PUBLIC HEALTH ASSESSMENT
POWNAL TANNERY
POWNAL, BENNINGTON COUNTY, VERMONT
The Pownal Tannery National Priorities List site is a former cow and sheep hide tanning and finishing operation in southwestern Vermont. The property originally consisted of a landfill, five lagoons, a warehouse building, a clarifier building, a tanning building, and a screen house.
The nature and extent of environmental contamination is still being determined. Staff from the Agency for Toxic Substances and Disease Registry (ATSDR) have reviewed the available on-site environmental data, and found that people trespassing on the site were possibly exposed to contaminants (metals, 2-methylnaphthalene, dioxin, 4-nitroaniline, DDT, bis(2-ethylhexyl)phthalate, dibenzofuran, endrin ketone, polycyclic aromatic hydrocarbons (PAHs), and pentachlorophenol) in the on-site building surface soils. They were possibly exposed by dermal contact and by incidental ingestion and inhalation of the contaminants while trespassing upon and playing in the buildings. Arsenic, cadmium, dioxin, PAHs, and 4-nitroaniline have the potential to cause adverse health effects in humans following dermal contact. For those contaminants with an adequate amount of toxicological and epidemiological information, ATSDR believes it unlikely adverse non-cancer health effects would have occurred due to the past exposures. For those contaminants with known carcinogenic endpoints, ATSDR believes that there is no significant increased risk of developing cancer due to these past exposures.
Children have been observed fishing in the waters of the Hoosic River adjacent to the tannery building. These waters are known to be contaminated with heavy metals. Fish sampling data are needed to determine if fish have accumulated metals which could pose a public health hazard to anyone that has consumed the fish.
People who lived near the site were concerned about possible health effects caused to children who were playing on the site and the public health threat given the current physical condition of the site. The on-site buildings, which have recently been removed, were contaminated with potentially hazardous chemicals. Based upon current environmental data, exposure to contaminants should be avoided. Some of the contaminants are easily absorbed through the skin and some of them may cause adverse health effects. It should be noted that since the site is still undergoing characterization, it is possible that contaminants are present at levels higher than those evaluated in this public health assessment. People should avoid entering the site.
Some of the chemicals found in the basement surface soil samples have the potential to cause adverse health effects in humans upon direct contact. However, the likelihood of exposures are minimal, if any, and adverse health effects are not expected to have occurred. Although the site is bordered by a residential area, no soil sampling in the residential area has occurred since 1992.
The site was considered a public health hazard in previous versions of the public health assessment, because of the physical hazard presented by the dammed area adjacent to the former main tannery building. The Environmental Protection Agency rectified these hazards by erecting guardrails and handrails along the river after demolition of the main tannery building was completed during summer 2000. ATSDR has changed the site category to an indeterminate public health hazard, because available data do not indicate that humans are being or have been exposed to levels of contamination that would be expected to cause adverse health effects, but data is not available for all environmental media, specifically fish sampling.
ATSDR has made recommendations to (1) reduce and prevent exposure to contaminants by restricting access to the site, particularly the dammed area along the Hoosic River and (2) address or fill certain toxicological and environmental data gaps by gathering additional sampling data for a more accurate idea of what compounds are present both on and off the site. ATSDR recommends sampling of off-site media: including the residential area surface soils; drinking water at the tap to insure that on-site groundwater contamination has not migrated off-site into the drinking water supply; surface water, sediment, and biota in the Hoosic River downstream of the site in areas used for recreational purposes; and ambient air in the residential area during remedial activities to determine if inhalation exposure to site contamination is occurring during the remedial efforts. ATSDR recommends sampling of biota from the Hoosic River in the vicinity of the site to determine if fish being caught by children and possibly consumed could pose a public health hazard. In addition, sampling of on-site surface soils in the vicinity of the buildings, landfill, and lagoons in areas most likely to have been frequented by trespassers is recommended.
Purpose
In September 1998, the United States Environmental Protection Agency (EPA) proposed that Pownal Tannery be put on the National Priorities List (NPL). The Agency for Toxic Substances and Disease Registry (ATSDR), located in Atlanta, Georgia, is a federal agency within the United States Department of Health and Human Services (DHHS). ATSDR, under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) conducts public health assessments for sites the EPA proposes to the NPL. The site was added to the NPL in January 1999. Therefore, ATSDR has, under its mandate, evaluated the public health significance of this site. They considered whether adverse health effects are possible and have recommended actions to mitigate possible future exposure.
The purpose of this public health assessment is to describe ATSDR's activities and to report the agency's conclusions, recommendations, and public health actions.
Public Health Issues
During the course of preparing this public health assessment, ATSDR identified the following public health issues with regard to the Pownal Tannery NPL site:
Do current physical conditions at the site pose a public health threat?
How will my children be affected if they were to play on the site?
Introduction to the Site
The Pownal Tannery National Priorities List (NPL) site is located in North Pownal, Bennington County, off Route 346 in the southwestern portion of Vermont. Cow and sheep hide tanning and finishing operations were conducted on the 28-acre site from 1937 through 1988 (1 - 3). The property originally consisted of a landfill, five lagoons, a warehouse building, a clarifier building, a tanning building, and a screen house. Public access to the site is currently restricted by fencing.
