample collection). VTSR - Verified Time of Sample Receipt at the laboratory S1205G Table 3-8 (continued) MONITORING PARAHET ERS METHOD OF ANALYSIS, PRESERVATION AND HOLDING TIMES Samole Lo¢a&ion Sample Tyne Saeole Matrix Laboratory Method Blank Water Samole Fraction Volatile Organics N~er Container Sable of Samoles' Freauencvt Tree/Size/No? Preservatlon~ Volatile Organics 3** Method Blank Water Base Neutral and Acid Extractable Organics Method Blank Water Pesticides/PCBs 3* Method Blank Water Metals 3* 1 Glass, clear/ Cool to 4aC 40 mL/3 1 Glass, clear/ Cool to 4°C 40 mL/3 1 Gl&ss, amber/ Cool to 4°C 1L/2 1 Glass, amber/1 Cool to 4aC 1L/2 1 Plastic/IL/1 HNO3 to pH<z, Cool to 40C Method Blank Water Cyanide 3" 1 Plastlc/1L/1 NaOH to pH>12, Cool to 4°C Method Blank Water Leachate 3" 1 See Table See Table Parameters No. 5-2 No. 5-2 Maximum Holdinq Time 7 days after VTSR for extraction and analysis 7 days after VTSR for extraction and analysls 5 days after VTSR for extraction, 40 days after VTSR for analysis 5 days after VTSR for extraction, 40 days after VTSR for analysis 26 days after VTSR for Mg analysis, 6 months after VTSR for analysis of others Analytical Hethod 1986 USEPA SW846 Method 8240 1986 USEPA SW846 Method 601/602 1986 USEPA SW846 Method 8270 1986 USEPA SW846 Method 8080 1909 NYSDEC ASP, Method 12 days after VTSR for analysis See Table No. 5-2 1989 NYSDE£ ASP, Method 335.2 See Table No. 5-2 "As required in accordance with 1989 NYSOEC ASP (based upon 7 soil samples, 14 groundwater samples and 3 leachate samples ~*Analysis depends on Method 8240 results. ***and SW846 Methods for Selenium (7740), Lead (7421). Thallium (7841), Mercury (7470), Arsenic (7060). VTSR - Verified Time of Sample Receipt at the laboratory [total of 24]). St205G Table 3-8 (continued) MON~TORTNG PARAMETERS HETHOD OF ANALYSTS, PRESERVATION ArID HOLDING TIMES Samle Location Site/Study Area Sammle Type Matrix Spike and Matrix Spike Duplicate SamoleHatrix Liquid Semele Fraction Volatile Organics Number of Samles Volatile Organics Liquid Base Neutral 1' end Acid Extractable Organics Liquid Pesticides/PCBs 1' Liquid Hetals Container Sample Maxlmtm Frequency Type/Size/No. Preservation Holdlnq Time Analytical Hethod 1 Glass, clear/ Cool to 4°C 7 days after 1986 USEPA SW846 40 mL/3 VTSR for Method 8240 extraction and analysis 1 Glass, clear/ Cool to 4°C 7 days after 1986 USEPA SW846 40 mL/3 VTSR for Method 601/602 extraction and analysis 1 Glass, amber/ Cool to 4°C 5 days after 1986 USEPA SW846 1L/2 extraction, Method 8270 40 days after VTSR for analysis 1 Glass, amber/ Cool to 4°C 5 days after 1986 USEPA 5W846 1L/2 VTSR for Method 8080 extraction, 40 days after VTSR for analysis 1 Plastic/IL/1 HNO3 to 26 days after 1989 NYSDEC ASP, pM <2, VTSR for Hg Method 200.7'*' Cool to 4°C analysis, 6 months after VTSR for analysis of others Liquid Cyanide 1" 1 Liquid Leachate 1' 1 Parameters Plastic/IL/1 NaOH to pH >12, Cool to 4°C 12 days after VTSR for analysis 1989 NYSDEC ASP, Method 335.2 See Table See Table See Table See Table No. 5-2 No. 5-2 No. 5-2 No. 5-2 'One for the liquid sample matrices (groundwater [14 samples] and leachate [3 samples]). "*Analysis depends on Method 3240 results. *"*and SW846 Methods for Selenium (7740), Lead (7421), Tha11ium (7841)o Mercury (7470), Arsenic (7060). VTSR - Verified Time of Sample Receipt at the laboratory S1205G Sample Location Samele Tvoe Site/Study Area Matrix Spike and Matrix Spike Duplicate Table 3-8 (co~tlnued) MONITORING PARAMETERS METHOD OF ANALYSIS, PRESERVATION ~ HOLDING TIMES Number Samole Ha~rlx Samole Fraction of Samoles Frequency Solid Volatile Organlcs 1" 1 Volatile Organics 1'" 1 Solid Base Neutral 1' 1 and Acid Extractable Organics Solid Pesticides/PCBs 1' 1 Solid Metals 1' 1 Container Sample Type/Size/No. Preservation Glass, clear/ Cool to 4°C 40 mL/3 Glass, clear/ Cool to 4°C 40 mL/3 G1 ass, amber/ Cool to 4°C 150 mL/1 Glass, amber/ Cool to 4°C 150 mL/1 Glass, amber/ Cool to 4°C 1SO mL/1 Solid Cyanide 1" 1 Plastic/IL/1 Maxlu Holding Tiee 7 days after VTSR for extraction and analysis 7 days after VTSR for extraction and analysis 5 days after VTSR for extraction. 40 days after VTSR for analysis 5 days after VTSR for extraction, 40 days after VTSR for analysis 26 days after VTSR for Hg analysis, § months after VTSR for analysis of others Analytlcal Method 1986 USEPA SW846 Method 8240 1986 USEPA SW846 Method 601/602 1986 USEPA SWB46 Method 8270 1986 USEPA SW846 Method 8080 1989 NYSDEC ASP, Method 200.7**" NaOH to pH>12 Cool to 4°C 12 days after VTSR for analysis 1989 NYSDEC ASP, Method 335.2 'One for the solid sample matrix (soil [1 sample]). **Analysis depends on Method 8240 results. ***and SW84G Methods for Selenium (7740), Lead (7421), Thallium (7841), Mercury (7470), Arsenic (7060). VTSR - Verified Time of Sample Receipt at the laboratory S1205G Sazmle Location Samole Type Sample Matrix Laboratory Spt ke B1 ank Water Table 3-8 (continued) ~ONITORING PAPJU4ETERS METHOD OF ANALYSIS, PRESERVATION AND HOLDING TIMES Samole Fraction Number Container Sample of Sables' Frequency' Type/Size/No.* Pre~ervati Volatile Organics 3* Volatile Organics 3** Spike Blank Water Base Neutral and Acid Extractable Organics Spike Blank . Water Pesticides/PCBs 3' 1 Glass, clear/ Cool to 4°C 40 mL/3 1 Glass, clear/ Cool to 4°C 40 mL/3 1 Glass, amber/ Cool to 40C 1L/2 1 Glass, amber/1 Cool to 4°C 1L/2 1 Plastic/IL/1 HNO3 to pH(Z, Cool to 4°C Spike Blank Water Metals 3* Spike Blank Water Cyanide 3* 1 Plastlc/1L/1 NaOH to pH>12, Cool to 4°C Spike Blank Water Leachate 3* 1 See Table See fable Parameters No. 5-2 No. 5-2 Maxiu Holdinq Time 7 days after VTSR for extraction and analysis 7 days after VTSR for extraction and analysis 5 days after VTSR for extraction, 40 days after VTSR for analysis § days after VTSR for extraction, 40 days after VTSR for analysis 26 days after VTSR for Hg analysis, 6 months after VTSR for analysis of others Analytical Method 1986 USEPA SW$C5 Method 8240 1986 USEPA SW846 Method 601/602 1989 NYSDEC ASP, Method 8270 1986 USEPA SW846 Method 8080 lg8g NYSDEC ASP, Method 200.7*** 12 days after VTSR for analysis See Table No. 5-2 1989 NYSOEC ASP, Method 335.2 See Table No. 5-2 *As required in accordance with 1989NYSDEC ASP (based upon 7 soil samples, 14 groundwater samples, and 3 leachate samples **Analysis depends on Method 8240 results. '='and SW846 Methods for Selenium (7740), Lead (7421), Thallium (7841), Mercury (7470), Arsenic (7060). VTSR - Verified Time of Sample Receipt at the laboratory [total of 24]). S1205G Table 3-9 METHOD OF ANALYSIS, PRESERVATION AND HOLDING TIMES* Ammonia Method 350.3 Total Organic Carbon H2SO4 to pH <2; Cool to 4°C Container Plastic or Glass Method 415.1 HCI or H2SO4 Glass to pH <2; Cool to 4°C Holding Time 26 days 5 days S 12050 *Taken from the 1989 NYSDEC ASP. Total Dissolved Method 160.1 Cool to 4°C Plastic or Glass 26 days Solids Alkalinity Method 310.1 Cool to 4°C Plastic or Glass 12 days Chloride Method 325.3 None Requited Plastic or Glass 26 days pH Method 150.1 None Required Glass Field Measurement Specific Method 120.1 None Requited Glass Field Measurement Conductance Total Kjedahl Method 351.3 H2SO4 to pH <2; Plastic or Glass 26 days Nitrogen Cool to 4°C Nitrate Method 352.1 H2SO4 to pH <2; Plastic or Glass 26 days Cool to 4°C BOD (5-day) Method 405.1 Cool to 4°C Plastic or Glass 24 hours COD Method 410.1 H2SO4 to pH <2; Plastic or Glass 26 days Cool to 4°C Section 4 I I I I I i I I 4.0 SI'rE ASSESSMENT 4.1 Background and History 4.1.1 Site Location and Background Infonnatio!! The Town of Southold operates a municipal solid waste landfill for the disposal of approximately t50 tons per day (in winter months) to 300 tons per day (in surmner months) of municipal solid waste. The existing Southold (Cutchogue) landfill comprises approximately 45 acres (excluding the 17 acres on Town property and north of the landfill area which was previously used as a mining/borrow area). The landfill site is located between Oregon Road and North or Middle Road (County Road 48) to the north and south, respectively, and Cox Lane and Depot Lane to the east and west, respectively, in Cutchogue, Suffolk County, New York (see Figure 1-1). A site plan of the Southold landfill is shown in Figure 1-2. The Southold landf'fll is situated in a rural, agricultural area in Cutchogue, approximately 2.5 miles east of Mattituck and 8 miles west of the Incorporated Village of Greenport. The landfill is located in an agricultural-industrial zoned area, with the existing landfill and planned landf'fll both zoned LI (Light Industrial) as illustrated in Figure 4-1. Directly adjacent to the northern, eastem and southem boundaries of the landfill is LI zoned land, and LIO (Light Industrial/Office Park) zoned land is located adjacent to the western boundary. Further to the north, south, east and west of the landfill is A-C (Agricultural Conservation) zoned land. The Town of Southold initiated operations at the landffil site in 1920 for the disposal of municipal solid waste, refuse, debris and scavenger (septic system) waste. Figure 4-2 shows the location of past and present landfill operations. As shown in this figure, the landfill site includes a large excavated area in the northern comer of the site (the planned landfill site), which was used to obtain cover material for the present landfdling operation, and two abandoned scavenger waste lagoons along the western border of the landfill. The lagoons formerly accepted septic system waste from both commercial and residential sources. Since the present landfill initiated operation prior to the promulgation of the Part 360 requirements, it was constructed without a liner. Also, portions of the currently required 100 foot buffer zone between the land£dl and its property boundaries have been used for landfflling solid waste in the past prior to the current requirements. In 1984, the Town of Southold requested a variance for an exemption from these requirements as specified in the Part 360 regulations S 12060 4-1 I ! I I I I ! I I I I i I I A-C LIO LI , -- $OU'THOLD L~ LEGEND ~ AGRICULTURAL CONEERVATION ~'~ REEIDENTIAL LOW DENSITY AA ~ RESIDENTIAL .LOW DENSITY A ~'~ RESORT/RESIDENTIAL ~'~ LIMITED BUEINE88 ~ LIQHT'INDUETRIAL/OFFICE PARK r-~ L,Q.T ,.D..T"'AL 80URCE:TOWN OF $OUTHOLD ZONING MAP,198I TOWN OF SOUTHOLD SOUTHOLD LANDFILL ~ ~ ZONING MAP U (.~) ~ FORMER COMPOSTING AREA - FORMER SCAVENGER WASTE LAGOONS MUNICIPAL ,~ts~) \ STORAGE GARAGE CLEARING AND )MOBILES CONSTRUCTION DEBRIS AND MUNICIPAL SOLID WASTE · ?.~- - PLANNED ,~ ~ LANDFILL AREA OVERHEAD ELECTRIC WASTE OIL STORAGE TION CENTER WEIGHING STATION TOWN OF SOUTHOLD SOUTHOLD LANDFILL LANDFILL OPERATIONS MAP FIGURE 4-2 THOI~S H. WICK}lAM SUPERVISOR Town Hall, 53095 Main Road P. O. Box 1179 Southold, New York 11971 Fax (516) 765-1823 Telephone (516) 765-1889 October 18, 1994 Raymond E. Cowan, P.E. Regional Director, Region I New York State Department of Environmental Conservation Bldg. 40, Stony Brook University Stony Brook, NY 11790-2356 Re: Cutchogue Landfill Town of Southold D&B No. 1314 Dear Mr. Cowan: In accordance with the Stipulation of Settlement executed between the Town of Southold and the New York State Department of Environmental Conservation on October 5, 1994, the Town is submitting in compliance with IIB of the Technical Requirements, the following existing reports and data relative to landfill gas and hydrogeologic conditions at the site. The reports/data comprise the following: 1. Part 360 and Phase II Hydrogeologic Investigation Report, October 1991 2. Groundwater Quality Assessment Report July 1992 Sampling Event, December 1992 3. Groundwater Quality Assessment Report January 1993 Sampling Event, March 1993 As presented in the reports, Baseline Parameters were afialyzed for the groundwater samples collected from the 16 on-site monitoring wells sampled in July 1991 and July 1992, and from downgradient private water supply wells in July 1992. Routine Parameters were analyzed for the groundwater samples collected from the monitoring and water supply wells in January/February 1993. . - Raymond E. Cowan, P.E. Page 2 O~ober 18, 1994 Based on the results of the initial Part 360 and Phase II Hydrogeologic Investigation, ground- water was found not to be significantly impacted by the landfill on-site and the landfill does not appear to impact off-site private water supply wells. As a result of these findings, the Cutchogue Landfill was delisted by NYSDEC as a potential (Class 2A) hazardous waste site. A good base- line of groundwater quality has been established. The results of the last sampling program conducted for the landfill (in early 1993), in general, indicated lower levels of contaminants than previously detected in July 1991 and 1992. As a result of these findings, we request a waiver of the Stipulation requirement ora second round of Baseline Parameters one (1) year from the date of initial baseline monitoring and a waiver of the second year of quarterly routine monitoring, provided there are no significant changes in water quality detected in the first round of Baseline Parameter sampling. Very tml~¥6urs, Thomas Wickham Supervisor nl-W:rbw Enclosures cc: Frank Isler, Esq. Thomas Maher (Section 360-1.7). The variance was requested on the basis of compatible surrounding land use, which is predominandy agricultural, vacant land, sand mining and only lhnited residential land, and the significant adverse economic and environmental impacts which would be associated with excavating landfilled refuse. This variance, however, was not granted by NYSDEC. Upon termination of operations at the existing landfill, the Town plans to close the landfill in accordance with NYSDEC Part 360 requirements and begin operation of the planned landfill, which will be constructed in accordance with the current Part 360 regulations. The planned landffil site consists of approximately 17 acres of almost entirely excavated land, which was the borrow area located immediately north of the existing landf'fll (see Figure 4-2). The planned site is located adjacent to an inactive and closed portion of the existing landfill, and consists of predominantly excavated and disturbed soil and sand that was used for clean cover material for the existing landfill. 4.1.2 Site History_ and Previous Investigations As previously discussed, the Town of Southold began operation of the landf'ill in 1920 for the disposal of municipal solid waste, refuse, debris and scavenger waste. Subsequent to the hurricane of 1938, large quantities of construction and demolition debris, land clearing debris, as well as other materials, were landf'illed in the southern portion of the site. This area was also used for burying old automobiles. In 1974, Holzmacher, McLendon and Murrell, P.C. (H2M), under contract to the Suffolk County Department of Health Services (SCDHS), conducted a subsurface investigation at the Southold landfill in order to determine the depth of fiil material and municipal sanitary waste at the site. Three borings were drilled at separate locations within the existing landfill area (approximately at the center and south-central portions, and west-central border of the currant landfall). Information obtained from the borings indicated that the landfill had been excavated to depth of approximately 3 feet above the water table and subsequently landfilled with municipal wastes and other fill material. In October of 1976, a methane gas survey was conducted at the landfill. Well points were driven into the ground in the nonhero, southeastern and southwestern portions of the landfill and measured for methane. The results of this survey showed low levels of gas in comparison to the Lower Explosion Level (LEL) for methane.. s~20c, o 4-4 In 1985, Woodward-Clyde Consultants prepared a Phase I investigation at the landffil for the New York State Department of Environmental Conservation. The results of this investigation have been used in the preparation of th/s report. In the summer of 1986, the scavenger waste lagoons at the landfill were abandoned upon commencement of operations at the Southold Scavenger Waste Pretreatment Plant. Sludge removal from the scavenger waste lagoons was performed during the summer of 1987. The sludge removed from the lagoon was disposed of in the landfill. Between 1980 and 1984, five monitoring wells (S-76687, 71045, 69761, 68916 and 68831) were installed on the landfill site and sampled by SCDHS. Surveillance of these wells continued in 1985 and the most recent sampling was conducted in 1989. On December 4 and 5, 1990, NUS Corporation performed a site inspection of the Southold landfill for the United States Environmemal Protection Agency. During the inspection, five groundwater and three soil samples were collected off-site, and three groundwater and six soil samples were collected on-site. The results of prior on-site sampling, and other groundwater and water supply quality monitoring conducted by SCDHS in the area of the Southold landfill, have shown that groundwater in the vicinity of the landfill has been contaminated primarily by fertilizers and pesticides originating from agricultural activities surrounding the site. Groundwater and water supply quality studies indicate that many wells in the vicinity of the landfill, including water supply, irrigation/agricultural and monitoring wells, have been found to be contaminated with the insecticide aldicarb. Other wells have been found to be contaminated by the agricultural chemical fertilizers, nitrate and (potassium) chloride, and the insecticide dichlompropane. All of these contaminants are pervasive within the upper glacial aquifer upgradient, below and downgradient of the Southold landfill site, and are found in concentrations that exceed groundwater and drinking water standards. These results indicate that the landfill is not a source of this contamination. Although one shallow well on the landfill site does indicate that leachate from the landfill is impacting groundwater in the immediate vicinity of the landfall, the inorganic chemical results from previous investigations indicate a weak (and limited) leachate plume, and only trace amounts (<10 ug/1) of nonpesticide organic compounds are found occasionally in concentrations exceeding standards. Based on this information, it appears that the Southold landfall is not a significant s~20c, o 4-5 I I I I I I I I I I I I I I I I I I I source of contamination. A detailed description of the results of previous sampling efforts at the Southold landfill can be found in Appendix G. All of the monitoring wells, private wells and soil sampling locations for the previous sampling programs are shown in Figure 4-3. 