PUBLIC HEALTH ASSESSMENT
PASLEY SOLVENTS & CHEMICALS INC.
GARDEN CITY, NASSAU COUNTY, NEW YORK
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
A summary of the environmental contamination data collected during the RI for the Pasley site is presented in Appendix B, Tables 1-9. The listing of a contaminant does not necessarily mean that its presence is a public health concern. Contaminants selected for further evaluation are identified and evaluated in subsequent sections of the public health assessment to determine whether exposure to them has public health significance. When selected for further evaluation in one medium, that contaminant will be reported in all media where it is detected. These contaminants are selected and discussed based upon consideration of the following factors:
The most recent on-site environmental data for the Pasley site were collected by the environmental engineering firm, Metcalf & Eddy of New York, Inc., under contract with Commander Oil Corporation, and were presented in the final RI report. These data are used to describe the nature and extent of contamination at the site on a media-specific basis.
Air and Soil Gas
Ambient air has not been analyzed at the Pasley site. However, hand-held field instruments were used during the collection of environmental samples and installation of monitoring wells in accordance with health and safety protocol to monitor for organic vapors. Hydrocarbon odors were detected at the borehole openings during the installation of all seven on-site monitoring wells and were also detected in soil boring samples. The highest organic vapor analyzer reading was 280 parts per million (ppm) from a soil sample collected at a depth of about 17 feet in soil boring 2. The highest photoionization detector (HNu) reading was greater than 1,000 ppm at a depth of about 20 feet in the boring for the shallow on-site monitoring well 2S.
Soil gas was investigated in December 1988 by EA Engineering of Newburgh, New York, a former consultant to Commander Oil Corporation. Results of the on-site soil gas study are presented in Table 4. Seventy-eight vapor samples were taken at forty-four locations. Nine of the sampling location points were on-site.
Six volatile organic compounds (VOCs) were targeted for analyses during the survey. These target compounds were selected based on the consultant's evaluation of historical information on the types of products stored on-site and the VOCs previously found in soil and groundwater samples from the local area. The targeted VOCs are benzene, toluene, ethylbenzene, o-xylene, trichloroethene (TCE) and tetrachloroethene (PCE). The sampling depths ranged from 3 to 20.5 feet below grade. Multiple sampling locations were used to vertically profile vapor contaminant levels. On-site, the multiple sampling intervals generally were at 3, 8, 15.5 and 20.5 feet below grade. Five multiple sample locations were located on site.
The targeted VOC vapor analyses found TCE and PCE in the subsurface at several on-site locations. The highest on-site concentrations of TCE and PCE vapors were in samples from the western portion of the site. TCE and PCE were detected at all sampling depth intervals of the on-site sampling locations except at the three feet interval for a sample from the northeast corner of the site.
The targeted petroleum hydrocarbon VOCs (benzene, toluene, ethylbenzene, o-xylene) were found at two on-site locations at the western to southwestern portion of the Pasley site. Benzene was not detected at any on-site sampling location. Toluene was present at four distinct depths with the highest concentration at a depth of 20.5 feet. Ethylbenzene/o-xylene were detected at only one on-site sampling location at a depth of 20.5 feet.
Soil (Surface)
Surface soil samples were not collected during the RI.
Soil (Subsurface)
Fifty soil samples were collected on the Pasley site at a depth between 6 to 12 inches and analyzed for VOCs, semi-volatile organic compounds, and metals (see Figure 3 for locations). Background surface samples were not obtained during the RI. The laboratory analyses found elevated levels of VOCs, primarily solvents and petroleum hydrocarbon compounds (see Tables 5 and 6). Twelve VOCs exceeded public health assessment comparison values and have been selected for further evaluation.
Ten composite soil samples (6-12 inch depth) were analyzed for semi-volatile organic compounds and metals. An additional composite sample was collected for duplicate analysis. Composite samples 1 and 4, collected on the western edge of the site, contained total semi-volatile compounds at levels of 56 and 88 milligrams per kilogram (mg/kg), respectively. Composite samples 8 and 9, collected on the eastern edge of the site, contained semi-volatile concentrations of 204 mg/kg and 127 mg/kg, respectively. The remaining composite samples, collected in the center of the site, contained total semi-volatile compounds in the concentration range from 2 to 16 mg/kg. The predominant semi-volatile compounds were polycyclic aromatic hydrocarbons (PAHs). Naphthalene and benzo(a)pyrene exceed the public health assessment comparison value and therefore will be further evaluated.
