PUBLIC HEALTH ASSESSMENT
NYANZA CHEMICAL WASTE DUMP
ASHLAND, MIDDLESEX COUNTY, MASSACHUSETTS
To identify possible facilities that could contribute to the air, water, and soil contamination near the Nyanza site, the MDPH searched the Toxic Chemical Release Inventory (TRI) database for 1987 and 1988. TRI is developed by the EPA from the chemical release information provided by certain industries. TRI contained four industries within a one-mile radius of the Nyanza site. The chemicals listed on the TRI for these four facilities include sulfuric acid, hydrochloric acid, 1,1,1-trichloroethane, toluene, methanol, dimethylphthalate, dibutylphthalate, tert-butyl alcohol, and antimony compounds.
The tables in Appendix B list the contaminants of concern. We evaluate these contaminants in the subsequent sections of the public health assessment and determine whether exposure to them has public health significance. The ATSDR selects and discusses these contaminants based upon the following factors:
- Concentrations of contaminants on and off the site.
- Field data quality, laboratory data quality, and sample design.
- Comparison of on-site and off-site concentrations with comparison values for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints.
- Community health concerns.
In the data tables presented in Appendix B, the listed contaminant does not
mean that it will cause adverse health effects from exposures. Instead, the
list indicates which contaminants will be evaluated further in the public health
|The data tables include the following acronyms:|
||= Cancer Risk Evaluation Guide|
||= ATSDR Environmental Media Evaluation Guide|
||= EPA Maximum Contaminant Level|
||= EPA Maximum Contaminant Level Goal|
||= EPA Reference Dose|
||= EPA Lifetime Health Advisory|
These comparison value contaminant concentrations in specific media 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 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. 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 ingestion 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.
Compounds of potential concern consist of the hazardous compounds associated with on-site dye manufacturing activities, and were obtained from records of Nyanza, Inc.'s raw product purchases and dye products. Generally, on-site environmental media were not monitored for these compounds of potential concern consisting of benzidine, o-tolidine, dye stuffs, and intermediates resulting from these compounds. Chlorinated and nitrated phenols, anilines, and benzenes were also purchased by Nyanza, Inc., and probably its predecessors, and were detected in on-site media. However, monitoring for these compounds was erratic.
Contamination at the Nyanza site has been investigated by different state and federal environmental agencies, as well as private contractors. A summary of the environmental media/contaminant monitoring program for each investigation follows.
Since 1970, at various times the U.S. Fish and Wildlife Service (USFWS), the Massachusetts Department of Fish and Wildlife (MDFW), the Department of Water Pollution Control (DWPC), and private contractors have monitored for mercury contamination in the sediments, surface waters, and fish at and near the Nyanza site including the Sudbury River and its reservoirs. In 1985, the RI was conducted for OU I. This report involved the collection and analysis of soil, sludge, sediment, groundwater, surface water, and ambient air samples for some or all of the following parameters: VOCs, semi-VOCs, and metals. Between 1986 and 1987, the EPA and private contractors sampled the soil, surface water, groundwater, ambient air, and sediments on-site including the wetlands, Chemical Brook, Trolley Brook, and Nyacol Corporation antimony pits. Off-site samples collected during this time period were analyzed for VOCs, semi-VOCs, and metals. During this time period, the EPA also monitored indoor air and water found in flooded residential basements in the vicinity of the site.
Between 1989 and 1990 as part of the RI for OU II, groundwater, surface water, sediment, soil and potable water samples were collected on-site and in the study area. These samples were screened for VOCs, semi-VOCs, metals, and other specific compounds that were thought to be related to the site activities (i.e., aniline, o-anisidine, p-cresidine, benzidine, 1-naphthylamine, 3,3'-dimethoxybenzidine (o-dianisidine), and 3,3'-dimethylbenzidine (o-tolidine)) .
In January of 1989, indoor air monitoring was performed by the EPA in the basement of a church located about 2,000 feet northeast of the site [35,51]. In June 1989, the contents of barrels found buried on Megunko Hill during the OU I remediation were screened and compatibility tested for disposal purposes [1,81]. In 1990, the EPA conducted a one day indoor air screening survey in the basements of the Town Hall and residential homes located on Pleasant Street, Tilton Avenue, Cherry Street, and Metcalf Avenue.
In 1989, the EPA monitored on-site soils for dimethylmercury and surface water for methylmercury . The U.S. Army Corps of Engineers (USACE) monitored ambient air for baseline levels of dimethylmercury prior to soil and wetland excavations during the OU I remediation .
The Phase I activities for the OU III RI/FS were completed in March 1990 . Surface water, sediment, and fish samples from the Sudbury River and associated reservoirs and tributaries were monitored for contaminants.
In 1971, the EPA sampled wastewater and sludge from various points in the former Nyanza, Inc. treatment system, and detected high levels of mercury . During the vault study , vertical composites of samples (0-4, 4-6 to 10 foot depth intervals) were obtained from three bore holes in the vault. A composite sludge sample was analyzed in 1987 during the vault removal. Compounds of concern detected in the vault include: trans-1,2-dichloroethene, (1,2-DCE), 1,2-dichlorobenzene (1,2-DCB), antimony, chromium, lead, mercury, trichloroethene (TCE), chlorobenzene, 1,3-dichlorobenzene (1,3-DCB), 1,4-dichlorobenzene (1,4-DCB), nitrobenzene, and aniline. Generally, higher contaminant levels were detected in the deeper composites which were generally discolored purple and pink. The solidified sludge (2,518 tons) was excavated from the vault and disposed of off-site in 1988. The data are presented in Table B-1.
In May of 1989 during the OU I remediation, the EPA discovered approximately 200 barrels buried on the hill portion of the site . Several barrels still contained purple and amber colored material. The air inside the barrels was screened for VOCs and the following compounds of concern were detected: benzene, ethylbenzene, toluene, TCE, DCE, and 1,1-DCE. Benzene was detected at the highest concentration of 265 parts per billion (ppb). The barrels were overpacked and disposed of off-site.
Between 1984 and 1989, surface and subsurface soil samples were collected from various places within the study area including the hill, wetland, lagoon area, adjacent to the vault, and in the lower industrial area around Nyacol. The soil data are presented in Table B-2.
- Surface Soils
Three surface soil samples were collected in 1985 from the antimony pits located on the lower eastern side of Megunko Hill. These samples were composites from the top three inches of soil and were monitored for inorganic compounds. The compounds of concern detected in these soil samples include chromium, lead, mercury, and antimony.
- Subsurface Soils
In 1984, 41 vertical composite samples were collected from the Megunko Hill, five samples were collected from the area between the hill and the northwest wetland, and 19 samples were collected from the low lying area north of Megunko Road. These samples were analyzed for heavy metals, total organic carbon (TOC), and total organic halogen (TOH). Surficial sludge and purple colored soil were noticed on Megunko Hill and between the hill and the wetland, respectively.
In 1985, five subsurface soil composites (1.5 to 2 feet) were collected from the antimony pits and analyzed for inorganic compounds.
Soil samples were composites from 2 foot intervals from the soil borings conducted near the Nyacol lagoons. A layer of maroon sludge was observed between 10 and 12 feet in some borings and below this depth the soil was often discolored black. These samples were analyzed for hazardous substance list (HSL) compounds. The samples collected closest to the ground surface contained the lowest levels of contamination and the sludge layer contained the highest levels of contaminants.
In 1987, soil samples were collected from bore holes adjacent to the vault. Soil and incinerator ash monitoring was also conducted in 1987 during the emergency removal actions pertaining to the vault. Three hundred and twelve tons of contaminated soil were removed from around the vault and incinerated. The ash was backfilled into the excavation and covered with clean fill. One soil sample from the excavation area and four ash samples were collected and analyzed.
During the 1988 preliminary activities of the RI/FS for OU II, subsurface soil samples were collected from the northern part of the lower industrial area, the northeast corner of the site between Megunko Road and the Conrail tracks, and the southeastern border of the site. In the lower industrial area, layers of purple and brown stained material were observed between 45 and 51 feet and one bore hole contained black greasy material within the fill layer (approximately 5 to 15 feet deep).
During June and July 1989, twenty-seven soil samples were collected from three to six inches depth in the northwest wetland. These samples were screened in the field for dimethylmercury and analyzed in the laboratory for total mercury. In July 1989, 75 samples (at unknown depths) were collected from various parts of the site and screened for dimethylmercury.
Compounds of concern detected during the various subsurface soil investigations include mercury, chromium, lead, antimony, chlorobenzene, 1,2-DCB, 1,3-DCB, 1,4-DCB, 1,2,4-TCB, nitrobenzene, TCE, trans-1,2-DCE, aniline, pentachlorophenol, naphthalene, and dimethylmercury.
Between 1973 and 1989, surface water samples were collected from various on-site sources including Trolley Brook, Chemical Brook, the wetlands, basins on Megunko Hill, and a spring located on the southeast side of the hill. Samples were analyzed for VOCs, metals, and semi-VOCs. Chlorinated VOCs and inorganic contamination have been detected in the surface water bodies.
Compounds of concern detected in the surface water bodies are as follows: (1) Trolley Brook: mercury, chromium, and lead; (2) Chemical Brook: mercury, nitrobenzene, trans-1,2-dichloroethylene, chlorobenzene, chromium, lead, and antimony; (3) Spring: aniline, 1,2-DCB, nitrobenzene, chlorobenzene, 1,4-DCB, chromium, lead, mercury, and TCE; (4) Basins: antimony, chromium, lead, and mercury; and (5) Wetland: mercury, methylmercury, and dimethylmercury. The concentrations detected were generally less than 100 ppb in the surface water samples. The surface water data are presented in Table B-3.
