PETITIONED HEALTH ASSESSMENT
HERCULES DUMPSITE
(a/k/a HERCULES LANDFILL)
MANSFIELD, BRISTOL COUNTY, MASSACHUSETTS
The Agency for Toxic Substances and Disease Registry has concluded the levels of contaminants associated with the Hercules dumpsite are not likely to cause adverse health effects. The site conditions do not pose a public health threat. Contaminated surface soil and sludge at the Hercules dumpsite were evaluated to determine if chemicals are at levels of health concern. Municipal water and private well sampling results were also evaluated to determine if residents near the Hercules dumpsite are being exposed to hazardous chemicals in their drinking water. The on-site soil and sludge contamination do not pose a health threat to residential areas because of the low levels of chemicals detected. The municipal and private well drinking water samples show no evidence of contamination at levels of health concern.
The Hercules dumpsite is an inactive solid waste landfill and liquid waste lagoon in Mansfield, Massachusetts. The dumpsite was a disposal area for solid and liquid wastes generated during the production of pentaerythritol and plasticizers by Hercules Incorporated. Solid waste debris has been exposed from erosion and sludge has emanated from the landfill. Community members are concerned that the landfill wastes are contaminating drinking water and causing seizure-related health disorders in nearby residents. The Agency for Toxic Substances and Disease Registry (ATSDR) was petitioned by a community member to evaluate the potential public health impact of the Hercules dump [1]. The purpose of this public health assessment is to identify potential human exposures to contamination related to Hercules Incorporated waste disposal practices by evaluating existing on- and off-site environmental data, community health concerns, and to recommend appropriate public health follow-up activities.
Hercules Incorporated (formerly known as Hercules Powder Company) used a 29 acre area in Mansfield from 1952 to 1959 to dispose solid and liquid wastes generated during the production of pentaerythritol and plasticizers (di-n-octyl phthalate) used for multiple industrial purposes such as flame retardant additives in paint, and constituents in varnish, chewing gum, and floor coverings [2] [3]. Filter cakes and other solid wastes were disposed of in a 0.92 acre landfill and liquid pentaerythritol wastes were disposed in a 0.28 acre lagoon [4]. Specific wastes disposed at the Hercules dumpsite were pentaerythritol liquid, calcium carbonate sludge, sodium formate, residual plasticizer, and filter cakes [3]. When Hercules Inc. closed the dumpsite in 1959, the area was covered with soil and vegetated [5]. The dumpsite was purchased by the Town of Mansfield in the early 1960s. Poor cover material and erosion at the site eventually exposed several drums. Calcium carbonate and plasticizer (di-n-octyl phthalate) sludge is also emanating from the slopes of the landfill [4].
The dumpsite is in a rural area abutted by a wetland to the north, woodlands to the east and west, and Stearns Avenue to the south (Appendix A). The nearest residence is about a quarter mile from the dumpsite. Public access to the site is available; however, boulders at the dirt access road exclude motor vehicle traffic. There is evidence that hunting, target shooting, and illegal dumping have taken place on-site [4].
The Town of Mansfield, the Mansfield Board of Health, the Massachusetts Department of Environmental Protection (MADEP), and the United States Environmental Protection Agency (EPA) have conducted various environmental investigations at the Hercules dumpsite, beginning in 1978. Private well water samples near the dumpsite were collected and analyzed for limited inorganic chemicals in 1978, 1982, and 2000; sludge, sediment, soil, and drum content sampling was conducted in 1979, 1982, 1984, and 1994; surface water samples were collected and analyzed in 1984; and private well samples near the site were analyzed in 1999 and 2000 [3]. Results from these investigations are discussed in the Extent of Contamination section of this public health assessment.
Specific health concerns expressed by some community members pertaining to the Hercules dumpsite are the possibility of on-site waste materials affecting nearby private and municipal drinking water wells. Some residents are concerned that exposure of children and teenagers to on-site contamination by recreation is attributing to seizure disorders.
There are 1,829 people living within a one mile radius of the Hercules dumpsite [6]. The population is 97% white, 2% black, and 1% Hispanic, Asian or another race. Of the total population, 12% are under age 6 and 3% are age 65 years and older. In 1990 there were 541 females of reproductive age (15-44 years) in the area. Refer to Appendix A for additional demographics.
