PUBLIC HEALTH ASSESSMENT
GARDEN CITY PARK INDUSTRIAL AREA (GCPIA)
(a/k/a FULTON AVENUE)
NORTH HEMPSTEAD, NASSAU COUNTY, NEW YORK
The 150 Fulton Avenue site is a light industrial property within the Garden City Park Industrial Area (GCPIA) of Garden City Park in the Town of North Hempstead, Nassau County, New York. Between approximately 1964 and 1976, several predecessors of Genesco Inc. manufactured fabrics and used a dry cleaning process on-site. Waste fluids and oils, including the drycleaning chemical tetrachloroethene (also known as perchloroethylene, perc, or PCE), were discharged into an on-site dry well. The PCE accumulated in sediments and soils in and around the subsurface dry well and subsequently contaminated groundwater beneath and downgradient of the facility. Some of the PCE may have degraded to trichloroethene (TCE), another groundwater contaminant detected in the study area. The TCE contamination appears to have originated at one or more other nearby industrial facilities.
The primary public health concern associated with the 150 Fulton Avenue property, the GCPIA, and the regional groundwater contamination is exposure to PCE and TCE from contaminated public water supply wells. Eighteen public supply wells in five water districts either near or generally downgradient from the GCPIA were contaminated with these volatile organic compounds (VOCs). In some cases, historic exposures occurred for unknown periods of time. The affected wells have either been removed from service (3), treated to remove these chemicals prior to public distribution (14), or have since cleared up (1). In all cases, a rigorous program of monitoring the water for VOCs has been implemented.
General investigations of the GCPIA began in 1985 when the Nassau County Department of Health (NC DOH) sought to determine the extent and source of VOC contamination affecting several public water supply wells downgradient of the GCPIA. The investigation was expanded in 1991 when test wells were installed beyond the GCPIA and at greater depths than previous test wells. In 1994, the New York State Department of Environmental Conservation (NYS DEC) began an investigation of possible VOC source areas within the GCPIA. NYS DEC's investigation continued through 1996 when a Focused Remedial Investigation (RI) was conducted at the 150 Fulton Avenue site. The site was nominated as the 150 Fulton Avenue site by the US Environmental Protection Agency (US EPA) for inclusion on the National Priorities List (NPL) in September 1997 and added in March 1998. Genesco Inc., the main tenant at 150 Fulton Avenue during the time when PCE was used, has signed a Consent Order with NYS DEC and has initiated a Remedial Investigation and Feasibility Study (RI/FS).
A focused RI at 150 Fulton Avenue discovered a PCE-laden dry well beneath the northeast corner of that property. Two interim remedial measures (IRM) were proposed for the property. The first IRM, presently nearing completion, involves removal of contaminated sediments from the dry well followed by soil vapor extraction and groundwater remediation with air sparging technology. The second IRM would have involved treatment of heavily-contaminated groundwater immediately southwest or downgradient of the site. Remedial alternatives for groundwater contamination associated with the 150 Fulton Avenue property will be developed in the RI/FS for that property.
Based upon ATSDR's public health hazard category classification (Appendix D), the Fulton Avenue/GCPIA sites posed a public health hazard in the past because actions were needed to interrupt or minimize exposure to TCE and PCE to persons who consumed contaminated drinking water. Exposures to TCE and PCE at levels in public water supplies could pose a low increased risk of cancer and a minimal risk of noncancer effects. Human exposure to these contaminants occurred via ingestion, inhalation, and dermal contact. Some of these exposures probably occurred for several years prior to 1977. Exposures to contaminants at concentrations exceeding the current drinking water standards occurred in some cases until about 1989, when the current drinking water standards became effective. Since that time, very few incidents of exposure in excess of drinking water standards have occurred. Studies of workers exposed to PCE and TCE suggest, but do not prove that these chemicals cause cancer in humans. Somewhat weaker evidence from other studies show that people living in communities with drinking water supplies contaminated with mixtures of chemicals including PCE and TCE have higher risks of certain types of cancers than people living in communities with uncontaminated water supplies.
The 150 Fulton Avenue site also presented a public health hazard because actions were needed to interrupt or minimize exposure to elevated concentrations of PCE in indoor air. Chronic exposure to PCE at the highest level detected in indoor air for a typical work week (eight hours per day, five days per week) over 30 years air would pose a low increased cancer risk and a minimal risk of non-cancer health effects. These exposures, which affected approximately 30 day-time employees at the facility, have been mitigated.