Site Investigations
The Environmental Protection Agency (EPA) has conducted and is continuing to conduct numerous investigations on the site. EPA has also conducted several removal actions at the site (2, 4). ATSDR's first involvement with the site resulted from an EPA request in November 1992. EPA requested that ATSDR comment on major pathways of concern, data gaps, and other health concerns. ATSDR provided a preliminary response in November 1992. ATSDR responded that it would be difficult to assess current exposures, because the data were too old for a health consultation to be done. ATSDR agreed to evaluate data on the tannery building and lagoons. ATSDR completed a public health consultation on the lagoons and tannery buildings in October 1993 (5).
In December 1998 and May 1999, ATSDR visited the site to get an overview of site conditions, to gather the community's health related concerns, and to gather additional data which may prove helpful in preparing this public health assessment and future documents. During the December 1998 visit, ATSDR noticed signs of trespassing upon the site. The on-site buildings were dilapidated. Trespassers were gaining easy entry to on-site buildings via missing doors and broken windows. It appeared that children were using the main tannery building for a clubhouse. There was also debris from site operations present on the ground and in the buildings. Other debris was also strewn about the ground. During the May 1999 visit, ATSDR noticed that access to the site was more restricted via a locked fence. As of February 2000, buildings on the site have been demolished and debris trucked away. Some remedial work has begun.
The full extent and characterization of site contamination is on-going. Therefore, this release of the public health assessment deals only with information available to ATSDR as of November 2000. Information obtained by ATSDR following the release of this version of the public health assessment will be included in future releases of this document or in additional documents.
Nature and Extent of Environmental Contamination
Results of on-site sampling activities are summarized as shown in Appendix B. The sampling data show that various on-site media are contaminated with heavy metals, dioxins, semi-volatile organic compounds (SVOCs), polycyclic aromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs). Prior to demolition, samples were collected from on-site buildings. These data will be discussed in more detail in the following sections of the document. Off-site sampling data are not yet available for analysis.
The basement floors of on-site buildings were sampled for metals, dioxins, pesticides, PAHs, SVOCs, and VOCs in surface soil. Elevated levels of metals, PAHs, pesticides and other organic compounds were detected (Table 1).
Sludge samples were collected from the interiors of on-site buildings. Samples taken from basement floor drains and sludge tanks showed elevated levels of metals, PAHs, and dioxins. 2-methylnaphthalene was also detected (Table 2).
Paint samples and bore samples of wood and concrete were collected from on-site buildings. The paint samples were analyzed for chromium and lead. The chromium was not speciated and lead was detected at a maximum concentration of 9,500 parts per million (ppm). The paint samples were not taken from fallen paint chips or window sills. The concrete samples were only tested for dioxin content. The wood samples were found to contain elevated levels of metals, PAHs and pesticides (Table 3).
Samples of sludge taken from the on-site lagoons were tested for VOCs, SVOCs, PAHs, dioxin, and metals. Elevated levels of metals and dioxins were found (Table 4). In addition, SVOCs and VOCs were detected. Chromium was found at a maximum concentration of 445,000 ppm, however, the chromium was not speciated.
Standing water samples were collected from an elevator shaft and pit in the basement of the Northern Building, the floor tank of the tannery building, and from the clarifier building. Elevated levels of metals, SVOCs, and PAHs were detected (Table 5).
Groundwater samples were collected from monitoring wells adjacent to the landfill and lagoons (Tables 6 and 7). These samples were found to be contaminated with metals, SVOCs, and chrysene. The full nature and extent of groundwater contamination has not been completely characterized. Since the site, the landfill and lagoons are adjacent to the Hoosic River, it is most likely that groundwater flow is towards and into the Hoosic River.
Sediment (dewatered sludge) samples were taken from the on-site landfill (Table 8). The samples were shown to contain elevated levels of metals, 4-methylphenol, pentachlorophenol, and dioxins.
Surface-water samples were collected from the run-off area of the on-site landfill (wetlands adjacent to the landfill) and analyzed for metal content (Table 9). High levels of arsenic, manganese, and vanadium were found. Aluminum, iron, and lead were also detected.
Surface water and sediment samples were taken from the various locations in the Hoosic River (Tables 10 and 11) and analyzed for metal content. The concentration of arsenic, manganese and vanadium were above comparison values. High concentrations of aluminum, iron, and lead were also detected.
Samples were taken from the tank of the leachate collection system and tested for acetone, diethyl phthalate, and metal content. The concentration of antimony, arsenic, and manganese were above comparison values (Table 12). A high level of sodium (333,000 parts per billion) was also detected.
Wipe samples were collected from the walls, floors, and window sills of on-site buildings and analyzed for dioxin levels, SVOCs, PAHs, and metal content. The maximum concentration of dioxin equivalents was 30 parts per trillion. Chromium and lead were detected at high concentrations, 3,940 micrograms per square foot (ug/ft2) and 4,640 ug/ft2 respectively (Table 13). The chromium was not speciated. Based on information provided to ATSDR the Tannery received shipments of Chromium VI and reduced it on site.
Physical Hazards
During the ATSDR site visits, multiple physical hazards were noted. Buildings throughout the site were old and in poor condition. Guard rails along the outside of the main tannery building in the area overlooking the dammed area of the Hoosic River were not in good condition. A person could fall into the river or onto the rocks below and be injured. As an interim measure, EPA installed wire barrier ropes in the area of the dam. During summer 2000, EPA completed demolition and removal of the main tannery buildings, excavated and re-seeded the site, and erected guardrails and handrails near the river. These actions have eliminated the previous physical hazards associated with the site.