The following sections contain an evaluation of all the environmental data available for the Hercules dumpsite. In preparing this evaluation, ATSDR uses established methodologies for determining how people may be exposed to potential contamination related to the Hercules dumpsite and what harmful effects, if any, may result from such exposure. Chemical exposure pathways (or routes of physical contact with chemicals) that ATSDR evaluates are ingestion, inhalation, and skin contact. ATSDR uses comparison values (CVs), which are screening tools used to evaluate environmental data that are relevant to the exposure pathways. Comparison values are concentrations of contaminants that are considered safe levels of exposure. Chemicals detected below CVs are not likely to represent a health concern; chemicals that are detected above CVs require a more detailed evaluation of site specific exposure conditions. ATSDR also evaluates the public health implications of exposures to combinations of substances that may be present in one or more environmental media to which populations may be exposed. For a complete discussion of these criteria (quality assurance considerations, human exposure pathway analyses, health-based comparison values, and the methods of selecting contaminants above comparison values), refer to Appendix B.
There are three towns near the Hercules dumpsite that rely on groundwater as the only source of potable, or drinkable, water. The contaminants detected in on-site sludge and soil (discussed below) are mainly polycyclic aromatic hydrocarbons (PAHs) which are typically insoluble and immobile, therefore, not likely to contaminate the groundwater. However, the on-site groundwater has not been characterized and the extent of groundwater contamination beneath the dumpsite is unknown. Groundwater monitoring wells should be installed and sampled at least annually to characterize the groundwater quality and detect potential chemical migration off-site towards private wells. Since on-site groundwater quality is unknown, ATSDR evaluated the drinking water supply (municipal water and private well sampling data) for nearby residents.
While most residents in Mansfield have been supplied municipal water since the 1960s, there are several homes near the Hercules dumpsite (along Stearns Avenue and Chestnut Street) that use private wells for potable water [7]. Mansfield residents receive drinking water from the Mansfield Water Department, a municipality that obtains its water from four municipal wells in the Canoe River Aquifer [8]. These municipal wells are about 1.5 miles from the Hercules dumpsite. Municipal water is protected under the Safe Drinking Water Act and is required by EPA to be monitored for environmental contamination at certain frequencies. ATSDR reviewed past and current water quality data from the Mansfield Water Department. There were no chemicals detected in the Mansfield Water Department municipal water system above health-based drinking water guidelines [3] [9][10].
There are approximately 20 private drinking water wells within one mile of the Hercules dumpsite [3]. The nearest operating potable private well to the dumpsite is approximately 1,320 feet, however, a residence with a private well is currently under construction about 400 feet from the site [3] [11]. This private well is 380 feet deep and water quality testing for volatile organic compounds (VOCs) shows no contaminants at levels of health concern [12]. From 1978 to 1982, the Mansfield Board of Health and MADEP sampled twelve private wells nearest the Hercules dumpsite (along Stearns Avenue, Wayne Drive, and Mill Street) because of community concerns about possible contamination from the dumpsite. Water quality parameters (i.e. coliform, hardness, turbidity, etc.), VOCs, semi-volatile organic compounds, and inorganic elements were analyzed. There were no contaminants detected above health-based drinking water guidelines. About 30 private wells were tested in 1999 and 2000 by the Towns of Mansfield and Easton. Private well sampling results showed no chemical contamination above health-based drinking water standards. However, private well owners should have their wells tested at least annually to verify potable water quality.