Subsurface contamination in the vicinity of a dry-well does not present direct exposure threats, but was very likely the source of continuing groundwater and soil vapor contamination. Groundwater in the vicinity of 150 Fulton Avenue and the GCPIA is extensively contaminated with PCE, TCE and, to a lesser extent, TCA. Groundwater contamination downgradient of the GCPIA, in areas of public supply wells, is extensively contaminated with TCE and, to a lesser extent, PCE. This groundwater contamination does not currently pose a public health hazard because of two institutional controls: VOC treatment systems at affected supply wells and routine monitoring of all wells for VOCs. These controls minimize the potential for exposure to VOCs through drinking water. Future investigation and remedial work is expected to alleviate the continuing threat of exposure by removal of contaminant sources and treatment of source area groundwater.
Exposure pathways other than contaminated water supplies and on-site indoor air are not considered to be significant.
The purpose of this health assessment is to provide an evaluation of past, present, and potential future exposures to contaminants, hazards and conditions related to the 150 Fulton Avenue site in the Garden City Park Industrial Area (GCPIA) and other potential groundwater contaminant sources in or near the GCPIA. This evaluation has been conducted by the New York State Department of Health (NYS DOH) under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). ATSDR is a federal agency within the U.S. Department of Health and Human Services and is authorized by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) as amended by the Superfund Amendments and Reauthorization Act (SARA) of 1986, to conduct public health assessments at hazardous waste sites proposed for the National Priorities List (NPL).
The GCPIA is in the western-central part of Nassau County on Long Island, New York (see Figure 1 in Appendix A). The GCPIA comprises several non-residential blocks north of the Long Island Railroad between Nassau Boulevard and Herricks Road. Approximately 48 companies have operated within the 65 acre GCPIA (beginning about 1950), several of which have periodically either illegally discharged waste onto or into the ground or have otherwise spilled or mismanaged hazardous chemicals. A significant plume (or plumes) of volatile organic compounds (VOCs) was identified in groundwater at and downgradient from the GCPIA. Several chlorinated solvents are in the plume(s), the primary ones being tetrachloroethene (also known as perchloroethylene, perc, or PCE) and trichloroethene (also known as trichloroethylene or TCE), along with lesser quantities of 1,1,1-trichloroethane (TCA). Groundwater in the GCPIA is at depths of approximately 45 to 55 feet below the ground surface and generally flows southwesterly. Eighteen public water supply wells (out of 20 in the area of study), in five different water districts and within a few miles of the GCPIA, primarily downgradient, have been affected by VOC contaminants, particularly TCE and PCE (see Figure 2 in Appendix A and Table 1 in Appendix B). Affected wells are either treated to meet drinking water standards or not used. Information about these wells is presented in Table 1 (Appendix B). A schematic of the GCPIA showing historic users of VOCs is included as Figure 3 (Appendix A).
The VOCs detected in groundwater in the area of study (PCE, TCE and TCA) are common solvents that have been used by many businesses over the past 40 years. This historic use has resulted in widespread contamination of groundwater with VOCs. The contamination varies with respect to nature, extent, and magnitude depending in large part upon the amount of solvent discharged, the location of such discharge(s), and the time period of the discharge(s).
A Preliminary Site Assessment (PSA) for the GCPIA was conducted for the New York State Department of Environmental Conservation (NYS DEC) in 1994 to locate the main source or sources of the VOC contamination. The assessment (see NYS DEC, 1994) identified the facility on the 150 Fulton Avenue property as a major contributor to the groundwater contaminant plume. An additional PSA was conducted to identify other potential source areas in the GCPIA. That assessment (NYS DEC, 1994a) identified the Precision Fabricators facility as a potential source of TCE contamination and possible contributor to TCA contamination in the groundwater. Precision Fabricators, at 200 Broadway, is approximately 400 feet northeast (and upgradient hydrogeologically) of 150 Fulton Avenue. That report also suggested that the Towne Sheet Metal facility, upgradient of Precision Fabricators, may be a contributor to TCA in the groundwater. There are four sites listed in NYS DEC's registry of inactive hazardous waste sites that are not in the GCPIA but are probable contributors to VOC contamination in the area of study. These include the Star Carting site, the Manfred Schulte site, Tres Bon Cleaners and, more recently, the Jackson Steel site. This latter site has also been listed on the US EPA National Priority List.
