Site conditions are characterized to evaluate if a site poses an existing or potential hazard to the exposed or potentially exposed population. This site characterization involves a review of sampling data for environmental media (e.g., soil, surface water, groundwater, air), both on- and off-site, and an evaluation of the physical conditions of the contaminant sources or physical hazards near the site which may pose an additional health risk to the community.
Contaminant(s) selected for further evaluation are identified based upon consideration of the following factors:
- Concentrations of contaminants in environmental media both on- and off-site;
- Field data quality, laboratory data quality and sample design;
- Comparison of on-site and off-site contaminant concentrations in environmental media with typical background levels;
- Comparison of contaminant concentrations in environmental media both on- and off-site with public health assessment comparison values for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints and drinking water standards. Contaminant concentrations greater than a comparison value do not necessarily pose a health threat; and
- Community health concerns.
The selected contaminants are evaluated in the Public Health Implications section (Toxicological Evaluation) of this Public Health Assessment (PHA) to determine whether exposure to these chemicals is of public health significance.
The On-Site Contamination subsection and the Off-Site Contamination subsection include discussions of sampling data for environmental media; summary tables of sampling data are presented in Appendix B. A listed contaminant does not necessarily mean that it will cause adverse health effects from exposure. If a chemical is selected for further evaluation in one medium, that contaminant will also be reported in all other media, if detected.
The environmental data in this section were gathered during the RI which was conducted between 1989 and 1991. The data in Tables 1 to 7 are from the remedial investigation report, Conestoga-Rovers and Associates, July 1992. Contamination has been found in subsurface soil, leachate seeps, surface soil near the seeps, and in surface water and sediment in drainage ditches on and off-site, and in sediment and surface water in a culvert which discharges to the Niagara River. Substances which exceed comparison values include volatile and semivolatile organic compounds, pesticides, and metals.
The wastes disposed at this site included household, yard, institutional, commercial, industrial, demolition, construction, agricultural, sewage treatment plant sludges, street sweepings, and tires. The industrial wastes include scrap resins, plating tank sludge, thiazole polymer blends, phenolic resin, and other manufacturing by-products. Waste samples have not been collected.
Leachate is a liquid within the landfill, which discharges where there are breaks in the landfill covering. There are many leachate seeps on the landfill. Several leachate samples were collected during the RI and contained many organic chemicals and metals. A listing of these compounds, the ranges of concentrations, the frequencies of detection, and health assessment comparison values are in Table 1 (Appendix B). Contaminants selected for further evaluation include benzene, methylene chloride, 2,6-dinitrotoluene, aldrin, heptachlor, delta-hexachlorocyclohexane, and arsenic.
Surface Water in Ditches
The surface water in ditches on and around the site were sampled during the RI and have shown contamination (see Table 2, Appendix B). The ditches on and directly adjacent to the landfill are considered on-site. Arsenic and bis(2-ethylhexyl)phthalate were found at levels exceeding health assessment comparison values in a few samples.
Sediment in Ditches
Several contaminants have been found in sediment samples collected from drainage ditches on and around the site (see Table 3A, Appendix B). None of the sediment samples were contaminated at levels exceeding public health assessment comparison values.
Subsurface soil samples were collected from boreholes for the monitoring wells and from test pits. Individual sample depths ranged up to 2 feet for a total maximum depth of 55 to 57 feet. None of the contaminants were found at levels exceeding public health assessment comparison values (see Table 4A, Appendix B).
Sufficient data are not available to completely assess on-site surface soil as only two samples of soil were collected at two dry leachate seeps. This soil is likely to be more contaminated than other soil because the samples were taken close to leachate seeps. None of the contaminants were found at levels exceeding public health assessment comparison values (see Table 5, Appendix B).