4.1.3 Site Reconnaissance Site visits and reconnaissance were conducted to collect infon-nation regarding past and present operations at the landfill, observe the existing conditions at the landfill and to verify background information and accessibility to the site for the purpose of conducting this investigation. Activities included locating existing monitoring wells, estimating the placement of proposed wells and sampling points, locating past, present and future landf'xlling operations, excavation areas, and landfill closure and construction areas. Also, photographs were taken of the existing site conditions and current landfilling operations in order to document observations. In addition, other information was obtained from the Town of Southold including tax maps, zoning maps, site maps, as well as aerial photographs and other pertinent information. 4.1.4 Literature Search A comprehensive search was made for pertinent and reliable existing information concerning regional and site-specific hydrogeologic and water quality conditions. The literature search included, available records, reports and maps of the Suffolk County Department of Health Services (SCDHS), U.S..Soil Conservation Service (SCS), U.S. Geological Survey (USGS), New York State Deparhnent of Environmental Conservation (NYSDEC), Town of Sonthold and reports prepared by several engineering consultants. In addition, aerial photographs of the landfill site and surrounding area were obtained at scales of 1 inch equals 100 feet and 1 inch equals 200 feet, and are enclosed in Appendix H of this document. Well completion/constxuction logs and boring logs of wells formerly constructed in the vicinity of the landfill are included in Appendices I and J, respectively. An initial survey of monitoring wells, and public and private water supply wells within 1 mile downgradient and 1/4 mile upgradient of the landfill site was conducted. The locations of the monitoring wells in the vicinity of the site are shown in Figure 4 4. Table 4-1 lists the available well construction data for these wells. Wells located within approximately 1/4 mile upgradient of s ~20~o 4-6 WELL NO.5 OW-5 WELL NO. WELL GW-6 WELL NO.1 OW-7 WELL NO.4 WS-IO FORMER SCAVENGER WASTE lAGOONS S-68916-- .' SOUTHOLD i · ' LANDFILL DIRECTORY: C:%1027 FIlE NAME: PGWATER DATE: SEPT 1991 · · · S-5 ........... S-7668 WS-~ ..... GW-2 . ' s-30 · .~ S-l, ' ' ¢) WS-8 ~ORI~ (u~oo~-) RoAO LEGEND DESIGN A'nON DESCRIPTION · GROUNDWATER MONITORING WELL AND WELL NO. 1 SAMPUNG LOCATION FROM PREVIOUS STUDIES · WATER SUPPLY WELL AND SAMPLING WS-1 LOCATION FROM PREVIOUS STUDIES · GROUNDWATER MONITORING WELL AND S-69761 SAMPLING LOCATION ON LANDF1LL SITE · APPROXIMATE USEPA GROUNDWATER OW-1 SAMPLING LOCATIONS 0 APPROXIMATE USEPA SOIL S1-S2 SAMPLING LOCATIONS 0 400 SCALE IN FEE-r d)Dvirka and Bartilucci TOWN OF SOUTHOLD SOUTHOLD LANDFILL PREVIOUS GROUNDWATER, WATER SUPPLY AND SOIL SAMPLING LOCATIONS FIGURE 4-5 -71287 S-71285 $-71284, '$-71044 · " S-68831 ~£'6ee'16 "$-7668?' _~'. ~-53326 $OUTHOLD LANDFILL -69761 -- ;-71045"' ' '~t :h. '-~ INFERRED DIRECTION OF !UND..WATER FLOW $-71170. UL~' 8-71191' S-53824 ~-71281 p,$:6542 8-10890 8-71279~ 8-71289 C., , $-7~,74 ~'.; 8-71275~ SOURCE: USGS. MATTITUCK HILLS & SOUTHOLD QUADRANGLE8 TOWN OF SOUTHOLD $OUTHOLD LANDFILL MONITORING WELLS LOCATED IN VICINITY OF LANDFILL SCAI1~ IN FEET 0 IOOO 2000 FIGURE 4-4 I I I I I I I I I I I I I I I I I I Well Number S-76687' S-75113' S-71289 S-71287 S-71286 S-71285 S-71284 S-71283 S-71282 S-71281 S-71280 S-71279 (~stboring) S-71278 S-71277 S-71276 S-71275 S-71274 S-71191 S-71171 S-71170 (~stboring) S-71045' S-71044(~stbo~ng) S-69761' S-68916' S-68831' S-65606 S-65605 S-53327 S-53326 S-53324 S-32390 S-10390 S-6542 *Wells located at landfill. **Feet Below MSL $1206~ Table 4-1 WELL CONSTRUCTION DATA Date Completed 5/1/84 9/4/81 8/25/81 7/30/81 7/29/81 7/27/81 7/20/81 7/22/81 7/8/81 6/24/81 9/23/81 9/10/80 4/24/80 4/17/80 99 80 24 23 95 23 11 (feet)** 91 14 330 52 19 25 30 285 22 310 60 102 51 260 4-9 Screened Interval (feet)** 23-33 94-99 75-80 20-24 19~23 90-95 19-23 86-91 9-11 48-52 15-25 28-30 20-22 52-57 97-102 3848 I I I I I i I I I i the landfill are wells S-71170, S-71171 and S-71191. One well located approximately 1/4 mile laterally west of the landfill is well S-71282. Although there are no NYSDEC-designated (numbered) wells shown within this area, there exists several private water supply wells located within this area, as well as several private wells located upgradient within 1/4 mile and adjacent to the site. These private wells were identified and discussed along with all other wells that had available water quality records in Appendix G of this report. 4.2 Geology 4.2.1 This section describes the general hydrogeologic conditions on Long Island as it relates to the regional hydrogeology of the North Fork in Suffolk County, and the Town of Southold and the vicinity of the Southold landfill. Long Island is composed of consolidated tilted basement rocks overlain by unconsolidated sediments that dip in a southeasterly direction. The consolidated rocks, known as bedrock, are dense crystalline metamorphic and igneous rocks of Precambrian age. Overlying the bedrock is a series of unconsolidated deposits that form Long Island's principal aquifers and confining units. During the Cretaceous period, unconsolidated sediments including sands, silts, gravels and clays were deposited on the bedrock platform. Cretaceous deposits are a terrestrial origin and were probably deposited by prograding shores and coalescing deltas. These Cretaceous sediments are divided into two formations, the Raritan formation and the Magothy formation - Matawan group, undifferentiated. The Raritan formation is probably a continental coastal plain deposit and is composed of the Lloyd sand member and an overlying unnamed clay member (Raritan confining unit) commonly referred to as the Raritan clay. Above the Raritan formation lies the Magothy formation - Matawan group, undifferentiated which is composed of continental and shallow marine or deltaic deposits. After the Cretaceous period, a long period of nondeposition or deposition followed by erosion occurred. Geologic activity by streams flowing across Long Island cut deep valleys into the Cretaceous sediments of the Magothy. These valleys were filled with glacial sediments during Pleistocene glaciation almost completely covering the older Cretaceous (Magothy formation) deposits. 4-10 The Cretaceous deposits are overlain by glacial outwash and morainal deposits of Pleistocene age, as well as Holocene deposits. The Pleistocene formations consist of several glacial, periglacial and interglacial units, including a marine clay known as the Gardiners clay. The Pleistocene or glacial deposits are believed to have been deposited during the Wisconsin stage of glaciation. This was the last stage of the glacial advance to reach Long Island. Prior to the southward movement/advance of the Pleistocene ice sheets to Long Island, an extensive clay unit (Gardiners clay) was deposited in shallow mar'me and brackish waters along the shores of what is now Suffolk County. This unit overlays the Magothy group and acts as a conf'ming layer 100 to 300 feet thick. The nortbem portions of the Gardiners clay were subsequently eroded by advancing ice and glacial meltwaters, and Gardiners clay beds are now found only in the south shore area. The Pleistocene glaciation created the hilly Ronkonkoma moraine and the Harbor Hill moraine. The Ronkonkoma moraine forms the "spine" of Suffolk County and the South Fork. The Harbor Hill moraine encompasses the north shore and forms the North Fork of Long Island. As the glaciers began to melt and retreat, these deposits (sand, gravel and boulders) were eroded and carried by the melt water, creating extensive outwash plains of sand and gravel in the intermorainal areas and south to the Atlantic Ocean. These highly permeable deposits comprise the upper glacial aquifer and represent the majority of Suffolk's surficial sediments which average 100 to 200 feet thick. In general, the surficial geologic units in the study area consist of Pleistocene outwash and recent or Holocene deposits. Holocene deposits include soil zone, shore, beach and salt-marsh sediments. A generalized isometric geological cross section of the Southold Peninsula is shown in Figure 4-5. The geologic and hydrogeologic units on the North Fork in the Town of Southold are summarized in Table 4-2. The sequence of stratigraphic units on the North Fork is similar to that found on the main body of Long Island. The stratigraphic sequence from youngest to oldest rocks and deposits, and water-bearing properties of deposits underlying the project site and vicinity are described in Table 4-2. A longitudinal cross section of the North Fork is depicted in Figure 4-6. As shown in Figure 4-6, the contact between upper glacial aquifer and Magothy aquifer deposits varies in depth from about -200 to 430 feet mean sea level (MSL). A thick clay layer is found at varying depths and flficknesses, but it is not certain whether the clays encountered are all part of a continuous layer that underlies the entke North Fork, or whether they occur as isolated lenses. 4-11 -APPROX. SALT WATER FRESH WATER INTERFACE UNCONFORMITY -- $00 UNCONFORMITY -500 --600 SOURCE: USGS, W.8.P. 1619-GG,1963 TOWN OF SOUTHOLD $OUTHOLD LANDFILL GENERALIZED ISOMETRIC I~,~-~ ~ GEOLOGICAL CROSS SECTION OF ~"~-~ ~ THE SOUTHOLD PENINSULA FIGURE I I I I I I I I I I I I I I I I I I I Table 4-2 GEOLOGIC AND HYDROGEOLOGIC UNITS IN THE TOWN OF SOUTHOLD Hydrogeologic Unit Upper glacial aquifer Gardiners clay Magothy aquifer Radtan clay Lloyd aquifer Bedrock Geolo~c Nam~ Holocene and upper Pleistocene deposits Gardiners clay Matawan group and Magothy formation, undifferentiated Unnamed clay member of the Raritan formation Lloyd sand member of the Raritan formation Undifferentiated crystalline rocks De. script~_ 'on and Water-Bearing Character Mainly brown and gray sand and gravel of moderate to high hydraulic conductivity; also includes deposits of clayey glacial till and lacustrine clay of low hydraulic conductivity. A major aquifer. Green and gray clay, silt, clayey and silty sand, and some interbedded clayey and silty gravel; low hydraulic conductivity. Unit tends to confine water in underlying aquifer. Gray and white frae to coarse sand of moderate hydraulic conductivity. Generally contains sand and gravel beds of low to high hydraulic conductivity in basal 100 to 200 feet. Contains much interstitial clay and silt, and beds and lenses of clay and low hydraulic conductivity. Not a highly developed aquifer in the study area. Gray, black and multicolored clay and some silt and fine sand. Unit has low hydraulic conductivity and tends to confine water in underlying aquifer. White and gray frae-to-coarse sand and gravel of moderate hydraulic conductivity and some clayey beds of low hydraulic conductivity. Not developed as a source of water in the study area. Mainly metamorphic rocks of Iow hydraulic conductivity; surface generally weathered; considered to be the bottom of the ground water reservoir. Not a source of water. Source: USGS W-RI Report 84-4271, 1986 S 12060 4-13 m m .m m mm m m m mmmm m m Imm m m m m ---- --, m LANDFILL .,,, ...... SOURCE: SCDHS, 1982 -?-- cA' KEY MAP TOWN OF SOUTHOLD SOUTHOLD LANDFILL LONGITUDINAL GEOLOGIC CROSS SECTION OF THE NORTH FORK FIGURE 4-6 Fresh groundwater under the North Fork is believed to exist as a series of four separate, irregularly shaped lenses as shown in Figure 4-6. The position of the freshwater-saltwater interface, however, has only been measured in a few places and appears to be located at approximately -250 to -300 feet MSL in the vicinity of the existing and planned Southold landfill site. 4.2.2 Local Geology The Town of Southold is located on the northeast protrusion of Suffolk County known as the North Fork. As discussed previously, this region of Long Island is an extension of the Harbor Hill moraine (along the north shore) which was produced during the advance of the last period of continental glaciation. The existing and planned Southold landfill is situated on an outwash plain, south of the Harbor Hill moraine. The topographic features of the site area are described as that of rolling moraines and level to gently sloping outwash plains. The landfill site lies on unconsolidated deposits of Pleistocene age associated with glacial outwash from the Wisconsin glaciation, as well as Holocene or recent deposits. These deposits overlie the Magothy formation. The Pleistocene deposits constitute the upper glacial aquifer and consist primarily of stratified sand and gravel containing little clay or silt, except for a clay layer sometimes referred to as the North Fork glacial clay. The Holocene or recent deposits include soil zone, stream bed, shore, beach and salt-marsh sediments, as well as fill material. A series of geologic cross sections were constructed based on previously obtained information. The location of each cross section is shown in Figure 4-7. Figures 4-8 and 4-9 are geologic and hydrogeologic cross sections, respectively, in the vicinity of the landfill. A geologic cross section through the landfill based on available information, is shown in Figure 4-10. The thickness of Pleistocene deposits and the upper glacial aquifer below the landfill is approximately 250 to 300 feet. The North Fork glacial clay layer appears to lie approximately 150 feet below the surface of the landfill and is estimated to be approximately 40 feet thick below the site. Groundwater in the upper glacial aquifer (overlying the North Fork glacial clay) is under unconfined (water table) conditions. The water table lies approximately 4045 feet below the surface of the site. The upper glacial aquifer constitutes the most important source of water for numerous small domestic private wells in the area. Well S-32390, situated approximately in the middle of the North Fork, approximately 3,500 feet southwest of the landfill (see Figure 4-7), penetrates the Magothy aquifer at a depth of 356 feet. Well S-33775, located 4.5 miles northeast of well S-32390, penetrates the Magothy 4-15 80UTHOLD./ LANDFILL- 8-71170 8-32300-" 8-71278 80URCE: USGS, MATTITUCK HILL8 & $OUTHOLD QUADRANGLES TOWN OF SOUTHOLD SOUTHOLD LANDFILL CROSS SECTION LOCATIONS $CAL~ IN FEET 0 I000 2000 FIGURE 4-7 I I I I AI -200 - ~ ~. · .... ~ ~se sand a~d ~ ' ., sancy and sol:~' , ~. ~ -. .' SOURCE: 8CDHS, 1982 TOWN OF $OUTHOLD $OUTHOLD LANDFILL GEOLOGIC CROSS SECTION IN VICINITY OF SITE FIGURE 4-8 I I I I I I I I I I I ./ 8OURCE: $CDHS, 1982 TOWN OF SOUTHOLD $OUTHOLD LANDFILL .HYDROGEOLOGICCROSS SECTION IN VICINITY OF SITE FIGURE 4-9 N C A' SOU THOLD LANDFILL top SOiL BROWN FINE- SAND GREY CLA~Y ,~e~D GRAVEL UPPER GLACIAL AQUIFER BROWN GREy VERY FINE-FINE BROWN FINE- S BROWN SILTY VERY FINE SAND TOWN OF SOUTHOLD SOUTHOLD LANDFILL HYDROGEOLOGIC CROSS SECTION THROUGH THE LANDFILL FIGURE 4-10 I I I I I i I I I I I I I I I I i at a depth of 205 feet accordh~g to a report prepared by Woodward-Clyde Consultants. Little detailed data are available at the present time on the vertical extent and water quality of the Magothy aquifer ou the North Fork in the vicinity of the site. There are no production wells tapping the Magothy on the North Fork near the la,~dfill; however, groundwater is believed to be salty in a large portion of this aquifer. The exact position and thickness of the zone of diffusion and the movement of the saltwater in the vicinity of the landfill site is not known. As shown in Figure 4-9, the freshwater-saltwater interface appears to occur at approximately -280 to -300 feet MSL below the landfill. Cores from well S-32390 located southwest of the site showed the interface to be at about -290 feet MSL. Thus, there may be some fresh water below the North Fork glacial clay layer (below -228 feet MSL) just south of the landfill at well S-71170, but the quantities would be extremely limited (if any) and any attempts to pump this water and use this portion of the glacial aquifer as a source of water supply would probably cause upconing of salt water from below. 