In 1973, 3-foot composite samples were collected from the on-site wetlands and analyzed for mercury. One sample was also collected from the Trolley Brook wetlands and analyzed for mercury. In 1985, seven sediment samples collected from the Trolley Brook wetlands and northwestern wetlands were monitored for heavy metals. Compounds of concern detected in wetland sediment were mercury, chromium, and lead at maximum concentrations of 4,985 ppm, 6,600 ppm, and 1,200 ppm, respectively. The highest mercury concentrations were detected in the 0-3 and 3-6 foot vertical composites. Wetland sediment data are presented in Table B-4.
- Chemical Brook
Two samples were collected from Chemical Brook during the preliminary investigation for OU II and analyzed for target compound list (TCL) constituents. Both samples were collected east of the northwest wetland. Compounds of concern detected in the samples include antimony, chromium, mercury, lead, chlorobenzene, TCE, 1,2-DCB, 1,2,4-TCB, and nitrobenzene. The sample collected closest to the northwest wetland contained higher concentrations of inorganic compounds when compared to the other sample. The Chemical Brook sediment data are presented in Table B-4.
Groundwater contamination was examined during the RIs for OU I and OU II [3,18,19]. In addition, limited groundwater monitoring was conducted as part of the vault investigation . For the description of the on-site groundwater contamination, the site will be divided into four areas. Groundwater data are presented in Table B-5.
- Megunko Hill
In the Megunko Hill area, the bedrock and overburden wells contained the following compounds: 1,2-DCE, TCE, chlorobenzene, 1,2-DCB, nitrobenzene, aniline, lead, chromium, antimony, mercury, vinyl chloride, and 1,4-DCB. No organic compounds were detected in the monitoring well on the uphill area along the southwestern border of the site. Concentrations of organic compounds were lower along the southeastern and northwestern borders of the site. Metal concentrations were generally consistent throughout the hill area except for mercury which was generally greater in downslope locations. Concentrations detected in the bedrock wells tended to be comparable to the overburden aquifer with the highest concentrations detected west and southwest of the lined lagoons.
- Low lying industrial area
The low lying industrial area is divided into two sub-areas. The first includes the area east of the lined lagoons to the portion of Megunko Road separating the Nyacol headquarters from the undeveloped Trolley Brook Wetlands area. The second area is located east of the northwest wetlands to the northeastern corner of the site where the Trolley and Chemical Brooks merge.
In the first area, five monitoring wells were installed in two clusters (between the lined lagoons and Nyacol headquarters and southeast of the headquarters near Megunko Road). Three overburden and two bedrock wells were sampled and the following compounds were detected: 1,2-DCE, chlorobenzene, TCE, 1,2-DCB, aniline, 1,3-DCB, 1,4-DCB, 1,2,4-TCB, nitrobenzene, chromium, mercury, lead, antimony, o-anisidine, p-cresidine, benzidine, 1-naphthylamine, 3,3'-dimethoxybenzidine, and 3,3'-dimethylbenzidine. In 1983/1984, 1,4-DCB and vinyl chloride were detected. The organic compound concentrations were comparable between the two monitoring locations. Inorganic compounds were higher in the bedrock wells when compared to the overburden wells. Organic and inorganic concentrations were higher in the bedrock and overburden wells located closest to Megunko Road.
Three overburden wells were located in the second sub-area. The three wells were located along Chemical Brook in each of the following places: (1) east of the northwest wetlands and north of the vault area; (2) near the confluence of the Trolley and Chemical Brooks; and (3) halfway between the two other places. Compounds detected in this sub-area include 1,2-DCE, TCE, chlorobenzene, 1,2-DCB, 1,3-DCB, 1,4-DCB, 1,2,4-TCB, nitrobenzene, aniline, chromium, mercury, and antimony. In 1987, a groundwater sample was collected from the vault and found to contain chromium, mercury, lead, aniline, TCE, chlorobenzene, trans-1,2-DCE, and 1,2-DCB.
- Northwestern Wetland
Two monitoring wells are located immediately west of the northwestern wetland area. Compounds detected in these two wells were mercury, 1,2-DCE, TCE, chromium, lead, and antimony. Generally, the concentrations were higher in 1983/1984 when compared to the 1988 data.
- Trolley Brook Wetlands
No monitoring wells are located in the Trolley Brook Wetlands area but two well clusters are located nearby. These clusters are located between Megunko Road and the Nyacol headquarters and at the foot of Megunko Hill near the eastern site boundary. The compounds detected in these wells in 1983/1984 and/or 1988 include 1,2-DCE, TCE, chlorobenzene, 1,2-DCB, 1,4-DCB, nitrobenzene, chromium, mercury, lead, antimony, aniline, vinyl chloride, and 1,3-DCB. Generally, higher concentrations were detected in the bedrock well when compared to the overburden wells.
- Municipal Water Supplies
In 1983, as part of the EPA RI for OU I, one sample was obtained from the portion of the Ashland municipal water distribution system that is located on-site . The sample was analyzed for HSL constituents. No contaminants were detected. During the preliminary portion of the OU II remedial investigation, the potable water supply used for drilling of the monitoring wells was checked periodically between February and May of 1988 . Eight samples were analyzed for TCL constituents and aniline. For each sample, it is unknown where in the municipal distribution system the samples were obtained (off-site or on-site locations). However, the only prevalent contaminants detected were chloroform and bromodichloromethane. These two compounds are trihalomethanes and are common by-products of drinking water disinfection processes. Total trihalomethane levels ranged from 41 to 73 ppb.
In March 1988, the DEQE monitored the portion of the municipal water distribution system located on-site for VOCs . Water samples were obtained from the Nyacol office/laboratory building, the Nyacol Production building, and the Tuff-Kote office. The samples contained chloroform, bromodichloromethane, and dibromochloromethane. The field blanks contained chloroform and toluene.
During January and June 1983, the EPA performed mercury vapor measurements in an area where sludge is exposed to the air (northwest slope of Megunko Hill) and 50-75 yards downwind at the gates to the Hill . The wind direction was west to southwest on both occasions. The ambient temperatures in January and June were 15-20 and 85-90 degrees Fahrenheit, respectively.
In June 1983, ambient air samples were collected three to four feet above ground throughout the hill area, at the gate to the hill, and downwind (north) of the industrial plant . Except for trace levels of unidentified organic compounds downwind of the industrial plant, no VOCs were detected at or above the detection limit of 0.5 ppb.
In July 1986, ambient air mercury vapor measurements were obtained during CDM's sediment and soil sampling of Trolley Brook, the Chemical Brook, and the antimony pits . No mercury vapor was detected during surface or subsurface sampling of the Trolley Brook or antimony pits. However, at Chemical Brook while sampling subsurface media (from a depth of 1.5 to 2 feet), seven of fourteen ambient air samples contained detectable levels of mercury vapor, and, while sampling surface media (from a depth of 2-3 inches), one ambient air sample contained a detectable level of mercury vapor.
In 1987 during the soil boring program of the vault study, two of four grab samples analyzed contained nitrobenzene and screening methods detected up to 900 ppm of VOCs. During the removal action at the vault area (soil excavation and on-site incineration), ambient air monitoring for select organic compounds was conducted on November 5 and 19, 1987. Excavation occurred inside a temporary dome structure containing an air lock. Incineration occurred outside. Monitoring occurred inside this structure, near the incinerator's feeder system, nearby between Nyacol's drum storage and warehouse buildings and the domed structure, upwind near Nyacol's headquarters, and 300 feet downwind to the east. Inside the domed structure the following compounds were detected: nitrobenzene, chlorobenzene, aniline, TCE, 1,2-DCB, 1,3-DCB, 1,4-DCB, and 1,2,4-TCB. Outside near the incinerator, the following compounds were detected: nitrobenzene, chlorobenzene, aniline, TCE, 1,2-DCB, 1,3-DCB, 1,4-DCB, and 1,2,4-TCB. Between the structure and the Nyacol buildings, lesser amounts of the same compounds were detected.
On November 5, 1987, the upwind and downwind samples contained trace levels of nitrobenzene, 1,4-DCB, and 1,2,4-TCB. On November 19, 1987, the upwind location contained TCE and the downwind location contained nitrobenzene, TCE, 1,2-DCB, and 1,2,4-TCB.
In 1989, prior to excavation of on-site soils and wetlands, monitoring of dimethylmercury in ambient air was conducted for baseline determinations . Ambient air monitoring for dimethylmercury was conducted for breathing zone samples obtained at the Megunko Hill area perimeter. The samples were 8-hour composites and were obtained on 35 days during the period 10/16/89-12/8/89. Three October samples and three November samples contained dimethylmercury. These samples were obtained on separate days. Ambient air data are presented in Table B-6.
Wastewater sludges were disposed of at a nearby property, namely, Sharon Bolt and Screw/Fenwal. High levels of arsenic, cadmium, chromium, mercury, and lead were reportedly detected. Cyanide was also detected at this property. The contaminant levels were not given.
During the preliminary investigation for OU II , analysis was conducted of 21 vertical composites of subsurface soil samples obtained during the installation of off-site monitoring wells. Monitoring depths ranged from 5.0-5.8 to 30-32 feet. One sample was obtained east of the Trolley Brook Wetlands, and only low levels of lead and chromium were detected. The highest levels of organic contamination in the off-site subsurface soil samples were observed in the area bounded by Forest Avenue to the west, Pleasant Street to the north, and the Conrail tracks to the south. The contaminants detected in this area are TCE, chlorobenzene, 1,2-DCE, chromium, lead, and mercury. Lesser amounts of contamination were detected west of Metcalf Avenue. The subsurface soil sample obtained at a depth of 30-31.5 feet along the southern bank of the Sudbury River contained TCE, chlorobenzene, chromium, and lead. Across the Sudbury River at MW-116B, the sample obtained from a depth interval of 15-19 feet contained chromium, lead, and mercury. No other compounds of concern were detected. Off-site soil data are presented in Table B-7.