Antimony, lead, and magnesium were detected at levels which exceed comparison values and as such have been selected for further evaluation.
Eight on-site subsurface soil borings were drilled and sampled at depths of 12 to 14 feet and 22 to 24 feet (see Figure 4). Sixteen soil boring samples were analyzed for VOCs, semi-volatile organic compounds and metals (see Table 6). Two additional samples were collected for duplicate analysis. Organic compounds which exceed comparison values are methylene chloride, trichloroethene, tetrachloroethene, 1,2-dichloroethane, naphthalene, and bis(2-ethylhexyl)phthalate. These compounds will be further evaluated. Metals were detected at levels below public health assessment comparison values.
Groundwater (Monitoring Wells)
Each of the six well clusters installed for the RI consist of 3 monitoring wells. Each well cluster has one well screened at 30 feet (shallow wells) and one well screened at 60 feet (intermediate wells) in the shallow (Glacial) aquifer. Each well cluster also has one well screened at 90 feet (deep wells) in the deeper (Upper Magothy) aquifer (see Figure 5). One well cluster (2S, 2I, 2D) is installed on-site. Groundwater was sampled twice. In February 1990, the first round of samples were collected from each of the eighteen wells and analyzed for VOCs, semi-volatile compounds, and metals. In April 1990, nine wells were sampled (three well clusters) and analyzed for VOCs and semi-volatile compounds. The well data and comparison values are presented in Table 7.
The on-site groundwater contained thirteen VOCs (primarily solvents and petroleum hydrocarbon compounds) and two semi-volatile compounds at concentrations exceeding comparison values. These contaminants are acetone, 1,1-dichloroethene, 1,1-dichloroethane, trans-1,2-dichloroethene, ethylbenzene, tetrachloroethene, toluene, trichloroethene, benzene, 1,1,1-trichloroethane, chlorobenzene, xylenes (total), methylene chloride, 2-methylnaphthalene, and naphthalene. These compounds have been selected for further evaluation in this public health assessment. The majority of VOCs and semi-volatile compound concentrations were highest in the sample from the shallow, on-site monitoring well. Trans-1,2-dichloroethene at 37,000 micrograms per liter (mcg/L) had the highest overall concentration in this same well.
Cobalt, iron, lead, manganese, and sodium were detected in groundwater samples from the on-site monitoring wells at concentrations above the respective comparison values. These inorganic compounds will be further evaluated in the Public Health Implications section. Groundwater samples collected for metals analysis were not filtered.
Air and Soil Gas
Off-site ambient air analyses were not performed during the RI. However, 35 off-site locations were sampled during a soil gas study conducted in December 1988 (results in Table 8). With the exception of two sampling locations, all off-site sampling points were located in the area south of Commercial Avenue, north of Locust Street, west of Oak Street, and east of Boylston Street. The two remaining sampling locations were located just to the north of the site and south of the Long Island Railroad tracks. The study was conducted on a 50 to 100 feet grid spacing. The soil gas samples were collected along four east to west transects: Commercial Avenue; Custer Park-Abandoned Railway; Brook Street-Brook Street extension; and Chestnut Street-Chestnut Street extension. These transects were intended to be perpendicular to groundwater flow which is to the southwest. Six volatile organic compounds were targeted for analyses; benzene, toluene, ethylbenzene, o-xylene, TCE and PCE. The sampling depths ranged from 3 to 20.5 feet below grade. Single sample locations generally were conducted at 10.5 feet. Multiple sampling intervals were used and were typically at 10.5, 15.5 and 20.5 feet below grade. Eleven multiple sampling locations were off-site, 10 of which were located downgradient from the site.
The VOC vapor analyses showed TCE and PCE in the subsurface at several off-site locations. TCE and PCE were detected in a narrow plume area which extended in a south-southwest direction from the western half of the site toward Brook Street in the eastern end of Custer Park. Beyond this area, TCE and PCE were not detected above 1 ppm. The four targeted petroleum hydrocarbon VOCs were not detected at any off-site sample location.
In August 1993, the NYS DOH and the NYS DEC investigated the possibility that contaminants in soil gas may have had an impact on the indoor air of two schools in the Garden City School District. The two schools evaluated were the Stewart Avenue and Locust Street Elementary, being in the general direction of groundwater flow from the Pasley Solvents and Chemicals site and other inactive hazardous waste sites including the Roosevelt Field site. A third school, the Little Village school, was selected for comparison purposes because there is no known groundwater contamination in that area.
