PUBLIC HEALTH ASSESSMENT ADDENDUM
NEW BEDFORD, BRISTOL COUNTY, MASSACHUSETTS
To identify possible facilities that could contribute to the air, surface water, and surface soil contamination near the site and study area, the MDPH searched the Toxic Chemical Release Inventory (TRI) database for 1987 and 1988. TRI is developed by the U.S. EPA from the chemical release information provided by certain industries. TRI did not contain any industries within a one-mile radius of the Middle Marsh Study Area.
The following sections briefly describe the known contaminants of concern detected in the study area. Contaminants of concern are those compounds whose concentration in at least one environmental medium exceeds the health assessment comparison values established by the Agency for Toxic Substances and Disease Registry (ATSDR). The first section is utilized for preliminary screening of the contaminants. The contaminants listed in this section will be further assessed in the following sections. The presence of a contaminant in the tables does not imply that a human health threat exists. Some contaminants may be eliminated as a concern in subsequent sections.
Comparison values for health assessments are contaminant concentrations in specific media that are used to select contaminants for further evaluation. These values include Environmental Media Evaluation Guides (EMEGs), Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines. CREGs are estimated contaminant concentrations based on a one excess cancer in a million persons exposed over a lifetime. CREGs are calculated from EPA's cancer slope factors. EPA's Maximum Contaminant Level Goal (MCLG) is a drinking water health goal. The EPA believes that the MCLG represents a level that no known or anticipated adverse effect on the health of persons should occur which allows an adequate margin of safety. Proposed Maximum Contaminant Level Goals (PMCLGs) are MCLGs that are being proposed. Maximum Contaminant Levels (MCLs) represent contaminant concentrations that the EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters of water per day. While MCLs are regulatory concentrations, PMCLGs and MCLGs are not. EPA's Reference Dose (RfD) and Reference Concentration (RfC) are estimates of the daily exposure to a contaminant that is unlikely to cause adverse health effects.
Environmental monitoring was conducted on June 26-28, 1989 as part of the "Middle Marsh Investigation" and during May and October 1990 as part of the supplemental remedial investigation [4,7]. Environmental samples were collected from the Middle Marsh, adjacent wetland areas, the unnamed stream, and selected areas of the golf course.
Soil/Sediment (0-6 inches)
Aroclor 1254, a polychlorinated biphenyl (PCB), was detected in the majority of the samples. Generally, the concentrations ranged from 10 to 30 parts per million (ppm) and were highest in the unnamed stream and in the upstream areas closest to the Sullivan's Ledge Disposal Area. Pesticides, volatile organic compounds (VOCs), semi-VOCs, and some metals were detected in the study area at low levels. Manganese and iron concentrations were elevated in the sediment/soil. The elevated levels of iron could explain the reddish-brown color observed in the stream sediment during the site visit. Iron will not be considered further in this health assessment because it is not considered a toxic compound. Please refer to Table B-1.
The samples were collected from the top 15 centimeters of soil during the Middle Marsh Investigation and were composites from the top six inches of soil during the Remedial Investigation (RI). Composites from the top six inches of soil might not be representative of what is actually present in the top inch or two of soil. The samples from the RI were also composites from multiple sampling locations covering a ten-foot radius. Soil composites tend to over- or underestimate what is actually present on site. The highest Aroclor 1254 concentration detected was 22.5 ppm but 15 out of 18 samples had Aroclor 1254 concentrations less than 8 ppm.
No data exist for contaminant concentrations in the fugitive dusts that might be generated due to dry surface sediment/soil conditions in the study area. This represents a data gap because the various activities in the study area could result in fugitive dust generation if dry conditions exist in the surface sediment/soil.
Core sampling stations were utilized to collect subsurface sediment/soil samples in the study area (Figure A-2). PCB contamination was generally found to decrease with depth. The highest concentration (97 ppm) of PCB (Aroclor 1254) was located near the unnamed stream in the adjacent wetland. Aside from this high concentration, all other samples contained Aroclor 1254 concentrations of less than 27 ppm. Pesticides, VOCs, and semi-VOCs were detected infrequently and at low concentrations. Metals were generally detected in the same concentration range as in the surface soils. Please refer to Table B-2.