The 150 Fulton Avenue site is in the Town of North Hempstead, Nassau County, New York. It is approximately 0.8 acre in size and is bordered by Atlantic Avenue on the south, Fulton Avenue on the north and Thorens Avenue and a Long Island Lighting Company Transformer Station on the east. Most of the property is covered with a one-story masonry building (20,000 square foot) with slab on grade construction. The remaining portions of the property are paved and used as parking and loading areas. The building can be accessed from Atlantic, Fulton or Thorens Avenue. A sketch of the 150 Fulton Avenue site is included as Figure 4 (Appendix A).
The property owner (Gordon-Atlantic Corporation) leased the property to Genesco, Inc. between 1965 and 1976. From 1964-1969, the property was sublet to Knit-Fab Industries, a division of Flagg-Utica Corporation (which merged with Genesco in 1965). From 1969-1974, Halperin Knitting Mills occupied the building. From 1975-1976 Halknit Finishers, Inc. occupied the building. A Nassau County Department of Health (NC DOH) survey inspection was conducted at Halknit Finishers in 1975. The inspection indicated that the company was a cutting mill that received knit fabrics in a bulk form, cut the fabric, cleaned the material and sewed the fabric together. The waste products generated at the facility were described as office paper, plastic bags, cardboard tubes, and strips of material. Waste oils were also produced from a dry cleaning process that used PCE. The oils were reported to be picked up by a private firm.
In 1977, Robelan Displays, Inc. leased the property. NC DOH inspected the site again in 1978. Robelan Displays, Inc. reportedly manufactured displays at the facility, and utilized paints and lacquer thinners in their process. All paints and lacquers were reported to be used up in the process. The facility was inspected two more times, once in 1981 and again in 1986. No changes were noted since the initial inspection. There are no indications in the record that significant violations were found in any of these visits. In 1988, Cymann Designs, Inc. leased the property. Its operation was a furniture distribution warehouse and reportedly did not use any chemicals at the facility. Cymann Designs vacated the property in January 1996 and the building remained empty for approximately two years. In March, 1998 a new tenant, New York Business Systems, occupied the facility. The company sells photocopy and fax machines and uses 150 Fulton Avenue as a distribution center, a shop for limited repairs, and an office.
History of Investigations at the GCPIA
During the late 1970s, laboratory analytical capabilities had progressed such that detection and quantitation of volatile organic compounds (VOCs) in water samples became possible in the parts per billion range (ppb). In November 1976, NC DOH began to sample all public supply wells in Nassau County. At least one public supply well and several industrial wells were contaminated with VOCs at levels above the NYS DOH drinking water quality guideline concentration in effect at that time for public water supplies (50 micrograms per liter, equivalent to 50 ppb). Other wells were contaminated with lesser concentrations of VOCs. Continued water quality monitoring in the County revealed a number of contaminated wells near or hydrologically downgradient from the GCPIA.
In 1985 and 1986, the NC DOH conducted a groundwater contamination study entitled "Investigation of Contaminated Aquifer Segments, Nassau County, New York" for which a report was issued in June 1986 (NC DOH, 1986). One of the five areas investigated in the study was the GCPIA. Nine groundwater monitoring wells were installed and sampled (GCP1-GCP9). Additionally, information on groundwater quality was obtained from four existing groundwater monitoring and four public supply wells in the area and incorporated into the report. The nine wells constructed as part of the investigation were installed at or just below the groundwater table surface (i.e., between 40 and 65 feet deep). The public water supply wells sampled in that study are between 405 and 480 feet deep and the existing monitoring wells are between 76 and 96 feet deep. Groundwater samples collected from the wells were analyzed for VOCs.