Groundwater in three distinct aquifers at the site has been sampled. No distinction has been made between on-site and off-site groundwater samples since the aquifers are continuous and the off-site monitoring wells are close to the site and on- and off-site contamination is similar. Some samples contained pentachlorophenol, bis(2-ethylhexyl)-phthalate, beta-hexachlorocyclohexane, heptachlor, 4,4'-DDD, 4,4'-DDT, aluminum, antimony, arsenic, chromium, iron, lead, magnesium, manganese, nickel, sodium, and vanadium at levels exceeding drinking water standards or public health assessment comparison values (see Table 6, Appendix B).
Air samples were collected upwind, downwind and directly over two leachate seeps. Some of the laboratory data were rejected as discussed in subsection C (Quality Assurance and Quality Control) of this report. None of the contaminants were found at levels exceeding public health assessment comparison values (see Table 7, Appendix B). Methane may be present but has not been measured.
Surface Water and Sediments
The ditches around the site may carry contaminated surface water from the landfill to the Niagara River and to surrounding wetlands. Water in the ditches on the southern portion of the site flows towards the Niagara River; water in the ditches of the northern portion flows towards the wetlands. The marshy area to the north are the headwaters of Black Creek, which discharges into the Niagara River. Surface water in the wetland area north of the site has not been sampled. Off-site surface water and sediment samples were collected from ditches that run near the site and from a culvert discharge to the Niagara River; the results are shown on Tables 2, 3A and 3B, Appendix B. The surface water and sediment from ditches near the site show contamination similar to that found on-site. Bis(2-ethylhexyl)phthalate was found in the surface water sample collected from the culvert discharge into the Niagara River at a level exceeding its cancer comparison value. It is likely that the culvert has been contaminated by other sources in addition to the Niagara County Refuse site. The sediments in the Niagara River adjacent to the culvert discharge have not been sampled, and neither has the river water.
Seasonal surface water is present in the spring due to flooding. In response to community concerns about this flooded water, four samples of this surface water were collected by the US EPA in 1994 and analyzed for volatile, semi-volatile and inorganic chemicals, pesticides, and polychlorinated biphenyls (PCBs). Only acetone and inorganics were reported. None of these detected chemicals were above their respective health based comparison values. Therefore, seasonal surface water in residential areas will not be considered further in this PHA.
Four subsurface samples were collected from off-site locations. No organic chemicals were found (see Table 4B, Appendix B). None of the metals were found at levels exceeding public health assessment comparison values.
In response to community concerns about the possibility of contaminant migration into residential yards, the US EPA collected surface soil samples in 1994. Two surface soil samples were collected and analyzed for volatile, semi-volatile and inorganic chemicals, pesticides, and PCBs. No volatile chemicals, pesticides, or PCBs were reported. Some semi-volatile chemicals, polyaromatic hydrocarbons, were reported at estimated concentrations below the laboratory detection limit. These semi-volatile chemicals and all of the reported metals are within expected background ranges. Surface soil in residential areas will not be considered further in this PHA.
The on-site and off-site groundwater data are being evaluated together since the three aquifers at and near the site are continuous and interconnected. It appears that groundwater flow is generally toward the north. However, this flow may be influenced by the clay mining operation and may change in the future. The ponds that have been created by the clay mining operations, may be impacted by groundwater borne contaminants.
In preparing this public health assessment, the ATSDR and NYS DOH rely on the information in the referenced documents and assume that adequate quality assurance and quality control (QA/QC) measures were followed with regard to chain-of-custody, laboratory procedures and data reporting, unless otherwise noted. The validity of the analysis and the conclusions for this public health assessment is determined by the completeness and reliability of that information.
There are no obvious physical or other hazards at the site. The site is not fenced, but the access road has a locked gate at the entrance. Landfill gases (e.g., methane, carbon dioxide, and volatile organic compounds [VOC's]) are probably being generated. One public health threat from methane generation is the potential for explosive levels of methane to accumulate in enclosed spaces.