4.2.2.1 - Soils The central part of the North Fork is covered with softs classified as Haven-Riverhead Association, and described as deep, nearly level to gently sloping, well-drained, medium textured and moderately coarse textured soils on outwash plains. Softs of the Carver-Plymouth-Riverhead Association are found on the northern shore of the North Fork and on the middle part of the south shore. These softs axe deep, rolling, excessively drained and well-drained, coarse textured and moderately coarse textured softs on moraines. In general, the North Fork softs are highly permeable and allow relatively rapid groundwater recharge. This condition is beneficial in terms of groundwater replenishment; however, it also provides fairly direct access of surface pollutants to the aquifer. A soil map of the existing and planned landfill site and vicinity is shown in Figure 4-11. The map shows that there are seven specific types of soils that exist on the site, namely, HaA-Haven Loam (0 to 2 percent slopes), Ha.B-Haven Loam (2 to 6 pement slopes), Ma-Made Land, PLA-Plymouth Loamy Sand (0 to 3 percent slopes), PIB-Plymouth Loamy Sand (3 to 8 percent slopes), PIC-Plymouth Loamy Sand (8 to 15 percent slopes and RdC-Riverhead Sandy Loam (8 to 15 percent slopes). Descriptions of each of these softs are as follows: s ~ 2o~ 4- 20 I I I I I I I I I !I I I I I I I I HaA-Haven Lo,un (0 to 2% slope~%L These soils are deep, well drained and medium textured, and are mostly nearly level generally found on outwash plains. They were formed in a loamy or silty mantle over stratified coarse sand and gravel. The available moisture capacity hq this soil is high to moderate. Natural fertility is low. Internal drainage is good, while pemaeability is moderate in the surface layer and subsoil and rapid or very rapid in the substratum. The hazard of erosion is slight. HaB-Haven Loa~n (2 to 6% _slopes). These soils are deep, well drained and medium textured and is found on outwash plains and moraines, commonly along shallow, intermittent drainage channels. Slopes are short. They were formed in a loamy or silty mantle over stratified coarse sand and gravel. The hazard of erosion is moderate to slight. Ma-~. Made land includes m~ that are mostly covered with pieces of concrete, bricks, trash, wi~e, metal and other nonsoil material. Some areas are on the surface of the original soil, others are in large holes dug for disposal purposes, and still others are in old gravel pits converted to this use. Included with this unit in mapping are sanitary landfills that have been excavated and subsequently filled with trash and garbage. After these areas are filled, they are covered with several feet of soft material. PI.A-Plymouth Loamy Sand (0 to 3% slopes). These soils are deep, excessively drained and coarse textured. They formed in a mantle of loamy sand over thick layers of stratified coarse sand and gravel. These nearly level soils are found on broad, gently sloping to level outwash plains. The available moisture content is low to very low. Internal drainage is good. Permeability is rapid. The hazard of erosion is slight. PIB*Plymouth Loamy Sand (3 to 8% slopes). These soils are deep, excessively drained and coarse textured. They are found on moraines and outwash plains. Slopes are undulating, or they are single along the sides of intermittent drainage ways. The hazard of erosion is slight. (See PlA soils for other soil properties.) PIC-Plymouth Loamy Sand (8 to 15% slot>e_s). These soils are deep, excessively drained and coarse textured. They are moderately sloping and found on moraines and outwash plains. The hazard of erosion is moderate to severe because of slope and the sandy texture of this soil. (See pLa, soils for other soil properties.) RdC-Riverhead Loamy Sand (8 to 15% slot)es). These soils are deep, well drained and moderately coarse textured. They formed in a mantle of sandy loam or fine sandy loam over thick layers of coarse sand and gravel. These soils occur in narrow bands on outwash plains along the side slopes of deep intermittent drainage ways. Slopes are short. These soils have moderate to high available moisture capacity, internal drainage is good, and permeability is moderately rapid. Thc hazard of erosion is moderately severe. 4.2.3 Stratigraphic logs were developed from information collected as part of the Part 360 and Phase II Hydrogeologic Investigation monitoring well drilling program in order to specifically define subsurface geology of the Southold landfill site. These boring logs can be found in Appendix F. s{20r, o 4-21 OREGON ROAD 80UTHOLD LANDFILL-- HQA HaA PlA ~C.R. 45) ROAI NoRT~ 80URCE: SOIL CONSERVATION SERVICE LEGEND CpE Carver and Ply~uth sands, 15 to 35 percent slopes HaA Haven loam, 0 to 2 percent slopes HaB Haven loam, 2 to 6 percent slopes HaM land PIA Ply~uth loamy sand, 0 to 3 percent slopes PIB Ply~uth loamy sand, 3 to 8 percent slopes PIC Plymouth loamy sand, 8 to 15 percent slopes RdA Riverhead sandy loam, 0 to 3 percent slopes RdB Riverhead sandy loam, 3 to 8 percent slopes RdC Riverhead sandy loam, 8 to 15 percent slopes TOWN OF $OUTHOLD $OUTHOLD LANDFILL SOIL MAP FIGURE ,-il I I I I I I i I I ! I I I I I I I Two cross sections were constructed for the site based on data obtained during this investigation. The location of the cross sections are shown in Figure 4-12. Cross section A-A' incorporates monitoring well clusters MW-I, MW-7, MW-3 and MW-5 and is shown in Figure 4-13. Cross section B-B' runs perpendicular to cross section A-A' and includes monitoring well clusters MW-6, MW-2 and MW-3. Cross section B-B' is illustrated in Figure 4-14. The lowest geologic unit of the site consisted of gray-brown silty clay and was encountered at an average depth of approximately 130 feet below ground surface at all locations drilled. Overlying the clay is a unit composed of medium to coarse sand and gravel with an average thickness of approximately 15 feet, except for cluster locations MW-1 and MW-4 (not shown in the cross sections [see Appendix F for boring logs]), where the clay was overlain by a roughly 10-foot thick transitional zone consisting of Frae sand with thin intermittent layers of clays and silts. At monitoring well cluster locations MW-6 and MW-7, the clay was overlain by the next most prevalent stratigraphic unit composed of medium to f'me sand with traces of gravel and mica. At the MW-1 cluster, this unit was not vertically continuous but was interrupted by a layer of medium to coarse sand and gravel. This same condition occurred at the MW-6 cluster location. This medium to fine sand unit is approximately 50 to 60 feet in thickness. Overlying this unit and extending to the surface is medium to coarse sand and gravel, similar to that found overlying the clay. Some isolated lenses of brown silty fmc sand were encountered within this layer at well cluster MW-1. Silty sands were also encountered within this unit in isolated lenses at cluster MW-6. Throughout drilling operations, isolated pockets of reddish brown to orange-brown (iron-stained) sand were encountered indicating a high natural concentration of iron bearing minerals. The results of the soil gas survey indicate a close correlation between areas of elevated MicroTip readings and high lower explosive limits (LELs). In general, readings were relatively elevated in fill areas and the area of former land clearing debris and automobile disposal areas. Readings taken from the bottom surface of the former scavenger waste lagoons were very low compared with those obtained from the landftll for both VOCs and explosive gas. No significant anomalies were encountered. Results of the soil gas survey were submitted to NYSDEC on June 20, 1991. No additional soil boring investigations were recommended by NYSDEC at that time. Two maps were generated showing the results of the MicroTip and percent LEL measurements and are included in Appendix C. 4-23 m mm m mm m m MW~4D FORMER MINING AREA STORAGE I I I I / / WEIGHING STATION OVERHEAD ELECTRIC LINES DESIGNAllON DESCRIPllON · MONITORING WELL LOCATION MW-4D DIRECTORY: C:¥027 FILE NAME: LOCSEC DA~: SEPT lggl SCALE: 1=1 DESiGN[R: LV.G. Dvirka and Bartilucci LOCATION TOWN OF SOUTHOLD SOUTHOLD LANDFILL OF LANDFILL SITE CROSS 0 400 800 SECTIONS FIGURE 4-12 I I I I I I I I I I I I I I I I I ! I lO0 MW-5D. =ROPERTY LINE ROAD , HOUSE 75 5O 25 <{ Z Ld -25 0 f../'~ .2 '~ -50 -75 -100 -125 0 200 400 600 800 1000 1200 1400 SW Dvirka and Bartilucci 1600 1800 2000 DISTANCE iN FEET 2200 2400 2600 2800 30OO 3200 NE GEOLOGIC TOWN OF SOUTHOLD SOUTHOLD LANDFILL CROSS-SECTION A - A' LEGEND MED-COARSE SAND AND GRAVEL MED-F!NE SAND TR. GRAVEL AND MICA BROWN SILTY FINE SAND BROWN GREY CLAY F~NE SAND WITH CLAY STREAKS FINE SAND FIGURE 4-13 6O 4-O 20 -20 -40 -60 -8O - 1 O0 -120 0 1 O0 200 300 400 500 600 700 800 900 1000 1100 1200 1300 SW DISTANCE IN FEET Dvirka and Bartilucci GEOLOGIC TOWN OF SOUTHOLD SOUTHOLD LANDFILL CROSS-SECTION B - B' LEGEND MED-COARSE SAND AND GRAVEL MED-FINE SAND TR. GRAVEL AND MICA MED-COARSE GRAVEL BROWN GREY CLAY NE MED-COARSE SAND AND GRAVEL WITH BLACK SILT I t MED-FINE SAND FIGURE 4-14 I 4.2.3.2 - Geophysical Survey Resul,,3 I I I I I I I The results of the downhole geophysical survey conducted during this investigation indicate that, based on the natural gamma ray logs, bedding dips gently from north to south. This slope corresponds closely with the general dip of the clay surface underlying the landfill. The results of the geophysical investigation also indicate that the conductivity measured for the groundwater in the two wells located upgradient of the landfill (MW-1 and MW-7) and the wells located downgradient of the former scavenger waste lagoons (MW-6), was distinctly different from the four wells located downgradient of the landfill (MW-2, MW-3, MW-4 and MW-5). The conductivity in monitoring wells MW-2 and MW-3 was elevated starting at the water table, whereas the conductivity of wells MW-4 and MW-5 located further north was elevated starting at a depth of 40 feet below the water table. In all cases, these anomalies seem to extend down to the deep well screening zone, just above the clay surface. This data infers that a conductive fluid with a density greater than water is emanating from the landfill. The data also indicates that leachate present in this plume should be detected in the deep monitoring wells located downgradient of the landf'fll. The geophysical report is included in Appendix D. I 4.2.3.3- ! I I In general, the natural topography of the landfill site slopes gently upward in a northward direction, from a low of approximately 45 feet (MSL) near County Road 48 to a high of approximately 66 feet (MSL) along the northem boundary of the site near monitoring well cluster MW-5. This natural gradual slope has been interrupted by both the Southold landfill in the center of the site and the area north of the landfill which has been excavated to an elevation of approximately 10 feet (MSL). 4.3 Groundwa~r Hydvogeology 4.3.1 I I The primary groundwater aquifer on the North Fork is the upper glacial or water table aquifer. The saturated thickness of this aquifer ranges from approximately 50 to 200 feet. Most wells drawing freshwater from these permeable deposits are between 10 and 100 feet deep, and extend about 10 to 35 feet below MSL. I 4-27 Upper glacial regional groundwater flow in the Town of Southold in the vicinity of the existing and planned Southold landfill is shown in Figure 4-15. Groundwater elevations are highest near the center of the North Fork and lowest near the shoreline. The horizontal component to groundwater flow is shown in the regional water table contour map. As this map indicates, regional horizontal flow is toward the noah-northwest in the vicimty of the landfill. As shown in Figure 4-15, regional groundwater flow is separated into north and south groundwater flow regimes by the groundwater divide that runs generally northeast to southwest across generally the center of the North Fork. Flow moves outward from the central groundwater divide toward either shoreline (northward toward Long Island Sound and southward toward Great Peconic Bay and Little Peconic Bay). Near the center of the divide, downward, nearly vertical flow and recharge of groundwater occurs (with velocities of approximately 0.1 ft./day). Moving north or south away from the divide, shallow groundwater flow becomes increasingly horizontal (with velocities of 0.2 to 0.4 ft./day) until groundwater discharge occurs near the shorelines. Within approximately 1/4 mile of the shoreline, the vertical component of flow is upward as groundwater is influenced by the boundary effects of the saltwater interface and is discharged via seepage and undefflow to surface waters. 4.3.2 Based upon previous information, groundwater flow within the upper glacial aquifer, in the area of the existing and planned landf'dl site, is generally in a north-northwesterly direction. This flow continues in this direction until it reaches the Long Island Sound. Direction of groundwater flow may be influenced by local well withdrawals and proximity to the North Fork groundwater divide. The average hydraulic conductivity of the glacial aquifer is approximately 1,950 gallons per day per square foot (gpd/sf) and transmissivity is approximately 300,000 gpd/ft. As previously discussed in Section 3.2.1, within the upper glacial aquifer is an extensive clay layer referrexl to as the North Fork glacial clay (the upper surface of which varies from I00 to 150 feet below sea level), and separating the Magothy from the underlying Lloyd aquifer is a semipermeable layer of Raritan clay which somewhat inhibits the vertical flow of water from the Magothy to the Lloyd aquifer. Figure 4216 shows the groundwater flow patterns beneath the landfill and surrounding area. The Magothy (in general) and Lloyd aquifers in this area are not usable for potable water purposes because of saline conditions. 