Pathways Analyses
ATSDR identifies human exposure pathways by examining environmental and human components which may lead to contact with contaminants of concern. A pathways analysis considers five principal elements: (1) a source of contamination, (2) transport through an environmental medium, (3) a point of exposure, (4) a route of human exposure, and (5) an exposed population. Completed exposure pathways are those for which the five elements are evident, and indicate that exposure to a contaminant has occurred in the past, is currently occurring, or will occur in the future. ATSDR regards people who come into contact with contamination as exposed. For example, people who reside in an area with contaminants in air, or who drink water known to be contaminated, or who work or play in contaminated soil are considered to be exposed. Potential exposure pathways are those for which exposure seems possible, but one or more of the elements is not clearly defined. Potential pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now, or could occur in the future. Identification of an exposure pathway does not imply that health effects will occur. Exposures may be, or may not be, substantive. Thus, exposures may or may not cause adverse health effects.
ATSDR staff reviewed site history; information on past, current, and planned activities; and media sampling data. They identified various exposures pathways which warranted consideration. Those are discussed in this subsection. Although this site lies adjacent to a residential area off-site sampling data are very limited preventing a thorough evaluation of off-site pathways of exposure. No soil sampling has taken place in the residential area since 1992. The Vermont Department of Environmental Conservation (VTDEC) has collected annual drinking water samples from two residences in the vicinity of the lagoon area since 1993. The annual drinking water samples were analyzed for VOCs, chromium and lead. In 1999, samples were also collected from two residences in the vicinity of the sludge landfill. Methyl-tertiary butyl ether (MTBE) was detected at a concentration of 1 microgram per liter in one of these samples. This level is well below both federal and state drinking water standards.
A. Completed Exposure Pathways
Elements of completed exposure pathways are provided in Appendix C, Table 1.
Based upon reports and evidence present at the site during ATSDR's first site visit, children have trespassed upon the site. Signs of trespassing were found on, around, and in the various buildings located on site. The number of people who trespassed upon the site is not known but assumed to be less than 100. It is possible that these trespassers were exposed, intermittently, to contaminants present in these buildings, in the past. Surface-soil samples taken from the buildings (Appendix B, Table 1) have been shown to be contaminated with various metals, polycyclic aromatic hydrocarbons (PAHs), dioxins, and semi-volatile organic compounds (SVOCs). Wipe samples (Appendix B, Table 13) were collected from the walls, floors, and window sills of on-site buildings and analyzed for dioxin levels, SVOCs, PAHs, and metal content. In general, wipe samples are difficult to interpret. The maximum concentration of dioxin equivalents was 30 parts per trillion. Chromium and lead were detected at high concentrations of 64,000 micrograms per square foot (µg/ft2) and 1,380 µg/ft2, respectively. The chromium was not speciated. Chromium VI was reduced on site to Chromium III, which is the form most often used in the tanning process. The principal route of exposure would be via direct contact with contaminants in the soil and on surfaces. Inhalation of contaminants in fugitive dusts is also possible. Remedial activities at the site have begun. The site is currently fenced and on-site buildings have been removed. This should reduce the possibility of current and future exposures.
The surface water and sediments of the Hoosic River (Appendix B, Tables 10 and 11), in the vicinity of the site, have been shown to be contaminated with various heavy metals. The concentration of these metals are above available water quality standards. According to reports reviewed by ATSDR (3), children have been observed fishing in the Hoosic River adjacent to the site. ATSDR currently does not have information regarding the quality of the waters and sediments downstream of the site, nor fish quality data.
B. Potential Exposure Pathways
Elements of potential exposure pathways are provided in Appendix C, Table 2.
The groundwater of on-site lagoons (Appendix B, Table 6) has been shown to be contaminated with metals, VOCs, and dioxins. While the full nature and extent of groundwater contamination is still being characterized, current testing has not shown nearby wells to be contaminated with these constituents via migration. ATSDR assumes that the flow of groundwater in the vicinity of the lagoons would be toward the Hoosic River.
The groundwater beneath the on-site landfill (Appendix B, Table 7) has been shown to be contaminated with metals, endrin aldehyde, and 4-methylphenol. The full nature and extent of groundwater contamination has not been completely characterized. Given the location of the onsite landfill, ATSDR assumes that the flow of groundwater in the area is toward the Hoosic River. Samples taken from nearby supply wells have not yet indicated contaminant migration from the landfill.
Surface-water samples taken from the run-off area of the landfill (Appendix B, Table 9) have been shown to be contaminated with various metals. Persons who trespass upon the site may be exposed intermittently to these contaminants via direct contact.
During remediation, workers conducting activities in the on-site buildings, have the potential to become exposed to contaminants present in surface soil, waste, standing water, paint, and concrete (Appendix B, Tables 1, 3, 5, and 13). If proper procedures are followed and personal protective equipment is used these exposures should be minimal, if any. Occupational exposures are under the venue of the Occupational Safety and Health Administration (OSHA) and are not addressed further in this assessment.
C. Pathways Considered and Eliminated
A description of elements of pathways considered and eliminated are provided in Appendix C, Table 3.
