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PUBLIC HEALTH ASSESSMENT

INDUSTRI-PLEX
WOBURN, MIDDLESEX COUNTY, MASSACHUSETTS


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

To identify possible facilities that could contribute to the air, water, and soil contamination near the Industriplex site, the Massachusetts Department of Public Health (MDPH) searched the Toxic Chemical Release Inventory (TRI) database from 1987 to 1992. TRI is a database developed by the EPA from chemical release information provided by certain industries. TRI contained information reported by five industries within a one mile radius of the boundaries study area, and include releases within and outside of the study area. The majority of the reported releases within that radius were to the air rather than to soil or water. Chemicals released to the air include copper, acetone, sulfuric acid, cyanide compounds, nickel, 1,1,1-trichloroethane, toluene, butyl benzyl phthalate, zinc, and methyl ethyl ketone. Toluene was also released to the land.

The following sections briefly describe the known compounds of concern detected in the study area. Compounds of concern are those compounds with concentrations in at least one environmental medium exceeding the health assessment comparison values established by the ATSDR and the EPA. This section is utilized for preliminary screening of the contaminants; the contaminants listed will be further assessed in the following sections. Information on the health implications of identified compounds is discussed in the "Toxicological Evaluation" section. The presence of a contaminant on the compound of concern list does not imply that a human health threat exists. Some contaminants may be eliminated as a concern in the "Pathways Analysis" section due to an incomplete past, present, or future exposure pathway. The investigations conducted for each medium will be described prior to qualitative presentation of results.

A. On-Site Contamination

Soil

Tables B-1 and B-2 present the quantitative results of all soil sampling and analysis. As part of the Phase I Investigation, fifty-three boring for soil sampling were installed on-site. In addition, one hundred and twenty-three test pits were dug on-site. A total of four hundred and sixty-two soil samples were collected from the soil boring and test pits; one hundred and ninety-nine samples were analyzed for heavy metals, one hundred and fifty-one were screened for VOCs and semi-VOCs. In the Phase II Remedial Investigation, three hundred and fifty test pits were excavated on-site. In on-site contaminated areas, four hundred and twenty-five soil boring were drilled on a grid of five borings per acre. From these borings, one thousand and thirty-two samples were collected for heavy metals analysis. Ten soil boring were drilled in areas of high VOCs and twenty-nine discrete samples were taken at the depths of 1 foot, 5 to 11 feet, and 7 to 21 feet. Samples were analyzed for VOCs.

During the "PDI Task S-1", the following tasks were completed in order to provide a comprehensive view of soil contamination: (1) thirty-seven soil boring were drilled in areas of open ground in developed areas; (2) sixteen boring were drilled in undeveloped parts of the site where data currently exist for only one depth interval; (3) nineteen boring were drilled in the Boston Edison Right-of-Way Number 9; and (4) nineteen boring were drilled in areas suspected to contain or to have used hazardous substances. Samples were analyzed for arsenic, lead, chromium, metals, VOCs, semi-VOCs, PCBs, and pesticides. A "Supplemental Bore Hole Program" was conducted in 1991 in which soil samples were collected at twelve on-site locations and analyzed for arsenic, lead, and chromium.

In October 1979, eighteen soil samples were collected by the DEQE (now the DEP) from waste deposits in six locations and analyzed for metals.

Soil (0-12 inch depth) (Table B-1)

Because surface soil was not specifically sampled, soil (0-12 inch depth) will be used to characterize soil which exhibited a greater potential of exposure in the past. The disadvantages of using soil 0-12" to characterize exposure is discussed in detail in the "Pathways Analysis" section of this public health assessment. Discrete samples were taken within this 0-12 inch depth range. Compounds of concern detected during the analysis of soil include: arsenic (7,959 ppm), chromium (80,600 ppm), copper (15,100 ppm), lead (33,900 ppm), manganese (10,900 ppm), thallium (258 ppm), vanadium (130 ppm), benzene (275 ppm), diethylene glycol (513 ppm), and PAHs (5 ppm).

The following site areas can be approximately located in Figure A-3. The top two feet of soil were well mapped and the following areas were defined as areas where chemical concentrations exceeded 100 ppm: (1) the arsenic pit located in the north central portion of the site (11 acres), (2) the chromium lagoons located in the southwestern portion of the site (9.5 acres), (3) the wedge area west of the railroad tracks (6.0 acres), and (4) the northwest railroad ditch (2.0 acres) [22]. Along New Boston Street, low ppm levels of organic compounds were found including benzene (20 ppm) and diethylene glycol (500 ppm) [22]. Hide residues were found in four distinct areas for a total of 13 acres. The east hide pile covers 3.2 acres with an estimated volume of 125,000 cubic yards; the west hide pile covers 2.6 acres with an estimated volume of 50,000 cubic yards; the east central buried hides cover 5.7 acres with an estimated volume of 106,000 cubic yards; and the south central hide pile covers 1.4 acres with an estimated volume of 60,000 cubic yards [22].

Subsurface Soil (Table B-2)

Contaminants of concern detected in on-site subsurface soil included antimony, arsenic, chromium, copper, lead, thallium, Arocolor 1254, PAHs, thallium, vanadium, zinc, diethylene glycol, 1,1,1-trichloroethane (1,1,1-TCA), and benzene.

The following site areas can be approximately located in Figure A-3. Approximately 100 acres of the site contained waste deposits ranging from less than 1 to 80 feet deep. In several areas, wastes have been piled on the ground up to 40 feet above grade [22]. The area to the east of Commerce Way and its extension does not contain waste materials [22]. There are approximately 29 acres of the site where greater than 1,000 ppm of lead and/or arsenic were found and an additional 28 acres containing 100 ppm of lead and/or arsenic. Chromium was found on approximately 18 acres of the site at levels greater than 1,000 ppm and on an additional 17 acres at greater than 100 ppm. Chromium is generally found in the same areas as the hide residues and in the chrome lagoon area. Hide residues covered approximately 13 acres of the site [22].