Surficial soil at the Three-C Electrical Co., Inc. (a 21E site) was monitored for PCBs following removal of contaminated soil during facility closure activities at 280 Pleasant Street . The residual PCB level in the soil was determined to be 7.8 mg/kg.
For ease of presentation, off-site surface water contamination is divided into 10 locations. The locations are (1) the off-site portion of the Trolley Brook Wetlands; (2) the small wetland located west of Metcalf Avenue and the other side of the Conrail tracks from the site; (3) the stretch of the Chemical Brook from its confluence with Trolley Brook and its interception with Cherry Street/Main Street; (4) the 2.37-acre wetland where the Chemical Brook culvert discharges after crossing beneath downtown, and including the portion of the Raceway within this wetland area; (5) the upstream portion of the Raceway and the Sudbury River from the 2.37-acre wetland to the Myrtle Street dam; (6) the portion of the Sudbury River upstream from the dam, which includes the Mill Pond; (7) the portion of the Sudbury River downstream from its confluence with the Raceway and upstream from the MDC Reservoir #2; (8) the Ashland Reservoir and the Cold Spring Brook to its confluence with the Sudbury River; (9) MDC Reservoirs #1 and #2; and (10) the portions of the Sudbury River downstream from the MDC Reservoir system. Samples were collected from the different locations at various times between 1972 and 1989 and analyzed for some or all of the following parameters: VOCs, semi-VOCs, and metals. Off-site surface water data are presented in Table B-8.
The compounds detected at the various locations include mercury, chromium, lead, TCE, 1,2-DCE, chlorobenzene, 1,2-DCB, antimony, trans-1,2-DCE, chloroform, and nitrobenzene. Metals were detected in the majority of the surface water samples that were analyzed. The metal concentrations were generally low (<76 ppb). Organic and inorganic compounds were detected in the following areas: (1) Trolley Brook Wetlands, (2) Trolley Brook, (3) Chemical Brook, (4) 2.37-acre wetland which receives discharge from Chemical Brook, and (5) Sudbury River in the vicinity of the confluence with the Raceway. The concentrations of organics and inorganics were generally in the low parts per billion range (<30 ppb). However, elevated concentrations of metals, organics, and inorganics were detected in the vicinity of Chemical and Trolley Brooks.
In April 1986, sump water from 3 residential basements located near the Nyanza site was sampled by NUS Corporation . In June 1986 following several days of heavy rain, sump water from 4 (three different and one repeat) residences was sampled . The sump water, believed to originate from groundwater seepage, was monitored for HSL constituents. The residential locations can be divided into three areas: (1) both sides of Pleasant Street northwest of the site (two residences); (2) the western side of Metcalf Avenue (three residences, of which one residence was sampled during both events); and (3) the western side of Tilton Avenue (the residence located nearest the site). In area one, no site-specific compounds of concern were detected except for lead [20, 54-56]. In area two, site-specific contaminants were detected in the sump water from all three residences. The compounds of concern detected are trans-1,2-DCE, TCE, chlorobenzene, 1,2-DCB, 1,2,4-TCB, nitrobenzene, chromium, lead, and mercury. Contaminants were detected during both sampling events. The sump sample from area three contained trans-1,2-DCE, TCE, lead, and mercury.
Off-site sediment samples were collected from the same locations as the off-site surface water samples. Compounds detected in the sediment samples include chromium, mercury, lead, antimony, vinyl chloride, trans-1,2-DCE, TCE, chlorobenzene, 1,2-DCB, 1,2,4-TCB, 2,4,6-trichlorophenol, 1,4-DCB, benzene, 1,3-DCB, aniline, and methylmercury. Off-site sediment data are presented in Table B-9.
The concentrations of the VOCs and semi-VOCs generally ranged from low parts per billion to less than 20 parts per million. The concentrations of metals were higher when compared to the organic compounds. The highest concentrations of contaminants were detected in the vicinity of Chemical Brook and its confluence with the Raceway.
In 1989, two surface sediment samples were obtained from the Sudbury Reservoir . One sample was monitored for inorganic and organic compounds. Chromium and lead were the only compounds of concern detected in the reservoir sediment.
Between 1971 and 1989, fish samples were collected from various locations around the Nyanza site including the Sudbury River, Mill Pond, Sudbury River watershed, Cedar Swamp Pond, MDC Reservoirs #1, 2, and 3, Concord River, Heard Pond, Assabet River, Fairhaven Bay, and Sudbury Reservoir. Throughout this time frame, the following fish species were collected: white perch, largemouth bass, yellow perch, carp, yellow bullhead, white perch, pickerel, catfish, and chain pickerel. Analysis was performed on edible fillets, offal, fish composites, and/or whole fish for some or all of the following compounds: metals, PCBs, pesticides, methylmercury, and acid/base/neutral extractable compounds.
Compounds detected in the fish samples were mercury, lead, chromium, methylmercury, aroclor-1254, 4,4'-DDD, 4,4'-DDT, and 3,3'-DDE (a degradation product of 3,3'-DDT). Concentrations of these contaminants are presented in Table B-10.
No monitoring wells are located to the west or south of the site boundaries. One on-site well near the southwest corner contained no contamination. Another well placed along the western boundary at the foot of Megunko Hill contained low levels of site related VOCs and mercury.
Very little or no site related groundwater contamination has been detected in the wells north of the Sudbury River and northwest of the site. The greatest contamination has been detected in the wells adjacent to the site, specifically northeast of the vault/Nyacol building.
Groundwater samples collected from the overburden and bedrock wells to the north and east of the site contained the following contaminants: TCE, 1,2-DCE, nitrobenzene, chlorobenzene, 1,4-DCB, 1,2-DCB, 1,3-DCB, 1,2,4-TCB, aniline, chromium, mercury, lead, and antimony. The concentrations of these contaminants are presented in Table B-11.
- Municipal Water Supplies
Distribution system monitoring for trihalomethanes from 1986-1988 indicated total trihalomethane levels ranging from 49-99 ppb . Monitoring for VOCs in March and August of 1988 at the Howe Street wells indicated the presence of trihalomethanes . Trihalomethanes detected were chloroform (44-82 ppb), bromodichloromethane (6-12 ppb), and dibromochloromethane (0.5-0.8 ppb). These levels are consistent with the disinfectant used and the influence of the nearby surface water body on the wells. 1,1,1-TCA was detected at 10 ppb. Monitoring for Safe Drinking Water Act inorganic compounds in January 1988 indicated lead at 0.2 ppb. Mercury and chromium were not detected.
- Private Water Supplies
A total of 24 private water supply wells were monitored by the DEQE and the MDPH in January 1989 [33,37]. The wells are located west of the site and east of the convergence of the Sudbury River and the Cold Spring Brook. The results indicated the wells to be free of pollutants, except for one well containing low levels of petroleum-related compounds and two others containing coliform contamination.
The Timex Clock Company located at 200 Homer Street approximately 3,500 feet east of the Nyanza site, made use of an on-site production well . This production well was dismantled in early 1984, and no information is available on any monitoring performed on it. Because it is a State of Massachusetts Hazardous site (21E site), monitoring wells were installed to monitor groundwater contamination. Goldberg-Zoino Associates, Inc. (GZA) installed three wells in April of 1983 and six additional wells in May of 1983. They were monitored for purgeable halogen compounds and for VOCs. Elevated levels of TCE, trans-1,2-DCE, and vinyl chloride were detected in several wells within the study area .
During March 1987, the EPA monitored indoor air from the basement of a home situated over an area of groundwater contamination . This home, located on the western side of Metcalf Avenue closest to the site, was chosen based on the results of the sump water monitoring program . Grab samples were obtained from the space immediately above the sump, above cracks in the basement floor, and above the flooding water, and were analyzed for select VOCs. No compounds of concern were detected in these indoor air samples.
On January 31, 1989, the EPA Region I conducted an 8-hour indoor air monitoring study of the basement of a church located at 118 Main Street in Ashland . Four classrooms were sampled, and TCE and 1,4-DCB were the only site related compounds detected. Other compounds detected were 1,1,1-TCE, PCE, benzene, total xylenes, toluene, alkylbenzene, and ethylbenzene. The concentrations of these compounds are presented in Table B-12.
On December 19, 1990, the EPA conducted a one day indoor air screening survey in the Town of Ashland. Indoor grab air samples were collected in the basements of the Town Hall and residential homes located on Pleasant Street, Tilton Avenue, Cherry Street, and Metcalf Avenue. Indoor grab air samples were collected in the five selected basements at locations where emissions from soil and underlying groundwater would be most concentrated (i.e., incoming gas or water pipes and sumps). In addition, air grab samples were collected outside the homes to determine background levels. Low levels of benzene, toluene, and TCE were detected in indoor air (<15 ppb).
Different investigators have monitored different locations of the study area at various times. EPA's Contract Laboratory Program (CLP) Quality Assurance and Quality Control (QA/QC) guidelines for media sampling as well as inorganic and organic chemical analyses are documented as having been followed for the studies performed since 1986. Prior to 1986, QA/QC information was not provided for most of the studies, but an assumption is made that protocols for media sampling, handling, and analysis were followed and that the data gathered underwent QA/QC review.
Specifically, the DEQE and the EPA have found the investigation by Carr Research Laboratories, Inc. and Connorstone, Inc.  deficient due to improper sampling and analytical protocols. The data from this investigation were not considered in the health assessment.
The 1985 RI for OU I  contains data inadequacies and the data were never validated. Upon review by the DEQE, the sampling and analytical protocol was found to be deficient due to a lack of information on field sampling procedures, preservation techniques, sample holding times, and analytical techniques. Furthermore, the report contained numerous inconsistencies between the text, figures, and tables. In addition, sample locations and depth composites were often not given for soil samples. Based on the information presented in the report, it was difficult to match surface water monitoring data with surface water sampling stations. Off-site surface water samples were obtained from three locations on the Sudbury River in 1983 and 1984. Although the results were described within the text, the raw data were not presented. Therefore, the information was disregarded. Organic compound monitoring of soils was restricted to TOC and TOH analyses. These methods rely on the presence of large concentrations of halogenated organic compounds in order to discern contamination, and are actually screening methods. The data from these methods are inappropriate for the health assessment, and were not even used as a surrogate.