Sludge samples were collected from basement tanks and floor drains in on-site buildings (Appendix B, Table 2). These samples were found to be contaminated with heavy metals, PAHs, and dioxins. The most likely route of exposure would be via direct contact, however; it is unlikely that trespassers came into contact with these contaminated sludges because they were located in basement trenches.
Paint, concrete and wood boring samples (Appendix B, Table 3) collected from the interiors of on-site buildings were found to contain metals, PAHs and pesticides. Paint samples were not taken from peeling paint chips or window sills, making interpretation of the results difficult with regards to possible exposures. Wood and concrete boring samples are difficult to interpret because the bioavailability of these materials is unknown. However, ATSDR does not believe that persons trespassing within the on-site buildings would have ingested a significant amount of contaminants from these media.
The sludges of the on-site lagoons (Appendix B, Table 4) have been shown to be contaminated with metals, VOCs, and dioxins. ATSDR believes that it is unlikely that persons trespassing in the vicinity of the lagoons came into contact with the contaminated sludges since they are subsurface.
Standing water collected from various locations in the basements of on-site buildings (Appendix B, Table 5) has been shown to be contaminated with metals, SVOCs, and PAHs. Based upon the locations where these samples were taken, ATSDR believes that it is unlikely that persons trespassing within the buildings would have come into contact with the contaminants.
Dried sludge taken from the on-site landfill (Appendix B, Table 8) has been shown to be contaminated with metals, pentachlorophenol, and dioxins. ATSDR believes that it is unlikely that persons trespassing upon the landfill came into direct contact with these sediments since they are in subsurface soil.
Samples taken from the on-site leachate collection system (Appendix B, Table 12) have been shown to be contaminated with antimony, arsenic, and manganese. The samples were collected from areas that would not be expected to be easily accessible to trespassers. The leachate collection system has been renovated and is currently collecting leachate from the landfill. ATSDR believes that it is highly unlikely that people came into contact with the contaminants in the leachate collection system.
Demographics
The demographics of the community consist of approximately 520 residents living within a one-mile radius of the site. The nearest residence is approximately 200 feet from the site boundary. There are approximately 58 children aged six years and younger living within a mile radius of the site. There are many lower income households near the site perimeter. There are 12 houses located upgradient of the site along Highway 346. In the past, homes near the site relied on a mix of public and private groundwater sources for drinking water (2, 8). The public water supply was from a surface impoundment located less than a mile west of the site and at a higher elevation than the site (22). The water supply is outdated and reportedly has had problems meeting drinking water standards. It has been out of service for the past four years. Residents currently rely on private wells or use bottled water. The town is investigating other possible sources of public water.
Public Health Implications
Introduction
The contaminants of concern released into the environment at the Pownal Tannery National Priorities List site have the potential to cause adverse health effects. However, for adverse health effects to occur, the pathway for exposure must be completed. A release does not always result in exposure. Health effects resulting from the interaction of an individual with a hazardous substance in the environment depend on several factors. One is the route of exposure; that is whether the chemical is inhaled; consumed with food, soil, or water (ingestion); or whether it contacts the skin (dermal). Another factor is the dose to which a person is exposed, and the amount of the exposure dose that is actually absorbed. Mechanisms by which chemicals are altered in the environment or inside the body, as well as the combination (types) of the chemicals is also important. Once exposure occurs, characteristics such as age, sex, nutritional status, genetics, life style, and health status of the exposed individual influence how the contaminants are absorbed, distributed, metabolized, and excreted. Together those factors and characteristics determine the health effects that may occur as a result of the exposure to a contaminant. Much variation in those mechanisms exists among individuals. For example, all children mouth or ingest nonfood items to some extent. This type of behavior is known as pica. The degree of pica behavior varies widely in the population, and is influenced by nutritional status and the quality of care and supervision (9). Groups that are at increased risk for pica behavior include children aged 1 to 3 years old and children with neurological disorders (e.g., brain damage, epilepsy, and mental retardation).
Based upon information reviewed, children have been seen fishing in the waters of the Hoosic River adjacent to the former tannery building. Surface waters and sediments in the area are known to be contaminated with heavy metals above screening value concentrations. The main route of exposure to the contaminants in the surface waters and sediments would be via direct contact. ATSDR does not believe that these intermittent exposures to the metals would cause adverse health effects. However, it is assumed the fish caught by the children fishing in the area would be consumed. ATSDR currently does not have data on fish caught in the area. Such data is needed in order to evaluate the degree and significance of exposures caused by the ingestion of possibly contaminated fish.
The methods for calculating exposure doses due to ingestion and evaluating the exposure doses are presented in Appendix D.
Exposure Scenarios
Exact information about the habits of trespassers upon the site are unknown. In order to evaluate possible exposures certain assumptions were made by ATSDR. The following assumptions were made:
ATSDR has no methodology to determine amounts of chemicals absorbed through the skin; therefore, an exposure dose for this route of exposure was not calculated. For those contaminants which ATSDR has established health guidelines, persons exposed to manganese in on-site surface soil could display adverse health effects. It should be noted, however, that this is based upon the conservative assumptions detailed above. Contaminants which are above health guidelines, are carcinogenic and those for which there are no health guidelines available (Appendix E) will be discussed further.