Surface Water (Table B - 3)

On-site surface water data were obtained from the document titled "Surface Water Quality Sampling Report for the Fourth Quarter at the Industriplex Site Remediation Project". As part of the Remedial Action Work Plan for OU-1, surface water samples were collected and analyzed for metals, total suspended particles (TSS) and hardness.

During the on-going remediation of OU-1, ten locations were selected to sample surface water throughout the study area. The points were chosen to sample surface water in-flow and out-flow. The data represent samples collected over a thirteen week period from October to December 1993. Surface water was analyzed for arsenic three times per week. Once every four week period samples were selected from each sample site and analyzed for chromium 3+, lead, hardness, and TSS [23]. In general the levels of arsenic and lead exceeded surface water comparison values only during periods of precipitation.

Surface water compounds of concern are arsenic, manganese, 4-methyl-2-pentanone, dichloroethane, and trichloroethene.

The highest level of arsenic detected in surface water was 14.6 ppb. However, it should be noted that even the lowest level of arsenic was fifty times higher than the comparison value for that media. Although the highest levels of manganese (777 ppb), 4-methyl-pentanone (10 ppb), and trichloroethane (11 ppb) also exceeded there respective comparison values, all included the comparison value in the range of contaminant levels detected in this media.

Sediment (Table B - 4)

The Groundwater\Surface Water Investigation Plan Phase I and II (GSIP I & II) evaluated the nature and extent of organic and inorganic contamination of sediments within the study area, on and off-site [24,25]. Sampling for GSIP I was performed by Enesco - ERCO and took place during July - August 1990. Seventeen samples were taken consisting of a 0 - 3' core. Of these samples four were taken on-site in the Aberjona River. GSIP II was done in October 1991 and provided data to supplement GSIP I. An additional study being done by MIT also involved sampling on-site and off-site sediments [31]. The preliminary results of this study is consistent with the results of GSIP I and II. The data from the MIT study will not be presented in this health assessment.

No pesticides or PCBs were detected in on-site sediment samples. The contaminants of concern detected in on-site sediment are arsenic (371 ppm), lead (212 ppm), and PAHs (<45,000 ppm). Neither arsenic nor PAHs included the comparison value in the range of concentrations detected in this media. The lowest level of PAH detected was three orders of magnitude higher it's comparison value.

Ambient Air (Table B-5)

Table B-5 presents the quantitative results of all on-site ambient air sampling and analysis. A Baseline Air Survey was conducted as part of the "PDI Task A-1". Sampling locations were selected based on the results of air dispersion modeling using regional meteorological data and the historical location of odor complaints. A total of 12 sites were selected for air sampling, five of which were located on-site. Samples were collected during a 24 hour period in August, 1990 and were analyzed for VOCs, methane, reduced sulfur compounds, and arsenic, lead, and chromium in dust. Three of the five on-site sampling stations detected compounds of concern.

As part of "The Analysis of Industriplex 128 Hi Vol Filters by Inductively Coupled Argon Plasma (ICAP)", fifteen samples from the Woburn Industriplex site were analyzed for lead, arsenic, chromium, and antimony, and other metals.

Compounds of concern detected in on-site ambient air include: 1,1,1-TCA, MEK, arsenic, barium, lead, vanadium, and zinc. Generally, the concentrations of these compounds of concern did not exceed 1 ug/m3. Methylene chloride and 1,1,1-TCA were detected at up to 2,300 ug/m3 and 32 ug/m3, respectively in the northern portions of the site with the wind blowing from the south and east-southeast.

There are currently seven ambient air monitoring stations operating 24 hours on-site at Industriplex. These stations are checked periodically by remedial workers for H2S and other air contaminants. The data from these stations was not available during the writing of this health assessment. Personal communication with the DEP Remedial Project Manager revealed that there are no serious problems with ambient air contaminants at Industriplex at the present time.

Soil Gas (bore hole air) (Table B-6)

Table B-6 presents the quantitative results of all bore hole air sampling and analysis. During the Phase I Investigation, ten bore holes were installed in the waste deposit areas and air samples from inside the bore holes were collected and analyzed for total reduced sulfur (TRS) compounds, arsine, and VOCs. Samples varied in depth from 6 to 39 feet. A total of 98 samples were collected; 30 were analyzed for TRS compounds, 30 for arsine, and 38 for VOCs. However, only 6 VOC analyses were valid because cross contamination between samples and high concentrations of reduced sulfur compounds invalidated the other VOC samples.

As part of the Phase II Remedial Investigation, the site was screened for VOC emissions and odor sources. In addition, during test pit and soil boring programs, air screening was conducted to locate possible organic vapor sources. Measurements of hydrogen sulfide and methane gas concentrations were also made in air. Based on the site screening, 19 locations were selected as potential gas emission and/or odor sources. Bore holes were drilled in these locations and gas emission rates were measured. Air samples from 15 bore holes selected on the basis of gas emission rates were collected and analyzed for VOCs.

The levels of hydrogen sulfide and methyl mercaptan found in the east waste pile bore holes indicate that this waste pile is one probable source of odor. Hydrogen sulfide was not detected above ground in ambient air. In the limited sampling, the VOCs found were reduced sulfur compounds that might produce odors at minute concentrations [21]. Four major areas on-site were identified as displaying potential for gas emissions and odor: (1) the east hide pile located at the north end of the site; (2) the west hide pile located at the north end of the site; (3) the east central hide deposit located directly north and adjacent to the currently developed commercial area; and (4) the south hide pile located directly west and adjacent to the currently developed commercial area [22].