4-28 I I I I I I I I I I /~ 06~0~5 ouND //~ o / oC-=(__ - // fl -47233 ~ 016780 .............. LANDFILL SIT/ ~ E / ~ LITTLE PECONIC BAY 0 gsz~$ ~> I I I I I I I I I G~EAT P£CONIC BAY LEGEND APPROXIMATE LOCATION OF GROUND WATER DIVIDE 0 71045 OBSERVATION WELL AND WELL NUMBER WATER TABLE CONTOUR LINE INTERVAL (DATUM 18 MEAN SEA LEVEL) APPROXIMATE DIRECTION OF GROUND WATER FLOW 80URCE: 8CDHG,MARCH 1989 TOWN OF SOUTHOLD $OUTHOLD LANDFILL REGIONAL WATER TABLE CONTOUR MAP 0 0.5 I SCALE: I I J MILE FIGURE 4-15 4O 3O ~.z.a' / I I ~ / I I I I \ / .os I \./ .zs · · /I ~e ~ J.l i ~ / I ~ ).o I I ~ I / ~ ~ / / t ~ / I % I I I i el SOURCE; SCDHS, 1982 / I i , -/ .15 .Z5 TOWN OF SOUTHOLD SOUTHOLD LANDFILL GROUND WATER FLOW PATTERNS IN VICINITY OF SITE FIGURE 4-16 I I I I I I I I I I I I I I I I I I Groundwater elevation data was obtained from the SCDHS for on-site well S-69761 and two nearby off-site wells (S-53326 and S-65606). The locations of these monitoring wells are shown in Figure 4-17. This data reflects water table elevations of June 1988 which indicates that groundwater flow in the upper glacial aquifer is in a north-northwest flow direction, as illustrated in the figure, which is consistent with the regionally defined groundwater flow direction. This groundwater elevation data was used for the purposes of selection of monitoring well locations for the hydrogeologic investigation. The Southold landfill is located in Hydrogeologic Zone IV, as defmed in the Long Island Waste Treatment ('208') Management Plan. Zone IV is characterized by generally shallow, horizontal groundwater flow and groundwater discharge near the shorelines. Zone IV was described in the '208' study as an area that has local water quality problems caused by agricultural practices, but has potential for groundwater development. Figure 4-18 shows the landfill site to be located outside of the Special Groundwater Protection Area (primarily deep flow recharge area) defined for the Town of Southold. Thus, any comaminant releases from the existing landfill, or extremely unlikely releases from the planned landf'fll which would be constructed with double liners and leachate detectinn/collection systems according to NYSDEC Part 360 requirements, would have an insignificant impact on the water supply of the Town. 4.3.3 As previously discussed, the principal aquifer of interest in the study area is the upper glacial aquifer. Intersecting the upper glacial aquifer is the North Fork glacial clay which represents a laterally continuous flow boundat~ underlying the Southuld landfall. Therefore, the Part 360 and Phase H Hydrogeologlc Investigation was focused primarily on that portion of the upper glacial aquifer overlying the North Fork glacial clay. 4.3.3.1-Etllllr~hil~ Slug tests were performed at eight monitoring wells consisting of shallow and deep wells located at clusters MW-l, MW-2, MW-5 and MW-7. The results of the slug test analysis are shown in Table 4-3. Hydraulic conductivities within the water table wells were relatively high and ranged in value from 2.2 x 104 to 8.6 x 10.2 cm/sec. The average hydraulic conductivities at the deep wells were higher and generally more uniform, and ranged from 1.8 x 10'3 to 3.1 x 10.2 4-31 / Duc~ >/ S-53326(3.16') · ..~ 90UT.O'O: LANDFILL ;' 8-69761(6.0d) -INFERRED DIRECTI01~ OF ,,GROUND WATER FLOW~ S-65606(, \ Cern '..~-~'CUtc: NOTE: WATER TABLE ELEVATIONS OBTAINED IN JUNE, 1988 SOURCE: H2M, 1988 )D~rka TOWN OF SOUTHOLD SOUTHOLD LANDFILL GROUND WATER FLOW DIRECTION IN VICINITY OF SITE SCA[~ iN FEET 0 ~000 2000 FIGURE 4-17 SOUTHOLD LITTLE PECONIC BAY GREAT PECONIC BAY SPECIAL GROUND WATER PROTECTION AREA 8OURCE: LIRPB,1990 0 8000 SCALE IN FEET TOWN OF SOUTHOLD SOUTHOLD LANDFILL SPECIAL GROUND WATER PROTECTION AREAS IN THE TOWN OF SOUTHHOLD 16000 FIGURE 4-18 Table 4-3 SLUG TEST RESULTS Monitoring Well Shallow Wells 1: Rising Head Test Hydraulic Conductivity (K) ecru/s) Falling Head Test Hydraulic Conductivity (K) Average Hydranlic Conductivity (K) (cra/s} MW-IS 2.2 x 104 -- 2.2 x i0"~ MW-2S 3.8 x 10.2 -- 3.8 x lO'2 MW-5S 2.6 x 10'~ - 2.6 x 10'~ MW-7S 8.6 x 10-2 -- 8.6 x 10-2 Deep Wells: MW-iD 2.5 x 10'3 1.1 x 10'3 1.8 x 10'3 MW-2D 4.8 x lif2 1.3 x 10'2 3.1 x 10.2 MW-5D 1.1 x 10.2 1.3x 10.2 1.2x 10.2 MW-7D 3.4 x 10.2 1.2 x 10.2 2.3 x 10-2 Falling head tests wen not performed in the shallow wells since the screen intercepted the water table. Perfonxfing a test of this type under these conditions would measure the hydraulic conductivity above the water table within the unsaturated zone and would not be representative of formation permeability. 4-34 I I I I I I I I I I I I I I 1 I I cra/sec. The lower hydraulic conductivity values found in both MW-1S and MW-ID are probably due to the presence of silty sands found within the screen zones. Appendix K contains graphs and calculations used to derive hydraulic conductivities for each slug test conducted. 4.3.3.2 - Groundwater Flow Pattem~ 4.3.3.2.1 - Shallow Water Table Measurements of groundwater elevations in all monitoring wells were obtained on July 22, 1991, and are presented in Table 4-4. Based on these data, a water table groundwater contour map was prepared and is illustrated in Figure 4-19. The water table contour map indicates a general north to northwesterly flow of groundwater through the site conf'uming previous regional and local findings. The groundwater gradient across the site varies from 7.8 x 10-2 feet of head loss per foot of horizontal distance to 3.6 x 10.4 foot of head loss per foot of horizontal distance. The shallower gradient is found between monitoring well MW-IS and monitoring well MW-7S. The gradient becomes steeper north of MW-7S. Such flat hydraulic gradients are expected in areas which are located relatively close to a hydraulic divide believed to exist south of the Southold landf'ffi. 4.3.3.2.2 - Deep Groundwater Based on the water level measurements obtained from the deep monitoring wells on July 22, 1991, a potentiometric surface map was consmacted and is presented in Figure 4-20. Based on this data, it appears that groundwater along the clay interface flows in the same direction (north to northwesterly) and under approximately the same hydraulic gradient (2.3 x 10.4 foot of head loss per foot of horizontal distance) as the shallow groundwater at the site. The difference in hydraulic head between each shallow and deep well at each well cluster was calculated in order to determine the vertical gradient at each location, the results of which are presented in Table 4-5. This data indicates that a very slight downward gradient exists at the site. The slight upward gradient found at well cluster MW-3 and MW-6 is too small to be considered significant and may be the result of a local topographic high in the clay surface between these two monitoring wells which may be acting to divert groundwater flowing northward along the clay 4-35 I I I I I I I I I I I I I I I I I I Table 4 4 GROUNDWATER ELEVATIONS JULY 22, 1991 (m~asured in fee0 D~pth to Groundwater Monitoring Well (firm top of riser) MW-tS 38.84 MW-ID 38.68 MW-2S 12.85 MW-2D 11.85 MW-3S 43.05 MW-3D 43.16 MW4S 58.81 MW4D 58.57 MW-5S 63.41 MW-5D 62.81 MW-6S 47.01 MW-6D 47.16 MW-7S 42.54 MW-7D 41.48 S-697611 40.32 S-689162 47.85 Well Elevation eMiL) Top of 44.38 44.39 18.15 17.23 48.50 48.63 63.60 63.76 68.44 67.89 52.50 52.59 48.07 47.03 45.69 53.23 1Corresponds to a shallow water table well. 2Corresponds to a deep clay interface well. S 12060 4-36 5.54 5.71 5.30 5.38 5.45 5.47 4.79 5.06 5.03 5.08 5.49 5.43 5.53 5.55 5.37 5.38 4.7 4.8 FORMER MIIiING AREA 4-.9 5.0 MW-5S STORAGE GARAGE ? FORMER LAND CLEARING''-~ "---.. DEBRIS AND AUTOMOBILE /MW-2S 5.1 ~ ~ ACTIVE ', ~,NDF LL / /.... M W - - 7 /-OVERHEAD / ELECTRIC LINES WASTE OIt CENIER SlOP, AGE WEIGHING STATION (cOON/_¢ ¢,OAB LE(;END DESIGNATION DESCRIP'RON · MONITORING WELL LOCATION MW-4S 5.0 GROUNDWATER ELEVATION CONTOUR ~ GROUNDWATER FLOW DIRECTIOn___ DATE: SEPT 1991 SCALE: 1=1 Dvirka and Bartilucci WATER TOWN OF SOUTHOLD SOUTHOLD LANDFILL TABLE CONTOUR MAP 0 4.00 800 FIGURE 4-19 ,/ AREA ) ~ MW-6D // ~ ACTIVE // STORAGE GARAGE - ? FORMER LAND CLEARING DEBRIS AND AUTOMO[31[E I DISPOSAt AREA ~C~ Iici OVERHEAD ELECTRIC LINES SOLLECTIOrl - - WASTE OIL CENTER STORAGE WEIGHINO SIATIOH ROAP 48) LEGEND DESIGNATION t DESCRIPTIOH · [ MONITORING WELL LOCATIOH MW-4D ~ J. GROUNDWATER FLOW DIRECTION DIRECTORY: C:%1027 FILE NAME: PSURMAP DAllY: SEPT 1991 SCALE: 1=1 DESIGNER: L.V.C. Dvirka and Bartilucci TOWN OF SOUTHOLD SOUTHOLD LANDFILL POTENTIOMETRIC SURFACE MAP 0 40O 800 FIGURE 4-20 I I I ! I I I I I I I I I I I I I I I Table 4-5 SOUTHOLD LANDFILL HYDROGEOLOGIC INVESTIGATION VERTICAL HYDRAULIC GRADII~.NTS AT EACH WELL CLUSTER Difference Between Shallow and D~p Well Direction of VelXical Weft Cluster Number Elevations (ft.) Hydraulic Gradient MW- 1 0.16 Downward MW-2 1.00 Downward MW-3 -0,11 Upward MW-4 0.24 Downward MW-5 0.60 Downward MW-6 -0.15 Upward MW-7 1.06 Downward SI2060 4-39 I I I I I I I I I I I I I I I I I I I interface toward well clusters MW-3 and MW-6. A three-dimensional representation of the clay surface was created based on data obtained during the drilling program and is presented in Figure 4-21. 4.4 Surface Water As discussed in Section 3.1.3, Long Island Sound is the closest surface water body, and is located approximately 3,500 feet north of the Southold landfill. The closest freshwater body, East Creek, lies approximately 1.3 miles to the southeast of the landfill site. No surface water bodies are located within or immediately adjacent to the landfill. Since groundwater in the vicinity of the landfill flows north-northwesterly, and there are no other surface water bodies located between the landfill and Long Island Sound, no surface water bodies should be impacted by the landf'fll. 4.5 Sampling PrOm~l, Results 4.5.1 Introduction The purpose of this section of the Part 360 and Phase II Hydrogeologic Investigation Report is to present the analytical results of samples collected from monitoring wells installed during this investigation. The goal of the subsurface sampling program is to determine whether or not there has been a release of hazardous chemicals from the landfill into either soil or groundwater or both. 4.5.2 Data Validation Results All sample data was evaluated to ensure that analyses were performed according to the 1989 NYSDEC ASP. The semivolatile organic fraction analyzed was not in complete compliance with the ASP Quality Control and Quality Assurance requirements due to low surrogate recoveries for selected compounds and/or from exceeding holding time requirements. Data is estimated but usable. All other organic and inorganic fractions analyzed yielded acceptable data. Completed review sheets used to evaluate both the organic and inorganic data can be found in Appendix B. Data validation summaries and data user advisory tables can also be found in Appendix B. 4~5.3 ~5~[LSamlglh~ 4.5.3.1 - Organic Sampling Results The volatile organic compounds (VOCs) detected in soil sample MW-6A are presented in Table 4-6. Method 601/602 volatile results are presented in Table 4-7. The MW-6A soil sample was collected from a depth of 11-13 feet due to slightly elevated MicroTip/total organic sl20(,o 440 I ! °° I _1~ ~gi~ka SOUmOm ~ND~ J ~~ ~,jp~, 3-D C~Y SURFACE ELEVATION MAP ~uR~~-~ I I ! TABLE 4-6 TOWN OF SOUTHOLD LANDFILL SOIL SAMPLING VOLATILE ORGANICS NYSDOH MW6A FB01 TB711 5 NYSDEC CLASS GA DRINKING 7/15/91 7/15/91 7/15/91 STANDARDS/GUIDELINES STANDARDS VOLATILE COMPOUNDS (ug/kg) (ug/I) (ucj/I) (ug/I) (ug/I) Chloromethane U U U 5 ST 5 Bromomethane U U U 5 ST 5 Vinyl Chloride U U U 2 ST 2 Chloroethane U U U 5 ST 5 Methylene Chloride ~!??~i??:~:.i~::!~::'::~ii::~::i' I J 1 J 5 ST 5 2-Propanone 34 U U .... 50 Carbon disulfide U U U .... 50 1,1 -Dichloroethene U U U 5 ST 5 1,1-Dichloroethane U U U 5 ST 5 1,2-Dichloroethene (total) U U U 5 ST 5 Chloroform U U U 5 ST 5 1,2-Dichloroethane U U U 5 ST 5 2-Butanone U U U .... 5 1,1,1-Trichloroethane U U U 5 ST 5 Carbon Tetrachloride U U U 5 ST 5 Vinyl Acetate U U U .... 5 Bromodichloromethane U U U 50 GV 5 1,2-Dichloropropane U U U 5 ST 5 cis-1,3-Dichloropropene U U U .... 5 Trichloroethene U U U 5 ST 5 Dibromochloromethane U U U 50 GV 5 1,1,2-Trichloroethane U U U 5 ST 5 Benzene U U U ND ST 5 Trans-1,3-Dichloropropene U U U .... 5 Bromoform U U U 50 GV 5 4-Methyl-2~Pentanone U U U .... 5 2-Hexanone U U U 50 GV 5 Tetrachloroethene U U U 5 ST 5 ,1,2,2-Tetrachloroethane U U U 5 ST 5 Toluene U U U 5 ST 5 Chlorobenzene U U U 5 ST 5 Ethylbenzene U U U 5 ST 5 Styrene U U U 5 ST 5 Xylene (total) U U U 5 ST* 5 QUALIFIERS U: analyzed for but not detected J: compound found below detection limit NOTES GV: Guidance Value ST: Standard .... : Not established ST*: Applies to each isomer iiiiiii!i!iiiiiii!iii;iii~iiiii!iiiilili?~i: value exceeds standards/guidance TABLE 4-7 TOWN OF SOUTHOLD LANDFILL SOIL SAMPLING VOLATILE ORGANICS NYSDOH MW6A FB01 TB 7/15 NYSDEC CLASS GA DRINKING 7115191 7/15191 7/15191 STANDARDS/GUIDELINES STANDARDS VOLATILE COMPOUNDS (ug/kg) (ug/I) (ug/I) (ugll) (ug/I) Chloromethane U U U 5 ST 5 Bromomethane U U U 5 ST 5 Vinyl Chloride U U U 2 ST 2 Chloroethane U U U 5 ST 5 Methylene Chloride U U U 5 ST 5 2-Chloroethylvinyt ether U U U ........ Trichlorofluoromet hane U U U 5 ST 5 1,1-Dichloroethene U U U 5 ST 5 1,1-Dichloroethane U U U 5 ST 5 1,2-Dichloroethene (trans) U U U 5 ST 5 Chloroform U U U 5 ST 5 1,2-Dichloroethane U U U 5 ST 5 1,1,1-Trlchloroethane U U U 5 ST 5 Carbon Tetrachloride U U U 5 ST 5 Bromodichloromethane U U U 50 GV 5 1,2-Dichloropropane U U U 5 ST 5 cis-1,3-Dichloropropene U U U .... 5 Trichloroethene U U U 5 ST 5 Dibromochloromethane U U U 50 GV 5 1,1,2-Trichloroethane U U U 5 ST 5 Benzene U U U ND ST 5 Trans-1,3-Dichloropropen U U U .... 5 Bromoform U U U 50 GV 5 Tetrachloroethene U U U 5 ST 5 1,1,2,2-Tet rachloroethane U U U 5 ST 5 Toluene U U U 5 ST 5 Chlorobenzene U U U 5 ST 5 Ethylbenzene U U U 5 ST 5 Xylene (total) U U U 5 ST* 5 1,2-Dichlorobenzene 2 U U 4.7 ST 5 1,3-Dichlorobenzene 2 U U 5 ST 5 1,4-Dichlorobenzene U U U 4.7 ST 5 QUALIFIERS U: analyzed for but not detected NOTES ST: Standard GV: Guidance Value .... : Not established ST': Applies to each isomer individually vapor readings, as well as visibly stained soil. Methylene chloride, a common laboratory contaminant, was found below the detection limit. 2-Propanone was found at a low concentration of 34 ug/kg. 1,2-Dichlorobenzene and 1,3-dichlorobenzene were both detected at a very low concentration of 2ug/kg. 2-Propanone and 1,3-dichlorobenzene were not found in any groundwater samples obtained during this investigation. 1,2-Dichlorobenzene was detected at four monitoring wells but at a very low concentration of 1 ug/1. Table 4-8 lists the semivolatile compounds detected in soil sample MW-6A. The only semivolatiles detected were di-n-butylphthalate, butylbenzylphthalate and bis(2-ethylhexyl) phthalate. Di-n-butylphthalate was the only compound found above the detection limit. This compound was found at a concentration of 2,500 ug/kg and was also found present in the laboratory method blank at a 518ug/kg. Phthalates are common laboratory contaminants. Pesticides/PCBs were not detected in soil sample MW-6A. The results of the pesticide/PCB sampling are shown in Table 4-9. 4.5.3.2 - Inorganic Sampling Results The results for the metals analysis for soil sample IVlW-6A is presented in Table 4-10. Metals detected include aluminum, arsenic, barium, chromium, copper, iron, lead, magnesium, manganese, sodium, vanadium and zinc. Of these, only iron (3,980 mg/kg), magnesium (490 mg/kg), manganese (53.8 mg/kg) and sodium 373 mg/kg) were detected above NYSDEC Class GA Standards/Guidelines in groundwater samples collected as part Of this investigation. A total of nine soil samples (SI and S2 are duplicates) were collected as part of the USEPA site inspection in December 1990. Results for organic and inorganic analyses resulting from the USEPA sampling program are presented in Tables 4-11 and 4-12. The soll sample locations are shown in Figure 4-3. All samples were collected from the surface (0-6 inches) except for sample S7 (10-16 inches) and sample S8 (16-24 inches), which were collected just below the ground surface. The results indicate the presence of elevated levels of aluminum, barium, copper, lead, silver, zinc and 4-chioroanaline. Toluene was detected in soil sample S7 at a low concentration of 7 ug/kg. Pesticides such aa aldrin, 4,4'DDE and 4,4'DDT were also detected. The distribution of contaminant concentrations among both the on-site and off-site soil samples are generally uniform except for sample S6 collected from within one of the former scavenger waste lagoons which showed relatively higher levels of metals. Samples S7 and S8, also collected from within the former lagoons, showed levels of contaminants in the same range as 4-44 I I I TABLE 4-8 TOWN OF SOUTHOLD LANDFILL SOIL SAMPLING SEMIVOLATILE ORGANICS NYSDOH IVlW6A FB01 NYSDEC CLASS GA DRINKING 7/15/91 7/15/91 STANDARDS/GUIDELINES STANDARDS SEMIVOLATILE COMPOUNDS (ug/kg) (ug/I) (ug/I) (ug/I) Phenol U U 1 ST 50 Bis(2- Ch Ioroet hyl)Et her U U I ST 5 2-Chlorophenol U U I ST 5 1,3-Dichlorobenzene U U 5 ST 5 1,4-Dichlorobenzene U U 4.7ST 5 Benzyl Alcohol U U .... 50 1,2-Dichlorobenzene U U 4.7ST 5 2-Methylphenol U U .... 50 bis-(2-C hloroisopropyl)Et her U U .... 5 4-Methylphenol U U .... 50 N-Nitroso-Di-n-Propytamine U U .... 50 Hexachloroethane U U 5 ST 50 Nitro~enzene U U 5 ST 5 Isof3horone U U 50 GV 50 2-Nitrophenol U U .... 50 2,4-Dimethylphenol U U .... 5 Benzoic Acid U U .... 50 Bis-(2- Chloroet hoxy)Met hane U U 5 ST 5 2,4-Dichlorophenol U U I ST 5 1,2,4-Trichlorobenzene U U 5 ST 5 Naphthalene U U 10 GV 50 4-Chloroaniline U U 5 ST 50 Hexachlorobutadiene U U 5 ST 5 4-Chloro-3-Methylphenol U U 1 ST 5 2-Methylnaphthalene U U .... 