Contaminants with concentrations that exceed health guidelines
Persons who trespassed upon the site and entered the basements of on-site buildings could have been exposed to manganese in surface soil at a maximum concentration of 15,000 milligrams per kilogram (mg/kg). The estimated exposure dose for children slightly exceeds EPA's reference dose (RfD) of 0.005 milligrams per kilogram per day (mg/kg/day). The no-observed-adverse-effect-level (NOAEL) is approximately 0.0048 mg/kg/day. Gastrointestinal absorption of manganese is approximately 3%-5%. ATSDR does not believe that adverse non-cancer health effects would occur due to these exposures.
Dermal exposure is not usually a concern since manganese has not been found to enter the body through undamaged skin. No studies were found that reported cancer in humans associated with manganese, and few animal studies on this subject are available.
Contaminants below health guidelines but are carcinogenic
Arsenic was detected in on-site surface soil at a maximum concentration of 12.5 mg/kg. The estimated exposure doses do not exceed ATSDR's Minimal Risk Level (MRL). Non-cancer adverse health effects are not expected to occur. Arsenic is classified by EPA as a known human carcinogen. The EPA has calculated a cancer unity risk factor, which can be used to estimate the probability of excess cancer risks for a lifetime of exposure to arsenic. Cancer risks for exposure were estimated based on the maximum concentration of arsenic in the contaminated medium. There does not appear to be a significant increased risk of cancer based upon these estimations (11).
Several studies of humans in the workplace have shown that arsenic can cause contact dermatitis. The arsenic is usually in the form of arsenic trioxide. The dermal contact rates that cause effects such as erythema and swelling in humans has not been quantified, but a similar direct irritation of the skin has been noted in mice exposed to 2.5 mg/kg of sodium arsenite. Dermal sensitization may be possible. The chemical form of the arsenic found on the site is not known at this time.
Cadmium was detected in on-site surface soil at a maximum concentration of 33.4 mg/kg. The estimated exposure doses did not exceed ATSDR's MRL. Non-cancer adverse health effects are not expected to occur. Cadmium is classified by EPA as a probable human carcinogen based upon epidemiological studies of humans. The epidemiological studies indicate that cadmium may be a carcinogen via the inhalation route of exposure with the resulting condition being lung cancer. These conditions occurred in occupational settings at concentrations much higher than those found in the building surface soil samples. Based upon where the samples were taken, ATSDR believes that the inhalation route of exposure is not of significance in this pathway. Given the above exposure scenarios, ATSDR believes that there is no significant increased risk of developing cancer due to these intermittent exposures (12).
Cadmium has the ability to cause dermal irritation. Some eczema patients patch-tested with 2% cadmium chloride showed some reaction.
Dioxins were detected in the basement surface soil of on-site buildings at a maximum concentration of 0.000459 mg/kg. The estimated exposure doses do not exceed ATSDR's minimal risk levels (MRLs). Therefore, it is unlikely that individuals would have non-cancer health effects due to the past, intermittent exposures to the dioxin contaminated soil. The chemical can be absorbed through the skin. The estimated exposure doses are at least six orders of magnitude less than the dose which caused increased incidence of thyroid follicular cell adenoma in rats. ATSDR believes that there would be no increased risk of developing cancer with these low-level intermittent exposures (13).
Dioxins have the ability to cause chloracne. The chloracne usually occurs on the face and neck, but may extend to the upper arms, back, chest, abdomen, outer thighs, and genitalia. In mild cases, the lesions may clear several months after exposure ceases, but in severe cases they may still be present 30 years after the initial onset. In some cases the lesions may resolve temporarily and reappear later. Based on the concentration of dioxins in the surface soil samples and the limited (if any) exposures, ATSDR does not expect persons trespassing upon the site to develop chloracne.
Surface-soil samples taken from the basement of the Northern building contained 4,4'-DDT at a maximum concentration of 5.8 mg/kg. The estimated exposure doses do not exceed ATSDR's MRLs or EPA's RfD. It is unlikely that adverse non-cancer health effects would occur due to these exposures. DDT is classified by EPA as a probable human carcinogen based upon animal data. Based upon one study, the estimated exposure doses are at least four orders of magnitude lower than the dose which caused liver tumors in mice. In addition, the doses are more than four orders magnitude below the minimum dose believed to cause adverse health effects in tested animals. ATSDR believes that there is no increased risk of developing cancer based upon the above exposure scenarios (14).
No studies regarding adverse health effects in humans following dermal contact with DDT were found.
Di(2-ethylhexyl)phthalate (DEHP) was found in the building's surface soil at a maximum concentration of 4,000 mg/kg. The estimated exposure doses did not exceed ATSDR's MRLs or EPA's RfD; therefore, it is unlikely that adverse non-cancer health effects would occur due to these exposures. DEHP is classified by EPA as a probable human carcinogen based upon animal studies. The cancer effect level (CEL) in rats for the development of hepatocellular carcinomas is 300 mg/kg/day. The estimated exposure doses are at least six orders of magnitude lower than that CEL; therefore, ATSDR believes that there would be no increased risk of developing cancer due to exposure following the above exposure scenarios (15).
A study conducted on people in the past indicates the DEHP is neither a dermal irritant, nor a sensitizer in humans.