The CDM field work  samples were analyzed at a CLP facility, however, the data were not validated . The soil samples were composites and homogenized prior to analysis, and thus, volatilization of some contaminants may have occurred.
For the DEQE vault investigation , the organic compound detection limit for groundwater samples was 100 ppb. During the vault removal action , the detection limits of organic compounds in sludge ranged from 100,000 to 500,000 ppm. The compatibility testing for the barrel contents  did not include monitoring for specific compounds, but was conducted to determine the appropriate disposal of the barrels. The results of this investigation were not used for the public health assessment.
From 1986 to 1988, groundwater contamination was monitored for select compounds at the Sharon Bolt and Screw/Fenwal facility on Pleasant Street . The contamination detected was consistent with that associated with the Nyanza site, however, these data were disregarded because no information was available for this location and time period.
The residential air screening survey  by the EPA did not include any QA/QC validation information, nor detection limits for the instruments used in the screening portion of the survey. The detection limits for the detector tube portion of the survey were too high for the purpose of the health assessment. In addition, HNu photoionization instrument readings were obtained during this survey and a preceding study on the sump water [20, 53-57]. HNu instruments do not detect a specific chemical but groups of chemicals. Because the target organ and potency of toxicity vary depending upon the chemical, monitoring results for specific chemicals are needed in order to determine the potential health effects. These instruments are also insensitive and prone to numerous interferences. For these reasons, HNu monitoring results are not considered for the purpose of the health assessment. The EPA's indoor air monitoring study of a church in Ashland was conducted using method T01 for VOCs in ambient air . The sensitivity of the method and the quality of the data are sufficient for the purpose of the public health assessment.
The data from the dimethylmercury investigations [60,61] are controversial because of QA/QC concerns [60,69,82]. For the soil data , limitations exist because: (1) the integrity of the samples from the Trolley Brook Wetlands were compromised due to the previous headspace analysis, the elapse of the two week holding time for volatile organic compounds, and dimethylmercury calibration standards exceeding the quantities detected in the samples; (2) the lack of confirmation monitoring for samples from the northwestern wetland; and (3) the compromised integrity of the other on-site samples or the lack of confirmation monitoring. Other limitations are presented in reference #82. For ambient air data , incomplete information is available for each sample with regard to sampling information and location, meteorologic conditions, and analytical results. The actual levels detected are approximate values because of QA/QC limitations [61,82] (e.g., (1) some samples were held for more than two weeks prior to analysis; (2) the calibration standards do not bracket the sample values; and (3) the inappropriate use of blanks and controls).
In preparing this public health assessment, the ATSDR relies on the information provided in the referenced documents and assumes that adequate quality assurance and quality control measures were followed with regards to chain-of custody, laboratory procedures, and data reporting. The validity of the analyses and conclusions drawn for the health assessment are determined by the availability and reliability of the referenced information.
Because of remediation, portions of the Nyanza site are fenced. Because the site is an active
industrial area, anyone who accesses the site, including young people who in the past were
known to use it as a shortcut to the High School, could be exposed to potential physical hazards.
Excavation pits posed a potential physical hazard in the past. Within the Nyanza site, Nyacol
Products, Inc. operated a wastewater treatment chamber. As of the 1988 site visit, the area
around this chamber was not completely fenced and the trap door on the chamber was
unsecured. The physical hazards presented by this treatment chamber were eliminated with its
removal during vault excavation activities .
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 categorizes an exposure pathway as a completed or potential exposure pathway if the exposure pathway can not be eliminated. Completed exposure pathways exist when the five elements of a pathway link the contaminant source to an exposed population. Potential exposure pathways exist when information on one or more of the five elements is missing. An exposure pathway can be eliminated if at least one of the five elements is missing and will never be present. The discussion that follows incorporates only those pathways that are important and relevant to the site.
Past exposures to site related contaminants are possible from the ambient air around the site. Potentially impacted populations include workers on-site and in the site vicinity and residents in the surrounding neighborhoods.
Site related wastewater was discharged to the Chemical and Trolley Brooks and sludge and other solid wastes were disposed on-site. Inhalation of vapors and dusts emanating from these materials could have occurred resulting in exposure to VOCs, semi-VOCs, mercury, and methylmercury. In particular, mercury vapors have been detected over sludge deposition areas and wetland areas. In addition, inhalation of dimethylmercury near wetland areas may also have occurred. Inhalation of organic compounds is uncertain due to a lack of monitoring data, but is possible. Current and future exposures to contaminated wetland soils and surface waters are unlikely because the on-site wetlands have been remediated and wastewaters are no longer discharged to the wetlands and brooks.
Limited on-site ambient air monitoring near surface sludge resulted in the detection of mercury in both winter and summer. Levels were highest on the warm summer day. The excavation of soils near the vault area resulted in the emission of VOCs and semi-VOCs at levels requiring excavation in an air locked enclosure. These data are from sampling conducted over a short period and do not represent the range of conditions that might have existed over the years on-site. The air monitoring data indicate that the mercury and methylmercury concentrations on-site are generally less than 0.5 and 1.9 µg/m3, respectively.
Based on numerous citizens' complaints, exposure to off-site ambient air contaminants occurred in the past, although the extent of such exposure and the chemicals to which people were exposed are unknown. Sources of exposure to off-site ambient air contamination are emissions from the dye manufacturing operations, smoke from the occasional fires, fugitive dusts emanating from the site, and vapors from the Chemical Brook, Sudbury River, and nearby wetlands. The current and future potential is much less in comparison to the past, and is most limited to areas immediately adjacent to the site, and perhaps, the wetlands where the Chemical Brook discharges from the culvert.
When the facility was in operation, emissions from the dye manufacturing processes and various accidents occurred. It is likely that workers, children, and other individuals accessing the site and in the site vicinity were exposed via inhalation to the aerosols, particulates, and vapors emanating from the facility. Because dye manufacturing no longer occurs at this location, current and future exposure to facility emissions is no longer possible.
It is not possible to assess the historical impact of ambient air contamination around the site due to a lack of ambient air and particulate data. While no data exist for contaminants in the ambient air during the site operations, it is suspected that air concentrations at this time were greater than or equal to the concentrations detected during the limited sampling periods.
Due to site remediation and facility shutdown, it is expected that the current and future ambient air contaminant concentrations will be less than historical levels. Ambient air is not a suspected exposure pathway now or in the future.
Past exposures to site related contaminants are possible from the ingestion of fish in the Sudbury River and associated reservoirs. Potentially impacted populations include the individuals who fished in these water bodies and consumed the contaminated fish.
Mercury and methylmercury are the two contaminants in fish to which people could have been exposed. Fishing is known to have occurred in these waterbodies but the number of people who historically caught and ate the fish is unknown.
Past exposure pathways are possible from contamination of the on-site and off-site surface water bodies. Children playing in the surface water bodies are the individuals most likely to be affected by the contaminants via dermal absorption and possibly through accidental ingestion. Adults could possibly be exposed to contaminants via dermal absorption when using the Sudbury River and its reservoirs for recreational activities (i.e., wading and fishing).
Surface waters present on-site consisted of discolored brooks and lagoons. Dermal contact is the most likely route of exposure. Accidental ingestion is unlikely because the waters were often brightly colored and malodorous. The concentrations of contaminants detected in on-site surface water do not represent a threat to human health.
Past exposures to site related contaminants are possible from contact with sludges and solid wastes. Potentially impacted populations included children accessing the site and on-site workers. Sludge and other solid wastes were disposed on-site, mostly on Megunko Hill. Children played near these disposal areas and dermal contact with the sludge and contaminated soils probably occurred. The reported occurrence of children with blistered hands and discolored clothing after playing in this area further supports this possibility. Incidental ingestion of these materials is less likely, but possibly occurred. There are limited data available for the wastes and sludges at the site, therefore, it is not possible to assess this exposure pathway.
Past, current, and future exposures to contaminants are possible due to the presence of metals, VOCs, and semi-VOCs in the sediment of on-site and off-site wetlands and surface water bodies. The potentially impacted populations include on-site workers, children who access the site and the off-site wetlands and surface water bodies, and other individuals accessing the off-site contaminated areas. Current and future exposures are unlikely to occur in the northwest wetlands, Chemical Brook, and the floodplain of the Chemical Brook because contamination from these source areas has been removed.
Children were known to play in the wetland areas, brooks, and lagoons. Dermal contact is the most likely route of exposure to sediments. Incidental ingestion is also possible for the children who access the wetlands and surface water bodies. Incidental ingestion of on-site lagoon sediments is unlikely because the surface waters were often brightly colored and malodorous.
Dermal contact to contaminated wetland sediment could have occurred in off-site locations bordering the site and downstream of the site along the floodplain of Chemical Brook, Trolley Brook, the Raceway, and Sudbury River.
Past exposures are possible due to the contamination of on-site and off-site soils. Potentially impacted populations include on-site workers, children accessing contaminated on-site and off-site areas, and adults accessing contaminated areas.
Past exposure to contaminated residential soils by dermal contact and incidental ingestion and, perhaps, garden produce (either dirt clinging to the produce or the produce itself) by ingestion occurred in at least one residence located along Chemical Brook near the site. Current and future exposures are not possible because the contaminated soil was excavated as part of permanent remediation. Past exposure to contaminated residential soils, garden produce, and personal belongings may have occurred following deposition of aerosols, particulates, fugitive dusts, and smoke ash (from occasional fires on Megunko Hill) emanation from the facility.