Results of sample analyses indicated VOCs at concentrations exceeding the current New York State Drinking Water Standards (10 NYCRR Part 5) in 9 of the 13 groundwater monitoring wells sampled. The primary contaminant detected was PCE. The highest levels were in monitoring well GCP1 at 36,000 micrograms per liter (µg/L) in December 1985 and 50,000 µg/L in January 1986. The data indicated that a distinct PCE groundwater contaminant plume was originating in the GCPIA. The data also suggested the possible presence of a distinct TCE plume and a smaller 1,1,1-trichloroethane (TCA) plume, and the data indicated substantial fluctuation of contaminant concentrations (on the order of 10) in at least one monitoring well during a one year period. The investigation report concluded that the "extent of the contamination cannot be assessed based on available data. More consistent data over time, as well as additional wells are needed."
In 1991, the Nassau County Department of Public Works (NC DPW) and NC DOH conducted a cooperative study during which 12 additional monitoring wells were installed within and downgradient of the GCPIA. Seven wells were screened at the water table surface and five were screened approximately 100 feet below the water table. In addition, two wells (one shallow and one deep) were installed upgradient of the GCPIA to provide background information on groundwater quality. Two rounds of groundwater samples were collected from both the existing wells and the twelve new wells and analyzed for VOCs. Results of this investigation are in a report entitled "Garden City Park Groundwater Quality Study Preliminary Report" issued by the NC DOH and NC DPW in April 1993 (NC DOH/NC DPW, 1993).
Results of the investigation confirmed the presence of high levels of VOCs in the groundwater. Again the highest VOC concentration detected, 13,000 µg/L of PCE, was near the downgradient edge of the GCPIA at well GCP1. The results of this study also showed that some of the deeper downgradient wells contained greater concentrations of VOCs than the water table wells at the same location (or in the same well "cluster"). Consequently, the investigation report concluded that the plume is moving vertically downward as it migrates downgradient to the southwest. Additionally, wells installed with the intent of defining the downgradient limits of the plume also contained significantly elevated concentrations of VOCs. One deep well, approximately one half of a mile downgradient of the 150 Fulton Avenue site, contained the highest VOC concentration of all the deep monitoring wells with 744 µg/L of PCE. The report concluded that seventeen public supply wells are or may have been impacted by what appears to be the largest VOC contaminated groundwater plume in Nassau County. These supply wells are owned and operated by five water suppliers which serve a combined population of approximately 170,000, although up to 215,000 people may have historically used water from the affected wells. At the present time, the affected wells are either removed from service or treated to meet drinking water standards and guidelines. The status of these wells is summarized in Table 1 (Appendix B).
Another aspect of the 1993 investigation was an update of Nassau County's industrial survey for facilities in and near the GCPIA. As part of the County's inventory of hazardous materials and potential sources of groundwater contamination, industrial surveys have been conducted by the NC DOH since 1977. The historic and updated surveys indicated at least eight users of one or more of the contaminants of concern (including PCE, TCE, and TCA) in the GCPIA (see Figure 3 in Appendix A). The 1993 report recommended that additional investigation is needed to further determine not only the extent of the groundwater contaminant plume but also to identify the exact source(s) of the contaminants.
As a result of these investigations by NC DOH and NC DPW, the GCPIA was designated as a potential inactive hazardous waste disposal site under the New York State Superfund Program. Under this program, potential sites must be investigated to determine whether a consequential amount of hazardous wastes was disposed there and, if so, the property must be listed in the State's Registry of Inactive Hazardous Waste Disposal Sites. In September 1993, NYS DEC began a PSA for the GCPIA. A PSA is typically an initial investigation of a suspected hazardous waste disposal area to determine if a site meets the State's regulatory criteria for listing as an inactive hazardous waste site under the Superfund program. NYS DEC contracted with Dvirka and Bartilucci Consulting Engineers (D&B) to conduct field investigations for the PSA during the spring of 1994. Field work was completed by June 1994 and the results of the PSA were published in a Report dated September 1994 (NYS DEC, 1994).