Calcium carbonate and di-n-octylphthalate were dumped at the site during Hercules' manufacturing operations. On-site sludge and soil samples have been collected and analyzed for volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), pesticides, polychlorinated biphenyls, and metals in 1984 and 1994 [3][4]. The results of the 1984 surface soil/sludge samples showed that the chemicals detected were not at levels of public health concern. Arsenic was the only chemical detected in 1984 over ATSDR's comparison value. Comparison values are used as screening tools to determine chemicals that need further evaluation; CVs do not represent chemical concentrations that cause health effects. Arsenic was detected on-site ranging from 0.003 to 210 parts per million (ppm). The maximum concentration of 210 ppm was detected one time in 1984 at the northern section of the landfill. In 1994, the on-site arsenic concentrations ranged from 0.36 to 11.4 ppm. ATSDR's comparison value for chronic (or daily) adult exposure to arsenic in soil is 200 ppm. The average on-site soil arsenic concentration was about 12 ppm (including the one time maximum of 210 ppm); arsenic in on-site soil is below levels of health concern. Although there were no off-site residential soil samples taken, the average on-site arsenic levels closest to residential areas (across Stearns Avenue) are about 5 ppm. ATSDR's chronic exposure CV for arsenic is 20 ppm for children. Since the average on-site arsenic concentrations are below level of health concern, the average off-site arsenic levels in residential areas are not likely to exceed ATSDR's CV for children and cause adverse health effects.
Flouranthene, pyrene, di-n-octylphthalate, and 2-methlynaphthalene are waste by-products from pentaerythritol and plasticizers manufacturing and were detected in sludge emanating from three sides of the landfill slopes and in an exposed drum [4]. However, the chemicals detected in the soil and sludge were not at levels that pose a health threat [9]. These organic chemicals tend to adsorb to soil and sediment, indicating that they will not move significantly in the soil or impact the underlying aquifer. Adverse health effects are unlikely to occur from intermittent exposure to on-site soil or sludge.
Surface water runoff from the Hercules dumpsite flows north into a wetland area. Surface water samples were taken in 1984 from on-site drainage ditches. Although several metals were detected in the surface water samples, there were no contaminants at hazardous levels. In 1994, sediment samples were also collected and analyzed from on-site drainage ditches; there were no contaminants detected at hazardous levels. Adverse health effects are not likely to occur from occasional exposure to surface water runoff or sediment in on-site drainage ditches.
C. ATSDR Child Health Initiative
Children are at greater risk than adults from certain kinds of exposure to hazardous substances emitted from waste sites and emergency events. They are more likely to be exposed for several reasons. Children play outside more often than adults, increasing the likelihood that they will come into contact with chemicals in the environment. Since they are shorter than adults, they breathe more dust, soil, and heavy vapors close to the ground. Children are also smaller, resulting in higher doses of chemical exposure per body weight. The developing body systems of children can sustain damage if toxic exposures occur during certain growth stages.
Many children live in homes near the Hercules dumpsite and the numbers have increased significantly within the last decade. ATSDR closely reviewed possible exposure situations of children while evaluating this site. Some nearby residents are concerned about seizure disorders; however, ATSDR could not associate seizures with the contamination detected on-site. Although difficult to estimate, most of the scientific literature estimates the prevalence (or rate of occurrence at a given time) of epileptic (defined as two or more unprovoked seizures) and non-epileptic seizures is about 0.5 to 1% [13][14]. Risk factors for epilepsy include vascular disease, head trauma, congenital or perinatal factors, central nervous system infections, and neoplasms; however, the etiology (or cause) of epilepsy is unknown for three forths of cases [15]. Based on the available sampling data, ATSDR did not identify any chemical contaminants at levels of health concern to children living near the Hercules dumpsite. However, for more information about epilepsy, contact the Epilepsy Foundation of America at (800) 332-1000 or (301) 459-3700.
There are approximately 1.5 acres of waste disposal area on the 29 acre Hercules dumpsite. The entire site is not restricted and accessible to the public. ATSDR did not identify any physical hazards to the public during the evaluation of the site and the site visit.
ATSDR uses one of five conclusion categories to summarize findings at a site. These categories are: 1) Urgent Public Health Hazard, 2) Public Health Hazard, 3) Indeterminate Health Hazard, 4) No Apparent Public Health Hazard, and 5) No Public Health Hazard. A category is selected from site specific conditions such as the degree of public health hazard based on the presence and duration of human exposure, contaminant concentration, the nature of toxic effects associated with site related contaminants, presence of physical hazards, and community health concerns. Based on these criteria, ATSDR determined that the Hercules dumpsite presents a No Apparent Public Health Hazard based on the on-site soil and sludge contamination levels and there is no evidence of past or present municipal or private well contamination from the Hercules dumpsite.