Past, current, and future exposures to site related contaminants in indoor air are possible in areas where basement flooding and/or vapor infiltration occur from the underlying groundwater plume. Potentially impacted populations include residents of the homes around the site and workers in nearby businesses.
Factors such as basement construction, ventilation, air gradients, and patterns of usage of each room (especially the basement) affect whether or not contaminants are migrating into the basements. Limited indoor air data are available from testing that was performed in the basement of the Ashland Federated Church, the Town Hall, and several homes around the site. Analytical results indicate the presence of low levels of VOCs.
Current and future exposures to site related contamination due to the ingestion of fish are expected to be less than past exposures due to a health advisory issued in the mid-1980's. It is not possible to assess the impacted population because it is not known how many people are still fishing in the river and reservoirs and consuming the fish.
Current and future exposures to on-site surface water are possible, but less likely because wastewaters are no longer being discharged to the brooks. Exposures to off-site contaminated surface water were greater in the past than that occurring now or likely to occur in the future. Exposures to the contaminated surface water of the Chemical Brook and the Sudbury River (and its associated reservoirs) probably occurred during recreational activities such as boating, swimming, and wading. Currently, the surface waters are much less contaminated than that observed (discolored and malodorous) as recently as the early 1980's, thus the potential for current exposures would be less. The concentrations detected in the off-site surface water do not represent a threat to human health.
Current and future exposure to contaminated surficial soils are less likely, but not impossible, because the most evident areas of surface soil contamination have been remediated or paved over. Current and future exposures of industrial and construction workers to contaminated subsurface soils are likely during soil removal activities (i.e., laying foundations, regrading, laying water or sewer mains) because: (1) complete subsurface soil investigations have not been conducted; (2) a shallow groundwater contaminant plume exists; and (3) similar soil removal activities in the past have resulted in the discovery of previously unknown pockets of soil contamination or sludge.
The groundwater beneath the site is highly contaminated with VOCs, semi-VOCs, and metals. However, the groundwater around the site is not used as a drinking water source. No potable or industrial water supply wells are located on-site, therefore, direct contact by any exposure pathway is unlikely.
Current ingestion of contaminated groundwater is unlikely because no off-site private water supply wells are known to exist in the area of the groundwater plume. Past ingestion of contaminated groundwater from private water supply wells is uncertain, but unlikely, because the groundwater plume is located in the section of town that first received municipal water. Future ingestion is possible, but not very likely. Eventual site related contamination of deep bedrock private wells could occur because the direction of water transport in any given deep bedrock fissure is difficult to predict and contaminants could be transported a distance from the site without being diluted.
Past and future exposures to contaminated municipal water are uncertain, but not very likely. A
municipal wellfield is located across the Mill Pond from the site. The Mill Pond/Sudbury River
may be an effective hydrological barrier against the infiltration of site related contaminants into
the wellfield. Current exposures from this pathway are not occurring, because the wellfield is
not being used at this time and the other municipal wellfields do not have the potential to be
impacted by the site. According to the Ashland Board of Health, no plans exist for future use of
the Mill Pond wellfield .
This section will discuss health effects in persons exposed to specific contaminants, evaluate state and local health databases, and address specific community health concerns. To evaluate health effects, the ATSDR has developed a minimal risk level (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. MRLs are developed for inhalation and ingestion routes of exposure, and for lengths of exposure, such as acute (fewer than 14 days), intermediate (15 to 364 days), and chronic (greater than 365 days). The ATSDR presents those MRLs in the Toxicological Profiles, which are chemical specific profiles that provide information on health effects, environmental transport, human exposure, and regulatory status. In the following discussion, ATSDR Toxicological Profiles and other sources were used for antimony, arsenic, chromium, lead, mercury/methylmercury, 1,2-dichloroethene, trichloroethene, chlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, aniline, nitrobenzene, and 1,2,4-trichlorobenzene.
Antimony exposure via ingestion could occurr in children who access surface water and/or sediments in the Northeast Wetland and the Cherry Street area. Past exposure could also have occurred to on-site workers and children who accessed the site due to the ingestion of on-site surface water, sediment, and soil. On-site workers and children who accessed the site could also have been exposed via dermal absorption from contact with the contaminated surface water, sediment, and soil.
The ATSDR does not have a MRL for antimony ingestion but the EPA has a chronic, oral RfD of 0.0004 mg/kg/day. Incidental ingestion of surface water is not expected to result in adverse health outcomes due to the low contaminant levels detected in this medium which results in an expected dose less than the RfD. Incidental ingestion of soil and sediment could result in adverse health outcomes due to the concentrations detected in these media. Soil and sediment are the primary exposure pathways at the site. Therefore, it is not expected that adults will be adversely impacted because they are not expected to ingest large quantities of soil or sediment.
It is estimated that young children ingest 200 mg of soil per day. Sediment and soil at the site contained a maximum of 1,660 ppm of antimony. Although ingestion of sediment and soils with those concentrations could result in an estimated dose greater than 0.0004 mg/kg/day, the levels ingested are probably well below concentrations related to adverse non-carcinogenic health effects. The ingestion of soil and sediment could result in vomiting and gastrointestinal irritation as a result of the antimony concentrations. These health effects are based on the ingestion of doses of antimony estimated from its concentration in contaminated on-site soil.
Dermal exposure to antimony can result in skin irritation and dermatitis. However, the ATSDR has no information on dose response relationships pertaining to exposure to antimony and development of dermatitis . Also, the ATSDR has no methodology to determine the level of absorption of chemicals through the skin. For that reason, it is difficult to determine other health effects of dermal exposure to antimony.
Antimony is not given a carcinogenicity class and there is no evidence of carcinogenicity due to antimony exposure. Adverse carcinogenic health effects are not expected due to exposure to antimony around the site.
Arsenic exposure via ingestion has occurred in on-site workers and children who accessed soil on-site and in residential yards, and sediments on-site. Current exposure to arsenic via ingestion could occur to children who access sediments in the Mill Pond, the Northeast Wetland, and the Cherry Street area. On-site workers and children who accessed the site could also have been exposed via dermal absorption from contact with the contaminated soil and sediment.
The ATSDR does not have a MRL for arsenic ingestion, but the EPA has a chronic, oral RfD of 0.0003 mg/kg/day. Incidental ingestion of sediment is not expected to result in adverse health outcomes due to the low contaminant levels detected in this medium which results in an expected dose less than the RfD. Incidental ingestion of soil in the past could have resulted in adverse health outcomes due to the concentrations detected in this medium. Soil and sediment are the primary exposure pathways at the site. Therefore, it is not expected that adults will be adversely affected because they are not expected to ingest large quantities of soil or sediment.
It is estimated that young children ingest 200 mg of soil per day. Soil at the site contained a maximum of 170 ppm of arsenic. Although ingestion of soil with this concentration could result in an estimated dose greater than 0.0003 mg/kg/day, the levels ingested are probably well below concentrations related to adverse non-carcinogenic health effects. The ingestion of soil could have resulted in vomiting and gastrointestinal irritation as a result of the arsenic concentrations. These health effects are based on the ingestion of doses of arsenic estimated from its concentration in contaminated on-site soil.
The ingestion of inorganic arsenic has been reported to increase the risk of cancer of the skin, liver, bladder, kidney, and lung. The Department of Health and Human Services has determined that arsenic and certain arsenic compounds are known carcinogens. The inhalation of inorganic arsenic has been reported to increase the risk of lung cancer. This has been seen mostly in humans exposed to arsenic in or around smelters. People who live near smelters, chemical factories, or waste sites with arsenic may have increased risk of lung cancer as well.
Chromium exposure via ingestion has occurred in on-site workers and children who accessed on-site surface water, sediment, and soil. Current exposure to chromium via ingestion could occur to children who access sediments in the Trolley Brook Wetlands, Northeast Wetland, Cherry Street area, and MDC Reservoir #2. On-site workers and children who accessed the site could also have been exposed via dermal absorption from contact with the contaminated surface water, sediment, and soil.
The ATSDR does not have a MRL for chromium but the EPA has established chronic, oral RfDs for chromium III and chromium VI at 1 mg/kg/day and 0.005 mg/kg/day, respectively. Incidental ingestion of surface water is not expected to result in adverse health outcomes due to the low contaminant levels detected in this medium which results in an expected dose less than the RfD. Soil and sediment ingestion are the primary exposure pathways at the site. Therefore, it is not expected that adults will be adversely affected because they are not expected to ingest large quantities of soil or sediment.
It is estimated that young children ingest 200 mg of soil per day. Sediment and soil at the site contained a maximum of 15,000 ppm of chromium. It is likely that ingestion of sediment and soils with that concentration could result in an estimated dose greater than 1 mg/kg/day and 0.005 mg/kg/day. However, the levels ingested are probably well below concentrations at which most adverse non-carcinogenic health effects have been observed. Based on the available data, it is possible that the past ingestion of on-site soils could have resulted in gastrointestinal irritation (abdominal pain and vomiting) and skin irritation (especially in chromium sensitive individuals).
Dermal exposure to chromium could result in skin irritation and dermatitis. However, the ATSDR has no information on dose response relationships pertaining to exposure to chromium and development of dermatitis . Also, the ATSDR has no methodology to determine the level of absorption of chemicals through the skin . For that reason, it is difficult to determine other health effects of dermal exposure to chromium.
Long-term exposure to chromium has been associated with lung cancer in workers exposed to levels in air that were 100 to 1,000 times higher than those found in the natural environment (<0.1 µg/m3). It is not clear which form(s) of chromium is capable of causing lung cancer in workers. Chromium VI is believed to be primarily responsible for the increased lung cancer rates observed in workers who were exposed to high levels of chromium in air. The Department of Health and Human Services has determined that chromium and certain chromium compounds are known carcinogens.