Although there was no clear documentation of hazardous waste disposal in the study area, significantly elevated levels of PCE (up to 46,000 µg/L) were detected in groundwater near 150 Fulton Avenue. Elevated levels of TCE (up to 1,900 µg/L) and TCA (up to 260 µg/L) were also found in the area. Based on a comparison of upgradient and downgradient groundwater contamination levels and the reported history of dry cleaning at 150 Fulton Avenue, NYS DEC concluded that a consequential amount of hazardous waste had been disposed of at 150 Fulton Avenue. In August, 1994 the GCPIA site was reclassified from a P (Potential) status and listed in the Registry of Inactive Hazardous Waste Sites as the Fulton Avenue (Garden City Park Industrial) site (ID #130073) with a classification of 2. The address for the "site" was listed as 150 Fulton Avenue. The classification of 2 indicates that the hazardous wastes disposed at the site may pose a significant threat to public health or the environment and action is required. Furthermore, the NYS DEC Commissioner found that the site also presents an imminent danger of causing irreversible or irreparable damage to the environment, in that there is likelihood of further contamination of drinking water supplies as the plume migrates. The Commissioner authorized the immediate conduct of a focused remedial investigation (RI) for the 150 Fulton Avenue property and implementation of any appropriate interim remedial measures (IRMs). IRMs are relatively simple cleanup measures that may be implemented readily to prevent, mitigate, or remedy environmental damage.
The focused RI began in December 1994 and continued through 1996. A major focus of the investigation was the possible presence of a contaminated dry well, a sub-surface disposal pit. Historic records at the Town of North Hempstead Building Department indicated that at least one dry well for roof drainage existed, but there was no depiction of the dry well location and the drainage system described differs from that presently at the site. Following extensive subsurface investigation, a dry well was located on-site near the northeast corner of the property. PCE-laden sediments were also discovered in the dry well along with PCE-contaminated soils around the dry well. The results of this investigation were compiled and presented at a public meeting in June 1996. The final "Focused RI Report" was issued in November 1996 (NYS DEC, 1996b).
Concurrent with the focused RI for 150 Fulton Avenue, PSAs were implemented in February 1995 for four other potential (P) sites identified within the GCPIA. As previously noted, these assessments (NYS DEC, 1996a) suggested that hazardous waste disposal may have occurred at two other facilities in the GCPIA: Precision Fabricators (TCE and TCA) and Town Sheet Metal (TCA). The assessments also suggested that significant hazardous waste disposal probably did not occur at three other previously suspected facilities: Sprague-Goodman Electronics, Joseph Struhl, and Mercury Electric.
The 150 Fulton Avenue site was nominated for inclusion on the United States Environmental Protection Agency's (US EPA) National Priorities List (NPL) because of VOC contamination at 18 public supply wells near or generally downgradient from the significant VOC groundwater plume associated with the property. In September 1997, the US EPA formally proposed the site as a candidate for inclusion on the NPL. The site was listed on the NPL in March 1998.
A focused feasibility study, included in the 1996 focused RI Report for 150 Fulton Avenue, recommended two IRMs for the property. The first involved removal of contaminated dry well sediments followed by soil vapor extraction (SVE) and air sparging (AS) to remove the heaviest concentrations of PCE in the source area. The combined AS/SVE system involves enhancement of VOC volatility and removal of subsurface vapors using blowers, vacuum pumps, and air injection. The design document for the AS/SVE System (first IRM) was approved in July 1998. Field activities for this IRM began in August 1998. Genesco, Inc., the parent corporation of the tenants that used PCE at the site, has implemented the first (AS/SVE) IRM. The AS/SVE system was constructed in September and continues to operate at this time. The second IRM involved the treatment of heavily-contaminated groundwater immediately downgradient of the site using in-well air stripping technology. This technology combines forced air, vapor extraction, and groundwater circulation techniques. PCE volatility in the groundwater is enhanced by subsurface bubbling and extracted vapors are subsequently removed and treated at the ground surface. Project documents for the groundwater treatment system (second IRM) were submitted to NYS DEC. Because the concentrations of VOCs in groundwater have decreased downgradient of the 150 Fulton Avenue property, the second IRM is not being considered at the present time. Remediation of groundwater will be addressed as part of the Remedial Investigation Feasibility Study (RI/FS).
In October 1997 NYS DEC executed a Consent Order with Genesco, Inc. whereby Genesco will conduct a Remedial Investigation (RI) and Feasibility Study (FS) for the off-site affected areas. The purpose of this area wide RI is to determine the length, depth, and width of contamination, the degree of contamination, and migration pathways. Remedial alternatives will be developed during the FS process. The RI/FS Work Plan was reviewed by the US EPA, NYS DEC, NYS DOH, and NC DOH and was approved in October 1998. Substantial groundwater investigation have been completed under the RI work assignments.