In May and August 1990 the H2M Group conducted a survey of soil gas to provide data to further evaluate alternative gas treatment strategies [30]. The sampling and analysis was done using existing gas vents and flux chamber techniques [30]. Compounds of concern detected in bore hole air include: benzene (11 ppm), toluene (3.9 ppm), carbon disulfide (11 ppm), dimethyl disulfide (7.8 ppm), dimethyl sulfide (20 ppm), ethanethiol (77 ppm), hydrogen sulfide (47,000 ppm), methyl furan (2.8 ppm), methyl mercaptan (470 ppm), 2-propanethiol (180 ppm), butanethiol and methanethiol (220 ppm). Current remediation of the site (which includes stabilization of the hide piles and thermal oxidation of soil gas [30]) has reduced the emission of bore hole air into the ambient air and it's migration off-site.

Groundwater (B-12 and B-13)

The most recent groundwater data for the Industriplex site is contained in the "GSIP I and II" reports and the "Preliminary Design Report Interim Groundwater Remedy". The reports were partially devoted to characterizing the contaminants found in groundwater in the study area [29]. The results showed that there is no PCB or pesticide present in this media. Inorganic metals detected were arsenic, chromium, lead and zinc. Benzene and toluene has been migrating off-site and has impacted the HBHA [29].

Benzene was detected in two on-site monitoring wells in 1983. The wells were located on the southern boarder of the site and just north of HBHA. As a result of this finding, four new wells were developed to evaluate the extent of organic chemicals in groundwater. Eventually, sixty-one wells were installed to delineate the benzene plume. In 1992, it was determined that the Benzene plume originated on the site flowed in the direction of HBHA [29]. A plume of toluene was also discovered to be moving with the benzene plume [29].

During the GSIP Remedial Investigations the benzene/toluene plume was delineated, the movement of heavy metals on and off-site was characterized, and it was determined that small amounts of chlorinated VOCs detected near HBHA are not site related [24,25]. Although heavy metal and organics are present in the groundwater at levels above the ATSDR comparison values, there is currently no known pathway for past, current, or future exposure to these site related chemicals through this media. The extent that activities at Industriplex may have impacted the Aberjona watershed (and municipal Wells G & H) is being investigated in an on-going study at the Massachusetts Institute of Technology (MIT) [31]. The results of the study are forthcoming.

B. Off-Site Contamination

Soil

The soil sampling studies are described in the section on on-site soil contamination. Quantitative results of off-site soil sampling are shown in Tables B-7 and B-8. In the Phase II Investigation, seventy test pits and five soil boring were installed off-site. During the "PDI Task S-1", nineteen boring were drilled in the Boston Edison Right-of-Way Number 9 and off-site soil samples were obtained to determine background levels of arsenic, lead, chromium, and organic compounds. A "Supplemental Bore Hole Program" was conducted in which soil samples were collected at twenty-two off-site locations. Off-site sampling locations were concentrated along the northern, southern, and western site boundaries, in the Boston Edison Right-of-Way, and along the railroad tracks.

Soil (0-12 inch depth) (Table B-7)

Since no data was available for surface soil (0-3"), soil 0-12" was used as a surrogate. The disadvantages of using soil 0-12" to characterize exposure is discussed in detail in the "Pathways Analysis" section of this public health assessment. Compounds of concern detected in off-site soil are: arsenic (1,748 ppm), lead (26,699 ppm), thallium (29 ppm), and diethylene glycol (336 ppm). The majority of the soil (0-12 inch depth) contamination was found along the railroad tracks and in the Boston Edison Right-of-Way. It should be noted that the lowest level of arsenic detected was four and one-half times higher than the comparison value for this media.

Subsurface Soil (Table B-8)

Compounds of concern detected in off-site subsurface soil include: arsenic (17,000 ppm), lead (8,788 ppm), thallium (56 ppm), benzene (72 ppm), and diethylene glycol (523 ppm).

Surface Water (Table B-9)

The Groundwater/Surface Water Investigation Plan Phase II (GSIP II) contains data obtained from six new off-site surface water sampling locations to supplement data collected during the phase I remedial investigation for OU-2. The six locations represent two upstream and four downstream locations. Sampling areas include the New Boston Street Drainway, Hall's Brook Holding Area, wetlands, and the Aberjona River [25]. Surface water was sampled for volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), total Target Analyte List metals (TAL metals), and total organic carbon (TOC). Quantitative results are presented in Table B-9.

In OU-2 the levels of arsenic (41 ppb) detected were consistently above the comparison value for surface water. The other surface water compounds of concern is lead (154 ppb).

Sediment (Table B-10)

The Groundwater\Surface Water Investigation Plan Phase I and II (GSIP I & II) evaluated the nature and extent of organic and inorganic contamination of sediments within the study area, on and off-site [24,25]. These studies are discussed in the section on on-site sediment. Of the seventeen samples taken in GSIP I, thirteen were off-site samples taken within the study area (five from the Aberjona River and eight from Hall's Brook Holding Area). GSIP II was done to supplement data collected during GSIP I.

No pesticides or PCBs were detected in off-site sediment samples. Compounds of concern that were detected are arsenic (1,380 ppm), beryllium (2.9 ppm), copper (1,100 ppm), lead (108 ppm), manganese (7,220 ppm), thallium (3.2 ppm), dibenzofuran (<45,000 ppm), 1,3 - dichlorobenzene (<45,000 ppm), 1,4 - dichlorobenzene (<45,000 ppm), 3,3'- dichlorobenzidine (<45,000 ppm), 4,6-dinitro-2-methyl phenol (<1,000,000 ppm), PAHs (<45,000 ppm), 1,1,1 Trichloroethane (<140 ppm), and vinylchloride (<140 ppm).

Ambient Air

Ambient air monitoring studies are described in the section on on-site ambient air contamination. Quantitative results of off-site ambient air sampling and analysis are shown in Table B-11.