Surface soil in on-site buildings contained pentachlorophenol (PCP) at a maximum concentration of 33 mg/kg. The estimated exposure doses did not exceed health guidelines; therefore, adverse non-cancer health effects are not expected to occur. PCP is classified as a probable human carcinogen based upon animal studies. The CEL for PCP is about 17.5 mg/kg/day based upon studies done on rats. The estimated exposure doses are at least seven orders of magnitude less than that CEL. ATSDR believes that it is highly unlikely that there will be an increased risk of developing cancer due to these intermittent exposures (16).
Absorption of PCP occurs predominantly through the skin. Most of the literature concerning effects of dermal exposure to PCP in humans describe case reports of individuals exposed either occupationally or in the home during misuse of PCP-containing solutions. No studies were found which reviewed PCP exposure at the low concentrations found on-site.
Contaminants without health guidelines and are carcinogenic
Lead was detected in on-site building surface soil at a maximum concentration of 1,380 mg/kg. ATSDR has no MRL and EPA has no RfD for lead. Exposure to lead is particularly dangerous for unborn children and young children (aged 0 - 5 years) because of their greater sensitivity during development. Studies have shown that lead contamination in exterior dusts and soil at concentrations of 500 to 1000 mg/kg can begin to influence blood lead concentrations in children residing in lead contaminated areas (17). Blood lead levels may be raised above background. The estimated exposure doses for each target population are below the lowest-observed-adverse-effect-level (LOAEL) for neurological effects in monkeys (0.05 mg/kg/day). Ingestion of lead at very high levels in soil may, over time, result in neurological impairment such as learning disabilities, especially in children. ATSDR is unable to determine whether adverse non-cancer health effects are/were likely due to lack of biological data. Lead has been shown to cause cancer in animals. The estimated exposure doses are at least 100,000 times lower than the CEL in animals.
Dermal exposures are not considered to be significant in humans because the dermal absorption rate for lead is low for inorganic compounds.
Polycyclic aromatic hydrocarbons (PAHs) were detected in on-site surface soils at a maximum concentration of 80.36 mg/kg. There are currently no health guidelines available for PAHs (18). EPA and others have developed a relative potency estimate approach for the PAHs. By using this approach, the cancer potency of the other carcinogenic PAHs can be estimated based upon their relative potency to benzo(a)pyrene (BaP). In order to calculate the exposure dose and evaluate the possible non-cancer and carcinogenic health effects for these PAHs, ATSDR converted the concentrations to BaP equivalents. The equivalents were summed and an exposure dose was calculated. ATSDR has not developed MRLs for these PAHs because there are no adequate human or animal dose-response data available to identify threshold levels for appropriate non-cancer effects. Based on animal studies reviewed, the estimated exposure doses are many orders of magnitude lower than the LOAEL of 120 mg/kg/day. Mice given BaP at this dose developed aplastic anemia or had an increase in liver weight. ATSDR does not expect any non-cancer adverse health effects.
EPA has classified carcinogenic PAHs as probable human carcinogens based upon animal studies. Although there are insufficient human studies, evidence exists to indicate that mixtures of PAHs are carcinogenic to humans. This evidence comes primarily from occupational case studies of workers exposed to mixtures containing PAHs as a result of their involvement in such processes as coke production, roofing, oil refining, or coal gasification. A quantitative cancer risk estimate has thus far been developed for BaP. The cancer slope factor for BaP is 7.3 (mg/kg/day)-1 and is based on the geometric mean of risk estimates calculated from previous studies. The CEL for PAHs, based on animal studies is 0.15 mg/kg/day. The estimated exposure doses for the target populations are many orders of magnitude lower than the CEL. Therefore, carcinogenic health effects are not expected to occur.
Mixtures of carcinogenic PAHs cause skin disorders in humans; however, specific effects in humans of individual PAHs, except for benzo(a)pyrene, have not been reported. Mixtures of PAHs are also used to treat some skin disorders in humans. Some of the conditions seen include warts and blisters.
Contaminants without health guidelines
Iron (maximum concentration 424,000 mg/kg) was detected in on-site building surface soil. ATSDR has not developed MRLs and EPA does not have a RfD for iron. Generally iron excess does not occur from normal routes of exposure because the absorption of iron is regulated according to need. Although iron is an essential trace element, it can be harmful if taken in excess. The exact mechanism of iron toxicity is not known, but it may shut down cellular metabolism by competing for electrons with the normal iron-containing electron transport proteins in the mitochondria of the cells (19). Since the most likely route of exposure is via dermal contact ATSDR believes that no adverse non-cancer health effects would occur due to this exposure.
2-Methylnaphthalene, a chemical related to naphthalene and 1-methylnaphthalene was detected in on-site soils at a maximum concentration of 9.1 mg/kg. ATSDR has no MRLs and EPA has no RfD for 2-methylnaphthalene. No studies were located that documented systemic effects in humans or animals after oral or dermal exposure to 2-methylnaphthalene (20).
Surface soil in the basements of on-site buildings contained 4-nitroaniline at a maximum concentration of 0.58 mg/kg. ATSDR has no MRL and EPA has no RfD for 4-nitroaniline. ATSDR currently does not have a toxicological profile for 4-nitroaniline. Based upon occupational exposure case studies and animal studies, the chemical can be rapidly absorbed through the skin and cause methemogloblinemia(1), thereby decreasing the level of oxygen in blood. Prolonged exposure may also result in liver damage; however, exposures at the site are considered to be minimal if any (21). ATSDR does not expect such exposures to cause adverse health effects.