Based upon the conclusions and information reviewed, ATSDR makes the following recommendation:
The actions described in this section are designed to ensure that this public health assessment identifies public health hazards and provides a plan of action to mitigate and prevent adverse health effects resulting from exposure to hazardous substances in the environment.
Actions Completed:
Actions Ongoing:
Action Planned:
Kimberly K. Chapman, MESH
Environmental Health Scientist
ATSDR/DHAC/EICB/PRS
Contributing Author:
Robert Williams, PhD
Toxicologist
ATSDR/DHAC/EICB/HCS
Technical Assistance:
Andrew Dent, MA
GIS Programmer/Analyst
ATSDR/DHAC/PERIS
Francisco Tomei Torres, PhD
Program Manager for Environmental Justice & Brownfields
ATSDR/OAA/OUA
Reviewers of Report:
Donald Joe, PE
Section Chief
ATSDR/DHAC/EICB/PRS
John E. Abraham, PhD
Branch Chief
ATSDR/DHAC/EICB
Review and Approval of this public health assessment for Hercules Dumpsite
Concurrence:
Environmental Health Scientist, PRS, EICB, DHAC
Section Chief, PRS, EICB, DHAC
Branch Chief, EICB, DHAC
Quality Assurance and ATSDR Methodology
Quality Assurance
In preparing this report, ATSDR relied on the information provided in the referenced documents and by contacts with the Massachusetts Department of Environmental Protection, Environmental Protection Agency, and community members. ATSDR assumes that adequate quality assurance and control measures were taken during chain-of-custody, laboratory procedures, and data reporting. The validity of the analyses and conclusions drawn in this document are determined by the availability and reliability of the information.
Human Exposure Pathway Evaluation and the use of Comparison Values
ATSDR assesses a site by evaluating the level of exposure in potential or completed exposure pathways. An exposure pathway is the way chemicals may enter a person's body to cause a health effect. It includes all the steps between the release of a chemical and the population exposed: (1) a chemical release source, (2) chemical movement, (3) a place where people can come into contact with the chemical, (4) a route of human exposure, and (5) a population that could be exposed. In this assessment, ATSDR evaluates the level of contaminants associated with the Hercules dumpsite that people living or working near may come into contact with.
Data evaluators use comparison values (CVs), which are screening tools used to evaluate environmental data that is relevant to the exposure pathways. Comparison values are concentrations of contaminants that are considered to be safe levels of exposure. Comparison values used in this document include EPA's Region III risk-based concentrations. Comparison values are derived from available health guidelines, such as ATSDR's minimal risk levels and EPA's cancer slope factor.
The derivation of a comparison value uses conservative exposure assumptions, resulting in values that are much lower than exposure concentrations observed to cause adverse health effects; thus, insuring the comparison values are protective of public health in essentially all exposure situations. That is, if the concentrations in the exposure medium are less than the CV, the exposures are not of health concern and no further analysis of the pathway is required. However, while concentrations below the comparison value are not expected to lead to any observable health effect, it should not be inferred that a concentration greater than the comparison value will necessarily lead to adverse effects. Depending on site-specific environmental exposure factors (for example, duration of exposure) and activities of people that result in exposure (time spent in area of contamination), exposure to levels above the comparison value may or may not lead to a health effect. Therefore, ATSDR's comparison values are not used to predict the occurrence of adverse health effects.
The comparison values used in this evaluation are defined as follows: The CREG is a concentration at which excess cancer risk is not likely to exceed one case of cancer in a million persons exposed over a lifetime. The CREG is a very conservative CV that is used to estimate cancer risk. Exposure to a concentration equal to or less than the CREG is defined as an insignificant risk and is an acceptable level of exposure over a lifetime. The risk from exposure is not considered as a significant risk unless the exposure concentration is approximately 10 times the CREG and exposure occurs over several years. The EMEG is a concentration at which daily exposure for a lifetime is unlikely to result in adverse noncancerous effects.