During the Baseline Air Survey, two of the seven off-site monitoring stations selected for air sampling detected compounds of concern with the wind blowing from the south and from the east/southeast. The monitoring stations were located 0.2 miles north of the site and 0.7 miles southwest of the site. The station located to the southwest of the site was probably not affected by site related compounds in ambient air on this day of sampling due to the predominant wind direction.

In a report entitled "The Evaluation of Hydrogen Sulfide Concentrations at Residential and Commercial Sites Surrounding a Woburn Construction Area", air samples were collected at representative commercial and residential sites within the region affected by odors emitted during site activities. Thirteen samples were collected at ten locations and analyzed for hydrogen sulfide and sulfur dioxide. Three off-site monitoring stations located northwest of the site, north of the site, and northeast/east of the site detected compounds of concern. The primary wind direction was from the southwest on the day of sampling. The station located to the northwest of the site was probably not affected by site related compounds in ambient air on this day of sampling due to the predominant wind direction.

In "The Interim Report of Particulate Monitoring at the Woburn Hazardous Waste Site", an air monitoring network consisting of twelve samplers located in the vicinity of the site was used to collect particulate samples from August to October 1980. Samples were analyzed for total suspended particulates (TSP), chromium, arsenic, lead, and antimony. Metal scans were also conducted.

Compounds of concern detected in ambient air include: arsenic, chromium, lead, antimony, toluene, MEK, and hydrogen sulfide. Hydrogen sulfide readings varied considerably during measurements of adjacent areas. Hydrogen sulfide seemed to collect and stay within a narrowly defined area, suggesting that all hide deposits may not actively be generating gases, and localized hot spots from previous decomposition may exist [22].

There are currently seven ambient air monitoring stations operating 24 hours on-site at Industriplex. These stations are checked periodically by remedial workers for H2S and other air contaminants. The data from these stations was not available during the writing of this health assessment. Personal communication with the MADEP Remedial Project Manager revealed that there are currently no serious problems with ambient air contaminants at Industriplex at the present time.

Indoor Air (Table B-11)

Indoor Air monitoring was performed at Digital Equipment Corporation (DEC) which is located within the study area for the Industriplex site. The monitoring was done by an industrial hygienist in the winter of 1994, from fixed locations at night [26]. These conditions represent a worst case scenario, since the ventilation system is shut down during these hours and the contaminants can build up in the air [26]. The indoor air was sampled for volatile organic compounds that are present in the plume emanating from the Industriplex site. These chemicals have the potential to volatilize into buildings and pose a risk to the exposed population. The samples were taken from different areas of the complex and compared to ATSDR comparison values (CVs) for air and Threshold Limit Values (TLV) (ACGIH standards for occupational exposures), for the purpose of this public health assessment.

Compounds of concern based on the CVs are carbon tetrachloride, chloroform, 1,1-dichloroethylene, methylene chloride, 1,1,1-dichloroethane, trichloroethane, trichloroethylene, thrichlorofluoromethane, benzene, chlorobenzene, and acetone. It should be noted that none of the contaminants detected exceeded any of the occupational limits for exposure.

On March 8th, 1994, personal air sampling was performed on DEC employees during normal working hours with the ventilation system operating [27]. These samples were taken over approximately an eight hour period in different areas of the facility. All exposures were extremely small and no contaminants of concern were detected. Monitoring of indoor air quality will continue on a periodic basis.

Groundwater (B-12 and B-13)

Recent groundwater monitoring studies are described in the section on on-site groundwater contamination. During the "PDI Task GW-2", eight temporary observation wells were installed at four separate cluster locations south of the site. In addition, a temporary well was hand driven into Hall's Brook to screen the groundwater immediately below the stream bed. Sixteen wells, located downgradient of the site, between the site and Mishawum Road were sampled. Samples were collected and screened for benzene, toluene, TCE, and arsenic.

A total of fifty-six wells were sampled off-site in "The Evaluation of the Hydrogeology and Groundwater Quality of East and North Woburn". Six wells were located upgradient and north of the site. A total of fifty wells were located downgradient of the site and occupied the area from the southern site boundary to just south of the Woburn/Winchester border. Municipal supply wells G & H were also sampled in this study.

As part of "The Inventory and Analysis for Existing Well Data for East and North Woburn", six off-site wells existing in East and North Woburn were sampled and analyzed for metals, VOCs, and semi-VOCs [6]. The types of wells sampled are unknown. These downgradient wells extended southward from the site boundary to the Woburn/Winchester border and included municipal supply wells G & H. Three domestic wells and several wells used for industrial purposes and for irrigation are also located downgradient of the site, but were not sampled as part of this investigation.

As a result of a long history of industrial development in the general area, there are numerous potential contaminant sources impacting the groundwater. The extent that activities at Industriplex may have impacted the Aberjona watershed (and municipal Wells G & H) is being investigated in an on-going study at the Massachusetts Institute of Technology (MIT) [31]. The results of the study are forthcoming. The city of Woburn currently obtains it water from municipal wells and other sources that are not impacted by the contamination from the Industriplex site. Furthermore, the contribution of Industriplex to the past contamination of Wells G & H has not been determined. Off-site groundwater is an eliminated pathway for future exposure. Please refer to the Health Assessment for Wells G & H for a discussion of past problems with drinking water in Woburn [1]. There are no contaminants of concern to discuss in relation to off-site groundwater.

C. Quality Assurance and Quality Control

Each of the major investigations summarized in the previous sections on environmental contaminants has its own quality assurance and quality control (QA/QC) procedures. Overall, the sampling, analytical techniques, and data were adequate for the purpose of the public health assessment. However, several problems were encountered in the various studies which could have compromised the quality of the data.