To identify other facilities that could possibly contribute to site-related contaminants in soil, air, groundwater, or surface water at or near the Niagara County Refuse site, or create health threats unrelated to the site, the NYS DOH searched the Toxic Chemical Release Inventory (TRI). The TRI has been developed by the US EPA from chemical release information provided by those industries that are required to report contaminant emissions and releases on an annual basis.
The NYS DOH uses a simple mathematical model to estimate if potential contaminant concentrations resulting from air emissions at industrial facilities within a 2.5 mile radius of the site may be contributing to community exposures to contaminants at a site. This model uses information about the facility location (distance from the exposed population) and annual air emission data from the TRI to calculate the radial distance from the facility at which contaminant concentrations in ambient air have been diluted to 1 microgram per cubic meter of air (mcg/m3) for most contaminants. The NYS DOH then evaluates what portion of the population, if any, living within this distance from the manufacturing facility may also be exposed to contaminants originating at the site.
Two facilities are within 2.5 miles of the site. The Precious Plate, Inc. and Buffalo Pump, which are 1.9 miles and 1.7 miles, respectively, from the site. For 1991, Buffalo Pump reported nickel, copper and zinc air emissions. No releases were reported by Precious Plate Inc. (see Table 9, Appendix B). The air emissions from Buffalo Pump were below the screening criterion of 1 mcg/m3 for copper and zinc and 0.02 mcg/m3 for nickel, and therefore would not have a measurable effect on the health of the community around the Niagara County Refuse site. Based on the results of this screening evaluation; the public health significance of contaminant emissions from TRI facilities as an additional source of community exposures at the NCR site will not be evaluated further in this PHA.
This section of the public health assessment (PHA) identifies potential and completed exposure pathways associated with past, present and future use of the site. An exposure pathway is the process by which an individual may be exposed to contaminants originating from a site. An exposure pathway has five elements: (1) a contaminant source; (2) environmental media and transport mechanisms; (3) a point of exposure; (4) a route of exposure; and (5) a receptor population.
The source of contamination is the source of contaminant release to the environment (any waste disposal area or point of discharge); if the original source is unknown, it is the environmental media (soil, air, biota, water) which are contaminated at the point of exposure. Environmental media and transport mechanisms carry contaminants from the source to points where people may be exposed. The exposure point is a location where actual or potential human contact with a contaminated medium may occur. The route of exposure is the manner in which a contaminant actually enters or contacts the body (i.e., ingestion, inhalation, dermal absorption). The receptor population is the persons who are exposed or may be exposed to contaminants at a point of exposure.
Two types of exposure pathways are evaluated in the PHA; a completed exposure pathway exists when the criteria for all five elements of an exposure pathway are documented; a potential exposure pathway exists when the criteria for any one of the five elements comprising an exposure pathway is not met. An exposure pathway is considered to be eliminated when any one of the five elements comprising an exposure pathway has not existed in the past, does not exist in the present, and will never exist in the future.
There are no known completed human exposure pathways to contaminants at the NCR site.
Unauthorized site visitors would be a receptor population for on-site contamination. Even though people have been observed at the landfill, it is not known if contaminated media were contacted. Therefore, these pathways are potential pathways. Remedial workers may be exposed to on-site contamination during site remediation. However, appropriate work practices and use of personal protective equipment will minimize worker exposures. In the future, people could be exposed to contaminants in drinking water if a groundwater well were installed. However, it is unlikely that private wells will be installed as the area is served by public water.
Past Potential Exposure Pathways
Surface Soil, Surface Waste, Surface Water, Sediments, and Air On-Site
The conditions of the landfill during the years of operation and before a cover was placed over the site are unknown. It is likely that wastes were exposed at the surface during the active years of the landfill. It is unknown if people were exposed to wastes or contaminated surface soil, surface water, sediments or air. Therefore, these potential pathways can not be fully evaluated.