50 Hexachlorocyclopentadiene U U 5 ST 5 2,4.6-Trichloroph enol U U 1 ST 5 2,4,5-Trichlorophenol U U 1 ST 5 2-Chloronaphthalene U U 5 ST 5 2-Nitroaniline U U 5 ST 50 Dimethyl Phthalate U U 50 GV 50 Acenaphthylene U U 20 GV 50 I ! I I I I I I ! I 1 I I I I QUALIFIERS: U: analyzed for but not detected J: compound found below detection limit NOTES: GV: Guidance Value ST: Standard .... : Not established I I ,I TABLE 4-8 (cont.) TOWN OF SOUTHOLD LANDFILL SOIL SAMPLING SEMIVOLATILE ORGANICS NYSDOH MW6A FB01 NYSDEC CLASS GA DRINKING 7/15/91 7/15191 STANDARDS/GUIDELINES STANDARDS SEMIVOLATILE COMPOUNDS (ug/kg) (ug/I) (ug/I) (ug/l) i2,6-Dinitrotoluene U U 5 ST 5 3-Nitroaniline U U 5 ST 50 Acenaphthene U U 20 GV 50 2,4-Dinitrophenol U U .... 5 ¢-Nitrophenol U U .... 50 Dibenzofuran U U .... 50 2,4-Dinitrotoluene U U 5 ST 5 Diethylt3hthalate U U 50 GV 50 ¢-Chlorophenyl-phenylether U U .... 50 Fluorene U U 50 GV 50 ¢-Nitroaniline U U 5 ST 50 ¢,6-Dinit ro-2-Met hylphenol U U .... 50 N-Nitrosodiphenylamine (1) U U 50 GV 50 ¢-Bromophenyl-phenylether U U 1 ST 50 Hexachlorobenzene U U 0.35ST 5 Pentachlorophenol U U I ST 5 Phenanthrene U U 50 GV 50 Anthracene U U 50 GV 50 Di-n-Butylphthalate 2500 B U 50 ST 5 Fluoranthene U U 50 GV 50 Pyrene U U 50 GV 50 Butylbenzylphthalate 230 J U 50 GV 50 3,3'-Dichlorobenzidine U U 5 ST 5 Benzo(a)Anthracene U U .002 GV 50 Chrysene U U .002 GV 50 bis(2-Ethylhexyl)Phthalate 310 BJ 13 B 50 ST 50 Di-n-Octylphthalate U U 50 GV 50 Benzo(b)Fluoranthene U U .002 GV 50 Benzo(k)Fluoranthene U U .002 GV 50 Benzo(a)Pyrene U U ND ST 50 Indeno(1,2,3-cd)Pyrene U U .002 GV 50 Dibenz(a,h)Ant hracene U U .... 50 Benzo(g,h,i)Perylene U U .... 50 I I I I I I I I I QUALIFIERS: U: analyzed for but not detected B: compound found in blank as well as sample J: comDound found below detection limit NOTES: GV: Guidance Value ST: Standard .... : Not established '1 I ! I I '1 I I I I I ! I I I TABLE 4-9 TOWN OF SOUTHOLD LANDFILL SOIL SAMPLING PEST/PCB'S NYSDOH MW6A FB01 NYSDEC CLASS GA DRINKING 7/15191 7/15/91 STANDARDS/GUIDELINES STANDARDS ORGANIC COMPOUNDS (ug/kg) (ug/I) (ug/I) (ug/l) alpha-BHC U U .... 5 beta-BHC U U .... 5 delta BHC U U .... 5 gamma-BHC (Lindane) U U ........ Hepatachlor U U ND ST 5 Aldrin U U ND ST 5 Heptachlor epoxide U U ND ST 5 Endosulfan I U U .... 50 Dieldrin U U .... 5 4,4'-DDE U U ND ST 5 Endrin U U ND ST 5 Endosulfan II U U .... 50 4,4'-DDD U U ND ST 5 Endosulfan sulfate U U .... 50 4,4'-DDT U U ND ST 5 Methoxychlor U U 35 ST 50 Endrin Ketone U U ........ alpha-Chlordane U U 0.1 ST 5 gamma-Chlordane U U 0.1 ST 5 Toxaphene U U ND ST 5 Arochlor-1016 U U 0.1 ST 5 Arochlor-1221 U U 0.1 ST 5 Arochlor-1232 U U 0.1 ST 5 Arochlor-1242 U U 0.1 ST 5 Arochlor-1248 U U 0.1 ST 5 Arochlor-1254 U U 0.1 ST 5 Arochlor-1260 U U 0.1 ST 5 QUALIFIERS NOTES I I I U: analyzed for but not detected GV: Guidance Value ST: Standard .... : Not established ND: Not detected TABLE 4-10 TOWN OF SOUTHOLD LANDFILL SOIL SAMPLING INORGANIC CONSTITUENTS NYSDOH MW6A FB01 NYSDEC CLASS GA DRINKING NYS 7115191 7115/91 STANDARDS/GUIDELINES STANDARDS BACKGROUND LEVELS (mg/kg) (mg/I) (mg/I) (mg/I) (rog/kg) CONSTITUENTS Aluminum 1640 U ............ Antimony U U 0.003 ST ........ Arsenic 1.7 B U 0.025 ST 0.05 3-12 Barium 12.2 B U I ST I .... Beryllium U U ............ Cadmium U U 0.01 ST 0.01 0.21-1.8 Calcium U U ........ 778-3532 Chromium 7.4 U 0.05 ST 0.05 .... Colbalt U U ............ Copper 5.9 B 23.3 0.2 ST .... AVG.=74.8 Iron 3980 U 0,3 ST 0.05 Lead 3.1 U 0.25 ST .... 15 -36 Magnesium 490 B U 35 GV ........ Manganese 53.8 U 0.3 ST ........ Memury U U 0.002 ST 0.002 .... Nickel U U ........ AVG.=19.5 Potassium U U ........ 47.5-117.5 Selenium U U 0.01 ST 0.01 .... Silver U U 0.05 ST 0,05 Sodium 373 U 20 ST ........ Thallium U U 0.004 ST ........ Vanadium 7.6 B U ............ Zinc 12.6 U 0.3 ST .... AVG.564 Cyanide U U 0.1 ST ........ QUALIFtERS: ~or but not detected B: Value is less than contract required limits but greater than the instrumen[detection limit NOTES: L~V: L~uidance value ST: Standard .... : Not established Volatiles: Acetone 3 Toluene U S~ivola[iles: 4-Chloroanallne U Phenanthrene U Di-n-Butylphthalate U Fluoranthene U Pyrene U Butylbenzlyphthalate U Benzo(a)anthracene U Chrysene U Benzo(b)fluoranthene U Benzo(d)fluorenthene U genzo(e)pyrene U Pesticides/PCBs: gamma-BHC (Lindane) U Aldrin U 4,4'-DOE g3E Endrin J Endosulfansulfate U 4,4'-DDT 410E gamma-Chlordane 3 Endosulfan II U Table 4-11 SO~THOLD LANDFILL HVDROGEOLOG[C INVESTIGAT[O# RESULTS OF ORGANEC ANALYSES FROf~ USEPA SUXL SA~PLXNG (all results in ug/kg) S11 S2 (Dup.)1 S~3 S~ Sj S62 S72 S~82 J U U U U U U U U U U U J 7 U U U U U U 1,000 J U U U U U 3 U U U U U U U U U U J U U U U J U U U U U U U J J U U U U U U U J U U U U U U 3 U U U U U U U 3 3 U U U U U U 3 U U U U U U U 3 U U U U U 3 J U U U U U U J U U U U U U U U U ll U U 120 J 3 U J 24 U J U U U U U U U U 57 J U U U U U J 450 71E U 76E U U U 32 3 3 J U 3 3 U U U U U 3 U U U J 1 _ Off-site sample 2 _ Sample collected from bottom of former scavenger waste lagoons. U - Analyzed for but not detected. 3 - Estimated value - present below CRQL but above IDL E - Estimated value NOTE: Only detected compounds shown. S1483G Hera1 s: Table 4-12 SOU[HOLD LANDFILL IJYDRO~EOLO~IC II~/ESTI~TIOg RESULTS OF IgORGANIC ANiLYSES FR0fl USEPA SOIL SAMPLING (all results in rog/kg) S11 S2 (Dup.)1 S3 S4 S5 S62 S_,Z72 S82 S~9 Aluminum 4640 5320 2140 4030 4310 12700 3080 1010 5280 Arsenic 8.3 8.7 3 3.2 3.7 15.6 6.8 3 8.5 Barium 3 3 3 3 52.2E 693E 61E J J Beryllium J U U U U 1.7 3 U U Cadmium U U U U U 8.5 U U U Calcium J 3 3 3 1300E 5180E 1500E J J Chromium 6.g 7.3 3.3 6.3 5 40.9 6.6 2.6 4.7 Cobalt U ~ U U U J U U U Copper 19.7E 16.7E 8.4 lO.SE 16.7E 3020E 51.7E 12.8E 7.8 Iron 6370 7280 5010 4940 6120 15200 6640 1590 7800 Lead 85.8 74.1 49.5 2036 117 412 24.5 13.2 28.1 Magnesium 3 J 3 J J ~ ~ J J Manganese 102E 106E 75.7E 45.7E 69.7E 57.2E 45.5E 20.9E 36.7E Mercury R R R R R 10.9 R U U Potassium 3 3 3 3 3 3 3 3 3 Selenium U U g $ J g.lE J U U Silver J 2.7 U J g 24.3 2.2 U 3.1 Sodium 3 3 3 3 3 J J J 3 Vanadium 13 13.8 3 J J ~ J J 17.9 Zinc 44.6E 44E 75.9E R 134E 1060E 215E R R 1 _ Off-slte sample. 2 _ Sample collected from bottom of former scavenger waste lagoons. U - Analyzed for but not detected. 3 - Estimated value - present below CRQL but above IDL E - Estimated value R - Analysis did not pass EPA QA/QC NOTE: Only detected metals shown S1483G I I I I I ! other on-site and off-site soil samples. Of the metals detected in the soil samples, iron, manganese, magnesium and sodium were the only metals found in groundwater at levels exceeding standards. Volatile and semivolatile compounds and pesticides/PCBs detected in soil were not found in any groundwater sample collected during the Part 360/Phase II investigation. 4.5.4 r war am1' 4.5.4.1 - Organic Sampling Results The VOCs detected in groundwater samples collected as part of the Part 360/Phase II investigation are listed in Table 4-13 and Method 601/602 VOCs in Table 4-14. Compounds detected include methylene chloride, 1,2-dichloroethane, 1,2-dichloropropane, chlorobenzene and the Method 601/602 vnlatiles, 1,2-dichlorobenzene and 1,4-dichlorobenzene. As mentioned previously, methylene chloride is a laboratory contaminant. 1,2-Dichlorobenzene and 1,4-dichlorobenzene were also detected in the trip blank. In all cases, each compound was detected at a low level of 1 ug/1. Therefore, the presence of these compounds cannot be confirmed since their presence could be the result of either laboratory contamination or contamination in the field. VOCs were detected in trace amounts (below standards) in all monitoring wells except for well MW-6D where 1,2-dichloroethane (12 ug/1) and 1,2-dichloropropane (11 ug/l) were found to contravene the NYSDEC Class GA groundwater standard of 5 ugtl for both compounds. MW-6D is immediately downgradient of the former scavenger waste lagoons. 1,2-Dichloropropane (an insecticide) has been found in elevated concentrations in previous sampling efforts both up and downgradient of the landfill. 1,2-Dichloropropane was found at monitoring well S-68916 at a concentration of 15 ug/l and at private well GW-6 at a concentration of 9 ug/1. It must be noted that dichloropropane was found in concentrations as high as 68 ugtl in an upgradient well (S-76687), indicating that the presence of this insecticide in groundwater is due to local agricultural activities and is not readily attributable to the landfill. 1,2-Dichloroethane has been detected previously on one occasion at a concentration of 2.0 ug/1 in on-site well S-68916, although it was not detected in subsequent sampling events. Previous groundwater sampling efforts have detected chlorobenzene in concentrations exceeding the New York State Class GA groundwater standard of 5 ugtl. Two samples collected from on-site well S-68916 showed concentrations of 9 ug/l and 23/24 ug/1 (USEPA investigation result) in two different sampling events. Since chlorobenzene was not detected in well cluster MW-6, which is further upgradient and closer to the former lagoons, it apl~ars that the lagoons are not a source of this compound in groundwater. 4-51 TABLE 4-13 TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING VOLATILE ORGANICS MW1S MWID MW2S MW2D MW3S MW3D MW4S MW4D NYSDEC CLASS GA DRINKING 7125/91 7125/91 7/24/91 7124191 7/25/91 7125/91 7126/91 ?/26/91 STANDARDS/GUIDELINES STANDARDS VOLATILE COf~POUNDS (ug/I) (ug/I) (ug/I) (ug/0 (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) Vinyl Chloride u u u u u u u u 2 ST 2 Methylene Chloride 2 J 2 J U u u 1 J u u s sT 5 2-Propanone U u u u u u u u -- 5o Carbon disulfide u u u u u u u u -- 5o 1,1 -Dichloroethene u U U u u u U U 5 ST 5 1,1 -Dichloroelhane u u u u u u u u s ST 5 1,2-Dichloroeihene (total) u u u u u u u u 5 ST 5 Carbon Tetrachloride u u u u U u U u 5 ST 5 Vinyl Acetate u U U u u u u U 5 1,2-Dichloropropane u u u u u u u u s ST 5 cis-1,3- Dichloropropene U U u u u U u U 5 Benzene u U u U u U U U ND ST 5 Trans-1,3-Dichloropropene u u u u u u u u ---- s 4-Methyl-2-Pentanone u u u u u u u u ---- 5 Xylene (total) u u u U u u u u 5 ST' 5 NOTES U: analyzed for but not detected B: compound found in blank as well as sample J: compound found below detection limit J*: estimated value GV: Guidance Value ST: Standard .... : Not established ST*: Applies to each isomer individually NP: not present m m m m m m m m m m m m m m m m m m m TABLE 4-13 (conf.) TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING VOLATILE ORGANICS NY~L)UH MW5S MW5D MW6S MW6D MW7S MWTD FB TB NYSDEC CLASS GA DRINKING 7125/91 7125191 7/24/91 7/24/91 7/25191 7126/91 7/25191 7/26/91 TANDARDS/GUIDEUNE STANDARDS VOLATILE COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) Chloromethane u u U U U U u u s ST S Bromomethane u U u u u U u u 5 ST 5 Vinyl Chloride u U u u u u u u 2 ST 2 Chloroethane u u u u u u u u $ ST 5 Mefhylene Chloride u u u 2 J u u 2 J u 5 ST 5 2-Propanone u u u U u U u u -- 5o Carbon disullide u u u u u u U u -- 5o 1,1 -Dichloroethene u u u u u u u u s ST S 1,1 -Dichloroethane u U u u U u u u 5 ST S 1,2-Dichloroethene (fofal) u u u u u u u u s ST 5 Chloroform U u u u u u u u SST s 1,2-Dichloroethane u u u i !!::!!ii:.!:::!:: ::!!i.:. ~ ~ :!! :: ::. !!:L::!! ?: u u u u s ST 5 2-Butanone u u u u u u u u -- s 1,1,1 -Trichloroethane U u U u u u u u s sT 5 Carbon Tetrachloride u u u u u u u u 5 ST S Vinyl Acetate u u u u u u u u -- 5 Bromodichloromethane u u u u u u u u 50 GV 1,2-Dichloropropane u u u !i! !i! !.!i!:.! ~ ~ !i!i! !i!i!i!i!i! u u u u 5 ST 5 C/S-1,3-Dichloropropene U U U U U u U U -- 5 Trichloroethene u u u u u u u u s ST S Dibromochloromethane u u u u u u u u 5o GV s 1,1,2-Trichloroethane u u u u u u u u s ST Benzene u u u u u u U U ND ST 5 Trans-1,3-Dichloropropene u u u u u u U u s Bromoform u u U u u u u u 5o GV S 4-Methyl-2-Pentanone u u u u u u u u 2-Hexanone u u u u u u u u 5o Gv s Tetrachloroethene U u U u u u u u s ST S 1,1,2,2-Tet rachloroet hane u U U U U U u U 5 ST 5 Toluene u u u u u u u u 5 ST s Chlorobenzene u U u U u U U u 5 ST 5 Ethylbenzene u u u u u u u u 5 ST 5 Styrene u u u u u u u u 5 ST S Xylene (total) U u u U u u u u $ ST' 5 Unknown NP 7 jo Np NP NP NP NP NP Freon 113 NP NP NP NP NP NP NP NP QUALIFIERS U: analyzed for but not detected B: compound found in blank as well as sample J: compound found below detection limit J': estimated value NOTES GV: Guidance Value ST: Standard .... : Not established ST*: Applies to each isomer individually NP: not present : value exceeds standards/guidelines TABLE 4-14 TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING METHOD 601/602 VOLATILE ORGANICS NYSDOH MW1S MWID MW2S MW2D MW3S MW3D MW4S MW4D ' MW5S NYSDEC CLASS GA DRINKING 7125/91 7125/91 7/24/91 7124191 7125/91 7125191 7126/91 7126191~7125191 STANDARDS/GUIDELINES STANDARDS VOLATILE COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) Chlorometl3ane U U U U u U U U U 5 ST 5 Bromomethane U U U U U U U U U 5 ST 5 Vinyl Chloride U U U U U U U U U 2 ST 2 Chloroethane U U U U U U U U U 5 ST 5 Methylene Chloride U U U U U U U U U 5 ST 5 2-Chloroethylvinyl ether U U U U U U U U U ........ Trichlorofluoromelhaoe U U U U U U U U U 5 ST 5 1,1 -Dichloroethene U U U U U U U U U 5 ST 5 1,1-Dichloroethane U U U U U U U U U 5 ST 5 1,2-Dichloroethene (trans) U U U U U U U U U 5 ST 5 Chloroform U U U U U U U U U 5 ST 5 1,2-Dichloroethane U U U U U U U U U 5 ST 5 1,1,1-Trichloroethane U U U U U U U U U 5 ST 5 Carbon Tetrachloride U U U U U U U U U 5 ST 5 Bromodichloromethane U U U U U U U U U 50 GV 5 1,2-Dichloropropane U U U U U U U U U 5 ST 5 cis-1,3-Dichloropropene U U U U U U U U U .... 5 Trichloroethene U U U U U U U U U 5 ST 5 Dibromochloromethane U U U U U U U U U 50 GV 5 1,1,2-Trichloroethane U U U U U U U U U 5 ST 5 Benzene U U U U U U U U U ND ST 5 Trans-1,3-Dichloropropen U U U U U U U U U .... 5 Sromolorm U U U U U U U U U 50 GV 5 Tetrachloroethene U U U U U U U U U 5 ST 5 1,1,2,2-Tet rachloroethane U U U U U U U U U 5 ST 5 Toluene U U U U U U U U U 5 ST 5 Chlorobenzene U U U U U U U U U 5 ST 5 Ethylbenzene U U U U U U U U U 5 ST 5 Xylene (total) U U U U U U U U U 5 ST* 5 1,2-Dichlorobenzene U U U U U U U U U 4.7 ST 5 1,3-Dichlorobenzene U U U U U U U U U 5 ST 5 1,4-Dichlorobenzene U U U U U U U U U 4.7 ST 5 QUALIFIERS U: analyzed for but not detected NOTES '5'TFS"~dard GV: Guidance Value .... : Not established ST*: Applies to each isomer individually m m mm m m m m m m m m m m m m m m m m TABLE 4-14 (cont.) TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING METHOD 601/602 VOLATILE ORGANICS NYSDOH MW5D MW6S MW6D MW7S MW7D TB 7125 FB GW NYSDEC CLASS GA DRINKING 7125/91 7124191 7125/91 7/25/91 7/26/91 7/25/91 7125/91 STANDARDS/GUIDELINES STANDARDS VOLATILE COMPOUNDS tug/I) tug/I) tug/I) tug/I) tug/I) tug/I) tug/I) tug/I) tug/I) Chloromethane U U U U U U U 5 ST 5 Bromomethane U U U U U U U 5 ST 5 Vinyl Chloride U U U U U U U 2 ST 2 Chloroethane U U U U U U U 5 ST 5 'Methylene Chloride U U U U U U U 5 ST 5 2-Chloroethylvinyl ether U U U U U U U Trichlorofluoromethane U U U U U U U 5 ST 5 1,1-Dichloroethene U U U U U U U 5 ST 5 1,1 -Dichloroethane U U U U U U U · 5 ST 5 1,2-Dichloroethene (trans) U U U U U U U 5 ST 5 Chloroform U U U U U U U 5 ST 5 1,2-Dichloroethane U U U U U U U 5 ST 5 1,1,1 -Trichloroet hane U U U U U U U 5 ST 5 Carbon Tetrachloride U U U U U U U 5 ST 5 Bromodichloromethane U U U U U U U 50 GV 5 1,2-Dichloropropane U U U U U U U 5 ST 5 cis-1,3-Dichloropropene U U U U U U U .... 5 Trichloroethene U U U U U U U 5 ST 5 Dibromochloromethane U U U U U U U 50 GV 5 1,1,2-Trichloroethane U U U U U U U 5 ST 5 Benzene U U U U U U U ND ST 5 Trans-1,3-Dichloropropen U U U U U U U .... 5 Bromolorm U U U U U U U 50 GV 5 Tetrachloroethene U U U U U U U 5 ST 5 1,1,2,2-Tetrachloroethane U U U U U U U 5 ST 5 Toluene U U U U U U U 5 ST 5 Chlorobenzene U U U U U U U 5 ST 5 Ethylbenzene U U U U U U U 5 ST 5 Xyiene (total) U U U U U U U 5 ST* 5 1,2-Dichlorobenzene U 1 I I U I U 4.7 ST 5 1,3-Dichlorobenzene U U U U U U U 5 ST 5 1,4-Oichlorobenzene U I U I U 1 U 4.7 ST 5 QUALIFIERS U: analyzed for but not detected NOTES ST: Standard GV: Guidance Value .... : Not established ST*: Applies to each isomer individually I I I I I I I I I I I I I I I I I Table 4-15 presents the results of the semivolatile analyses of groundwater. Naphthalene and bis(2-ethylhexyl)phthalate were both found in trace levels below the detection limit. As previously discussed, bis(2-ethylhexyl)phthalate is a laboratory contaminant. Naphthalene was found in trace quantities below the guidelines at only two wells (MW-3S and MW-6D). As shown in Table 4-16, pesticides/PCBs were not detected in groundwater. A table showing the results of all organic compounds detected in groundwater samples collected as part of this investigation, as well as groundwater samples collected as part of the recent USEPA site inspection, is presented in Table 4-17. All organic compounds found to exceed NYSDEC Class GA groundwater standards are listed in this table and presented in Figure 4-22. Organic compounds known to be common laboratory contaminants such as methylene chloride and phthalates are not included in Figure 4-22. 