Dibenzofuran, a compound used as an insecticide, was detected in basement surface soil at a maximum concentration of 18 mg/kg. ATSDR has no MRL and EPA has no RfD for this compound. ATSDR has not developed a toxicological profile for dibenzofuran. Epidemiological and experimental data are needed in order for ATSDR to determine whether adverse health effects may have occurred from exposure to dibenzofuran at the maximum concentration detected. Exposures to this compound at the site are expected to be minimal if any.
Dibenzofuran has not been tested for its ability to cause cancer in animals. However, it is derived from coal tar which is a substance that causes cancer in humans. It is not known if dibenzofuran itself causes cancer but exposures to the compound at the site would have been minimal, if any.
Endrin ketone was detected in the surface soil of on-site buildings at a maximum concentration of 0.018 mg/kg. ATSDR has not developed a toxicological profile for endrin ketone nor have health guidelines been established. Acute toxicity studies in animals have shown the chemical to be toxic at concentrations more than eight orders of magnitude higher than the estimated exposure doses. Based on the information from these acute toxicity studies, ATSDR does not expect any adverse health effects to occur due to exposure to endrin ketone in the building surface soils. However, more epidemiological and experimental data are needed in order for ATSDR to accurately determine whether adverse health effects may have occurred from exposure to endrin ketone at the Pownal Tannery National Priorities List site.
Toxicological Summary
The estimated exposure dose for manganese exposure in children slightly exceeded the health guideline. Based upon studies reviewed and toxicokinetic information, adverse non-cancer health effects from exposure to manganese at the Pownal Tannery National Priorities List site are unlikely. Many of the adverse health effects described for lead exposure are the result of exposure to lead at high concentrations. The children who played upon the site were older than most children who would ingest large quantities of soil. Therefore, adverse health effects although possible are unlikely to have occurred. Arsenic, cadmium, dioxin, polycyclic aromatic hydrocarbons, and 4-nitroaniline have the potential to cause adverse health effects via dermal contact. Exposure to these chemicals are minimal, if any, and therefore the adverse health effects are unlikely to have occurred.
Increased risk of cancer is not expected to occur from intermittent exposures to arsenic, cadmium, dioxins, 4,4'-DDT, bis(2-ethylhexyl)phthalate, pentachlorophenol, and polycyclic aromatic hydrocarbons. It is not known if exposure to lead and manganese cause cancer in humans.
More epidemiological and experimental data are needed to make a conclusive determination of possible health effects from exposure to 2-methylnaphthalene, 4-nitroaniline, dibenzofuran, and endrin ketone. Exposure to these contaminants at the site are minimal, if any, and unlikely to result in adverse non-cancer health effects.
Based on the data reviewed, exposure to contaminated on-site media would cause minimal effects, if any. However, direct contact should be avoided (especially with surface soils in on-site buildings).
Review of Health Statistical Data
Exposure to on-site contaminants would have been minimal, if any. It is unlikely that adverse non-cancer health effects and increased incidences of cancer would have been seen due to such exposures. It is assumed that less than 100 persons would have trespassed upon the site. Because it is unlikely that adverse health effects would occur in the limited number of people exposed, it was determined that the review of health statistical data would not provide any meaningful information.
To ensure that the health of the nation's children is protected, ATSDR has implemented an initiative for each investigation to protect children from exposure to hazardous waste. ATSDR recognizes that the unique vulnerabilities of infants and children demand special emphasis in communities faced with contamination of their water, soil, air, or food. Infants and children are usually more susceptible to toxic substances than adults due to immature and developing organs. Children are more likely to be exposed to contaminants because they play outdoors and they often bring food into contaminated areas. These activities may increase their exposure to toxicants in dust, soil, and airborne particulate matter. Some children exhibit excessive hand to mouth behavior (pica), which may increase their intake of toxicants. Children are smaller, which results in higher doses. Most importantly, children depend completely on adults for risk identification and management decisions, housing decisions, and access to medical care. ATSDR's evaluation contained within this document considered children as a susceptible subpopulation. Children of the age group that typically display pica behavior (0 -5 years) are not believed to have played on the site.
The area around the dam represented a physical hazard in the past, but EPA has erected fencing and guard rails to prevent children from falling into the river or onto the rocks below. On-site contamination has not been fully characterized. Some of the contaminants present on the site can enter the body via touch and possibly cause adverse health effects.
ATSDR has identified people trespassing upon the site and entering the basements of on-site buildings which was a completed exposure pathway in the past. Children playing in the buildings could have been exposed to contaminated surface soils. These soils contain metals including lead and manganese, dioxin, pesticides, and semi-volatile organic compounds (SVOCs). The most likely route of exposure would have been via direct contact. Several of these contaminants can easily enter the body through the skin which will cause adverse health effects via dermal absorption.
Lead presents a significant health hazard for children and presents a difference in the pharmacodynamic(2) and pharmacokinetic(3) parameters for adults and children. Lead exposure is hazardous for unborn children and young children because they are more sensitive to lead during development. Unborn children can be exposed to lead through the placenta. Such exposures could cause premature births, smaller babies, and a decrease in mental ability.
Children are more likely to experience lead-induced adverse health effects. Children absorb lead through the gastrointestinal (GI) tract more readily than adults. They also have immature detoxification enzyme systems which lead to an increase in body burden of lead once ingested. Children have lower thresholds for neurological and hematological adverse effects from lead exposure.