Five, four, and two soil gas samples were collected at a depth of ten feet at the Stewart Avenue, Locust Street, and Little Village schools respectively, and were tested for chlorinated volatile organic compounds and petroleum compounds. The soil gas samples were collected using a pneumatically driven Geoprobe and analyzed by a mobile laboratory situated outside the Stewart Avenue school. No compounds were found in these samples. On August 25, 1993, an ambient air sample was collected outside the Locust Street school and tested for the same organic compounds, none of which were detected.
Surface Water and Sediments
A surface water sample was collected from one location within a storm water/recharge basin located about six city blocks south (downgradient) of the site. A sediment sample was also collected directly below the surface water sampling location. The grab sample was collected using a hand auger and stainless steel scoop. Samples were analyzed for VOCs, semi-volatile organic compounds, metals, and cyanide. Tests of the recharge basin may not be indicative of contamination from the Pasley site since the basin serves a large drainage area including runoffs from streets.
Acetone was in both the surface water and the sediment sample at 42 mcg/L and 0.02 mg/kg, respectively. Chlorobenzene and 1,1,1-trichloroethane were also detected in the sediment sample at 0.005 mg/kg and 0.007 mg/kg, respectively. These VOCs did not exceed respective comparison values.
Fourteen semi-volatile compounds were found in the sediment sample at levels below comparison values; the concentrations ranging from 0.09 mg/kg to 2 mg/kg. No semi-volatile compounds were detected in the surface water sample.
Low concentrations of most inorganic compounds were found in the surface water sample, except iron and manganese, which were detected at 1,010 mcg/L and 426 mcg/L, respectively. Metals in the sediment sample were at concentrations near or below the typical background level.
Soil (Surface)
Surface soil samples were not collected at off-site locations.
Soil (Subsurface)
Soil boring samples were collected from five off-site locations (see Figure 5). Two samples were collected from each of the five boring locations at depths between 5 to 11 feet. With the exception of methylene chloride at low concentration, no other VOCs were detected in any off-site borings (see Table 9). However, data for several VOCs were determined to be unreliable and were not reported. Three semi-volatile compounds were detected in several borings ranging from 0.07 mg/kg to 0.7 mg/kg. These organic compounds did not exceed comparison values for soil.
With the exception of copper, the levels of metals in the subsurface off-site soils were within the typical background range.
Groundwater (Monitoring Wells)
A total of five monitoring well clusters were installed off-site during the remedial investigation (see Figure 5). The off-site groundwater sampling results showed nine VOCs and two semi-volatile compounds which exceeded comparison values (see Table 10). These organic chemicals will be discussed further in subsequent sections of this public health assessment.
Eight metals were detected in off-site monitoring wells at concentrations above comparison values. These inorganic chemicals will be discussed further in subsequent sections of this public health assessment. Groundwater samples collected for metals analysis were not filtered.
Groundwater (Geoprobe Wells)
In August 1993, the NYS DOH and the NYS DEC investigated the possibility that contaminants in groundwater may have had an impact on the indoor air of two schools in the Garden City School District. The two schools, Stewart Avenue and Locust Street Elementary, are in areas where, potentially, indoor air may be impacted by groundwater contamination from the Pasley Solvents and Chemicals site and other inactive hazardous waste sites. A third school, the Little Village School, was selected for comparison purposes because no groundwater contamination has been found near this school.
Shallow (24.5 to 47 feet deep) and deep (62 feet deep) groundwater samples were collected outside each school and tested for chlorinated volatile organic compounds and petroleum compounds. The groundwater samples were collected using a pneumatically driven Geoprobe and analyzed by a mobile laboratory situated outside the Stewart Avenue Elementary School. No chlorinated volatile organic compounds or petroleum related compounds were found in the shallow groundwater samples. One deep groundwater sample was taken at each school. No chemicals were found in either sample taken at the Stewart Avenue or the Little Village School. The sample taken at the Locust Street School contained several chlorinated volatile organic compounds, namely, 1,1,1-trichloroethane, trichloroethene, tetrachloroethene, at 11 mcg/L, 4.1 mcg/L and 1.7 mcg/L, respectively.
Groundwater (Private Supply Wells)
According to the Nassau County Department of Public Works, private groundwater wells are not used as drinking water supplies by homes and businesses in the area surrounding the site. However, private, industrial (non-potable) wells are used primarily to supply non-contact cooling water and were not sampled during the RI.