1,2-Dichloropropane was detected at a concentration exceeding standards during both investigations. Dichloropropane was present above standards in downgradient wells MW-6D, S-68916 and GW-6. MW-6D and S-68916 are located immediately downgradient of the former scavenger waste lagoons. Well GW-6 is located along Oregon Road approximately 2,000 feet downgradient of well S-68916. As previously mentioned, 1,2-dichloropropane is an insecticide and was found during other sampling investigations at levels exceeding standards both upgradient and downgradient of the landfill. Therefore, the presence of this compound in supply well GW-6 is not attributed to the landfill. Chlorobenzene was found to exceed standards in well S-68916 but was not found in any downgradient supply wells and was detected in only one other well (MV~-2D) at a very low concentration. 1,2-Dichloroethane, although found to exceed standards in well MW-6D, was only found in three other wells (MW-3S, MW-4D and S-68916) at very low concentrations that were below the detection limit. Trans-l,2-dichloroethene (total), tetrachloroethane and toluene were detected in wells sampled during the USEPA site inspection (wells S-68916 and GW-7) but at nonquantifiable concentrations below the detection limit. Naphthalene, a semivolatile compound, was detected during the Part 360/Phase II investigation at wells MW-3S and MW-6D. In both cases, the concentrations were low and below the method detection limit. Naphthalene was not found in any well sampled during the USEPA site inspection. These results indicate that the landfill is not causing an impact to downgradient water supply with respect to organic contaminants. 4-56 TABLE 4-15 TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING SEMIVOLATILE ORGANICS NYSDOH MW1S MW1D MW2S MW2D MW3S NYSOEC CLASS GA DRINKING 7/25/91 7/25/91 7/24/91 7/24/91 7/25/91 STANDARDS/GUIDELINES STANDARD.c SEMIVOLAT]LE COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) Phenol U U U U U 1 ST 50 Bis(2-Chloroet hyl)Ether U U U U U 1 ST 5 2-Chlorophenol U U U U U 1 ST 5 1,3-Dichlorobenzene U U U U U 5 ST 5 1,4-Dichlorobenzene U U U U U 4.7ST 5 Benzyl Alcohol U U U U U .... 50 1,2-Dichlorobenzene U U U U U 4.7ST 5 2-Methylphenol U U U U U .... 50 bis-(2-Chloroisopropyl)Ether U U U U U .... 5 4-Methylphenol U U U U U .... 50 N-Nitroso-Di-n-Propylamine U U U U U .... 50 Hexachloroethane U U U U U 5 ST 50 Nitrobenzene U U U U U 5 ST 5 Isophorone U U U U U 50 GV 50 2-Nitrophenol U U U U U .... 50 2,4-Dimethylphenol U U U U U .... 5 Benzoic Acid U U U U U .... 50 Bis-(2-Chloroethoxy)Methane U U U U U 5 ST 5 2,4-Dichlorophenol U U U U U 1 ST 5 1,2,4-Trichlorobenzene U U U U U 5 ST 5 Naphthalene U U U U 7 J 10 GV 50 4-Chloroaniline U U U U U 5 ST 50 Hexachlorobutadiene U U U U U 5 ST 5 4-Chloro-3-Methylphenol U U U U U 1 ST 5 2-Methylnaphthalene U U U U U .... 50 H exachlorocyctopentadiene U U U U U 5 ST 5 2,4,6-Trichlorophenol U U U U U 1 ST 5 2,4,5-Trichlorophenol U U U U U 1 ST 5 2-Chloronaphthalene U U U U U 5 ST 5 2-Nitroaniline U U U U U 5 ST 50 Dimethyl Phthalate U U U U U 50 GV 50 Acenaphthylene U U U U U 20 GV 50 2,6-Dinitrotoluene U U U U U 5 ST 5 3-Nitroaniline U U U U U 5 ST 50 Acenaphthene U U U U U 20 GV 50 2,4-Dinitrophenol U U U U U .... 5 QUALIFIERS: U: anatyzed for but not detected J: compound found below detection limit NOTES: GV: Guidance Value ST: Standard .... : Not established TABLE 4-15 (cont.) TOVVN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING SEMIVOLATILE ORGANICS NYSDOH MWIS MW1D MW2S MW2D MW3S NYSOEC CLASS GA DRINKING 7/25/91 7/Z5/91 7/24/91 7/24/91 7/25/91 STANDARDS/GUIDELINES STANDARDS SEMIVOLATILE COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) 4-Nitrophenol U U U U U .... 5O Dibenzofuran U U U U U .... 50 2,4-Dinitrotoluene U U U u U 5 ST 5 Diethylphthalate U U u U U 50 GV 50 4-Chlorophenyl-phenylether U U U U U .... 50 Fluorene U U U U U 50 GV 50 4-Nitroaniline U U U U U 5 ST 50 4,6-Dinitro-2-Methylphenol U U U U U .... 50 N-Nitrosodiphenylamine (1) u u u u u 50 GV 50 4-Bromophenyl-phenylether U U U U U I ST 50 Hexachlorobenzene U u U u U 0.35ST 5 Pentachlorophenol U U U U U 1 ST 5 Phenanthrene u u U U U 50 GV 50 Anthracene U u u u U 50 GV 50 Di-n-Butylphthalate U u u u U 5O ST 5 Fluoranthene u u U U U 50 GV 50 Pyrene U U U U U 5O GV 5O Butylbenzylphthalate U U U U U 5O GV 5o 3,3'-Dichlorobenzidine U U U U U 5 ST 5 Benzo(a)Anthracene U U U U U .OO2 GV 50 Chrysene U U U U U .o02 GV 5O bis(2-Ethylhexyl)Phthalate 2 J 4 BJ 2 J U 2 BJ 50 ST 50 Di-n-Octylphthalate U U U U u 50 GV $0 Benzo(b)Fluoranthene U U U U u .002 GV 50 Benzo(k)Fluoranthene U U U U U .002 GV 50 Benzo(a)Pyrene U U U U u ND ST 50 Indeno(1,2,3-cd)Pyrene U U U U U .002 GV 50 Dibenz(a,h)Anthracene u U u u u .... 50 Benzo(g,h,i)Perylene u U u u u .... 50 Unknown NP NP 20 J* 9 J* 31 J* - ....... Unknown NP NP 10J' 12J* 29J* - ....... Unknown NP NP 10J* 59J* 11 J* - ....... Unknown NP NP 9 J* 9 J* 8 J' - ....... Unknown NP NP 9 J ° 13 J* 11 J' - ....... Unknown NP NP NP 21 J° 14 J' - ....... Unknown NP NP NP 13J* 10J' - ....... Unknown NP NP NP 11 J* 11 J* - ....... Unknown NP NP NP NP 10 J* - ....... Unknown NP NP NP NP 8 J' - ....... Unknown NP NP NP NP 9 J* - ....... Unknown NP NP NP NP 34 J* - ....... Unknown Aromatic NP NP NP 17 j* Np ........ Unknown Aromatic NP NP NP 13 J* Np ........ Unknown Aromatic NP NP 11 J* 38J* 11 J* - ....... Unknown Aromatic NP NP 14 J* 10 J* 15 J* - ....... Unknown Acid NP NP NP NP NP ........ Unknown Acid NP NP NP NP NP ........ Unknown Acid NP NP NP NP NP ........ Unknown Acid NP NP NP NP NP ........ Unknown Acid NP NP NP NP NP ........ Hexadecanoic Acid NP NP NP NP NP ........ QUALIFIERS: U: analyzed for but not detected B: compound found in blank as well as sample J: compound found below detection limit NOTES: GV: Guidance Value ST: Standard .... : Not established ND: not detected NP: not present I I I TABLE 4-15 TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING SEMIVOLATILE ORGANICS NYSDOH MW3D MW4S MW4D MW5S MW5D NYSDEC CLASS GA DRINKING 7/25/91 7/26191 7/26/91 7/25/91 7/25/91 STANDARDS/GUIDELINE.~ ~TANDARDS SEMIVOLAT1LE COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) Phenol U U U U U 1 ST 50 Bis(2-Chloroet hyl) Ether U U U U U 1 ST 5 2-Chlorophenol U U U U U 1 ST 5 1,3-Dichlorobenzene U U U U U 5 ST 5 1,4-Dichlorobenzene U U U U U 4.7ST 5 Benzyl Alcohol U U U U U .... 50 1,2-Dichlorobenzene U U U U U 4.7ST 5 2-Methylphenol U U U U U .... 50 bis-(2-Chloroisopropyl)Ether U U U U U .... 5 4-Methylphenol U U U U U .... 50 N-Nitroso-Di-n-Propylamine U U U U U .... 50 Hexachloroethane U U U U U 5 ST 50 Nitrobenzene U U U U U 5 ST 5 Isophorone U U U U U 50 GV 50 2-Nitrophenol U U U U U .... 50 2,4-Dimethylphenol U U U U U .... 5 Benzoic Acid U U U U U .... 50 Bis-(2-C hloroethoxy)Methane U U U U U 5 ST 5 2,4-Dichlorophenol U U U U U I ST 5 1,2,4-Trichlorobenzene U U U U U 5 ST 5 Naphthalene U U U U U 10 GV 50 4-Chloroaniline U U U U U 5 ST 50 Hexachlorobutadiene U U U U U 5 ST 5 4-Chloro-3-Methylphenol U U U U U 1 ST 5 2-Methylnaphthalene U U U U U .... 50 Hexachlorocyclopentadiene U U U U U 5 ST 5 2,4,6-Trichlorophenol U U U U U 1 ST 5 2,4,5-Trichlorophenol U U U U U 1 ST 5 2-Chloronaphthalene U U U U U 5 ST 5 2-Nitroaniline U U U U U 5 ST 50 Dimethyl Phthalate U U U U U 50 GV 50 Acenaphthylene U U U U U 20 GV 50 2,6-Dinitrotoluene U U U U U 5 ST 5 3-Nitroaniline U U U U U 5 ST 50 Acenaphthene U U U U U 20 GV 50 2,4-Dinitrophenol U U U U U .... 5 I I I I I I I I I I I QUALIFIERS: U: analyzed for but not detected J: compound found below detection NOTES: GV: Guidance Value ST: Standard .... : Not established TABLE 4-15 (cont.) TOWN OF SOUTHOLD ~I~DFILL GROUNDWATER SAMPLING SEMIVOLATILE ORGANICS i NYSDOH MW3D MW4S MW4D MW5S MW5D NYSOEC CLASS GA DRINKING 7/25/91 7/26/91 7/26/91 7/25/91 7/25/91 ~TANDARDS/GUIOELINES STANDARD: SEMIVOLATILE COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (Ug/I) (ug/I) (ug/I) I 4-Nitrophenol U U U U U 50 Dibenzofuran U U U U U .... 50 2,4-Dinitrotoluene U U U U U 5 ST 5 I Diethylphthalate U U U U u 50 GV 50 ' 4-Chlorophenyl-phenylether U U U U U .... 50 Fluorene u u u u U 50 GV 50 i 4-Nitroaniline U U U U U 5 ST 50 ~l,6-Dinitro-2-Methylphenol U u U U U .... 50 N-Nitrosodiphenylamine (1) U U U U U 50 GV 50 ~*-Bromophenyl-phenylether U U U U U 1 ST 50 I Hexachlorobenzene U U U U U 0.35ST 5 !Pentachlorophenol U U U U u 1 ST 5 Phenanthrene U U U U U 50 GV 50 I Anthracene U U U U U 50 GV 50 Di-n-Butylphthalate U U U U U 50 ST 5 Fluoranthene U U U U U 50 GV 50 i Pyrene u U U U U 50 GV 50 Butylbenzylphthalate U U U U U 50 GV 5O 3,3'-Dichlorobenzidine u u U U U 5 ST 5 Benzo(a)Anthracene U U U U U .002 GV 50 I Chrysene U U U U U .002 GV 50 bis(2-Ethylhexyl)Phthalate 2 BJ 2 BJ 2 BJ 2 BJ 3 BJ 50 ST 50 Di-n-Octylphthalate U U u u U 50 GV 50 i Benzo(b)Fluoranthene u U U u U .002 GV 50 Benzo(k)Fluoranthene u U u u U .002 GV 50 Benzo(a)Pyrene U U U U u ND ST 50 Indeno(1,2,3-cd)Pyrene U U U U U .002 GV 50 I Dibenz(a,h)Anthracene U U .... 50 U U U Benzo(g,h,i)Perylene U U U U U .... 50 I Unknown 23J' 25J* 16J* 15J* 320J* - ....... Unknown 26 J' NP 35 J* 11 J* 15 J* - ....... Unknown 10 J' NP 9 J* NP 49 J * - ....... Unknown 12 J* NP 13 J* NP 26 J* - ....... I Unknown 29J* NP 9J' NP 13J* - ....... Unknown NP NP 9 J' NP 43 J* - ....... Unknown NP NP 28 J* NP 39 J* - ....... Unknown NP NP 10 J* NP 8 J* - ....... I Unknown NP NP 17 J* NP 18 J' - ....... Unknown NP NP NP NP 13 J' - ....... Unknown NP NP NP NP 260J* - ....... Unknown NP NP NP NP NA ........ I Unknown Aromatic NP NP NP NP 9 J' - ....... Unknown Aromatic NP NP NP NP NA ........ Unknown Aromatic NP NP NP NP NA ........ Unknown Aromatic NP NP NP NP NA ........ I Unknown Acid NP NP NP NP 13 J' - ....... Unknown Acid NP NP NP NP 26 J' - ....... Unknown Acid NP NP NP NP 290J* - ....... Unknown Acid NP NP NP NP 89 J* - ....... I Unknown Acid NP NP NP NP 51 J* - ....... Hexadecanoic Acid NP NP NP NP 67 J* - ....... IQUALIFIERS: U: analyzed for but not detected B: compound found in blank as well as sample I J: compound found below detection limit NOTES: GV: Guidance Value ST: Standard .... : Not established NP: not present ND: not detected TABLE 4-15 TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING SEMIVOLATILE ORGANICS NYSDOH MW5DRE MW6S MW6D MW6DRE MW7S NYSOEC CLASS GA DRINKING 7/25/91 7/24191 7124/91 7/24/91 7/25191 STANDARDS/GUIDELINES STANDARDS SEMIVOLATILE COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) Phenol U U U U U 1 ST 50 Bis(2-Chloroethyl) Ether U U U U U 1 ST 5 2-Chlorophenol U U U U U I ST 5 ,3-Dichlorobenzene U U U U U 5 ST 5 ,4-Dichlorobenzene U U U U U 4.7ST 5 Benzyl Alcohol U U U U U .... 50 ,2-Dichlorobenzene U U U U U 4.7ST 5 2-Methylphenol U U U U U .... 50 Dis-(2-Chloroisopropyl)Ether U U U U U .... 5 4-Methylphenol U U U U U .... 50 N-Nitroso-Di-n-Propylamine U U U U U .... 50 Hexachloroethane U U U U U 5 ST 50 Nitrobenzene U U U U U 5 ST 5 Isophorone U U U U U 50 GV 50 2-Nitrophenol U U U U U .... 50 2,4-Dimethylphenol U U U U U .... 5 Benzoic Acid U U U U U .... 50 Bis-(2-Chloroethoxy) Methane U U U U U 5 ST 5 2,4-Dichlorophenol U U U U U 1 ST 5 ,2,4-Trichlorobenzene U U U U U 5 ST 5 Naphthalene U U 5 J U U 10 GV 50 4-Chloroaniline U U U U U 5 ST 50 Hexachlorobutadiene U U U U U 5 ST 5 4-Chloro-3-Methylphenol U U U U U 1 ST 5 2-Methylnaphthalene U U U U U .... 50 Hexachlorocyclopentadiene U U U U U 5 ST 5 2,4,6-Trichlorophenol U U U U U 1 ST 5 2,4,5-Trichlorophenol U U U U U I ST 5 2-Chloronaphthalene U U U U U 5 ST 5 2-Nitroaniline U U U U U 5 ST 50 Dimethyl Phthalate U U U U U 50 GV 50 Acenaphthylene U U U U U 20 GV 50 2,6-Dinitrotoluene U U U U U 5 ST 5 3-Nitroaniline U U U U U 5 ST 50 Acenaphthene U U U U U 20 GV 50 2,4-Dinitrophenol U U U U U .... 5 QUALIFIERS: U: analyzed for but not detected J: coml~ound found below detection NOTES: GV: Guidance Value ST: Standard .... : Not established TABLE 4-15 (cont.) 'rOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING SEMIVOLATILE ORGANICS NYSDOH MW5DRE MW6S MW6D MW6DRE MW7S NYSOEC CLASS GA DRINKING 7/25/91 7/24/91 7/24/91 7/24/91 7/25/91 STANDAROS/GUIDELiNE~ STANDARD~ SEMtVOLATILE COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) 4-Nitrophenol U U U U U .... 50 Dibenzofuran U U U U U .... 50 2,4-Dinitrotoluene U U U U U 5 ST 5 Diethylphthalate U U U U U 5o GV 5O 4-Chlorophenyl-phenylether U U U U U .... 5o Fluorene U U u U u 50 GV 50 4-Nitroaniline U U U U U 5 ST 50 4,6-Dinitro-2-Methylphenol U U U u U .... 50 N-Nitrosodiphenylamine (1) U U U U U 50 GV 50 4-Bromophenyl-phenylether U U U u U I ST 50 Hexachlorobenzene U U U u U 0.35ST 5 Pentachlorophenol U u U U U 1 ST 5 Phenanthrene U U U U U 50 GV 50 Anthracene U U U U U 50 GV 50 Di-n-Butylphthalate U u U U U 50 ST 5 Fluoranthene U U U U U 50 GV 50 Pyrene u U U u U 50 GV 50 Butylbenzylphthalate U u u U u 50 GV 50 3,3'-Dichlorobenzidine U u U U U 5 ST 5 Benzo(a)Anthracene u U U u U .002 GV 50 Chrysene U u U U u .002 GV 50 bis(2-Ethylhexyl)Phthalate U 4 J 8 BJ U 3 J 50 ST 50 Di-n-Octylphthalate U U U U U 50 GV 50 Benzo(b)Fluoranthene U U U U U .002 GV 50 Benzo(k)Fluoranthene U U U U u .002 GV 50 Benzo(a)Pyrene u U U U U ND ST 50 Indeno(1,2,3-cd)Pyrene U U U U U .002 GV 50 Dibenz(a,h)Anthracene U U u U u .... 50 Benzo(g,h,i)Perylene U U U U U .... 50 Unknown 10J* 11J' 10J* 11 J* 34J' - ....... Unknown 8 J* Np 28 J* 10 J* Np ........ Unknown 37 J' Np 27 J' 30 J* Np ........ !Unknown NP NP 19 j' Np NP ........ ~Unknown Np NP 29 J* Np NP ........ Unknown NP NP NP NP NP ........ Unknown NP NP NP NP NP ........ Unknown NP NP NP NP NP ........ Unknown NP NP NP NP NP ........ Unknown NP NP NP NP NP ........ Unknown NP NP NP NP NP ........ Unknown NP NP NP NP NP ........ Unknown Aromatic 10 j* Np NP NP NP ........ Unknown Aromatic NP NP NP NP NP ........ Unknown Aromatic NP NP NP NP NP ........ Unknown Aromatic NP NP NP NP NP ........ Unknown Acid NP NP NP NP NP ........ Unknown Acid NP NP NP NP NP ........ Unknown Acid NP NP NP NP NP ........ Unknown Acid NP NP NP NP NP ........ Unknown Acid NP NP NP NP NP ........ Hexadecanoic Acid NP NP NP NP NP ........ QUALIFIERS: U: analyzed for but not detected B: compound found in blank as well as sample J: compound found below detection timit NOTES: GV: Guidance Value ST: Standard .... : Not established NP: not present ND: not detected TABLE 4-15 TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING SEMIVOLATILE ORGANICS MW7D MW7DRE FB NYSOEC CLASS GA DRINKING 7/26/91 7/26/91 7/25/91 STANDARDS/GUIDELINE.~ STANDARDS SEMIVOLATILE COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) Phenol U U U 1 ST 50 Bis(2-Chloroethyl)Ether U U U 1 ST 5 2-Chlorophenol U U U 1 ST 5 ,3-Dichlorobenzene U U U 5 ST 5 ,4-Dichlorobenzene U U U 4.7ST 5 Benzyl Alcohol U U U .... 50 ,2-Dichlorobenzene U U U 4.7ST 5 2-Methylphenol U U U .... 50 ~)is-(2-Chloroisopropyl)Ether U U U .... 5 4-Methylphenol U U U .... 50 N-Nitroso-Di-n- Propylamine U U U .... 50 Hexachloroethane U U U 5 ST 50 I Nitrobenzene U U U 5 ST 5 Isophorone U U U 50 GV 50 2-Nitrophenol U U U .... 50 2,4-Dimethylphenol U U U .... 5 Benzoic Acid U U U .... 50 !Bis-(2-Chloroethoxy)Methane U U U 5 ST 5 12,4-Dichlorophenol U U U 1 ST 5 1,2,4-Trichlorobenzene U U U 5 ST* 5 Naphthalene U U U 10 GV 50 i4-Chloroaniline U U U 5 ST 50 iHexachlorobutadiene U U U 5 ST 5 4-Chloro-3-Methylphenol U U U 1 ST 5 2-Methylnaphthalene U U U .... 50 Hexachlorocyclopentadiene U U U 5 ST 5 2,4,6-Trichlorophenol U U U 1 ST 5 2,4,5-Trichlorophenol U U U 1 ST 5 2-Chloronaphthalene U U U 5 ST 5 2-Nitroaniline U U U 5 ST 50 Dimethyl Phthalate U U U 50 GV 50 Acenaphthylene U U U 20 GV 50 2,6-Dinitrotoluene U U U 5 ST 5 3-Nitroaniline U U U 5 ST 50 Acenaphthene U U U 20 GV 50 2,4-Dinitrophenol U U U .... 5 QUALIFIERS: U: analyzed for but not detected J: compound found below detection NOTES: GV: Guidance Value ST: Standard .... : Not established TABLE 4-15 (cont.) TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING SEMIVOLATILE ORGANICS NYSDOH MW7D MW7DRE FB NYSOEC CLASS GA DRINKING 7/26/91 7/26/91 7/25/91 ~'q'ANDARDS/GUIDEM N ES STANDARDS SEMIVOLATILE COMPOUNDS (ug/I) (ug/I) (Ug/I) (Ug/I) (Ug/I) 4-Nitrophenol U U U .... 50 Dibenzofuran U U u .... 50 2,4-Dinitrotoluene U U U 5 ST 5 Diethylphthalate u U u 50 GV 50 4-Chlorophenyl-phenylether U U U .... 50 Fluorene U U U 50 GV 50 4-Nitroaniline U U U 5 ST 50 4,6-Dinitro-2-Methylphenol U U u .... 