Lead exposure via ingestion has occurred or could be occurring in the following populations: (1) on-site workers and children who accessed the surface water, sediment, and soil on-site and soil in residential yards; (2) children who access surface water and/or sediments in Mill Pond, the Northeast Wetland, Trolley Brook Wetlands, Cherry Street area, and MDC Reservoir #2; and (3) adults and children who consume fish caught in the MDC Reservoir and Saxonville Impoundment. The ATSDR does not have a MRL nor does the EPA have a RfD for lead. The comparison values are currently being re-evaluated by the ATSDR, the EPA, and the Centers for Disease Control.
Sediment, soil, and surface water ingestion are the primary exposure pathways with relation to lead contamination around the site. 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 adults will be ingesting large quantities of contaminated surface water, sediment, or soil. Primary exposure is to children who might be ingesting sediment, soil, or surface water. Young children around the site are the group most sensitive to lead exposure.
Based on the concentrations detected in the surface water, it is not likely that intermittent ingestion or dermal exposure to contaminated surface water will result in adverse health effects. It is estimated that young children ingest 200 mg of soil per day. Sediment and soil around the site contained a maximum of 2,300 ppm of lead. Exposure to these levels of lead could cause adverse health effects. In infants and young children, lead exposure via ingestion can cause a decrease in intelligence (IQ) scores, slow growth, and hearing problems. The effects can persist as children get older and can interfere with successful performance in school . Such children could be classified as learning disabled. A blood lead level greater than 25 micrograms per deciliter (µg/dL) in children is considered lead poisoning .
Lead exposure is especially dangerous for the fetus because of potential harm during development. Pregnant women exposed to lead can pass lead to the fetus, resulting in premature birth, low birth weight, and miscarriages . Ingestion is the primary exposure pathway related to lead contaminated soils and sediment around the site. Therefore, it is not expected that pregnant women residing near the site would be at an increased risk because of their minimal ingestion of soil and sediment.
In addition, exposure to high levels of lead can damage the brain and kidneys of adults and children . Lead exposure can increase blood pressure in men, but it is unknown whether that effect occurs in women. Lead exposure may affect sperm or damage other parts of the male reproductive system . However, adult residents are not expected to be at an increased risk of such effects because soil ingestion is the primary exposure route. It is not expected that adults will ingest large quantities of contaminated soil. Based on the available data, it is not expected that intermittent ingestion of lead contaminated soils around the site in the past would have resulted in adverse non-carcinogenic health outcomes.
Fish data for the various water bodies around the site indicate that fish in the MDC Reservoirs and Saxonville Impoundment contain low levels of lead in their tissue. There are no guidelines established to indicate the maximum allowable lead concentration in fish. However, all lead tissue concentrations were below 1 ppm and adverse health effects are not expected based on these concentrations.
The ATSDR has no information on dose response relationships pertaining to dermal exposure to lead and subsequent health effects. Also, the ATSDR has no methodology to determine the level of absorption of chemicals through the skin. However, it is not expected that dermal exposure to contaminated sediment, soil, or surface water would result in adverse health effects.
Lead is classified by the EPA as a B2 carcinogen indicating that it is a possible human carcinogen based on sufficient animal evidence but inadequate human evidence. Based on the exposure routes around the site and the concentration of lead detected, it is not expected that adverse carcinogenic outcomes will result.
Exposure to mercury and methylmercury has occurred or could be occurring due to contamination of surface water, soil, sediment, fish, and ambient air. Potentially exposed populations include (1) on-site workers and children who accessed the surface water, sediment, and soil on-site; (2) children who access surface water and/or sediment in Mill Pond, Trolley Brook Wetlands, Northeast Wetlands, Cherry Street area, and MDC Reservoir #2; and (3) adults and children who consume fish caught in the Sudbury River and its tributaries. A health advisory that was issued in 1986 warning against fish consumption due to mercury contamination is still in effect. Although some fishing still occurs, it is expected that historical exposures would be greater than current or future exposure due to fish consumption.
To estimate acute methylmercury exposure, it was assumed that children, women, and men ate 4, 8, and 13 ounces of fish per meal, respectively. To estimate long-term exposure to methylmercury from eating contaminated fish, a range of fish consumption patterns ranging from one fish meal per week to 1 meal per month was evaluated. These values are used to estimate intermediate and chronic methylmercury exposure.
Approximately 80% of the mercury in freshwater fish occurs as methylmercury. We will assume that the total mercury measurement for the fish consists of methylmercury. For adults and children who eat 1-3 fish meals per month from the Sudbury River and its tributaries, the methylmercury ingested exceeds ATSDRs ingestion MRL for acute and intermediate exposure (0.00005 mg/kg/day and 0.00002 mg/kg/day, respectively). A chronic MRL is not available for comparison because the ATSDR is reevaluating this value. When a chronic MRL is not available, the ATSDR refers to EPA's RfD. The RfD is an estimate of daily human exposure to a contaminant for a lifetime below which (non-cancer) health effects are unlikely to occur. However, EPA's RfD for methylmercury of 0.0003 mg/kg/day is higher than ATSDRs intermediate MRL and therefore, impractical as a chronic health value. The World Health Organization (WHO) also has developed total mercury and methylmercury guidelines. This guideline suggests that a weekly intake not exceed 0.3 mg of total mercury with no more than 0.2 mg as methylmercury. The later value for methylmercury, which equals 0.00048 mg/kg/day methylmercury, is greater than ATSDRs intermediate MRL.
The Food and Drug Administration (FDA) has established an action level of 1 ppm, or 1 µg/g of methyl mercury. FDA's action level, which is based on national average consumption rates for fish, applies only to commercially distributed fish destined for interstate commerce. It may underestimate the risk to sport and subsistence fishermen, who have higher than average consumption rates than the national average. The average levels of mercury in fish from the MDC reservoirs exceeded the FDA action level of 1 ppm; the average levels were 1.2 and 1.4 ppm. Although the average mercury level for fish caught in the river itself was below the FDA action level, individual fish caught at the different sampling stations did contain mercury at levels above 1 ppm. Therefore, the amount of methylmercury ingested by persons who ate and are eating contaminated fish from the River exceeds several guidelines established by national standards and international organizations. Because the level of exposure is so great, these persons are likely to experience harmful health effects.
The most sensitive sites to methylmercury exposure are the brain, the nervous system, the kidney, and the fetus. Neurologic symptoms in adults and children with brain damage include prickling, tingling sensations in the arms and legs, loss of sensation in the arms and legs, tunnel vision, slurred speech, incoordination, irritability, memory and hearing loss, and difficulty sleeping.
While data in humans are limited on harmful effects to the kidney, animal studies have shown that methylmercury can cause kidney damage. Kidney effects include increased urine output and elevated levels of albumin in the urine. Albumin is a blood protein that normally is not present in the urine.
In addition, past methylmercury exposure during pregnancy could damage the fetus. Human studies have shown that methylmercury exposure during pregnancy causes neurologic effects in offspring such as mental retardation, incoordination, and inability to move. Milder health effects include delayed neurologic development and slower movements. These health effects could also occur in infants who are breast fed. Furthermore, animal studies of methylmercury exposure during pregnancy show problems with behavioral maturation and learning ability in offspring. Mild forms of these health effects could be possible in children of women who ate and are eating contaminated fish from the River and its tributaries.
Past exposure to 1,2,4-trichlorobenzene could have occurred to on-site workers and children who ingested on-site sediment and soil. The ATSDR does not have a MRL for 1,2,4-trichlorobenzene, but the EPA has a chronic, oral RfD of 0.01 mg/kg/day. Soil and sediment on-site contained a maximum of 1,500 ppm 1,2,4-trichlorobenzene. Because the doses estimated from the ingestion of these concentrations of 1,2,4-trichlorobenzene are below the RfD, adverse health effects are not expected to occur.
The ATSDR does not have a MRL for aniline. The EPA does not have a RfD for this compound. Aniline was detected above comparison value levels in the surface water and soil on-site. Past exposure to aniline could have occurred to on-site workers and children who ingested on-site surface water and soil. However, until more information is available, it is not possible to determine whether adverse health effects occurred to children and on-site workers who accessed the site.
Long-term exposure of humans to aniline dye manufacture has been associated with malignant bladder growths. However, the excess of bladder cancer deaths observed in clusters of cases in workers in the aniline dye industry has been attributed to chemicals other than aniline. Epidemiological studies of workers exposed to aniline but to no other known bladder carcinogen show little evidence of increased risk. On the basis of all the available data, no evaluation could be made of the carcinogenicity of aniline to humans.
Nitrobenzene exposure via ingestion has occurred in on-site workers and children who accessed on-site surface water, sediment, and soil. On-site workers and children who accessed the site could also have been exposed via dermal absorption from contact with contaminated surface water, sediment, and soil.
The ATSDR does not have a MRL for nitrobenzene ingestion but the EPA has a chronic, oral RfD of 0.0005 mg/kg/day. Incidental ingestion of surface water is not expected to result in adverse health outcomes due to the low contaminant levels detected in this medium which results in an estimated dose less than the RfD. Soil and sediment ingestion are the primary exposure pathways at the site. It is not expected that adults will be adversely impacted because they are not expected to ingest large quantities of soil or sediment.
It is estimated that young children ingest 200 mg of soil per day. Soil and sediment at the site contained a maximum of 9,100 ppm nitrobenzene. Ingestion of soils with those concentrations could result in an estimated dose greater than 0.0005 mg/kg/day. However, no adverse health effects have been documented which could occur from the ingestion of this estimated dose.
1,4-Dichlorobenzene (1,4-DCB) exposure via ingestion has occurred in on-site workers and children who accessed on-site soil. Exposure could also occur to children who access sediments in the Northeast Wetland and the Cherry Street area. On-site workers and children who accessed the site could also have been exposed via dermal absorption from contact with contaminated soil. Exposure could also occur via inhalation of indoor air to individuals in a residential basement that was sampled.