Groundwater (Public Supply Wells)
Potable water in the area surrounding the Pasley site is supplied through public water supplies derived entirely from groundwater wells (see Table 3). The RI did not include provisions for sampling public supply wells. However, information was obtained from the NC DOH (Bureau of Public Water Supply) for downgradient wells less than about one mile from the Pasley site. The closest downgradient public supply wells (well #8474 and #8475) are about 1,600 feet southeast of the Pasley site. To date, monitoring has not detected any VOC contamination in well #8475. Since March 1992, trichloroethene has consistently been detected in well #8474 at concentrations ranging between 0.5 to 2 mcg/L. The Village of Hempstead's Clinton Street wellfield is about 3,800 feet southwest of the Pasley site and consists of seven production wells identified by the NC DOH as wells #79, 80, 81, 82, 83, 4425 and 7298. To date, VOC contamination has not been detected in wells #80 and #82.
Tetrachloroethene (up to 86 mcg/L) and trichloroethene (up to 36 mcg/L) were measured in municipal well #4425 from November 1977-December 1988. The well was taken out of service in September 1988 and was not returned to service until October 1990 following the installation of an air stripper treatment system for removal of VOCs. Wellhead samples taken from November 1977 to December 1989 on well #83 contained tetrachloroethene (up to 15 mcg/L) and trichloroethene (up to 145 mcg/L). Between 1978 and 1989, well #83 was removed from service three times due to the presence of trichloroethene above the NYS DOH guideline of 50 mcg/L in effect at the time for this compound in public drinking water supplies. Well #83 was last removed from service in January 1989. Eight samples from well #7298 taken since 1977 have detected low levels (up to 2 mcg/L) of trichloroethene. Low levels (up to 2 mcg/L) of tetrachloroethene have also been detected in samples collected between 1989 to date. Tetrachloroethene was not detected in samples collected from this well prior to 1989. This well is currently active and not treated. Well #79 is currently active with no treatment. No VOCs were detected in well #79 prior to 1989. From 1989 to date, tetrachloroethene and trichloroethene have been detected in this well at concentrations up to 5.3 mcg/L and 1.5 mcg/L, respectively.
On September 9, 1993, dichlorodifluoromethane (freon-12) was detected in well #81 at 3.6 mcg/L. A resample taken on September 15, 1993 also had dichlorodifluoromethane at 2.0 mcg/L. However, this compound was not detected when the well was retested on September 23, 1993.
C. Quality Assurance and Quality Control (QA/QC)
In preparing this public health assessment, NYS DOH relied on the information provided in the referenced documents and assumed that adequate quality control measures were followed with regard to chain of custody, laboratory procedures, and data reporting. The analyses and conclusions in this public health assessment are valid only if the referenced information is correct.
No RI data were reported for the VOC, 2-butanone, as they were regarded to be unreliable. As a result, the data were not complete for many soil samples, groundwater samples, and the surface water/sediment samples. In addition, data were not reported for a significant number of off-site subsurface soil samples analyzed for VOCs due to the same reason.
First round groundwater analyses found acetone (up to 3,800 mcg/L) in samples obtained from on-site and off-site monitoring wells. These data are suspect because this compound (up to 2,300 mcg/L) was in the majority of the first round equipment blanks which suggests the possibility of laboratory contamination. Therefore, the acetone in the groundwater samples may not be indicative of actual environmental contamination.
There are no known physical or other hazards present at the Pasley site.
E. Toxic Chemical Release Inventory (TRI)
A search of the 1989 TRI facilities list was conducted to identify
those industries located near the Pasley Solvents and Chemicals
site (within 2.5 miles) which could contribute to groundwater,
soil, or air contamination and/or create health threats unrelated
to the site. TRI is developed by the US EPA from the chemical
release (air, water, and soil) information provided by certain
industries. Using a screening method developed by the NYS DOH, two
TRI facilities were identified as reporting 1989 air emissions.
These facilities are "Johnson & Hoffman", and "Continental
Extrusion Corporation". These facilities are located north and
northeast of the site (Figure 6). These facilities did not report
emissions to water or soil. Johnson & Hoffman reported the
following releases to the environment via fugitive or non-point air
emissions: trichloroethene - 15,000 pounds per year;
tetrachloroethene - 6,500 pounds per year. The Continental
Extrusion facility reported annual emissions (fugitive or non-point) of 1,1,1-trichloroethane at 30,000 pounds and 121,000 pounds stack or point air emissions. Based on TRI data and air emissions
modeling, results of the screening evaluation indicate that the
contribution of these two industrial facilities to health risks in
the community around the Pasley Solvent and Chemicals site is
minimal. Trichloroethene, tetrachloroethene, and 1,1,1-trichloroethane are, however, recognized as contaminants of concern
at the Pasley Solvent and Chemicals, Inc. site and are evaluated
further in this public health assessment.