50 N-Nitrosodiphenylamine (1) U U U 50 GV 50 4-Bromophenyl-phenylether U U u I ST 50 Hexachlorobenzene U U U 0.35ST 5 Pentachlorophenol U U U I ST 5 Phenanthrene U U U 50 GV 50 Anthracene U U u 50 GV 50 Di-n-Butylphthalate U U u 50 ST 5 Fluoranthene u U U 50 GV 50 Pyrene u U U 50 GV 50 Butylbenzylphthalate U U U 50 GV 50 3,3'-Dichlorobenzidine U U u 5 ST 5 Benzo(a)Anthracene U U u .002 GV 50 Chrysene U u u .002 GV 50 bis(2-Ethylhexyl)Phthalate 2 BJ U U 50 ST 50 Di-n-Octylphthalate U U U 50 GV 50 Benzo(b)Fluoranthene U u U .002 GV 50 Benzo(k)Fluoranthene U U u .002 GV 50 Benzo(a)Pyrene U u U ND ST 50 indeno(1,2,3-cd)Pyrene U U U .002 GV 50 Dibenz(a,h)Anthracene U U U .... 5o Benzo(g,h,i)Perylene U U U .... 5O Unknown 130 j* 130 j* Np ........ Unknown NP NP NP ........ Unknown NP NP NP ........ Unknown NP NP NP ........ Unknown NP NP NP ........ Unknown NP NP NP ........ Unknown NP NP NP ........ Unknown NP NP NP ........ Unknown NP NP NP ........ Unknown NP NP NP ........ Unknown NP NP NP ........ Unknown NP NP NP ........ Unknown Aromatic NP NP NP ........ Unknown Aromatic NP NP NP ........ Unknown Aromatic NP NP NP ........ Unknown Aromatic NP NP - Np ........ Unknown Acid NP NP NP ........ Unknown Acid NP NP NP ........ Unknown Acid NP NP NP ........ Unknown Acid NP NP NP ........ Unknown Acid NP NP NP ........ Hexadecanoic Acid NP NP NP ........ ,. QUALIFIERS: ' · U: analyzed for but not detected i ~ B: compound found in blank as well as sample I J: compound found below detection limit NOTES: GV: Guidance Value ST: Standard .... : Not established NP: not present ND: not detected mm mm m m TABLE 4-16 TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING PESTIPCB'S MWlS MW1D MW2S MW2D MW3S MW3D MW4S MW4D NYSDEC CLASS GA DRINKING 7/25/91 7125/91 7124/91 7/24/91 7125191 7125/91 7/26/91 7/26/91 STANDARDS/GUIDELINES STANDARDS ORGANIC COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ugll) alpha-BHC U U U U U U U U .... 5 beta-BHC U U U U U U U U .... 5 lelta BHC U U U U U U U U .... 5 gamma-BHC (Lindane) U U U U U U U U ........ Hepatachlor U U U U U U U U ND ST 5 Aldrin U U U U U U U U ND ST 5 Heptachlor epoxide U U U U U U U U ND ST 5 Endosulfan I U U U U U U U U .... 50 Dieldrin U U U U U U U U .... 5 4,4'-DDE U U U U U U U U ND ST 5 Endrin U U U U U U U U ND ST 5 Endosuifan II U U U U U U U U .... 50 4,4'-DDD U U U U U U U U ND ST 5 Endosulfan sulfate U U U U U U U U .... 50 4,4'-DDT U U U U U U U U ND ST 5 Methoxychlor U U U U U U U U 35 ST 50 Endrin Ketone U U U U U U U U ........ alpha-Chlordane U U U U U U U U 0.1 ST 5 gamma-Chlordane U U U U U U U U 0.1 ST 5 Toxaphene U U U U U U U U ND ST 5 Arochlor-1016 U U U U U U U U 0.1 ST 5 Arochlor-1221 U U U U U U U U 0.1 ST 5 Arochlor-1232 U U U U U U U U 0.1 ST 5 Arochlor-1242 U U U U U U U U 0.1 ST 5 Arochlor-1248 U U U U U U U U 0.1 ST 5 Arochior-1254 U U U U U U U U 0.1 ST 5 Arochlor-1260 U U U U U U U U 0.1 ST 5 QUALIFIERS U: analyzed for but nol detected NOTES GV: Guidance Value ST: Standard .... : Not established TABLE 4-16 (cont.) TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING PESTIPCB'S MW5S MW5D MW6S MW6D MW7S MW7D FB N¥SDEC CLASS GA DRINKING 7125191 7/25/91 7124/91 7124/91 7/25191 7126/91 7125/91 STANDARDS/GUIDELINES STANDARDS ORGANIC COMPOUNDS (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/I) (ug/i) alpha-BHC U U U U U U U .... 5 beta-BHC U 0.24 U U U U U .... 5 delta BHC U U U U U U U .... 5 gamma-BHC (Lindane) U U U U U U U ........ Hepatachlor U U U U U U U ND ST 5 Aldrin U U U U U U U ND ST 5 Heptachlor epoxide U U U U U U U ND ST 5 Endosulfan I U U U U U U U .... 50 Dieldrin U U U U U U U .... 5 i4,4'-DDE U U U U U U U ND ST 5 Endrin U U U U U U U ND ST 5 Endosulfan II U U U U U U U .... 50 4,4'-DDD U U U U U U U ND ST 5 Endosulfan sulfate U U U U U U U .... 50 4,4'-DDT U U U U U U U ND ST 5 Methoxychior U U U U U U U 35 ST 50 Endrin Ketone U U U U U U U ........ alpha-Chlordane U U U U U U U 0.1 ST 5 gamma-Chlordane U U U U U U U 0.1 ST 5 Texaphene U U U U U U U ND ST 5 Arochlor-1016 U U U U U U U 0.1 ST 5 Arochlor-1221 U U U U U U U 0.1 ST 5 Arochlor-1232 U U U U U U U 0.1 ST 5 Arochlor-1242 U U U U U U U 0.1 ST 5 Arochlor-1248 U U U U U U U 0.1 ST 5 Arochlor-1254 U U U U U U U 0.1 ST 5 Arochlor-1260 U U U U U U U 0.1 ST 5 QUALIFIERS U: analyzed for but not detected NOTES GV: Guidance Value ST: Standard .... : Not established m m Chloro- 1,2-DJchloro- benzene benzene (5 ST) (4.7 ST) New Monitorlno Wells: ~b/-1S (U) ND ND MW-lO (U) ND NO MW-2S iD) ND NO MW-2D (0) 33 NO MW-3S iD) ND NB MW-3D iD) ND ND MW-4S iD) ND ND MW-4D iD) ND ND MW-SS iD) ND ND MW-5D iD) ND ND MW-6S (O) ND 1 MW-6D iD) ND 1 MW-7S iD) ND 1 MW-7D iD) ND NO USEPA Samole Locations: GW-1 (U) ND NA GW-2 (U) ND NA GN-3/GW-4 24/23* NA (S-68g16) (D) GW-S (O) ND NA GW-6 iD) ND NA GW-7 iD) ND NA GW-8 iD) ND NA Table 4-17 ORGANIC COHPOUNOS DETECTED IN GROUND~ATER - PART 360 AND PHASE II INVESTIGATION AND USEPA SITE INSPECTION RESULTS (all results in ug/1) 1,4-Oichloro- 1,2-Dichloro- 1,2-Oichloro- benzene ethane propane Freon 113 (4.7 ST) (5 ST) (5 ST) 0 ND ND ND NA ND ND ND NA ND ND ND NA ND 43 ND NA ND 43 ND NA ND ND ND NA ND ND NB NA ND 4J NO 83 ND ND ND NA ND ND ND NA 1 NO ND IdA, ND 12' 11' NA I ND ND NA ND NO ND NA Trans-l,2- Tetrachloro- Oichloroethane ethane Toluene Napthalene (Total) (5 ST) (5 ST) (5 ST) (10 GV) ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND 7J ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND NO ND ND ND ND ND ND ND ND 5J ND NO ND ND ND ND ND ND NA ND ND NA ND NA ND ND NA ND NA 3/3 15/15' NA ND NA ND ND NA ND NA ND g* NA ND NA ND ND NA 3 NA ND NO NA ND ND ND ND ND ND ND ND ND/J ND ND NO ND ND ND ND 3 ND ND ND ND ND ST - Standard GV - Guidance Value J - Below Detection Limit NA - Not Analyzed ND - Not Detected U - Upgradient D - Oowngradient S1483G COMPOUND CONCEN~ATION COMPOUND CONCENI~A~ON COMPOUND CONCENI~A~ON DCA ND I 2 DCA ND 3,2 DCA ND COMPOUND ~ALLOW DEEP CH~ENZENE' NO-- ~ ~ '~ / COMPOUND SHALLOW' DEEP ~ OW- 3,G~-4(5 -68916) / CHBENZCNE HD ND ~ ~RHTWA/b ~ ~ COHCENmA~ON ~NDFILL SH*~°w ~ 1,2 DCA ND ND MW-7 COMPOUND SHALLOW DEEP ~CP ND ND ~ ND ND MW-1 L m ~/~ /~ LEGEND ....~ ~ HYDROGEOLOGIC INVESTIGATION GROUNDWATER J S-68916 MONITORING WELL AND SAMPLING LOCATIONS ~ USEPA GROUNDWATER SAMPLING LOCATIOHS GW-1 1,2 DCA 1,2 DICHLOROETHANE 1,2 DCP 1~2 DICHLOROPROPANE CHBENZENE CHLOROBENZENE ND NOT DETECTED · PRESEHT ABO~ STANDARDS DIRECTORY: C:X1027 J ESTIMATED VALUE BELOW DE~C~ON LIMIT FILE NA~E: OR~ST 0 400 SCALE: ~::~ SCALE IN ~ ALL RESULTS IN ug/I TOWN OF SO.HOLD  Ovirka SOUTHOLD ~NDFILL ~ and ORGANIC COMPOUNDS EXCEEDING C~SS GA ~}[~i}~Ei[., GROUNDWATER STANDARDS IN GROUNDWATER F~URE CONCENTRA~nON COMPOUND SHALLOW DEEP 1~2 DCA ND ~- J 1,2 DCP ND ND CHBENZENE ND ND CONCENTRA~ON COMPOUND SHALLOW DEEP 1~2 DCA ND 4 J_ 1,2 DCP ND ND CHIBENZENE ND ND CONCEN1RA~ION COMPOUND GW-3 GW-4 1,2 DCA J __ J (;HBENZENE 24 * 23 · CONCENTRA'flON COMPOUND SHALLOW DEEP I I I I I I I 4.5.4.2 - Inorganic Sampling Results The inorganic constituents detected in groundwater samples are listed in Table 4-18. Iron, manganese, magnesium and sodium were the metals found to exceed New York State Standards Guidelines for Class GA groundwater in a number of samples. The highest concentrations of magnesium and sodium were found in monitoring well MW-2D, while the highest level of manganese was found in well MW-3D. Both of these wells are directly downgradient of the existing landfill. Elevated levels of these metals were also found in the corresponding shallow wells, MW-2S and MW-3S, but in lesser concentrations. The highest level of iron was found in monitoring well MW-7D and to a lesser degree in MW-6S. No metals were detected exceeding standards in the northernmost shallow wells MW-5S and MW4S. This confirms the geophysical findings of a dense but chemically weak plume of conductive groundwater emanating from the landfill and sinking beneath the screen zones (water table) of shallow wells MW4S and MW-5S as the groundwater migrates off-site in a northwesterly direction. The concentrations of metals in MW4D and MW-5D are consistently lower than those found in the downgradient wells located adjacent to the landfill (MW-2 and MW-3 well clusters), which indicates attenuation of the plume with distance downgradient. Data collected from monitoring well clusters MW-2 and MW-3 show consistently higher levels of metals in the deep wells at these locations which indicates that the bulk of the plume has migrated downward to the top of the clay surface. The well screen intervals were superimposed onto the conductivity logs and included on the site plan as shown in Figure 4-23. The results indicate that the plume extends down to screen zones at both MW4D and MW-5D, which makes these wells effective for monitoring the plume at the site boundary. The results of previous private well smnpling investigations downgradient of the landfill along Cox Lane and Oregon Road confirm attenuation of the leachate plume and little or no impact on groundwater quality off-site. Magnesium and manganese were all found in concentrations below the New York State Class GA standards and guidelines in off-site wells. Sodium was found to contravene standards at private well GW-7 (27.4 mg/l), which is roughly six time less than the concentrations found at the site boundary (MW4 and MW-5). Sodium was also present in upgradient wells IVlW-IS and MW-ID at a concentration of 41.6 mW1 and 16.3 mg/1, respectively, which indicates that groundwater quality downgradient of the landfill is representative of background conditions. s ~2o6o 4-69 TABLE 4-18 TOWN OF SOUTHOLD LANDFILL I MWI$ MWID MW2S MW2D L4W3~ MW3D MW4~ MW4O NYSOEC C~ GA DRINKING 7/2~1 7/2~1 7/2~1 712~1 712~1 712~1 7/2~1 712~1 ~ANDA~GUID~INES PAR~ERS (mgll) (mg/I) (mgm) (m~l) (m~l) (mgfl) (mgm) (mgll) (mgfl) (mgll) Turbidity, N.T.U 255 26 2~ 17.5 1820 75 700 24 .- ~i~hemical Oxygen Demand 5 U 3 U 6 U U U ~ONSTITUENTS (m~) ~Umony U U U U U U U U 0.003 ST mic U U U U U U U U 0.025 ST 0.05 Be~lium U U U U U U U U :hr~ium U U U U U U U U 0.05 ST 0.~ :opper U 0.0128 0.021 B U U U U U 0.2 ~ Mercury U U U U U U U U 0.~2 ST 0.~2 ~lenium U U U U U U U U 0.01 ~ 0.01 ~il~r U U U U U U U U 0.05 ~ 0.0~ 'h~lium U U U U U U U U 0.~ ~  lanadium U U U U U U U U C~nide U U U U U U U U 0.1 ST Results in mgAg IQUALIFIERS; ed NOTES: U: Analyzed for but no~ detect GV: Guidanoe value TOC: Total Organic Carbon ST: ~andard I B:value les8 than contract ~: Nd iltabli~hed TABLE 4-18 (coe~t.) I TOWN OF SOUTHOLD LANDFILL GROUNDWATER SAMPLING INORGANIC CONSTITUENTS NYSOOH MWSS MWSO MWe8 MW~D MW7S MW7D F'~ NYSOEC CLASS GA DRINKING 7125/91 7/25/91 7/24/gl 7/24/91 7/25/91 7/2~91 7/25Jgt STANDARDS/GUIDELINES STANDARDS ~OARAM ETERS (rog/I) (mg/I) (mgll) (mg/1) (rog/l) (mg/I) (mg/I) (mg/I) (rog/I) Loloc Pt/Co. 15 15 35 50 15 250 10 iTurbidity, N,T.U 495 13.5 113 3.8 154 516 0.28 I Results in mg/I !Alkalinity 8 230 267 401 46 60 1 -- --- ?mmonia Nitrogen U U iiii~iiiiiiii ?:!iiii~i~iiiiiiil 0.15 0.10 U 2 ST 3iochemical Oxygen Demand U 353 U 5 U U U -- =hemical Oxygen Demand 24 492 41 41 U 32 U .~hloride 14 115 42 150 13 74 U 250 ST Hardness 10 290 160 38~ 75 50 U Nitrate U 0.21 0.13 0.05 1.39 ::::::::::::::::::::::: 0.17 10 ~ullate 11 70 125 157 20 49 2 250 ST Total Kjeidahl Nitrogen 0.23 1.18 13.15 21.6 1.56 12.7 U ',ONSTITU ENTS (mg~l) eduminum 0.460 0.319 0.754 U 0.664 8.88 U ~nOmony U U U U U U U 0.003 ST ~'eenic U U U U U U U 0.025 ST 0.05 Barium U O.05aB 0.140B 0.134B 0.072B 0.110B U 1 ST Beryllium U U U U U U U :edmium U U U U U U U 0.01 ST 0.01 :alcium U 51.1 42.3 80.4 15.6 109 U Chromium U U U U U 0.021 U 0.05 ST 0.05 :olbalt U U U U U U U :opper U U U U U 0.022 B U 0.2 ST ............................. i:;iiiii~i!~ii!i!i!i O.3 ST earl 0.005 0.005 0.01S U U 0.018 U 0.25 ST 0.05 ~agnesium 2.18B 28,7 11.1 iii: ~:i?! ~ ii:!i~i::! 3.49B 6.27 U 35aY ...................... .............. .... Uanganese 0.11o :!::i~:~i !i!i!i~!::~!~iiiiiii U aercury U U U U U U U O.OO8 ST 0.002 lickel U U U 0.051 U U U Potassium U 3.77 42.5 44.8 5.31 3.92 B U ;elenium U U U U U U U 0.01 ST 0.01 iilver U U U U U U U 0.05 ST 0.05 Sodium 8.12 .......... ........ i::::iii~i!ili;iii! le.e ~?.r:~::::~::[ U 20 ST 'hallium U U U U U U U 0.004 ST tanadium U U U U U 0.031 B U Zinc U 0.049 0.020 0.014 B U 0.067 U 0.3 ST :yanide U U U U U U U 0.1 ST Io~a~ U .221 .158 .393 U U .538 I ST Results in mg/kg TOC 2.2 149 02.g 78.8 48.6 12.9 U U: Analyzed fo~ but no~ detected GV: Guidance value f 3C; Tolal Organic Carbo~ ST: S~andard :value less than contract : No~ established required limits but greater than ::[i[:ii[??:![::!i[iii!ii~alua exceeds allowable standard/guidance value instrument detectlo~ limits. :::'::: ........... AREA MW-5 $-6883 Source: HAGER - RICHTER GEOSCIENCE, INC. GEOPHYSICAL SURVEY AUGUST~ 1991 OVERHEAD ELECTRIC LINES WASTE OIL STORAOE LEGEND EXISTING BUILDING ON LANDFILL SITE --x--x--x-- EXISTING FENCE LINE EXISTING GROUND WATER MONITORING WELL GROUND WATER MONITORING WELL CLUSTER S - 69761 · MW-I WELL SCREEN INTERVAL o 3oo SCALE IN FEET ;TION CENTER TOWN OF SOUTHOLD $OUTHOLD LANDFILL CONDUCTIVITY LOGS AND WELL SCREEN INTERVALS FIGURE 4-23 Iron was found at a concentration of 1.55 mg/l at private well GW-7, which is directly downgradient of monitoring well MW-4D where it was found at a concentration of oniy 0.518 mg/1. Similar to sodium, iron concentrations in the upgradient wells MW-1S and MW-ID are elevated and above standards (1.35 mg/1 and 0.99 mg/l, respectively). Although it is possible that the elevated levels of iron and sodium present in well GW-7 are the result of the leachate plume, the presence of these metals at similar elevated concentrations in upgradient wells makes it appear more like ambient conditions. Selenium was found to exceed the NYSDEC Class GA standard of 0.01 mg/l in wells S-68916, WS-6 and WS-10 (see Figure 4-3) during previous sampling investigations. Selenium was undetected in groundwater samples collected as part of this investigation. Selenium was detected in two rounds of sampling in well S-68916 but was not detected in two subsequent sampling rounds. Relatively high levels of 12.0 mg/1 and 23.0 mg/l of selenium were found in wells WS-6 and WS-10, respectively. Well WS-6 is located upgradient of the landfill. Well WS-10 is located too far west of the landfill to be considered either up or downgradient of the landfill. The presence of selenium in wells WS-6 and WS-10 is, therefore, due to other sources or was an isolated occurrence. A comparison of upgradient water quality (MW-IS) to downgradient water quality at the site boundary (MW-4S and MW-5S) indicates higher levels of metals (iron, manganese and sodium) exceeding standards upgradient of the landfill in the water table wells as compared to downgradient. Although metal concentrations were elevated at the downgradient site boundary at the deep well locations, the levels were generally lower or equal to those found in the remainder of the on-site monitoring wells. Table 4-19 shows the metals found to contravene NYSDEC Class GA standards and guidelines in groundwater samples collected a part of this investigation as well as the recent USEPA site inspection. All inorganic constituents found to exceed standards were summarized and presented in Figure 4-24. Phenol was not included in this figure because it was found in uniform concentrations in all wells sampled (both upgradient, on-site and downgradient) and, therefore, does not aid in the characterization of the plume. Copper was detected slightly above standards in upgradient well GW-I but was not found elsewhere contravening standards. Similarly, zinc was detected at a concentration above NYSDEC standards in downgradient supply well GW-5 but at a low concentration throughout the remainder of the study area. The results of the USEPA sampling program indicate that there is no impact from the landfill due to metals in downgradient water supply wells. As previously discussed, the only metals found to exceed s ~20~o 4-73 Table 4-19 NETALS EXCEEDING STANDARDS/GUIDELINES IN GROUNgdATER PART 360 AND PHASE II INVESTIGATION AND USEPA SITE INSPECTION RESULTS (all results in rog/l) Iron ~agneslum~ Hanganese Sodium Copper Z(nc NewNonltorinoWells (0.3 ST) (35 GV) (0.3 ST) (20 ST) (0.2 ST) (0.3 ST) HW-1S (UT 1.35' 7.74 0.620* 41.6' ND 0.016 liV/-1D (UT 0.988* 9.22 0.243 16.3 0.012 0.036 MW-2S (D) 5.85* 22.0 4.0* 75.9* 0.021 0.017 Ft~-2D {0) 1.78' 63.2* g.89' 202* ND 0.017 HW-3S (D) 1.55' 32.8 21.7' 135' ND ND F~I-3D (D) 5.39* 57.8* 23.5* 155' ND 0.019 NV-4S (D) O.07g 1.g5 0.040 2.40 ND ND HV/-4D (D) 0.518' 60.3* 1.42' 167' ND ND H~-SS (D) 0.757* 2.16 O.110 8.12 ND ND NV-SD (D) 1.03' 28.7 0.627* 62.6* ND 0.049 HW-6S (D) 17.5' ll.1 1.59' 85.7* ND 0.020 Ft~-6O (O) 0.758* 3g.3' 13.4' 114.0' ND 0.014 F~/~TS (D) 2.24* 3.49 0.455* 16.6' ND ND 1~-7D (D) 19.2' 6.27 1.Og* 88.6* 0.022 0.067 Well Depths (ft) 52 152 27 85 55 125 73 150 77 136 56 145 50 125 USEPA Sample Locati~n~: GW-1 (UT 0.335* J 0.367* 27.1' 0.213' 0.024 90 GW-2 (UT 3.44* 9.57 3 21.7' 0.084 0.297 -- GW-3/GW-4 (S-68916) (D) 10.1'/9.72' 43.4*/42* 3.02'/2.9' 158'/153' 0.031/0.031 0.197/0.195 102 GW-5 (D) 0.246 12.4 3 12 0.156 0.405* -- GW-6 (O) 0.284 9.14 3 8.73 0.185 0.038 85 GW-7 (D) 1.55' 19.2 J 27.4* ND 0.214 lO1 GW-8 (D) J J ND 8.67 0.059 0.022 90 ST - Standard GV - Guidance Value O - Downgradlent U - Upgr&dient *Exceeds Standard/Guidance Value ND - Not Detected J - Below Detection Limit S14830 mm mm m mmmm imm mm mm CONSTITUENT CONCENTRA3]ON CONS~IUENT CO~CENTRA~ON I CONSTI~JENi I COflCEN~A~ON Zn -- 0.405 * ~ Zn ..... 