Selecting Contaminants of Concern
Contaminants of concern (COCs) are the site-specific chemical substances that the health assessor selects for further evaluation of potential health effects. Identifying contaminants of concern is a process that requires the assessor to examine contaminant concentrations at the site, the quality of environmental sampling data, and the potential for human exposure. A thorough review of each of these issues is required to accurately select COCs in the site-specific human exposure pathway. The following text describes the selection process.
In the first step of the COC selection process, the maximum contaminant concentrations are compared directly to health comparison values. ATSDR considers site-specific exposure factors to ensure selection of appropriate health comparison values. If the maximum concentration reported for a chemical was less than the health comparison value, ATSDR concluded that exposure to that chemical was not of public health concern; therefore, no further data review was required for that chemical. However, if the maximum concentration was greater than the health comparison value, the chemical was selected for additional data review. In addition, any chemicals detected that did not have relevant health comparison values were also selected for additional data review.
Comparison values have not been developed for some contaminants, and, based on new scientific information other comparison values may be determined to be inappropriate for the specific type of exposure. In those cases, the contaminants are included as contaminants of concern if current scientific information indicates exposure to those contaminants may be of public health concern.
The next step of the process requires a more in-depth review of data for each of the contaminants selected. Factors used in the selection of the COCs included the number of samples with detections above the minimum detection limit, the number of samples with detections above an acute or chronic health comparison value, and the potential for exposure at the monitoring location.
Exposure Pathway Table
Table 1. POTENTIAL EXPOSURE PATHWAY
| Pathway Name |
Source | Medium | Route of Exposure |
Exposure Elements
|
Exposure Activities | Chemicals of Concern |
||
| Point of Exposure |
Receptor Population |
Time | ||||||
| On-site Sludge | Landfill and waste lagoon | Sludge | Dermal contact | On-site | Trespassers | p, c, f | Trespassing, Recreation | PAHs |
| Key: p = past; c = current; f = future; | ||||||||
Public Comments
Response to Public Comments
ATSDR issued a draft for the public comment petitioned public health assessment on December 14, 2000 for the Hercules Dumpsite. Between December 28, 2000, and February 7, 2001, the public had the opportunity to provide comments on the draft public health assessment. ATSDR received written comments and questions from Hercules Incorporated Law Department. These comments/questions are presented below. Each italicized comment is followed by a response from ATSDR.
Hercules Incorporated
Comment: In the Purpose and Health Issues section of the public health assessment: This paragraph focuses on the waste disposal practices of Hercules Incorporated. We believe the Town of Mansfield shares responsibility for any potential human exposure. The Town of Mansfield knew the site history prior to its purchase of the property for the purpose of using it as a landfill. The Town of Mansfield has been negligent in its maintenance and control of illegal dumping. The provisions of the Consent Order which was agreed to with the Commonwealth of Massachusetts have been virtually ignored.
Response: ATSDR addresses issues affecting public health impact and cannot comment on the responsibility of liability.
Comment: In the Site Background section of the public health assessment: Hercules Incorporated was formerly known as Hercules Powder Company. The plasticizers that Hercules manufactured at the Mansfield facility were unrelated to the manufacture of gunpowder. Hercules never manufactured gunpowder at this site.
Response: ATSDR has clarified the documented upon verifying with Hercules Incorporated that solid and liquid wastes disposed at the Hercules dumpsite were generated during the production of pentaerythritol and plasticizers (di-n-octyl phthalate) that were used for multiple industrial purposes such as flame retardant additives in paint, and constituents of varnish, chewing gum, and floor coverings.
Comment: For the record, Hercules has offered to help fund site characterization and remedial actions and is in negotiations with the Town of Mansfield on cost sharing. The Town of Mansfield owns the site and has not yet granted Hercules access to it.
Response: ATSDR has not addressed this comment as it is not public health related.
Comment: In the Public Health Action Plan, Actions Ongoing section of the public health assessment: Please revise this section to read as follows:
Response: ATSDR has revised the public health assessment Public Health Action Plan, Actions Ongoing #1 as requested. The requested revision #2 was retracted on March 12, 2001 by representatives from Hercules Incorporated Law Department after an agreement was made between Hercules Incorporated and the Town of Mansfield to jointly fund the site characterization or Immediate Response Action Plan. This change has been noted in the Public Health Action Plan.