To determine whether nearby residents and persons on-site are exposed to contaminants migrating from the site, an evaluation was made of the environmental and human components that lead to human exposure. The pathways analysis consists of five elements: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population.
An exposure pathway is categorized as a completed or potential exposure pathway if the exposure pathway cannot be eliminated. A completed exposure pathway occurs when the five elements of an exposure pathway link the contaminant source to a receptor population. Should a completed exposure pathway exist in the past, present, or future, the population is considered exposed. A potential exposure pathway exists when one or more of the five elements are missing, or if modeling is performed to replace real sampling data. Potential pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now, or could occur in the future. An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present. The discussion that follows incorporates only those pathways that are important and relevant to the site.
A. Completed Exposure Pathways
Groundwater Exposure Pathway
Groundwater is contained in two water producing aquifers at the site. The two aquifers are hydraulically connected. The shallow aquifer, which is referred to as the Upper Glacial aquifer, extends from the surface to a depth of about 50 to 65 feet and consists of sands and gravel. The saturated thickness of this aquifer at the site is about 30 to 45 feet. Groundwater appears to flow southwest in this aquifer. Groundwater contamination in this aquifer has been detected on-site, primarily from the 30 foot shallow monitoring well.
The aquifer system underlying all of Long Island has been designated as a sole source aquifer since no other source of drinking water is available. There are four major water producing aquifer formations on Long Island. The two water producing aquifers underlying the site are the ones used most as sources for potable water.
A number of public drinking water supply wells are within one mile downgradient from the site. The Magothy aquifer is the source of groundwater for all of these active and/or inactive supply wells. In the past, VOC contaminants have been detected in several of these wells, and in some instances, concentrations have exceeded comparison values. The Village of Hempstead Clinton Street Wellfield is located less than one mile southwest from the site. To date, VOC contamination has been detected in five wells at this wellfield; two with levels above comparison values are being treated. For an undetermined period of time (more than 12 years), residents in the Village of Hempstead may have been exposed to low levels of volatile organic contaminants in drinking water distributed from the Clinton Street Wellfield. According to information included in US EPA's Draft Baseline Risk Assessment for the Pasley site, the Clinton Street Wellfield is not within the boundary of the contamination plume from the Pasley site. The risk assessment also states that during transport, the chemical plume is expected to sink from the Upper Glacial to the Upper Magothy aquifer, which is flowing in a more southerly direction thus chemical migration to the wellfield is not expected. Although this past completed exposure pathway is not considered to be site related, it will be discussed further in the Public Health Implications section.
VOC contaminants have also been detected in three other active wells located in the same wellfield. However, to date the levels of VOCs have not exceeded NYS DOH drinking water standards. VOC contamination has not been detected in the two remaining active supply wells located in this wellfield. The Village of Hempstead wells are not used individually but they all enter a common reservoir which then feeds the distribution systems. This arrangement naturally provides some aeration which will remove portions of the VOCs and blending with other wells which will reduce any VOC levels. Blending is not allowed as a method to reduce such contamination and any wells exceeding drinking water standards individually are either removed from service or treated.
The VOC contaminants found in the aforementioned wells are prevalent throughout the groundwater in Nassau County. As such, it is only supposition to attribute the contamination to any specific site. The RI suggests that other nearby sites may have contributed to the area's groundwater contamination. One of the sites is Roosevelt Field, a former airfield which is now occupied by a large shopping mall. The Roosevelt Field contamination includes many of the same contaminants detected in the Pasley site monitoring wells including the upgradient well cluster. In 1984, when groundwater data was collected in the area by the US Geological Survey, a contaminant plume in the upper glacial aquifer extended in excess of a mile south-southwest of the Roosevelt Field site.
The Purex/Mitchell Field Transit facility is the second major groundwater contamination source in the area, and is located about 300 yards east of the Pasley site. VOC plumes attributed to the site were found in the Upper Glacial, the Upper Magothy, and the Lower Magothy aquifers. These investigations indicate that groundwater contamination has migrated from the Purex site into the Pasley RI study area. On-going remediation work at the Purex site includes the operation of a groundwater extraction and treatment plant for removal of VOCs.