The ATSDR does not have a MRL for 1,4-DCB, nor does the EPA have a RfD. Little information exists on the adverse health effects which could result from exposure to 1,4-DCB. As a result, it can not be determined if adverse health effects will result from exposure to site related contamination.
Exposure to 1,2-DCE via inhalation has occurred and may be occurring in residents and workers in area buildings. The ATSDR does not have a MRL for 1,2-DCE nor does the EPA have a RfC. As a result, it can not be determined if adverse health effects will result from exposure to site related contamination. Because 1,2-DCE was detected in the indoor air at a maximum concentration of 2 µg/m3, it is not expected that exposure to indoor air will result in adverse health effects.
TCE exposure via ingestion has occurred in on-site workers and children who accessed on-site surface water and sediment. On-site workers and children who accessed the site could also have been exposed via dermal absorption from contact with the contaminated surface water and sediment. Exposure could also occur to children who access surface water in the Northeast Wetland and Cherry Street area and sediment in the Trolley Brook Wetlands. Exposure could also occur to residents and workers in the area due to the inhalation of contaminated indoor air.
The EPA does not have a RfD for TCE, but the ATSDR has an intermediate, oral MRL of 0.1 mg/kg/day. Incidental ingestion of surface water and sediment is not expected to result in adverse health outcomes due to the low contaminant levels detected in these media which result in an expected dose less than the MRL. Because TCE was detected in the indoor air at a maximum concentration of 9 µg/m3, it is not expected that exposure to indoor air will result in adverse health effects.
Studies in animals show that ingesting or breathing levels of TCE that are higher than typical environmental levels can produce tumors of the liver, kidney, lung, and male sex organs, and possibly leukemia. At present, information is not sufficient to determine whether cancer in animals following exposure to TCE may also occur in humans. The Department of Health and Human Services, through its National Toxicology Program, could not find "clear evidence" that TCE causes cancer in humans or animals.
Chlorobenzene exposure via ingestion could occur in children who access surface water in the Northeast Wetland. Children who accessed this area could also have been exposed via dermal absorption from contact with the contaminated surface water. Exposure could also occur to residents and workers in the area due to the inhalation of contaminated indoor air. Because chlorobenzene was detected in the indoor air at a maximum concentration of 3 µg/m3, it is not expected that exposure to indoor air will result in adverse health effects.
The ATSDR has an intermediate, oral MRL of 0.4 mg/kg/day and the EPA has a chronic, oral RfD of 0.02 mg/kg/day for chlorobenzene. Incidental ingestion of surface water is not expected to result in adverse health outcomes due to the low contaminant levels detected in this medium which result in an expected dose less than the RfD and the MRL.
Exposure to 1,3-DCB via ingestion has occurred in on-site workers and children who accessed soil on-site. Exposure could also occur to children who access sediment in the Northeast Wetland.
The ATSDR does not have a MRL for 1,3-DCB, nor does the EPA have a RfD. Little information exists on the adverse health effects which could result from exposure to 1,3-DCB. As a result, it can not be determined if adverse health effects will result from exposure to site related contamination.
Two related health studies exist. The first is a descriptive health study of bladder and kidney cancer incidence and mortality as well as infant and neonate mortality . This study, which was conducted by the MDPH in December 1988, was initiated because of community health concerns regarding the Nyanza site. The only cancers targeted were bladder and kidney cancers, because kidney cancer was the only cancer elevated for the town based on "The 1982-1985 Report of Cancer Incidence in Massachusetts"  and bladder cancer has been associated with occupational exposure to azo dye manufacture using benzidine and 2-naphthylamine. The second study is a case series investigation released by the MDPH in December 1990 to address the questions raised as a result of the findings of the first study . The text of the first study is presented in its entirety. For the second study, the methods and results are briefly described. Also presented are the findings of the Expert Advisory Panel , which was convened in August 1990 by the MDPH to review the available health and environmental information. Background information and supporting tables can be found in reference #47.
Bladder and Kidney Cancer Incidence and Mortality, Infant and Neonate Mortality in the Town of Ashland, Massachusetts .
In response to a request from the Citizens Advisory Committee of the Town of Ashland, the Community Assessment Unit (CAU) of the Massachusetts Department of Public Health, Division of Environmental Epidemiology and Toxicology (MDPH, DEET) reviewed bladder and kidney cancer incidence for 1982-1986; mortality from these cancers was reviewed for 1979-1986, and infant and neonatal mortality was reviewed for 1980-1986. [The division has recently been named the Bureau of Environmental Health Assessment.]
Cancer incidence data for 1982-present were obtained from the Massachusetts Cancer Registry. Standardized Incidence Ratios (SIRs) were calculated for bladder and kidney cancer to determine if the Town of Ashland had experienced a higher than expected number of bladder and kidney cancer cases. For calculation of the SIR, cancer incidence data were used only from 1982-1986 as 1986 was the last year for which the Cancer Registry had complete data files. Mortality data were reviewed using the Massachusetts Mortality Profiles and are reported in much the same way as cancer incidence is reported. Infant and neonate mortality was reviewed using Public Document #1, which outlines vital events for the State on a year to year basis. The SIR is the ratio of the observed number of cancer cases to the number that would have been expected based on the State's cancer incidence experience. An SIR equal to 100 indicates that the number of cases in an area is equal to what would have been expected. An SIR of greater than 100 indicates that more cancer cases occurred than were expected, while an SIR of less than 100 means that fewer cases occurred than were expected. Care must be taken when interpreting the SIR since one must take into account not only how large it is but also how stable it is. An SIR of 200 based on one expected case and two observed cases is certainly large, but may be due primarily to cases occurring from random variation in cancer incidence patterns. Alternatively, an SIR of 200 based on 100 expected cases and 200 observed cases has the same magnitude as the previous SIR, but it is quite stable. It is unlikely that 100 excess cases would occur by chance alone.
A standard statistical test (chi-square, or X²) was used to determine the stability or statistical significance of the SIR where at least five cases were observed. A significant difference between the actual number of cases and the number expected means that the occurrence is probably not due to chance. Two common cut-off points for statistical significance, referred to as "p-values", are probabilities of less than 0.05 (p<0.05) and less than 0.01 (p<0.01). This means that the probability that the difference between the observed number and expected number was due to chance is less than five chances in 100 where p<0.05 and less than one chance in 100 where p<0.01. Place of residence at the time of diagnosis was examined to determine if there was any geographic clustering of cases. Other case-specific information that was obtained from the Cancer Registry and evaluated included smoking status, occupation, and histology.
Male bladder cancer cases occurred essentially at the rates that would have been expected for this time period based on the State's cancer incidence experience (4 observed/4.3 expected, SIR=92). Females experienced a slight elevation in bladder cancer incidence (2 observed/1.6 expected, SIR=122). Kidney cancer in males was statistically significantly elevated for 1982-1986 (5 observed/2.1 expected, SIR=235, X²=3.91, p<0.05). Female kidney cancers, however, occurred at the rate that would be expected (1 observed/1.3 expected, SIR=75). For 1987 to December 1988, one new case of bladder cancer had been reported to the Cancer Registry. No new cases of kidney cancer were reported for this time period.
Cancer cases were mapped to assess any clustering of events. Preliminary assessment indicates that there are two areas where cases appear to be concentrated. Kidney cancer cases are more prevalent to the south of the Nyanza site, while bladder cancer cases appear to be clustered on the eastern side of Route 135 near the Framingham border.
Residential histories of the cases diagnosed from 1982-1986 were obtained from existing town records to determine whether individual cases' length of residence in Ashland matched the latency period, or the time between exposure and the development of cancer. Two of the kidney cancer cases lived at the residence reported to the Cancer Registry for more than 30 years. Three other cases lived for 19 or 20 years at the reported address. The remaining kidney cancer case could only be located at the reported address for the year of diagnosis - this case is one of the cases to the south of the Nyanza site. The residential histories for the bladder cancer cases were slightly more variable; one individual had lived at the reported residence for 30 years, three others lived at the reported address for 12, 16, or 17 years. One person had only resided in Ashland (to the best of our knowledge) for four years prior to diagnosis and one person could not be located in the town books - probably because of group residence.
A review of the specific histologies reported for each cancer did not indicate anything unusual with regard to the distribution or proportions of histological types within the town. The clustering of events observed in these two areas of Ashland led to further investigation.
Mortality data from the Massachusetts Mortality Profiles are broken down into two different periods: 1979-1983 and 1984-1986. Overall, there were 1.6 male bladder cancer deaths expected and 0.8 female bladder cancer deaths expected; 1 female bladder cancer death was observed during this period. This was listed on the death certificate as "probable bladder cancer." With regard to kidney cancer deaths, 1.4 were expected in males and 0.8 expected in females; 1 female kidney cancer death occurred during this time period.
- Infant/Neonate Mortality:
Four infant deaths were observed for the period 1980-1986; three of these were neonatal deaths. The statewide average infant and neonate death rate per 100 live births for this 7 year period was 9.4 and 6.7, respectively. Ashland's average infant and neonate death rate per 1000 live births was 3.8 and 2.4, respectively. One would expect Ashland's infant/neonate mortality rate to be somewhat lower than the State's since the statewide rate is reflective of many urban populations and infant mortality rates are typically higher in urban populations than suburban populations. Infant and neonate deaths were evenly distributed throughout the town.
Follow-Up Report on the Occurrence of Bladder and Kidney Cancer in Ashland, Massachusetts 
- Case Series Investigation
Because the original information known for each bladder and kidney cancer case diagnosed between 1982-1986 is limited to that obtained from the Cancer Registry, the medical records of each case were reviewed to confirm histological diagnosis, smoking history, age at diagnosis, occupation and residential histories, and to obtain additional information pertaining to other factors that could cause bladder or kidney cancer and that may have been documented in the medical records.