Pore water samples were collected when water was present at the sediment/soil core sample station. A perforated PVC well point was inserted into the two-foot core holes and samples were collected from the well points with PVC bailers. Aroclor 1254 was detected in both the filtered and unfiltered water samples at concentrations of 0.2 to 4.4 parts per billion (ppb) and 1.8 to 2.9 ppb, respectively. PCBs in the unfiltered samples are probably dissolved in the water as well as adsorbed onto particulates in the water. VOCs, semi-VOCs, and metals were detected infrequently and at low concentrations in the pore water samples. Please refer to Table B-3.
During the RI, surface water samples were collected when water was present at the sediment/soil (0-6 inches) sampling stations. PCB and metals analyses were conducted on both the filtered and unfiltered samples. Surface water samples were generally collected directly into the sample containers prior to removal of sediment/soil samples. When standing water depth was too low to collect directly into the sample containers, a decontaminated stainless steel scoop was used to collect the sample. PCBs were detected at lower concentrations when compared to the pore water samples. Concentrations ranged from not detected to 0.19 ppb for filtered samples and 0.98 to 4.9 ppb for unfiltered samples. PCBs in the unfiltered samples are probably dissolved in the water as well as adsorbed onto particulates in the water. Iron, lead, magnesium, and manganese were detected at elevated concentrations in both the filtered and unfiltered surface water samples. VOCs and semi-VOCs were detected infrequently and at levels near or below the method detection limit and below available comparison values.
Seven surface water samples were collected during the Middle Marsh Investigation from the unnamed stream and surface water in the Middle Marsh. The unfiltered samples were analyzed for pesticides and PCBs. Pesticides were not detected in the samples and PCBs were detected in one sample at a concentration of 0.35 ppb. Please refer to Table B-4.
Tissue samples were collected in the Middle Marsh Study Area from aquatic insects, earthworms, frogs, small mammals, and plants. PCBs were detected in all the animal but not the plant species. Please refer to Table B-5.
No data exist for contaminant concentrations in the tissue samples of fish in the study area. This represents a data gap because fish are the biota that would most likely be consumed by individuals in the study area.
All sampling locations will be considered on-site for the purpose of this addendum because all samples were collected within the Middle Marsh Study Area which is an operable unit of the Sullivan's Ledge site.
The Quality Assurance/Quality Control (QA/QC) summary was obtained from the RI and information relevant to field data and laboratory data quality was reviewed. The initial set of unfiltered water data for PCBs was rejected due to analytical problems and therefore was not utilized for this health assessment. The initial set of filtered water samples identified Aroclor 1260 as well as Aroclor 1254. However, further analysis via chromatography indicated that the Aroclor 1260 was actually highly weathered Aroclor 1254. Some sediment/soil and surface water samples were found to contain methylene chloride, acetone, and 2-butanone. This was generally determined to be the result of laboratory contamination because these compounds were also found in the blanks. During metals analysis, low concentrations had to be estimated due to the analytical methodology. The EPA determined that these samples were still valid and usable despite the estimation.
The QA/QC program for the Middle Marsh Investigation included the collection of duplicate and blank samples. The results of the duplicate and blank samples were sufficient to insure the adequacy of the sample results.
The presence of physical and other hazards in the Middle Marsh Study Area was investigated during the August 1,
1991 site visit. The water hazards at the golf course and the unnamed stream represent the only physical hazards to
individuals present in the study area.
To determine whether nearby residents are exposed to contaminants migrating from the site, the ATSDR evaluates the environmental and human components that lead to human exposure. This pathways analysis consists of five elements: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population.
The ATSDR identifies exposure pathways as completed, potential, or eliminated. Completed pathways require that the five elements exist and indicate that exposure to a contaminant has occurred in the past, is currently occurring, or will occur in the future. Potential pathways, however, require that at least one of the five elements is missing but could exist. Potential pathways indicate that exposure to a contaminant could have occurred in the past, could be occurring now, or could occur in the future. Eliminated pathways require that at least one of the five elements is missing and will never be present. Completed and potential pathways may also be eliminated when they are unlikely to exist. Table C-1 identifies the completed exposure pathways, and Table C-2 identifies the potential exposure pathways. The discussion that follows incorporates only those pathways that are important and relevant to the site.