Exposure to contaminants in drinking water supplies occur via ingestion; dermal contact and absorption during showering, bathing, or other household uses; and inhalation of aerosols and vapors from water used in the household. If site-related contaminants migrate to the active, downgradient public drinking water supply wells, the routine monitoring that is mandated by New York State will detect contamination. If contamination is detected, controls will be implemented to minimize human exposures from occurring via this potential exposure pathway.
B. Potential Exposure Pathways
Air and Soil Gas Exposure Pathway
All soils contain voids between solid particles which are either filled with liquids (usually water) or gases. The gas that fills these voids is known as soil gas. Near the surface the soil gas will be similar in makeup to surface ambient air including associated pollutants. Volatile organic contaminants in on-site and off-site groundwater will tend to partition into the soil gas phase. Volatile components in the vapor phase will tend to migrate either vertically or horizontally depending on localized soil conditions and confining layers. Elevated levels of VOCs in the soils and shallow groundwater may contaminate ambient air on-site and/or off-site depending upon the migration potential of the soil gas.
Ambient air was not sampled during the RI. However, an ambient air sample was collected in August 1993 outside the Locust Street Elementary School and did not indicate any VOC contamination.
Hydrocarbon odors and high readings were recorded on portable air monitoring instruments places at the borehole during installation of the on-site monitoring wells. Elevated concentrations of TCE and PCE have been detected in the subsurface at several on-site locations and depths, primarily at the western portion of the site. These contaminants have also been detected in the subsurface at several off-site locations in a narrow plume area which extends south-southwest from the western half of the site. The groundwater plume appears to extend under occupied commercial/industrial buildings located near the site. Thus, the site contaminants could migrate off-site through porous media as soil gas and enter confined spaces of buildings (basement) through crawl spaces, plumbing holes, other floor holes (e.g., sumps) and foundation cracks, and contaminate indoor air of rooms.
At this time, the air and soil gas exposure pathway is categorized as a potential human exposure pathway since limited ambient air data exists and recent soil gas data exists only for the three off-site schools. Contaminants released to ambient air (breathing zone) will likely be dispersed and diluted to levels below detection limits at unconfined on-site and off-site areas. However, the possibility exists for intrusion of soil gas into basements of nearby buildings. Persons living or working in these confined areas may potentially be exposed to elevated levels of soil gas contaminants. Soil gas samples recently collected at three Garden City schools were tested for chlorinated VOCs and petroleum compounds. No compounds were found in the samples. If soil gas is not contaminated, it cannot serve as a source for affecting indoor air quality in the school buildings.
C. Eliminated Exposure Pathways
Soil Exposure Pathways
Contaminants related to the past storage and distribution of chemicals at the site are present and are migrating through soils and into the groundwater beneath the site. The surface and subsurface soil serve as a continuing source of contamination to the groundwater.
Because of the highly permeable soil materials (course sands and gravel) which exist beneath the site, many of the contaminants at the site will readily move through the soil. The majority of the site is covered with gravel which allows rainwater to percolate through the underlying soils and leach contaminants into the groundwater.
On-site exposure to contaminated surface soils by trespassers is not expected since site access is controlled by a chain link fence topped with barbed wire and soils are beneath a gravel cover. Exposure to contaminated surface soil via wind transport of soil dust is not likely due to the gravel cover material at the site.
Exposure to contaminated subsurface soils will not occur unless subsequent on-site excavation of soils is conducted. Future excavation of on-site soils could expose workers and nearby residents to contaminants via several routes including ingestion, inhalation and skin contact. Use of appropriate dust suppression methods, proper procedures, and air monitoring during clean-up would minimize any low level increased risk to nearby workers and residents.
The transport of contaminated soils to off-site areas via surface water runoff is a remote possibility. Extensive surface runoff from the site is not expected based on the predominantly flat topography of the site and general lack of paved areas combined with the permeable on-site soils. These conditions would allow rainwater to infiltrate freely with limited restrictions or diversions that typically cause surface runoff. Any surface water runoff from the site is directly routed into storm catch basins along Commercial Avenue. The runoff is eventually transported to a fenced recharge basin located about 2,200 feet southeast of the site. This recharge basin is a pit that has been excavated into the shallow aquifer deposits for infiltration. Water within the basin infiltrates rapidly into the ground.
Based on past and current on-site conditions and controls, the soil exposure pathway may be eliminated from further discussion. Although soil contamination exists at the site, the possibility of human contact with site related soil contaminants is remote given existing land use.