Present and Future Potential Exposure Pathways
Most of the surface soil at the site is probably not contaminated because a clay cap and soil cover were placed over the closed landfill sections. However, the cap has been compromised by the many leachate seeps around the site. Visitors to the site may be exposed to potentially contaminated surface soils on and around the landfill and soils contaminated by leachate near seeps. However, none of the contaminants in soils were found at levels exceeding public health assessment comparison values and, therefore, these contaminants are not discussed in the Toxicological Evaluation section of this Public Health Assessment.
Workers, during site remediation, may be exposed to on-site contaminants by direct contact, incidental ingestion or inhalation of dust and soil particulates in ambient air. However, during site remediation activities, appropriate control measures and personal protective gear would be used to minimize worker exposure to site contaminants.
Ditch Surface Water and Sediment, and Leachate
People visiting the site may be exposed to contaminants in on-site leachate on-site and surface water and sediment in ditches on and around the landfill through dermal absorption or incidental ingestion.
Contamination may migrate off-site through these drainage ditches. Some of these ditches discharge to the north into a marshy area which is the headwaters of Black Creek and some of the ditches discharge to the south into the Niagara River.
Other Surface Water and Related Sediments
Exposures to possible contamination in the wetlands north of the site would be similar to those discussed in the previous section dealing with surface water and sediment in the drainage ditches.
People could come in contact with Niagara River water and sediments. Site-related contamination would be greatly diluted in the Niagara River water. The level of contamination in the Niagara River sediments from this site is unknown.
Persons on-site may inhale VOCs which may be released into the air from surface soils, leachate seeps and surface water. However, none of the contaminants in ambient air were found at levels exceeding public health assessment comparison values or background levels; therefore, these contaminants are not discussed in the Toxicological Evaluation section of this Public Health Assessment.
Fish that live in the Niagara River may be affected by contaminants that may migrate from the landfill. There are no fish data specific to this site. However, an advisory is in effect that states that no more than one meal per month of carp caught in the upper Niagara River should be eaten and that women of childbearing age and children under the age of 15 should not eat any fish from these waters. This advisory is not related specifically to contamination from the NCR site.
Public water is available to area residents. No private wells have been identified to date and it is not likely that nearby residents would be exposed to contaminated groundwater. However, a well survey would identify if there are any existing wells that are still being used for drinking water. If any wells are identified, this pathway will be re-evaluated. A long-term groundwater monitoring program will be included as part of the remedial program and provide early warning if contaminated groundwater moves towards residential areas.
Landfill gases are most likely present. However, it is unlikely that soil gases are able to migrate laterally towards nearby residences, because the soils in the area tend to be dense, a condition unfavorable for the transport of soil gas. In addition, the remedy calls for placing a cap over the site and the construction of a gas venting layer, which will further reduce the potential for gas migration.
The Niagara River is a source for public water. A waterline for the Town of Wheatfield Water Department runs through the northwest corner of the site. This waterline may traverse potentially contaminated subsurface soil. If the "positive pressure" inside the pipe were to be compromised, contamination could leak into the pipe. However, this is not likely to occur.
An analysis of the toxicological implications of the human exposure pathways of concern is presented below. To evaluate the potential health risks from contaminants of concern associated with the NCR site, the NYS DOH has assessed the risks for cancer and noncancer health effects. The health effects are related to contaminant concentration, exposure pathway, exposure frequency and duration. For additional information on how the NYS DOH determined and qualified health risks applicable to this public health assessment, see Appendix C.
On-site leachate seeps and surface water at the NCR site and groundwater monitoring wells are contaminated at levels of concern for potential human exposure pathways (Tables 1, 2 and 6, Appendix B). There have been no documented human exposures to contaminants at the NCR site. An analysis of the toxicological implications of the potential human exposure pathways of concern is presented below:
- Potential dermal, ingestion and inhalation exposure to contaminants in on-site leachate seeps
and surface water drainage ditches.