Two pathways, namely, subsurface sediment/soil and pore water, have been eliminated from further discussion in this report because there has been no exposure to the contaminants in these media nor is there expected to be any exposure in the future that would result in adverse health effects. Elevated levels of PCBs, metals, and polynuclear aromatic hydrocarbons (PAHs) were detected in these media. However, these contaminants are present in the subsurface and exposure could only occur through disruptive activities, such as building or digging, in the study area. It is not expected that future disruptive activities will occur in the study area which could expose the residents, golfers, and workers in the area to these subsurface contaminants.
Surface Water Pathway
Past, current, and future exposure pathways are possible from contamination of surface water in the unnamed stream and the golf course water hazards. Potentially exposed populations include golfers, workers at the golf course, and children who access the study area. Please refer to Table C-1.
Surface water data show the migration of Aroclor 1254 and metals (lead and manganese) from the Sullivan's Ledge Disposal Area to the Middle Marsh Study Area via sediment and surface water migration from the unnamed stream.
In the Middle Marsh Study Area, the number of individuals accessing the surface water would be limited to the occasional golfer who had to retrieve a golf ball and the children who have been observed playing on the site. These individuals would be contacting the contaminants via accidental ingestion or dermal exposure. Dermal contact is not expected to be a primary exposure route because the contaminants of concern present in the surface water are generally not absorbed through the skin in large quantities.
The children who access the unnamed stream and water hazards might accidentally ingest small quantities of surface water. Adults who access the study area are not expected to ingest the surface water. Therefore, this exposure route is not of concern for the adults in the study area.
Sediment/Soil (0-6 inches) Pathway
Past, current, and future exposure pathways are possible from contamination of the sediment/soil (0-6 inches) in the Middle Marsh, banks of the unnamed stream, and the golf course. Potentially exposed populations include golfers, workers at the golf course, and children who access the study area. Please refer to Table C-1.
Sediment/soil (0-6 inches) data show the migration of Aroclor 1254, PAHs, and metals (lead and manganese) from the Sullivan's Ledge Disposal Area to the Middle Marsh Study Area via sediment migration from the unnamed stream. The principle routes of exposure to sediment/soil contaminants is through accidental ingestion of sediment/soil. Dermal contact with contaminated sediment/soil or inhalation of contaminated fugitive dusts can also occur. However, these are not considered important routes of exposure because: (1) the contaminants present in these media will not be absorbed through the skin in large quantities, and (2) fugitive dusts will only be present if weather conditions cause the sediment/soil (0-6 inches) to dry out.
Children, particularly <6 years old, are most likely to accidentally ingest sediment/soil (0-6 inches) due to their greater hand to mouth activity. These young children typically ingest 200 milligrams (mg) of soil per day while older children and adults ingest less than 100 mg per day.
Some metals could be present on fugitive dust particles but a lack of data does not allow for evaluation of exposure via this route. Inhalation of contaminated fugitive dusts is possible during summer months when the golf course and Middle Marsh might be drier than usual due to warm weather. Although exposure via this pathway is likely to be minimal, it is not possible to determine the degree of exposure without ambient air or fugitive dust data.
Past, current, and future exposure pathways are possible from contamination of biota in the unnamed stream, Middle Marsh, and golf course water hazards. Children have been observed fishing in the golf course water and adults have been known to fish and hunt in the site area. However, it is not known if the fish and wildlife are consumed by the individuals participating in these recreational activities. Please refer to Table C-2.
Although the data indicate that PCBs have bioaccumulated in the biota (frogs, insects, small mammals, and earthworms) around the study area, the only possible exposure pathway is through ingestion. It is not expected that the types of biota sampled will be ingested by adults or children.
There are no data available for potential contamination of fish in the study area. However, based on the data for the
other biota as well as the environmental data, it is not expected that fish tissue will be highly contaminated.
Therefore, it is unlikely that ingestion of fish from the study area will result in adverse health effects.