Surface Water/Sediment Exposure Pathway
This human exposure pathway has been eliminated from further
discussion in this public health assessment since there are no
surface waters adjacent to the site. Access to the nearby storm
water recharge basin, which reportedly receives surface water
runoff from the Pasley site, is controlled via a chainlink fence.
Historical monitoring of public water supply wells by the Nassau County DOH indicates that for an undetermined period of time (more than 12 years), residents in the Village of Hempstead may have been exposed to low levels of volatile organic contaminants (VOCs) in drinking water. The Pasley site does not appear to be the source of this contamination. New York State drinking water standards (effective in 1990) for tetrachloroethene and trichloroethene are 5 mcg/L. Chronic exposure to chemicals in drinking water are possible by ingestion, dermal and inhalation exposures from water uses such as showering, bathing and cooking. Although exposures vary depending on individual life-styles, each of these exposure routes contributes to the overall intake and thus increases the potential for chronic health effects.
Tetrachloroethene and trichloroethene cause cancer in laboratory animals exposed to high levels over their lifetimes (ATSDR, 1989i, 1990e). Chemicals that cause cancer in laboratory animals may also increase the risk of cancer in humans who are exposed to lower levels over long periods of time. Whether or not tetrachloroethene and trichloroethene cause cancer in humans is not known. Based on the results of animal studies and the sampling results for municipal well water, we estimate the persons previously exposed to contaminated public drinking water may have a low increased risk of developing cancer over a lifetime of exposure. Given distribution practices (mixing of water supply wells), current exposure to low levels of tetrachloroethene would be associated with a very low increased cancer risk over a lifetime of exposure.
Tetrachloroethene and trichloroethene also produce a variety of noncarcinogenic toxicities (primarily nervous system, liver and kidney effects) at exposures many orders of magnitude greater than current or past exposure from municipal drinking water. Chemicals that cause effects in humans and/or animals after high levels of exposure may also pose a risk to humans who are exposed to lower levels over long periods of time. Although the risks of noncarcinogenic health effects from past or current exposures aren't completely understood, the existing data suggest that they are minimal.
On-site and off-site groundwater is contaminated with volatile and semi-volatile organic compounds and metals at concentrations which exceed comparison values (see Table 10). Although the Pasley site contaminant plume is not expected to migrate in the direction of the nearby wellfield, the possibility of potential impacts on municipal drinking water in the future cannot be completely discounted.
Volatile Organic Compounds
Benzene is a known human carcinogen (ATSDR, 1989a). Chlorobenzene, 1,1-dichloroethane, 1,1-dichloroethene, methylene chloride, tetrachloroethene, and trichloroethene cause cancer in laboratory animals exposed to high levels over their lifetimes (ATSDR, 1989b,e,g,i; 1990 a,e). Whether or not they cause cancer in humans is not known. Chemicals that cause cancer in laboratory animals may also increase the risk of cancer in humans who are exposed at lower levels over long periods. Exposure to these organic contaminants in drinking water at the levels found in on-site and/or off-site groundwater could pose a high increased cancer risk. Toxicological data are inadequate to assess the carcinogenic potential of trans-1,2-dichloroethene, ethylbenzene, toluene, 1,1,1-trichloroethane, xylenes and acetone (ATSDR, 1989f,h, 1990b,f,g; US EPA, 1991).
These volatile organic compounds are also known to produce a variety of noncarcinogenic toxicities (primarily liver, kidney, nervous system, and cardiovascular effects, and in the case of benzene, damage to blood-cell forming tissue and immune system) at exposure generally several orders of magnitude greater than potential exposures from on/or off-site groundwater. Chemicals that cause effects in humans and/or animals after high levels of exposure may also pose a risk to humans who are exposed to lower levels over long periods of time. Although the risks of noncarcinogenic health effects from potential exposure to VOC's in drinking water at levels found in on-site and off-site groundwater aren't completely understood, the existing data suggest that they could be high for benzene and trans-1,2-dichloroethene and low for acetone, chlorobenzene, 1,1,1-trichloroethane and trichloroethene.