Visitors to the site could come in contact with contaminated leachate seeps and surface water from the ditches on and near the landfill but contact would most likely be infrequent and short-term. Among the organic contaminants selected for further evaluation in leachate seeps (see Table 1, Appendix B), several are human or animal carcinogens. Benzene is a known human carcinogen (ATSDR, 1991k); methylene chloride, 2,6-dinitrotoluene, aldrin, heptachlor and delta-hexachlorocyclohexane are known to cause cancer in laboratory animals exposed to high levels over their lifetimes (ATSDR, 1989; 1991f,l,m; 1992b). Chemicals that cause cancer in humans and/or animals after high levels of exposure may also increase the risk of cancer in humans who are exposed to lower levels over long periods of time. Chronic (long-term) exposure to these chemicals at the highest concentrations found in leachate seeps could pose a low increased cancer risk. The potential health risk to persons visiting the site from possible exposure to these chemical contaminants would most likely be less because the contaminants were detected in only a few of the leachate samples.
The only metal contaminant selected for further evaluation in leachate seeps is arsenic. Studies of people exposed to high levels of arsenic in drinking water in foreign countries provide evidence of an association between arsenic ingestion and skin cancer (ATSDR, 1991a). To date, however, studies in the United States of exposure to arsenic in drinking water have not shown an increased risk of cancer. The existing data suggest that exposure to on-site arsenic in leachate seeps could pose a low increased cancer risk to people visiting the site.
As indicated in Table 2 (Appendix B), some samples of surface waters from on-site and off-site ditches contained bis(2-ethylhexyl)phthalate and arsenic at levels of potential concern to trespassers. Bis(2-ethylhexyl)phthalate is known to cause cancer in laboratory animals exposed to high levels over their lifetimes (ATSDR, 1991e). This organic contaminant is also known to adversely effect the male reproductive system (ATSDR, 1991e). The toxicological properties of arsenic have already been discussed. Exposure to these two contaminants could pose a low increased cancer risk to individuals coming in contact with contaminated surface waters on a frequent basis.
- Potential ingestion, dermal and inhalation exposure to contaminants in drinking water as a
result of contaminant plume migration.
As indicated in Table 6 (Appendix B), some samples of on-site and off-site groundwater contained organic chemicals and metals at concentrations that exceed New York State drinking water and/or groundwater standards. Although nearby residents are currently provided with public water, future installation of private drinking water supply wells is a remote possibility. These wells could be adversely affected by migration of the contaminant plume.
Chronic exposure to chemicals in drinking water would be possible by ingestion, dermal contact or inhalation from water uses such as showering, bathing and cooking. Although exposure would vary depending on the individual's lifestyle, each of these exposure routes could contribute to the overall daily uptake of contaminants and thus would increase the potential risk for chronic effects.
Pentachlorophenol, bis(2-ethylhexyl)phthalate, beta-hexachlorocyclohexane, heptachlor, 4,4'-DDT and 4,4'-DDE are known to cause cancer in laboratory animals exposed to high levels over their lifetimes (ATSDR, 1991e,f; 1992a,b,c). 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. Chronic exposure to these contaminants in drinking water at the highest concentrations found in the on-site groundwater samples would pose a moderate increased cancer risk.