0.038 ~ Zn ~ 0.022 C~LORIDE NA ~ ~L~C CHL~IBE NA CONSnmENT m CONCENmAnO)~ '[ gW 6 CHLORIDE ~X - ' O -7 ~_ ~-- ND ~ ~ ~ ' '~ ' -- CHLORIDE ~ 5 290; ~MW-4 Mq 22 63.2~ AMMONIA ND ND Ne ~5.~; 202. CHLORIDE '~ 115 ~~ J -~ _~ _ SHADOW DEEP CONC[m~TJO, COUS~EUT CW-~ ~W-4 ~ ~ Mq 0.064 ~.~{ ] ~ AMMONIA 38.3 * 26.1 j Mn 3.02 * 2.90 * ' gW--3,GW-4(S-6B916) NI~A~ 0.89 NP N~ 158 * 153 * MW-6 MW-3 Zn 0.020 0.014 J ~ .q 9.57 m ~ ~n J No - ~ ~ CHLORIDE HA NmmA~ ~ ' LEGEND ~ ~ DESIGNATION DESCRIP~ON ~o~T~ou ~ HYDROGEOLOGIC INVESTIGATION GROUNDWATER CONS~ENT ~ ~ S~68916 MONITORING WELL AND SAMPLING LOCATIONS Fe ~ ~* ~ USEPA GROUNDWATER SAMPLING LOCATIONS ~ ~ ~n ~;' ~ Fe IRON j ~~--JJ Zn 0.016 0.036 Mn MANGANESE ---~M~NIA ~ 0.17 0,09 No SODIUM ~E 24 Zn ZINC ~ AMMONIA AMMONIA NITRA~ NITRA~ CHLORIDE CHLORIDE ND NOT DETEC~D NA NOT ANALYZED d PRESENT BUT BELOW DE~C~ON LIMIT DIRECTORY: C:~1027 0 400 * PRESENT ABOVE STANDARDS/GUIDELINES DA~: SEPT lggl ~ SCALE: 1~1 SCALE IN FE~ ALL RESULTS IN ug~ TOWN OF SOUTHOLD SOUTHOLD ~NDFILL  Dvirka ~ and INORGANIC CONSTITUENTS EXCEEDING C~SS GA ~,[tiJy,~,~[~.~ GROUNDWATER STANDARDS/OUIDELINES IN OROUNDWATER Fi8URE 4-24 CONCENTRATION CONSIlTUENT Mn 0.040 1,42_ No 2.40 167 * Zn ND ~I_D_ _ AMMONIA ND 34~6 * NITRA1E 0.64 0.91_ CHLORIDE 5 290 * CONCENTRATION CONS~TUENT l SHALLOW DEEP AMMONIA _g_~ :_B_ * 88~0 * CHLORIDE 133 333 * I ! i I I I I I I I I I I I I I I NYSDEC Class GA standards, excluding zinc, were iron and sodium, which were found in supply well GW-7; however, these metals also exceeded standards in the upgradient wells. Therefore, it appears that the plume is fairly limited in areal extent and does not extend a significant distance downgradient of the landfill boundary. 4.5.4.3 - Leachate Parameter Sampling R¢sults Leachate parameters found to comravene NYSDEC Class GA groundwater standards include ammonia, chloride, nitrate and phenol. Sample results are shown in Table 4-18. Phenol was found to contravene standards in all of the monitoring wells sampled. Phenol was found in uniform concentrations ranging from 0.010 to 0.030 rog/l, as compared to the NYSDEC Class GA groundwater standard of 0.001 mg/l, but is well below the New York State Depax~ent of Health (NYSDOH) drinking water standard of 0.050 mg/l. Previous analytical data for phenols is quite limited but was found in slightly elevated concentrations in Suffolk County wells S-68916 (0.002 rog/l) and S-68831 (0.004 rog/l). Both these wells are located downgradient of the former scavenger waste lagoons. Since phenol was found in elevated concentrations both upgradiem and downgradient of the landfill, and in both the shallow and deep portions of the aquifer, it is likely that its presence is indicative of background conditions at the site. Ammonia was found exceeding the NYSDEC Class GA groundwater standard of 2 mg/1 at monitoring wells MW-2S and MW-2D (92.8 and 88.0 mg/l), MW-3S and MW-3D (38.3 and 26.1 mg/1) and MW4D (34.6 mg/1). Ammonia was undetected in shallow well MW4S. These elevated levels are most likely due to the leachate plume identified previously in the discussion concerning metals in groundwater. It is important to note that the concentration found in monitoring well MW-4D (located directly downgradient of MW-2D) is roughly half that found in monitoring well MW-2D. Again, this indicates an attenuation of the plume as it migrates off-site. Chloride, although not toxic, is a good leachate indicator since its presence corresponds closely with areas of elevated metal concentrations as well as areas of elevated ammonia. Chloride was found in concentrations contravening the NYSDEC Class GA groundwater standard of 250 mg/l at monitoring wells MW-2D (333 mg/l), MW-3S (293 mgtl), MW-3D (274 mg/l) and MW-4D (290 mg/1). Nitrate was found in contravention of the NYSDEC guideline of 10 mW1 in monitoring well MW-7D (11.9 mg/l). The concentrations in the remaining wells were generally low and ranged from undetected in wells MW-2D, MW-3D and MW-SS, to 1.69 mg/l in upgradient well MW-ID. s ~2060 4-76 i I I I I I I I I I I ! I I I I Groundwater samples collected during the USEPA site inspection were not analyzed for leachate parameters except for phenol. Phenol was not detected in any groundwater sample collected during the site inspection. However, previous analytical results obtained four downgradient private supply well Nos. 2, 3 and 4 (see Figure 4-3) show levels of ammonia, nitrate, chloride and phenol below NYSDEC Class GA standards. Nitrate was found above groundwater standards in upgradient wells S-69761 and S-76687, as well as upgradient private supply wells WS-4, WS-6, WS-7 and WS-9. Therefore, based on the results of this investigation, leachate has not caused an impact on downgradient water supply. s ~20~ 4-77 mm m mm mm m m, mm mm m mm ! I I ! I i I t ! ! I I ! ! I ! ! 5.0 CONCLUSIONS Based on the analytical results of the Part 360 and Phase ri Hydrogeotogic Investigation groundwater and subsurface soil sampling programs presented in Section 4.5 of this report, the following conclusions are presented. O O Groundwater - The only organic compounds found to exceed NYSDEC Class GA groundwater standards/guidelines were 1,2-dichloroethane and 1,2-dichloropropane at low levels. 1,2-Dichloropropane was found is previous investigations upgradient and downgradient of the landfill. 1,2-Dichluroethane was found only in deep wells MW-6D and S-68916 located just downgradient of the former scavenger waste lagoons. With regard to TAL inorganics, only iron, magnesium, manganese and sodium were found to exceed groundwater standards/guidelines. The distribution of these metals is well defined and appears to indicate a weak plume emanating from the landfill. It must be noted, however, that essentially all of these metals were present in upgradient wells in contravention of standards/guidelines, and downgradient water supply sampling results were indicative of background conditions. Iron and sodium were found to exceed standards in downgradient supply well GW-7 sampled during the USEPA site inspection. Zinc was also found to exceed standards in downgradient supply well GW-5 but was not found in any on-site water samples. Well GW-7 is located directly downgradient of well MW-4D where iron, magnesium, manganese and sodium were all found to exceed standards. The elevated levels of iron and sodium in well GW-7 may be attributable to the leachate plume emanating from the landfill, although the presence of elevated levels of these metals upgradient suggest ambient water quality. Leachate parameters which exceeded groundwater standards/guidelines included ammonia, nitrate and phenol. As with the metals, the distribution of these parameters del'me a limited plume from the landfdi. Nitrate was found to contravene standards only in downgradient well MW-7D, whereas phenol was found in all monitoring at relatively uniform concentrations indicating background conditions. Soil - Only one subsurface soil sample was collected as part of this investigation. The sample was colleted from well cluster MW-6 from a depth of 11-13 feet. Volatile compounds detected include 2-propanone, 1,2-dichlorobenzene and 1,3-dichloro- benzene although at levels considered insignificant for soil. No toxic metals were detected at levels posing a threat to groundwater. As a result of samples obtained during the Part 360/Phase II investigation, based on leachate indicators and a few metals, it appears that there is a weak, limited plume emanating from the Southold landfill. The plume is dense and appears to be migrating along the clay interface. Previous water quality sampling of off-site private wells indicate groundwater quality comparable to background (upgradient) conditions, although elevated levels of iron and sodium were found 5-1 Iff I I I I I I I I I i I I I I I I I above standards in downgradient well GW-7. It is uncertain whether the presence of these metals is due to the leachate plume or representative of background conditions since these metals were found in elevated concentrations in upgradient wells MW-IS and MW-ID. Contaminants found in soil samples obtained from the former scavenger waste lagoon as part of the USEPA site inspection show elevated levels of one semivolatile compound (chloroanaline) and a few metals. Although the elevated metals were found to contravene standards/guidelines in some on-site wells, none of the organics found in soil in the former lagoons were found in groundwater beneath the landfill site. Sl4710 5-2 6.0 RECOMM]~]~DATION$ The March 1991 USEPA site inspection report gave the Southold landfill site a recommendation of "Low Priority for Further Action." This recommendation was based on an analysis of the potential for contamination of domestic supply wells in the area, the potential for nearby residents to be exposed to hazardous substances through air releases (primarily methane) and the potential for direct contact with contaminated soil. The results of the Part 360 and Phase 12[ Hydrogeologic Investigation confirm the f'mdings of the USEPA site inspection report, as well as those of previous investigations. The findings of the Part 360/Phase 11 investigation indicate that a weak plume is emanating from the landfill, but is limited, in that the plume has not caused any observable impacts to downgradient water quality in any off-site water supply wells. It is felt that the 14 newly installed monitoring wells as part of this investigation provide an adequate and comprehensive groundwater monitoring network, eliminating the need for further drilling and sampling activities in the foreseeable future. Therefore, continued routine, long-term sampling of this monitoring network is recommended in order to provide sufficient data to fulfill the Part 360 landfill closure and expansion requirements. The long-term monitoring plan is designed to fulfill the Part 360 requirements for landfill closure. In developing this plan, all sampling data obtained from the Part 360 and Phase II investigation, as well as all previous investigations, was evaluated to determine the most reasonable and cost-effective approach to continued monitoring at the Southold Landfall. The Part 360 requirements call for all environmental monitoring points not previously sampled to be sampled and analyzed for two rounds of quarterly sampling. The first round of sampling was performed for baseline parameters. The second round of sampling will be performed for routine parameters. Although elevated levels of contaminants were detected just downgradient of the landfill calling for additional rounds of baseline sampling (as specified in Part 360), the existing data base is considered sufficient so that the second and subsequent rounds of sampling be performed for select routine parameters. Sampling frequency will be semiannually for the first year and annually thereafter. This second round of sampling is primarily designed to confirm the results of the f~rst (baseline) round of sampling. Sampling parameters for both and subsequent rounds are presented in Table 6-1. s~ac, ao 6-1 I I ! I 1 I 1 I i I I 1 I i Table 6-1 SOUTHOLD LANDFILL HYDROGEOLOGIC INVESTIGATION BASRI INE AND ROUTINE PARAM~I'~RS TO BE ANALYZED Parameters to be Analyzed(1) 1. Field Parameters First Round Closure of Existing Landfill (Baseline) - Completed* Second and Subsequent Rounds Closure of Existing Landfill (Routine ~ Static Water Levels X X Specific Conductance X X X X Temperature. -(2) Floaters or Sinke~ X pH X X Eh X X Field Observations(3) X X 2. Leachate Indicators Total Kjeldahl Nitrogen (TKN) X Ammonia X X Nitrate X X Chemical Oxygen Demand (COD) X Biochemical Oxygen Demand (BOD) X Total Organic Carbon (TOC) X Sulfate X Alkalinity X Phenols X Chloride X X Total Hardness (as CaCO3) X Turbidity X X Color X Boron X 3. Metals Potassium X Sodium X Iron X Manganese X Magnesium X Lead X Cadmium X Aluminum X Calcium X X X X X Toxic Metals I ! Antimony X Arsenic X Beryllium X Barium X Cadmium X Chromium (total) X s~r,4o 6-2 ,! Table 6-1 (continued) SOUTHOLD LANDFILL HYDROGEOLOGIC INVESTIGATION BASI~I.FNE AND ROUTINE PARAMETERS TO BE ANALYZED First Round Closure of Existing Landfill Parameters to be Analyze0(1) ~* Chromium - Hexavalent(4) Copper X Lead X Mercury X Nickel X Selenium X Silver X Thallium X Zinc X Second and Subsequent Rounds Closure of Existing Landfill CRoutine) Cyanide X 4. Volatile Organics(5) X X (1) All samples must be whole and unfdtered, except as otherwise specified by NYSDEC. (2) Any floaters or sinkers found must be analyzed separately for baseline parameters. (3) Any unusual conditions (colors, odors, surface sheens, etc.) noticed during well development, purging or sampling must be reported. (4) Since chromium has not been detected in previous sampling, hexavalent chromium was not analyzed for as part of this investigation. (5) Volatile organics are to be analyzed using EPA Methods 601/602. *Not all parameters in Part 373-2, Appendix 33 are analyzed under TCL+30. 6-3 All compounds/analytes detected hi groundwater during this investigation that were found at concentrations exceeding standards are included in Table 6-2. All compounds/analytes detected above standards in any previous sampling event that were either not found or in exceedance of standards during the baseline sampling are also included in Table 6-2. For the purposes of continued monitoring at the landfill, it is recommended that the NYSDEC Part 360 Routine Parameter list be modified to target specifically those compounds and analytes that are proven to be present as a result of landf'dl operations. The leachate indicator list was modified to include only ammonia, nitrate, chloride and turbidity. The metals list was modified to include only sodium, kon, manganese and magnesium since these were the only metals found to contravene NYSDEC Class GA groundwater standards and/or guidelines and NYSDOH drinking water standards. Volatile organic compounds will continue to be analyzed using Method 601/602 as per landfill closure investigation requirements. Since the number of compounds and analytes that are indicative of the leachate plume emanating from the Sonthold landfill is small and contaminant levels ave shown to approach background (upgradient) conditions in samples collected off-site and downgradient, it is recommended that the sampling frequency be modified from quarterly to semiannually for the first year and annually thereafter. Long Island landfill closure under Part 360 calls for continued monitoring for a 30-year period subsequent to closure, with the NYSDEC reviewing the sampling program every five years. A summary report showing all sampling results will be submitted to the NYSDEC annually. The results of this Part 360 and Phase II Hydrogeologic Investigation, as well as the findings of the most recent USEPA site inspection and previous sampling programs, indicate that, based on comparison to the NYSDEC Class GA groundwater standards/guidelines and the NYSDOH drinking water standards, the Sonthold landfffll is not a threat to human health or the environment and should be removed from the list of potential hazardous waste sites (Class 2a site) and be delisted entirely. S 14640 64 [I I I I i t I i I ti~ il I I I I I I Table 6-2 $OUTHOLD LANDFILL HYDROGEOLOGIC INVESTIGATION COMPOUNDS/ANALYTES DE'UEt:~'ED ABOVE NYSDEC CLASS GA STANDARDS/GUIDELINES AND/OR NYSDOH DRINKING WATER STANDARDS Volatiles 1,2 Dichloroethane (D) 1,2 Dichloropropane (U,D) Benzene* (U) Total Xylenes* (U) Chlorobenzene* (D) 1,1,1 Trichlorotrifluoroethane* (D)1 Tetrachloroethene* (U) 1,2,3 Trichloropropane* (U) Metals Iron (U,D) Magnesimn (U,D) Manganese (U,D) Sodium (U,D) Selenium* (U,D) Copper* (U,D) Zinc* (U,D) PesticidesYPCBs Toxaphene* (D) 1 Atdicarb* (U) Carbofuran* (U) PCB Arochlor-1260* (D)1 Ammonia (U,D) Nitrate (U) Phenol (U,D) Chloride (D) *Compounds/analytes found to exceed standards/guidelines only in previous rounds of sampling and mostly in off-site areas. U - Upgradient D - Downgradient 1Compounds found to contravene standards only during one sampling round. $146d~ 6-5