Three problems in the Phase I Remedial Investigation analysis program were discovered as a result of the QA program that required additional analytical work. These concerned the results of mercury in soil analyses, lead in surface waters and VOCs in bore hole air samples. Mercury results reported were found to be 100 times higher than results obtained due to a computational error made in the mercury analyses. Results of lead in surface water samples indicated that six sites had identical concentrations of 100 ppb. A review of the records indicated that five of the samples were below the lower limit of detection and only one sample contained 100 ppb lead. Results of analyses of VOCs in bore hole air samples were judged to be invalid due to a severe contamination problem with sulfur compounds that prevented the accurate measurement of VOCs.

In the Phase II Remedial Investigation, it was found that EPA methods were not suitable to determine the presence of chromium VI in Woburn soil samples, because the methods can not recover chromium VI in the presence of high organic concentrations and give false positive results in the presence of high levels of chromium III compounds.

For methyl mercury analysis in the "PDI Task SW-1", no usable data were obtained because interference from the sediment matrix resulted in poor chromatographic resolution. In the "PDI Task A-1", the sulfur compound stability documented in the laboratory report indicated that sulfur compounds might have been slightly affected by storage. The sample storage effects were noted on spiked canisters. Any corrections to the data will be assessed when all four rounds of spike sample stability data are available.

The above mentioned data were not included in the health assessment review process due to the various QA/QC problems.

There was no information presented on the QA/QC programs for "The Inventory and Analysis of Existing Well Data for East and North Woburn", the soil samples of waste deposits at the Industriplex site, or "The Interim Report of Particulate Monitoring at the Woburn Hazardous Waste Site".

D. Physical and Other Hazards

The presence of physical and other hazards was investigated during the February 22, 1994 site visit. Based on that visit, it is believed that the site is generally clean and well maintained.

As noted during the 1994 site visit, the undeveloped portion of the site is surrounded by a fence topped with barbed wire. The access gate is well maintained, and warning signs are prominently placed on the gates and periodically along the entire fence. Physical hazards at the site include the presence of heavy equipment used by remediation workers, and large pits caused by excavation activities on-site. The items mentioned here would be accessible to unauthorized individuals who access the site. However, it is unlikely that people will gain entry due to the 24 hour presence of a security guard and the fence.

PATHWAYS ANALYSIS

To determine whether nearby residents are exposed to contaminants migrating from the site, the factors influencing human exposure were evaluated. The 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.

Pathways are identified as completed or potential. Completed pathways consist of five elements and indicate that exposure to a contaminant has occurred in the past, is currently occurring, or will occur in the future. Potential pathways, however, require that at least one of the five elements is currently missing. Potential pathways indicate that exposure to a contaminant could have occurred in the past or could occur in the future. Pathways 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. Some eliminated exposure pathways are also discussed.

A. Completed Exposure Pathways (Table B-12)

Soil (0-12 inch depth) Pathway

Past exposures are possible from soil contamination in the undeveloped areas on-site, and off-site within the study area. On-site workers and trespassers were at risk for exposure via inhalation, ingestion, or dermal contact with contaminated soil. Workers and trespassers accessing the off-site portion of the study area are also at risk for past exposure to site contaminants via inhalation, ingestion, or dermal contact with contaminated soil. Nearby residents were at risk for exposure via inhalation of fugitive dust transported off-site by wind dispersion. Trespassers using All Terrain Vehicles (ATVs) to access the site were at a higher risk of exposure to contaminated soil through all routes.

The ATSDR considers surface soil to be the top 0-3" of soil on and off-site. This depth represents the soil to which most people are likely to be exposed. If the contaminants are more concentrated in the top three inches of soil, sampling of 0-12" will in general underestimate exposure. Conversely, if the contaminants increase in concentration as you increase depth, the exposure will be overestimated. At the time of the writing of this health assessment, no data was available for soil sampling at 0-3", so 0-12" will be used as a surrogate for surface soil exposure.

On-site contamination of soil 0-12" originated from the deposition of wastes directly into the soil and from on-site manufacturing processes that resulted in releases of contaminants on the ground. The contaminants, PAHs and metals, tend to adhere to soil particles and could be transported by water via runoff, flooding or through the air attached to particulate matter via wind dispersion and the fugitive dust generated by excavation and construction. Transport of soil contaminants to other points of exposure has probably occurred in the past by several pathways: wind dispersion, surface runoff, flooding, excavation and construction, dispersion of dust generated by ATV use on-site and on-site workers and trespassers carrying the contamination home on their clothes and shoes.

Past exposure to metals, PAHs, and organics could have occurred to on-site workers, trespassers, residents and workers in the site area due to incidental ingestion of contaminated soil, inhalation of fugitive dusts, or dermal contact with contaminated soil. The use of ATVs would have resulted in large quantities of dust being generated. Thus the exposure to contaminated soil would have been greater for trespassers using these vehicles on-site. Residents in the nearby community were most likely exposed to on-site contaminates carried in dust carried off-site by wind.

The principal exposure pathway would be the past exposure of on-site workers and trespassers to contaminants via incidental ingestion of the soil. Residents and workers in the area, as well as on-site workers and trespassers, may have been exposed via inhalation of particulate matter. The dermal exposure pathway would be minimal compared to the other exposure routes because the contaminants detected in the soil (0-12 inch depth) are not absorbed through the skin in large quantities. Trespassers using ATVs to access the site would have a higher level of exposure via ingestion and inhalation than someone accessing the site on foot.

Present remediation activities on-site reduce the transport of contaminated soil off-site by reducing dust and surface runoff. Decontamination of workers and equipment that enter and leave the site also reduces the possibility of off-site transport. Ingestion, inhalation, and dermal contact with contaminated soil are currently diminished due to the presence of soil cover over approximately one-third of the site; the presence of a fence and 24 hour security guard to eliminate trespassing; and remediation practices to reduce transport of contaminants off-site and workers exposure.