This section will discuss the health effects in persons exposed to specific contaminants. To evaluate health effects, the ATSDR has developed minimal risk levels (MRL) for contaminants commonly found at hazardous waste sites. The MRL is an estimate of daily human exposure to a contaminant below which non-cancer, adverse health effects are unlikely to occur. The MRLs are developed for each route of exposure, such as ingestion and inhalation, and for length of exposure, such as acute (less than 14 days), intermediate (15-364 days), and chronic (greater than 365 days). The ATSDR presents these MRLs in the Toxicological Profiles. These chemical specific profiles provide information on health effects, environmental transport, human exposure, and regulatory status. In the following discussion, the ATSDR Toxicological Profiles and other sources were used for Aroclors, lead, manganese, zinc, and PAHs .
Exposure to PCBs has probably occurred and could be occurring due to the contamination of sediment/soil (0-6 inches) and the surface water in the Middle Marsh Study Area. Biota in the study area have also been found to contain PCBs in their tissue. However, it is not known to what extent the biota are consumed.
Children are most at risk of exposure through ingestion of and contact with contaminated sediment/soil (0-6 inches) and surface water. Adults may be exposed to low levels of PCBs due to dermal absorption resulting from contact with contaminated sediment/soil (0-6 inches) and surface water. Adults are not expected to be exposed via ingestion of contaminated sediment/soil (0-6 inches) and surface water.
The ATSDR has established a chronic MRL of 5x10-6 mg/kg/day for PCB exposure via ingestion. The ATSDR has also established CREGs of 0.091 and 0.045 ppm for soil and water, respectively. To estimate chronic exposure to PCBs from ingestion, a range of exposure scenarios was examined. Estimations of chronic exposure doses exceed the chronic MRL. However, it is expected that any exposure at the site will be acute. Based on the concentrations detected, it is unlikely that adverse non-carcinogenic health effects will occur due to the expected acute exposures in the study area.
PCBs are classified as B2 carcinogens indicating that they are probable human carcinogens. A B2 classification indicates that sufficient animal evidence exists but there are inadequate or no data available to suggest carcinogenicity based on human evidence. Based on the concentrations detected and the expected exposure duration in the study area, it is unlikely that cancer endpoints will result due to ingestion of sediment/soil (0-6 inches) and surface water in the study area.
There is no methodology to determine the amount of absorption of chemicals through the skin. As a result, there are no MRLs for skin exposure and it is difficult to determine the health effects from dermal exposure.
Exposure to lead probably has occurred and could be occurring to individuals accessing the study area due to ingestion of and contact with sediment/soil (0-6 inches) and surface water. The ATSDR has no MRLs and the EPA has no RfDs for lead. The comparison values are currently being re-evaluated by the ATSDR, the EPA, and the Centers for Disease Control (CDC).
Sediment/soil (0-6 inches) and surface water ingestion are the primary exposure pathways with relation to lead contamination in the study area. Adult residents are not expected to be at an increased risk of these effects because ingestion is the primary exposure route. It is not expected that adult males and females will be ingesting large quantities of contaminated surface water or sediment/soil (0-6 inches). Primary exposure is to children who might be ingesting sediment/soil (0-6 inches) or surface water. Young children around the site are the group most sensitive to lead exposure.
Based on the concentrations detected, it is not likely that intermittent exposure to contaminated sediment/soil (0-6 inches) and surface water will result in adverse carcinogenic or non-carcinogenic health effects.
There is no methodology to determine the amount of absorption of chemicals through the skin. As a result, there are no MRLs for skin exposure and it is difficult to determine adverse health effects from dermal exposure.
Exposure to manganese probably has occurred and could be occurring to individuals on-site due to ingestion of or contact with sediment/soil (0-6 inches) and surface water. The ATSDR does not have a MRL for manganese ingestion, but the EPA has established an oral RfD of 0.1 mg/kg/day. The maximum dose possible in the study area does not exceed the RfD. Therefore, no adverse non-carcinogenic health effects are likely from exposure to manganese.
Manganese is not given a carcinogenicity class and there is no evidence of carcinogenicity due to manganese exposure. Adverse carcinogenic health effects are not expected due to exposure to manganese in the study area.
There is no methodology to determine the amount of absorption of chemicals through the skin. As a result, there are no MRLs for skin exposure and it is difficult to determine adverse health effects from dermal exposures.