Metal contaminants that have been selected for further evaluation (see Table 6, Appendix B) in on-site groundwater include aluminum, antimony, arsenic, chromium, iron, lead, magnesium, manganese, nickel, sodium and vanadium. The toxicological properties of arsenic have previously been discussed. Antimony can cause alterations in blood chemistry (ATSDR, 1990a). Although little is known about the chronic toxicity of aluminum in humans, some animal toxicity studies indicate that aluminum may cause nerve and skeletal damage and may also adversely affect the reproductive system (NYS DOH, 1990). The primary toxic effects associated with ingestion of large amounts of chromium have been kidney damage, birth defects, and adverse effects on the reproductive system (ATSDR, 1991d). Although iron is an essential nutrient, ingestion of extremely large amounts can lead to accumulation in the body and to tissue damage (WHO, 1984; Henretig and Temple, 1984). Chronic exposure to lead is predominantly associated with neurological and hematological effects (ATSDR, 1991g) and the developing fetus and young children are particularly sensitive to lead-induced neurological effects. Magnesium is an essential element in human nutrition. However, at very high levels (greater than about 250,000 mcg/L) magnesium may have a laxative effect, although the human body can adapt to this effect with time (NAS, 1977). Exposure to high manganese concentrations primarily causes nervous system effects (ATSDR, 1991h). Exposure to high levels of nickel can cause reproductive effects and allergic reactions (ATSDR, 1991i). The main health concern about sodium ingestion is its association with high blood pressure and possibly heart disease (WHO, 1984). Effects on the gastrointestinal tract (cramps, diarrhea, nausea) have been observed following ingestion of large amounts of vanadium (ATSDR, 1991j). Chemicals that cause effects in humans and/or animals at 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 adverse health effects from potential exposure to contaminated drinking water are not completely understood, the existing data suggest that they would be high for lead, manganese, and sodium at the highest concentrations found in groundwater monitoring wells, moderate for arsenic and aluminum, low for antimony and magnesium, and minimal for chromium, nickel, iron and vanadium.
- Potential inhalation, dermal and ingestion exposure of persons engaged in on-site cleanup
Persons engaged in on-site cleanup (remediation) activities have a potential for exposure by multiple routes to organic chemicals and metal contaminants and could be at increased risk of adverse health effects. However, use of proper procedures, personal protective equipment, appropriate dust suppression methods and monitoring of ambient air for organic vapors during cleanup activities would minimize the risk to workers and nearby residents.
NYS DOH has not evaluated health outcome data specifically for the Niagara County Refuse site. There are no community health studies planned at this time, because there are no known completed exposure pathways to evaluate or community health concerns to address.
- Residents near the site are concerned that flooding in the spring may have brought
contamination into their yards.
To address concerns about possible contaminant migration into residential yards, surface soil and surface water samples were collected by US EPA in June 1994. The chemicals found in surface water and surface soil samples were within expected background ranges or below health-based comparison values.
- Residents want to know if there is airborne contamination migrating off-site.
Sampling of ambient air from areas near two leachate seeps on-site did show some organic contaminants. However, the levels detected did not exceed background ranges for ambient air. The levels detected are not likely to be present off-site at levels that would be expected to result in adverse health effects.
- People who visited the site and nearby residents want to know what possible health effects
they might experience. Nearby residents want a health survey to determine if their community is
experiencing any health effects.
Chronic (i.e., long-term) exposure to the highest concentrations present at the site, at leachate seeps, could pose a low increased risk of cancer. However, it is not expected that casual visitors to the site would be repeatedly exposed to contamination at the high levels used in this evaluation and therefore, their risks would be lower. Non-carcinogenic effects are not expected. Since there is no indication that people living in the nearby community are being exposed routinely to site-related contamination at levels where possible health effects would be expected to occur, a health survey of the community is not planned.
- Nearby residents want to know if it is safe to plant a garden in their yards.
The results of the June 1994 residential sampling indicates that contaminants found in surface soil are within expected background ranges. These data do not show a need to restrict any usage of residential properties near the site.
- A concern was expressed about mosquitoes that breed in the wetlands near the landfill.
Mosquitoes are capable of transmitting viruses, but there has been no documented illness due to mosquitoes in the area in the past 10 years. With respect to the landfill itself, it is not expected that mosquitoes could transfer enough site-related contaminants to pose a health concern.
- Concerns were expressed over the effectiveness of the selected remedy and whether there will
be any follow-up activities to ensure its continued effectiveness.
The selected remedy is protective of public health since it will encapsulate the waste and prevent the build-up of leachate and landfill gases. There will be a long-term monitoring program to evaluate and monitor the effectiveness of the remedy. Site conditions will be evaluated at least once every five years following completion of the remedy and will include recommendations for continued remedial efforts at the site.
- Two accounts of possible exposures to contamination on-site were reported.
Not enough information was provided to verify or evaluate these exposures.