Although low levels of manganese intake are necessary for human health, chronic exposure (exposures occurring over a period of one year or longer) to high manganese levels may be harmful. Children especially neonates (less than one month old) may be unusually susceptible to the effects of manganese. There is some limited evidence that prenatal or neonatal exposure of animals to elevated levels of manganese can lead to neurological changes in the newborn. A number of studies indicate that neonates retain a much higher percentage of ingested or injected manganese than adults, both in animals and in humans. The result of high retention is increased levels of manganese in tissues of exposed neonatal animals especially in the brain. Dermal exposure is not a concern since manganese has not been found to enter the body through undamaged skin.
In studies of chronic exposure, children appear to be more severely affected by arsenic than adults, probably due to higher exposure per body weight (body burden). Unborn children can be exposed via transplacental migration(4). Neural tube defects are the most predominant and consistent malformations in mammalian species tested. The association between prenatal arsenic exposure and congenital malformations has not been fully established, but in light of arsenic's teratogenic(5) potential in other mammalian species, humans are likely to be sensitive to these effects.
Health effects seen in children from exposure to toxic levels of cadmium are expected to be similar to the effects seen in adults. Children are most likely to be exposed to cadmium in food or water. Most ingested cadmium passes through the GI tract without being absorbed. Cadmium has the potential to cause adverse neurological effects; however, only a few studies have reported an association between environmental cadmium exposure and neuro-psychological functioning. Endpoints that were affected included verbal IQ, acting-out, and distractibility. The placenta may act as a partial barrier to fetal exposure to cadmium. Long-term exposures of infants and children to cadmium may result in the accumulation of cadmium in the bone.
There is limited information available on the toxicity of dioxins in children. Children seem to be unusually susceptible to the dermal toxicity of dioxin. Shortly after an accidental release of trichlorophenol contaminated with dioxin, a number of children were observed to have early irritative dermal lesions (this effect may not have been related to the dioxin) and chloracne.
A wide variety of effects have been observed in adults exposed to dioxin at work or following an accidental release of dioxin into the environment. The primary targets appear to be the skin, liver, thyroid, cardiovascular, endocrine, and immune systems; an increased cancer risk has been observed. In the absence of data to the contrary, it is likely that these organs/systems will also be sensitive targets in children. It is not known if there is an association between exposure to dioxin and developmental toxicity in humans. Dioxin appears to interfere with the development of the reproductive, immune, and nervous systems; the mechanisms of action for these toxic effects are not yet known. Dioxins may be transferred from mother to infant via the placenta and breast milk.
Human fetuses may be particularly susceptible to the toxic effects produced by Polycyclic Aromatic Hydrocarbons (PAHs). Pre- and post-natal exposure to PAHs could produce adverse reproductive and developmental effects in human fetuses. Most PAHs cross the placenta because of their lipid solubility. Because of PAH exposure, higher incidences of embryo- and fetolethality, stillbirths, resorption, and malformations of the kidney and bladder have been observed in animals. PAHs in cigarette smoke have been associated with a decrease in placental size. Children with pre-existing skin conditions, such as pemphigus vulgaris and xeroderma pigmentosum, and those with normal skin may be at increased risk of developing adverse dermal effects ranging from rashes to cancer following exposure to some PAHs, such as benzo(a)pyrene. Children with significant exposure to ultraviolet radiation, such as from sunlight, may be at increased risk of developing skin cancer due to PAH exposure.
Given the infrequency of exposure and the concentrations of the contaminants in on-site media to which children could possibly have been exposed, ATSDR believes that these adverse health effects are unlikely to have occurred in children who trespassed upon the site. The extent of on-site contamination has not been fully characterized. Therefore, to be safe, children should avoid contact with site contaminants; especially arsenic, cadmium, dioxin, PAHs, and 4-nitroaniline.
Community Health Concerns
Do current physical conditions at the site pose a public health threat?
Yes, the condition of on-site buildings and the area surrounding the main tannery building represented a physical hazard in the past, but the buildings have since been removed. Parts of the site are perched high above the Hoosic River and there are places on the site where a person could easily fall into the river or onto the rocks below. In addition, on-site contamination has not been fully characterized. Some of the contaminants present on the site can enter the body via touch and possibly cause adverse health effects.
How will my children be affected if they were to play upon the site?
Parts of the site are perched high above the Hoosic River and there are places on the site where a person could easily fall into the river or onto the rocks below. Children should not be allowed to use the site as a playground. Children have been observed fishing in the waters of the Hoosic River adjacent to the site. ATSDR does not have fish sampling data which are required in order to determine if the fish have accumulated site related contaminants. If the fish caught in the river are consumed and they have accumulated site contaminants at levels of health concern, adverse health effects could occur. The full extent of contamination on the site has not been completely evaluated. Based upon available data, exposure to contaminants on-site should be avoided. Some of the contaminants are easily absorbed through the skin and some of them may cause adverse health effects. There is a landfill on the site. In the past a child playing upon the landfill could have come into contact with contaminants buried in the landfill, but this exposure pathway has been mitigated. During summer 2000, EPAcompleted capping of the landfill. There are lagoons present on the site. Some of these lagoons contain surface waters which could pose an exposure and drowning hazard for children.
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