Subsurface Soil Pathway

Past exposure to contaminated subsurface soil is possible in the undeveloped areas of the site. The exposed populations were on-site workers, and possibly trespassers who accessed the site. The transport mechanisms for subsurface soil are similar to those for soil (0-12 inch depth). PAHs, PCBs, and metals tend to adhere to soil particles. Organic solvents, such as benzene, toluene, and 1,1,1-TCA, tend to be transported in water filtering through the soil into the groundwater.

Past exposure to metals, PAHs, organics, and PCBs could have occurred to on-site workers who disturbed subsurface soil due to the ingestion of subsurface soil, inhalation of fugitive dusts, or dermal contact with contaminated subsurface soil. These routes of exposure are currently diminished due to the on-going remediation of the site. The principal exposure pathway would be the past exposure of on-site workers to contaminants via ingestion of the subsurface soil during and following excavation activities. Although the organic chemicals present in the subsurface soil are absorbed following dermal contact, this exposure pathway would be minimal compared to the ingestion route.

Ambient Air Pathway

Past exposures to site related contaminants are possible from the ambient air around the site. Contaminants were released into the air through manufacturing processes and the generation of fugitive dust from disturbances of contaminated soil. These contaminants were carried off-site by prevailing winds to affect the residents of nearby communities.

The ambient air data collected represent sampling conducted over a short time period and do not represent the range of conditions that might have existed during past excavation activities or over the years. Therefore, it is impossible to determine what past health effects may have occurred to past exposure to site related contaminants in ambient air. Currently, the installation of soil cover over one-third of the site makes the spread of contamination in the surface soils via fugitive dusts unlikely to contribute significantly to exposure.

Populations at risk for inhalation of contaminated air in the past are on-site workers, trespassers, residents and workers in the site vicinity. Repeated complaints were received in the past from local citizens, especially southeast of the site, with respect to offensive odors generated by the hide piles [14]. These complaints have been associated with the former site development activities and rain storms. Increased odors during storms are believed to be largely due to exposure of fresh areas of the hide piles to the atmosphere after slumping of the unstable slopes, and due to increased emissions as a result of pressure gradients induced by lower barometric pressure during storm events [14]. The east hide pile was determined to be the dominant odor source. The odorous compounds were determined to be mainly hydrogen sulfide (5,600 - 21,000 ppm within the east hide pile); however, hydrogen sulfide was not detectable above ground.

Indoor Air Pathway

The contamination of indoor air may result from the volatilization of VOCs in the groundwater passing beneath buildings. The volatilized chemicals can potentially seep through the cracks or spaces in the floor of the building and mix with the indoor air. When the chemicals are present in the indoor air, building occupants can be exposed by breathing in the contaminated air. Ventilation in the building can circulate the chemicals to other areas in the building, but it also tends to have a diluting effect. Workers in the site vicinity are at risk for past, current, and future exposure to contaminated indoor air. This contaminated ground water plume does not pass beneath any residential buildings. Therefore, area residents are not considered at risk due to exposure to contaminated indoor air.

Workers at Digital Equipment Corporation (DEC) are currently being exposed to very low levels of VOCs in the work place [26,27]. Inhalation of indoor air contaminants is the only route of exposure. The future operation of an air sparging system to remove VOCs in the groundwater will further reduce the risk of volatilization of VOCs from groundwater into the indoor air of buildings in the path of the plume.

B. Potential Exposure Pathways (Table B-13)

Surface Water Pathway

Past exposure pathways are possible from metal and organic compounds contaminating the Aberjona River and it's tributaries, the railroad drainage ditch and smaller ditches, Phillips Pond and other on-site ponds, Hall's Brook Holding Pond and the wetlands. The source of contamination was the disposal of wastes into on-site lagoons and hide piles. Surface water runoff from the wastes carried contaminated soil into the water bodies. The deposition of fugitive dust into the surface water, and the discharge of contaminated groundwater into surface water also carries contaminants into this media. Metal contaminants of the Aberjona River can be carried downstream and affect populations at great distances from the original source of contamination.

Once in the surface water metals can either exist in the dissolved state, or be absorbed to suspended particles. Exposure to metal contaminants in surface water can occur by ingestion of or dermal contact with this media. Inhalation exposure is relatively small because metals will not volatilize readily from the water into the ambient air. However, activities which may create aerosols will increase the exposure. Organic contaminants in surface water tend to be more volatile and thus inhalation exposures will be of more significance. Ingestion and dermal contact is also an important route for exposure to organic contaminants in this media.

Past, current, and future exposure may occur to people who access the surface water bodies for recreational purposes. These would include trespassers onto the site, and residents and workers who use Hall's Brook Holding Pond. People living downstream of the site can potentially be affected by contamination carried in the Aberjona River. People can be exposed through incidental ingestion of and/or dermal contact with water while swimming or wadings. Some of these compounds can bioaccumulate in the fish and shellfish found in contaminated surface water and eventually be ingested by humans. However, this pathway will be discussed in a separate section under "Biota Pathway".

The location and size of the on-site surface water bodies make them undesirable for recreational use. No recreational use of on-site surface water bodies has been known to occur in the past, therefore exposures are unlikely, but the potential for exposure existed in the past. Remediation of the wetlands on-site will eliminate the possibility for exposure in the future. Current and future exposure may occur to people who use Hall's Brook Holding Pond for recreational purposes. The exposure would be incidental ingestion and/or dermal absorption of contaminants found in the water. However, the location of Hall's Brook Holding Pond in a light industrial area makes it highly unlikely that people would access it for recreational purposes other than fishing. The extent of fishing activities at the Hall's Brook Holding Pond should be determined.

Sediment (0-12 inch depth) Pathway

Past exposures are possible to metals, organic compounds, and PAHs present in the sediment of the Aberjona River and it's tributaries, the railroad drainage ditch and smaller ditches, Phillips Pond, other on-site ponds and the wetlands. Past, current, and future exposures are possible for people accessing Halls Brook Holding Pond. Dermal exposure or incidental ingestion of sediments is possible for trespassers who may access these surface water bodies for recreational use.