Air samples were collected from indoor and outdoor locations at 150 Fulton Avenue in April 1995. No VOCs were detected; laboratory detection limits for PCE (perc) ranged from 190 to 260 micrograms per cubic meter (µg/m3). Because these detection limits were higher than NYS DOH's air guideline of 100 µg/m3 for PCE (NYS DOH, 1997b), indoor air was retested using a more sensitive method. On June 10 and 11, 1998, Mr. William Gilday of the NYS DOH visited 150 Fulton Avenue to collect passive air badge samples for PCE analysis. Air samples were collected from two indoor locations, one outdoor location, and one subsurface sump. PCE (perc) was detected in indoor air at 150 Fulton Avenue at concentrations of about 250 µg/m3 (see Table 2 in Appendix B).
Air samples were collected again in February 1999 after several months of soil vapor extraction and prior to air sparging. These results ranged from 9 - 11 µg/m3 , indicating substantial reduction in perc concentrations in indoor air at 150 Fulton Avenue. Samples were collected again in March 1999 after three weeks of air sparging. The results remained low, ranging from 11 - 14 µg/m3 , indicating that the reductions in perc concentrations achieved by SVE alone were not compromised by operation of the combined AS/SVE system.
In February 15, 1996, Mr. Tim Vickerson of the NYS DOH visited the site area and collected soil samples at Mineola High School. Public concerns had been expressed that contaminants related to the GCPIA might have impacted the school grounds. The High School is approximately one-quarter of a mile north of the 150 Fulton Avenue site. Analysis of the soil samples did not reveal any impacts from the 150 Fulton Avenue site or the GCPIA.
On March 13, 1998 Mr. William Gilday of the NYS DOH visited the GCPIA to conduct an on-site inspection at 150 Fulton Avenue and to survey the surrounding area. The block/brick structure at 150 Fulton Avenue is used as a distribution center for photocopy and telefax equipment. Parking areas surround the facility on two sides with a loading dock at the rear and a truck repair shop on the west. At that time, the contaminated dry well was covered with soil and was beneath an asphalt-paved parking area. The dry well has since been removed. No physical hazards were identified at the site.
The NYSDOH estimated from the 1990 Census that 166,696 people live within the five affected water districts. This includes the population living in the areas served by the Water Authority of Western Nassau, Garden City Park, Garden City Village, Franklin Square, and Mineola Village Water Districts. This population is 88.7% white, 5.3% Asian, and 4.8% Black. The percent of persons of Hispanic origin is 5.8%. About 6.7% of the population is under 6 years of age, 16.5% is 6-19 years of age, 59.6% is 20-64 years of age, and 17.2% is 65 years or older. In 1990 there were 36,426 females of reproductive age (ages 15-44) in the area. There are many schools and 363 nursing home residents in the area. The median household income is approximately $51,255, with 3.1% of the population living below the poverty level in the 36 census tracts that constitute the five water districts.
The 150 Fulton Avenue property is in a light industrial area, the GCPIA, within a very developed portion of western Nassau County. Residential neighborhoods of single family homes are immediately north of the GCPIA and also approximately 500 feet to the south beyond a corridor for the Long Island Railroad. Commercial areas lie to the immediate east and west of the GCPIA. A large groundwater recharge basin, used for the discharge of redirected runoff, lies to the southeast of the GCPIA beyond the rail corridor.
Natural Resource Use
The major natural resource of use associated with this site is the sole-source groundwater aquifer. Groundwater is used for potable water supplies throughout the affected areas. There are no streams or wetlands in the vicinity of the site. A few small parks and playgrounds exist in the study area approximately one-half of a mile or more from the GCPIA.
The NYS DOH maintains several health outcome databases which could be used to generate site-specific data, if warranted. These databases include the cancer registry, the congenital malformations registry, the heavy metals registry, the childhood lead reporting system, vital records (birth and death certificates) and hospital discharge information.
Exposure to contaminated drinking water is the primary concern of the community residents. Historic exposures to VOCs in drinking water have occurred. Some residents have suggested a possible correlation with the high incidence of breast cancer in Long Island.
Some residents and education officials have expressed concern about the proximity of the Mineola High School and playing fields to the GCPIA. Their concern is due to the potential for migration and/or deposition of GCPIA contaminants.
Community members have also expressed the desire that all sources of contamination affecting public supply wells be identified and remediated.