Exposure to zinc probably has occurred and could be occurring to individuals due to ingestion of sediment/soil (0-6 inches) in the study area. The ATSDR does not have an ingestion MRL for zinc but the EPA has established the RfD for ingestion at 0.2 mg/kg/day. Since the estimated dose does not exceed the RfD, adverse health effects are not likely in any segment of the population from exposure to this compound.
Polynuclear Aromatic Hydrocarbons (PAHs)
Exposure to PAHs probably has occurred and could be occurring to individuals on-site due to ingestion and dermal contact with sediment/soil (0-6 inches) in the study area. The ATSDR does not have a MRL nor does the EPA have a RfD for PAHs.
Individual PAHs are classified as being carcinogenic or non-carcinogenic. For the purpose of this addendum, PAHs are separated into two groups, namely, total carcinogenic PAHs and total non-carcinogenic PAHs. Based on the information in the ATSDR Toxicological Profile, it is not likely that adverse carcinogenic or non-carcinogenic health outcomes will result due to the low concentrations of PAHs detected in the study area.
Three health reports, summarized below, were completed for the New Bedford area prior to this addendum.
The Greater New Bedford PCB Health Effects Study, 1984-1987, Massachusetts Department of Public Health, Massachusetts Health Research Institute, and the U.S. Centers for Disease Control.
This health effects study consisted of two phases. Phase I was designed to determine the prevalence of elevated serum PCB levels among residents of greater New Bedford and to test the hypothesis that serum PCB level is associated with elevated blood pressure measurements. Phase I was also used to attempt to identify 150 exposed persons who would participate in a Phase II study to determine the relationship between serum PCB levels and a variety of outcomes.
Phase I consisted of 840 adult residents from New Bedford, Acushnet, Dartmouth, and Fairhaven. Eleven (1.3%) of the participants had elevated serum PCB levels (<30 ppb). Blood pressure levels did not seem to be correlated with serum PCB levels.
Health Assessment for the Sullivan's Ledge Site, Massachusetts Department of Public Health, Division of Environmental Health Assessment, 1988.
The health assessment was conducted in order to qualitatively assess the potential for adverse health outcomes due to exposure to contaminants from the Sullivan's Ledge Site. It was concluded that the site is of public health concern because of the risk to human health resulting from probable exposure to hazardous substances at concentrations that may result in adverse health effects. Based on the available scientific literature and community concerns, the incidence of leukemia and liver cancers was evaluated as part of the health assessment. These cancers did not appear to be elevated near the site. For a detailed description of the health outcome data in the health assessment, please refer to Appendix E.
New Bedford Liver, Leukemia, and Bladder Cancer Incidence 1982-1986, Massachusetts Department of Public Health, Division of Environmental Health Assessment, Community Assessment Unit.
In October 1990, the MDPH completed a review of cancer incidence data for 1982-1986 for leukemia, liver, and bladder cancer among residents of the City of New Bedford. Site specific cancer incidence data for New Bedford were analyzed to compare the actual number of cases to the number that would have been expected based on the statewide cancer incidence experience. Standardized incidence ratios (SIRs) were calculated for all three cancer types for the town as a whole and for each individual census tract. SIRs, which are adjusted for age and sex, are a measure used to compare the cancer incidence experience in a specific population with that of a larger, more stable population. It appeared that the overall cancer rates in New Bedford were returning to what would be expected based on the statewide experience. No unusual rates or patterns of cancer incidence were noted for any of the cancers assessed for the years 1982-1986. Limited information was available for smoking status and occupational history for the cancer cases. Therefore, the roles of these two factors in the development of cancer could not be determined.
Current Descriptive Health Study
As part of this addendum to the Sullivan's Ledge Health Assessment prepared on behalf of the ATSDR through the Massachusetts Demonstration Program, the Community Assessment Unit of the MDPH conducted an investigation of cancer incidence in the City of New Bedford and the Town of Dartmouth. This investigation was conducted to update the data presented in the report entitled "New Bedford Liver, Leukemia, and Bladder Cancer Incidence 1982-1986, Massachusetts Department of Public Health, Division of Environmental Health Assessment, Community Assessment Unit." Standardized Incidence Ratios (SIRs) were calculated for several cancers for the period 1982-1988 by census tract and for the city and town as a whole. SIRs were calculated for liver and bladder cancers, as well as for leukemia. Cancers were selected for investigation based upon the previous contaminants present at the site.