The ATSDR considers sediment from the top 0-3" to represent the depth to which most people are likely to be exposed. If the contaminants are more concentrated in the top three inches of sediment, sampling of 0-12" will in general underestimate exposure. Conversely, if the contaminants increase in concentration as you increase depth, the exposure will be overestimated. At the time of the writing of this health assessment, no data was available for sediment sampling at 0-3", so 0-12" will be used as a surrogate for sediment exposure.

Site related contaminants present in the surface water and soil have affected the sediments in the surface water bodies on and off-site. The source of contamination is the deposition of contaminated soil carried in surface water run-off into the sediment. Certain chemicals tend to adhere to sediment and be fairly resistant to degradation in this environment. As a result, people who come in contact with contaminated sediments are at risk of dermal absorption or incidental ingestion of the site related contaminants in this media.

Dermal absorption of contaminants can occur if the contaminated sediment gets on the skin as a result of activities such as swimming or wading in the affected body of water. Incidental ingestion of sediment can occur as a result of the same activities. People who use the contaminated rivers, ponds, or wetlands for recreational purposes are at risk of past exposure to contaminated sediments. Due to ongoing remediation and the restriction of site access, there is no known exposure pathway for sediment in on-site contaminated water bodies. People who access Hall's Brook Holding Pond are at risk for past, present, and future exposure to contaminated sediments. However, it should be noted that the location of Hall's Brook Holding Pond in a light industrial area makes it highly unlikely that people would use it for recreational purposes other than fishing.

Some of these contaminants present in the sediment can bioaccumulate in the fish and shellfish and eventually be ingested by humans. This pathway will be discussed in a separate section under "Biota Pathway".

Soil Gas Pathway

Past exposure pathways were possible from the migration of contaminated soil gas into the indoor air of buildings on-site and in the site vicinity. The workers and residents of these buildings would be exposed to soil gas through the inhalation of contaminated indoor air.

On-site soil gas generation resulted from the decomposition of animal hides buried underground in piles on-site. Diffusion of soil gas could have occurred through the soil pores to soil beneath the foundation of buildings in the vicinity of the site. Soil gas could then volatilize from beneath these buildings into cracks in the foundation or crawl spaces and contaminate the indoor air. Exposure to contaminants in soil gas could have occurred through the inhalation of indoor air to the occupants of these buildings on-site and in the site vicinity.

Residents and workers in the site vicinity are at risk for past exposure to soil gas. The route of exposure is the inhalation of indoor air that has been contaminated by soil gas. Current remediation of the site has reduced the risk of soil gas migration and contamination of indoor air. This in turns eliminates the possibility of current and future exposure to soil gas.

Biota Pathway

Past, current, and future exposures to site related contaminants are possible to people who consume fish caught from the Hall's Brook Holding Pond. The population at risk are the residents and trespassers who fish in this water body.

Some of the contaminants found in the surface water and sediments can accumulate in the fish living in the Hall's Brook Holding Pond. These chemicals can be taken into fish by diffusion from water through membranes or by the fish eating other contaminated plants or animals. Once in the fish the contaminates are not readily excreted, and therefore it tends to build up in the tissues. If the contaminant builds up in the tissues that humans eat, then ingesting this fish becomes a source of exposure to these chemicals for people.

Trespassers who fish in Hall's Brook Holding Pond are at increased risk of past, present, and future exposure to site related contaminants found in fish. The route of exposure is the ingestion of contaminated fish. At the present time it is unknown whether any of the fish caught in the Hall's Brook Holding Pond is consumed by the people who fish there for recreation. In addition, there have not been any measure of contaminants in the tissue of fish caught there.

PUBLIC HEALTH IMPLICATIONS

A. Toxicological Evaluation

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, 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 oral and inhalation exposures, and for lengths of exposure, such as acute (fewer than 14 days), intermediate (15 to 364 days), and chronic (greater than 365 days). 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. When MRLs are not available, reference doses (RfDs) developed by the EPA are used. A RfD is an estimate of the daily exposure of the human population to a potential hazard that is likely to be without risk of deleterious effects during a lifetime. In the following discussion, ATSDR's Toxicological Profiles were used for antimony, arsenic, cadmium, chromium, DEHP, PCBs, copper, lead, thallium, zinc, MEK, 1,1,1-TCA, PAHs, and methyl mercaptan [2].

The doses estimated for the different routes of exposure were based on calculations for non-pica children and adult trespassers using All Terrain Vehicles (ATVs) on site. Due to there smaller body mass children tend to experience higher doses than adults exposed to the same concentration of environmental contaminant through the same route. Therefore, a child's dose can serve a more sensitive indicator when determining the possibility of health effects as a result of exposure. Similarly, adults using ATVs will have a higher exposure to dust and soil (kicked up by the vehicles) than trespassers who access the site on foot.

The health effects which are expected to occur as a result of exposure to site related contaminants are mainly associated with exposure to contaminants in on and off-site soil 0-12". Ingestion of arsenic contaminated soil 0-12" may have resulted in abdominal pain and diarrhea. Dermal exposure to chromium in this media could have enhanced already existing dermatitis. Ingestion of lead contaminated soil may have caused mild hematological effects by disrupting enzyme activity. All these effects are reversible and would have been effectively halted with the termination of exposure.

Exposure to Soil (0-12"), Sediment, and Subsurface Soil

Past exposure to metals and organic compounds may have occurred to on-site workers, trespassers, residents and workers in the site area. It should be noted that the ATSDR considers surface soil and sediment to be the top 0-3" of soil on and off-site. This depth represents the soil or sediment to which most people are likely to be exposed. If the contaminants are more concentrated in the top three inches of soil, sampling of 0-12" will in general underestimate exposure. Conversely, if the contaminants increase in concentration as you go deeper, the exposure will be overestimated. At the time of the writing of this health assessment, no data was available for soil sampling at 0-3", so 0-12" will be used as a surrogate for surface soil exposure.