Semi-Volatile Organic Compounds
Bis(2-ethylhexyl)phthalate causes cancer in laboratory animals exposed to high levels over their lifetimes (ATSDR, 1991b). Exposure to this organic contaminant in drinking water at the level found in off-site groundwater could pose a low increased cancer risk. Toxicological data are inadequate to assess the carcinogenic potential of 2-methylnaphthalene and naphthalene (ATSDR, 1990d). Bis(2-ethylhexyl)phthalate can also adversely affect the male reproductive system, whereas 2-methyl-naphthalene and naphthalene can cause hemolytic anemia and liver damage. These compounds produce their noncarcinogenic effects at exposure levels many orders of magnitude greater than potential exposures from groundwater. Existing data suggest that the risks of noncarcinogenic health effects from exposure to these three chemicals in drinking water at levels found in on-site or off-site groundwater would be minimal.
Metals
Metal contaminants of potential concern in on-site and/or off-site groundwater include lead, antimony, beryllium, chromium, cobalt, manganese, nickel, iron and sodium. Chronic exposure to elevated lead levels is predominantly associated with neurological and hematological effects (ATSDR, 1991c). The developing fetus and young children are particularly sensitive to lead-induced neurological effects (ATSDR, 1991c). The primary toxicities associated with ingestion of large amounts of antimony are lung and heart damage (ATSDR, 1990h). Ingestion by experimental animals of elevated levels of beryllium has been associated with lung damage (ATSDR, 1991a). The primary toxicities associated with ingestion of large amounts of chromium have been kidney damage, birth defects and adverse effects on the reproductive system (ATSDR, 1989d). The primary adverse effect associated with exposure to elevated levels of cobalt is heart damage (ATSDR, 1990i). Exposure to high manganese concentrations primarily causes nervous system damage (ATSDR, 1990c). Gastrointestinal, hematological and cardiovascular systems in humans may be targets of toxicity after ingestion of high concentrations of nickel (ATSDR, 1991d). Although iron is an essential nutrient, ingestion of large amounts can lead to accumulation in the body and tissue damage. Its presence in drinking water, however, is objectionable primarily due to its affect on taste and staining of laundry and plumbing fixtures. Like iron, elevated levels of manganese in drinking water adversely affect taste and cause staining of clothes and plumbing fixtures. The levels of manganese (up to 16 mg/L) in on-site groundwater and iron (up to 152 mg/L) in off-site groundwater are more than 150 and 300 times, respectively, the levels at which the aesthetic quality of drinking water begins to be affected (WHO, 1984) and would render drinking water unpalatable. Sodium was found in on-site groundwater at levels up to 390 mg/L. Water containing more than 20 mg/L of sodium should not be used for drinking by people on severely restricted diets and water containing more than 270 mg/L of sodium should not be used for drinking by people on moderately restricted diets.
Chronic exposure to drinking water contaminated with lead at concentrations found in off-site groundwater could pose a moderate increased risk of adverse health effects. The health effects from antimony, cobalt, chromium and manganese could be low and for exposure to beryllium and nickel would be minimal.
If site-related contaminants migrate to the active, downgradient public drinking water supply wells, the public health implications summarized above would be minimized because the routine monitoring mandated by New York State will provide for early detection and implementation of controls to minimize human exposures.
Sufficient data are not available to adequately assess this potential exposure pathway. Volatile organic compounds have, however, been detected in several on-site and off-site soil gas samples at levels that could pose a significant health threat if nearby buildings are impacted. Levels of trichloroethene (as high as 400 ppm), tetrachloroethene (as high as 140 ppm), toluene (as high as 1,000 ppm), and ethylbenzene and xylene (as high as 800 ppm) on-site are in the range of levels known to damage the nervous system after even short-term exposure. The results of recent soil gas testing at the downgradient Locust Street Elementary School indicate that there does not exist the threat for indoor air contamination within the school building.
B. Health Outcome Data Evaluation
The NYS DOH has not evaluated health outcome data for the Pasley site or the Town of Hempstead. For an undetermined period of time (more than 12 years), residents in the Town of Hempstead may have been exposed to low levels of volatile organic compounds (VOCs) in drinking water. Because the health risks from these exposures are low for both cancer and non-cancer endpoints, the possibility of detecting any effect is very small. Therefore, these data bases will not be searched at this time. In 1990, the NYS DOH reported on breast cancer incidence rates for small geographic areas of Nassau and Suffolk Counties for the years 1978-1987. The relationship between breast cancer incidence and contaminated drinking water wells and hazardous waste sites was also examined. Variations were seen in breast cancer incidence rates among small geographic areas in these counties. A relationship was observed between high breast cancer incidence and high levels of household income. No association was found between breast cancer incidence patterns and contaminated drinking water wells or hazardous waste sites.
Next Section Table of Contents