For the purpose of this assessment, particular emphasis was placed on the census tracts within a one-mile radius of the Sullivan's Ledge Site and the Middle Marsh Study Area, including 6502, 6509, and 6510 in New Bedford, and 6531 in Dartmouth. Please refer to accompanying tables and figures located in Appendix D.
Cancer incidence data for the years 1982-1988 were obtained for the City of New Bedford and the Town of Dartmouth from the Massachusetts Cancer Registry (MCR) of the MDPH Bureau of Health Statistics, Research and Evaluation (BHSRE). The MCR has been monitoring cancer incidence in the Commonwealth since 1982. The seven-year period 1982-1988 is the most recent for which complete data exist.
In order to determine whether an elevated rate of cancer exists in New Bedford or Dartmouth, cancer incidence data were analyzed by age and sex to compare the actual (or observed) number of cancer cases to the number that would have been expected based on the statewide cancer incidence experience.
Reliable population information is necessary to calculate incidence rates. The population figures for New Bedford and Dartmouth were obtained by calculating the percentage of increase or decrease from the 1980 census information based on the 1984 MISER population estimates [6,12]. The percentage of growth or decline was applied to each of the four census tracts within a one-mile radius of the site to calculate the population for the area.
A standardized incidence ratio (SIR) is an estimate of the occurrence of disease in a population in relation to what might be expected if the population had the same cancer experience as some larger population designated a "normal" population.
Overall, for males and females combined, 1982-1988 cancer incidence in the City of New Bedford and the Town of Dartmouth was about what would be expected based on Massachusetts statewide cancer incidence rates. Slight elevations were noted in leukemia and liver cancer incidence among females in New Bedford and among males in Dartmouth. However, these elevations were based on a small excess in the number of cases and were not statistically significant. These data are summarized in Tables D-1 through D-3.
- Census Tract Analysis
Analysis of individual census tracts 6502, 6509, and 6510 in New Bedford and 6531 in Dartmouth revealed that cancer cases for the most part have occurred essentially as would be expected. No significant elevations were observed among males, females, or among both sexes combined.
An elevation in bladder cancer was noted among males and among both sexes combined in census tract 6502, as well as among females in census tract 6531. However, these elevations were due to a small excess in the number of cases which may be attributed to natural variations in the pattern of cancer incidence. These data are summarized in Tables D-1 through D-3.
A comparison was made between the 1982-1986 data and the 1982-1988 data in order to determine the number of cancer cases that have occurred since 1986. There were no new liver cancer cases in New Bedford between 1986 and 1988. A total of eighteen new leukemia cases were observed between 1986 and 1988 when 16.6 cases were expected between this time period. Three of the leukemia cases occurred within one mile of the site (1 case in CT 6502 and 2 cases in CT 6510). Twenty-six new bladder cancer cases were observed between 1986 and 1988 when 42.3 new cases were expected. During this time period, 4, 1, and 2 new bladder cases occurred within one mile of the site in CT 6502, 6509, and 6510, respectively.
- Geographic Distribution
Various attempts were made to evaluate the place of residence at the time of diagnosis for individuals with cancers of the bladder and liver, and leukemia in the census tracts within a one-mile radius of the golf course adjacent to the Sullivan's Ledge site.
In New Bedford, the analysis of the geographic distribution of cancer incidence in census tracts 6502, 6509, and 6510 revealed that cancer cases were fairly evenly distributed within each census tract.
Cancer cases could not be mapped in Dartmouth due to insufficient address information; thus the geographic distribution of cancer incidence in census tract 6531 could not be assessed.
As stated previously, communication with the EPA and the New Bedford Health Department did not reveal any information regarding community health concerns [8,10]. According to the EPA, residents in the area and the adults accessing the golf course are aware of the contamination at the Sullivan's Ledge Disposal Area as well as the Middle Marsh Study Area but are not concerned about adverse health effects. The citizens do not see Middle Marsh as a problem and they support a no action alternative for this area during the remedial phase.