Medical records were reviewed at the hospital where the case was diagnosed. The records provided information consistent with that obtained from the Cancer Registry, however, the information gaps for residential, occupation, and smoking histories remained. One case had previous medical problems, which may have resulted in an increased risk of cancer.
Bladder and kidney cases or their next-of-kin were interviewed using a questionnaire developed by the MDPH and reviewed by both the Expert Review Panel and the Ashland Board of Health. The interviews were conducted to fill the information gaps that existed following the medical record reviews. The Panel, Ashland CAC, and Ashland Board of Health agreed with this approach. The MDPH decided against a case-control study because the number of cases was too small to permit a causal determination for the cancer. Information sought using the questionnaire included residential history, potential occupational exposures, other risk factors for bladder and kidney cancer, medical history, and potential environmental exposures in Ashland.
Of the original 12 cases, five bladder and five kidney cases were interviewed. A brief summary of the interview results is given below. Detailed results and interpretations of the results are located in reference #47.
- The age of diagnosis for the bladder cases is slightly younger than expected, and for kidney cases is about what is expected.
- All five bladder cases were smokers, and two kidney cases were smokers.
- All female bladder and kidney cancer cases, but none of the males, reported a family history of bladder or kidney disease.
- Overall, one bladder and two kidney cases were possibly exposed to chemicals that can cause these cancers (this determination was based on a review of the reported job titles).
- Four bladder cases and four kidney cases lived in Ashland long enough to overlap the latency period for development of these cancers (12-15 years). The remaining kidney case lived in Ashland almost long enough.
- Only one kidney cancer case ever used a private well while living in Ashland.
- One case lived in Ashland when school-aged. Another case moved to Ashland as a teenager.
- Some of the cases engaged in recreational activities at the Nyanza site. Reports of discolored clothing were made by two cases. A third case reported seeing discolored snow and observing vapors emanating from the site.
- Eight of the ten cases interviewed reported that they experienced non-environmental risk factors.
- Expert Advisory Panel
An Expert Advisory Panel was convened to review the available site related environmental information and the health information obtained during the two health investigations. The panel was chosen on the basis of their experience in dealing with issues surrounding the definition of a cluster, the risk factors for bladder and kidney cancer, environmental exposure assessment, and risk communication. The charge presented to the Panel was:
- To assess the public health significance of the occurrence of bladder and kidney cancer in Ashland residents.
- To assess the adequacy of the existing data for determining the potential for health effects from exposure to contaminants.
- To recommend further epidemiologic and/or environmental studies to clarify significant scientific issues and fill relevant data gaps.
- To identify further actions, studies, and/or interventions which state and/or local officials could implement that would minimize current or future health risks, if any.
- To develop an action plan to communicate the group's findings and recommendations to the community.
In response to this charge, the Panel received documentation on the major pieces of available health and environmental data, received technical briefings from representatives of the EPA, DEP, and MDPH, and heard community concerns from representatives of the Ashland CAC and Board of Health. The Panel's conclusions and recommendations are given in their entirety below.
- Final Report of the Ashland Advisory Panel:
The Panel believes that the MDPH took appropriate steps in investigating the incidence of bladder and kidney cancer in Ashland. We commend their efforts.
- The Panel believes that the number and geographic distribution of bladder and kidney cancer cases observed in Ashland is not an atypical finding in public health investigations of geographic clusters and, as a result, this distribution or clustering of cancer in Ashland does not appear unusual.
- The best available health and environmental data do not support a causal role for environmental hazards in the occurrence of bladder and kidney cancer in Ashland.
- Based on information provided by community and public agencies, the Panel believes
that potential exposures to environmental contaminants may have existed in the past for
Ashland residents. The types of exposure that may have occurred include:
- Exposure via ingestion of and/or dermal contact with soils and surface water on the Nyanza site itself.
- Exposures via ingestion of and/or dermal contact with fish, sediment, and surface water from the Sudbury River and the Chemical Brook.
- Exposures via inhalation of and/or dermal contact with dust and vapors emanating from the Nyanza site and/or industries previously operating on the site.
These potential exposures could have contributed to a variety of disease outcomes. However, information on health outcomes, other than cancer, is not readily accessible from existing data.
- The Panel believes that, as an appropriate follow-up activity by the Town of Ashland, all
persons who resided in Ashland during the 1960's be identified, so that the mortality and
cancer incidence information on these individuals can be ascertained. We believe the
1960's to be the critical time period based on the in-migration of individuals in the 1970's
and 1980's, and on the latency period of the diseases plausibly related to these potential
exposures. The need for any additional follow-up action would be determined based on
the development of this community health profile.
Follow-up Report Conclusions
The purpose of the MDPH follow-up investigation was to determine if the geographic distribution of bladder and kidney cancer in Ashland appeared unusual or clustered in certain parts of town that might suggest a common environmental exposure. Particular attention was given to the potential for occupational and environmental exposures of the cases. The conclusion drawn from the various epidemiologic investigations, including the comments of the Expert Advisory Panel, is that the cases of bladder and kidney cancer diagnosed among Ashland residents between 1982 and 1986 do not appear to be unusually clustered, nor does it appear that the distribution of cancer cases in Ashland is likely related to the Nyanza site or environmental exposures associated with the site.
In addition, the CAU updated Standardized Incidence Ratios for bladder and kidney cancer incidence in Ashland. As of June 1993, cancer registry data exist for the period 1982-1989. Please refer to the accompanying Table B-15, "Bladder and Kidney Cancer Incidence, 1982-1989 in Ashland, Massachusetts," located in Appendix B.
Bladder cancer cases have occurred at the rates that would have been expected among males, females, and among males and females combined in Ashland for the period 1982-1989. The slight elevations observed among males as well as among males and females combined reflect less than one excess bladder cancer case and were not statistically significant. Kidney cancer cases occurred at the rate that would have been expected among females; an elevation was observed among males (observed number of cases=8/ expected number=4.7; SIR=172). This elevation was not statistically significant. An elevation was also noted among males and females combined, however, this elevation was attributed to the excess kidney cancers observed among males and was not statistically significant.
The CAU also evaluated the geographic distribution of bladder and kidney cancer cases diagnosed from 1986-1989. These cases appear evenly distributed throughout Ashland. It appears that the addition of new data no longer suggests a geographic pattern of these cancer types in Ashland.
- How much cancer is there in Ashland?
Between 1982 and 1986, six bladder cancer cases and six kidney cancer cases were diagnosed among the residents of Ashland. About three kidney cancer cases and six bladder cancer cases would have been expected based upon statewide cancer rates. The difference between the observed and expected numbers of kidney cancers among males was statistically significant, but the numbers were small.
A review of updated bladder and kidney cancer incidence data (1982-1989) revealed that bladder cancer cases occurred essentially as would have been expected based on the cancer rates in the Commonwealth for the same period. Kidney cancer incidence was elevated among males in Ashland, however this elevation was due to approximately three excess cases and was not statistically significant.
- Are there specific areas of Ashland where cancer appeared to be more common?
Initially, when the MDPH looked at the cancer incidence data in Ashland, an unusual grouping of four of the six bladder cancer cases in the northeastern part of town, and three of the six kidney cancer cases just south of the Nyanza site seemed to exist. Follow-up work was undertaken by the MDPH to determine if this distribution was unusual. The conclusion drawn from the various epidemiologic investigations, including the comments of the Expert Advisory Panel, is that the cases of bladder and kidney cancer diagnosed among Ashland residents between 1982 and 1986 do not appear to be unusually clustered. In addition, evaluation of the geographic distribution of bladder and kidney cancer cases diagnosed between 1986 and 1989 did not reveal any clustering of cases. It does not appear that the information available on cancer cases in Ashland indicates that they are related to the Nyanza site or environmental exposures associated with the site.
- Does the way the cancers were distributed in the town mean that the environment caused
When undertaking an environmental health investigation, the most important factor is that exposure must have occurred prior to the cases' cancer diagnosis. If the place of residence at the time of diagnosis is similar for a number of individuals with the same type of cancer, one possible explanation is that the individuals share a common exposure. One common exposure may be the environment, however, other exposures, such as occupational exposures, may be responsible. The geographic grouping of cases may also occur simply by chance alone.
- Is there a cancer problem in Ashland?
Based upon the compilation of all existing health and environmental information, the number and distribution of bladder and kidney cancer cases diagnosed since 1982 do not appear to be particularly unusual. Furthermore, it is the judgement of health experts outside the MDPH who reviewed these data that it is not likely that the environment caused these cancers. No other types of cancer were found to be significantly in excess among the residents of Ashland.
- Are fish in the Sudbury River or other nearby waterways contaminated? If so, do they pose a public health threat?
Mercury contamination has been found in Sudbury River fish at levels above the federal Food and Drug Administration's action level. Therefore, a health advisory was issued in March of 1986 by the MDPH recommending that individuals not consume fish caught in the Sudbury River. This advisory holds for the stretch of the Sudbury River from Ashland to its confluence with the Assabet River in Concord.
- Is it possible that children who played in or around the site were exposed to contaminants
that may have caused adverse health effects?
The exposure of children and adults to contaminated media in or around the site has occurred in the past. Health effects are possible from exposure to some contaminated environmental media. Exposure to antimony in soil and sediment and to arsenic in soil through the ingestion of these media may result in vomiting and gastrointestinal irritation. The ingestion of soil and sediment containing high levels of chromium may result in abdominal pain, vomiting, and in skin irritation. The ingestion of mercury or methylmercury through the consumption of contaminated fish may result in neurologic symptoms, kidney effects, and damage to the fetus. Based on the information reviewed for this public health assessment, it can not be determined at the present time if exposure to environmental contamination at the site is related to the adverse health effects which occurred to the residents of Ashland such as cancer and adverse reproductive outcomes.