Metals

Antimony, arsenic, chromium, copper, lead, manganese, thallium and vanadium were the contaminants of concern present in soil 0-12"on and off-site. Ingestion of antimony over prolonged periods can irritate your eyes, skin, and lungs, as well as cause heart problems, diarrhea and vomiting. Occupational exposure to high concentrations of antimony has been associated with increased blood pressure, respiratory irritation, and gastrointestinal tract distress. No effects have been found in humans after dermal exposure. Exposure to antimony has not been associated with cancer, reproductive effects or birth defects in humans [2]. The EPA has established a chronic oral RfD of 0.0004 mg/kg/day for antimony.

ANTIMONY

The dose estimated for the ingestion of antimony in soil 0-12" was equal to the established RfD, and is not expected to cause health effects in the general population. Doses estimated for on-site and off-site sediment were well below the RfD and are also not expected to cause adverse health effects. Estimates for the ingestion of subsurface soil are slightly higher than the chronic oral RfD, but no health effects have been documented at this level. Inhalation and dermal contact exposures are insignificant and not expected to cause any health effects, although ATV users may receive a greater dose than the average trespasser.

ARSENIC

Long term exposure to increased arsenic levels via ingestion can cause anemia, neurothropy, skin lesions, and liver and kidney damage. Possible outcomes of chronic exposure include skin and internal cancers. Inhalation of inorganic arsenic has been associated with nausea and anorexia in humans [2]. Dermal contact with high levels of arsenic has caused dermatitis in some workers in the occupational setting.

The ATSDR has set a chronic oral MRL of 0.0003 mg/kg/day for arsenic. The doses estimated for exposure to arsenic via ingestion of contaminated soil, off-site sediment, and subsurface soil were above this health guideline. The doses estimated for soil ingestion are associated with health problems such as abdominal pain and diarrhea. Ingestion of off-site sediment is not expected to cause any systemic effects. Based on the EPA cancer slope factor there is a increased risk of developing cancer as a result of exposure to arsenic contaminated soil and sediment. However, this is based on the worst case scenario of a child eating 100 mg of the most contaminated media everyday for her entire lifetime. Inhalation of dust and dermal contact exposures are insignificant and not expected to cause any health effects, although ATV users may receive a greater dose than the average trespasser.

BERRYLIUM

There is no data on the health effects resulting from the oral exposure to beryllium in humans [2]. Limited animal data exists showing muscoskeletal effects (bone fragility) in rats fed a diet supplemented with beryllium [2]. However, it is difficult to extract the results of this data to humans. There is evidence to suggest that beryllium is poorly absorbed in the gastrointestinal tract [2], thus reducing it's toxicity by the oral route of exposure. No studies were located regarding the health effects of dermal exposure to beryllium. Studies show that beryllium is not absorbed into the skin [2].

The EPA has established a chronic oral RfD for beryllium of .005 mg/kg/day. There is no MRL. The doses estimated to result from incidental ingestion of and dermal contact with beryllium in the surface water on and off-site are very small. This fact coupled with the fact that it is not well absorbed into the gastrointestinal tract suggests that it is highly unlikely that health effects will occur as a result of exposure to beryllium in the surface water on and off-site.

CHROMIUM

The health effects resulting from exposure to chromium (III) and chromium (VI) are fairly well characterized. The inhalation of high levels of chromium (VI) can cause soreness of the nose, ulcers, nose bleeds, and holes in the nasal septum. These effects are primarily the result of occupational exposures. The inhalation of small amounts of chromium (VI) does not cause non-cancer adverse health effects, although chromium can cause asthma attacks in individuals who are allergic to chromium. Small amounts of ingested chromium (VI) will not affect human health; however, large ingested amounts may cause stomach upsets and ulcers, convulsions, kidney and liver damage, even death. Dermal exposure to chromium (VI) in the workplace can cause skin ulcers. Allergic reactions consisting of severe redness and swelling of the skin have been reported [2].

Chromium (III) is an essential nutrient in the human diet. The inhalation of chromium (III) does not cause irritation to the nose. To be the more protective of human health all chromium detected is assumed to be chromium (VI) unless otherwise noted. The EPA has established a chronic oral RfD for chromium (VI) of 0.005 mg/kg/day. The estimated dose for the ingestion of soil 0-12", subsurface soil, and on-site and off-site sediment were above the RfD. These doses are high enough to enhance already existing dermatitis caused by past exposure to chromium. No other health effects are expected to occur as a result of this exposure. Based on the EPA oral cancer slope factor and the estimated doses no significant elevations in cancer should occur due to exposure to site related chromium. Inhalation of dusts and dermal exposure should not result in health effects in the general population.

LEAD

Studies of lead have shown that for infants and young children, lead exposure via ingestion can cause a decrease in intelligence (IQ) scores, slow growth, and cause hearing problems. These effects can persist as the children get older and can interfere with successful performance in school. Lead is especially dangerous for unborn children because they can be harmed during fetal development. Pregnant women exposed to lead can pass lead to unborn children resulting in premature birth, low birth weight, and miscarriage [2]. ATSDR has developed no MRL for lead. However, the EPA has developed a chronic oral RfD of 1 x 10-7 mg/kg/day for alkyl lead [2].

All of the doses estimated for the ingestion of lead contaminated soil 0-12", subsurface soil, and sediment are above the RfD. However, no adverse health effects have been documented in humans at the doses estimated for ingestion of sediment on or off-site. The ingestion of soil 0-12" and subsurface soil may result in mild hematologic effects characterized by a decrease in the activity of an enzyme involved in heme synthesis [2]. However, these effects are reversible once the exposure is terminated. Limited reports exists regarding dermal absorption of lead in humans [2]. Dermal absorption of lead is not considered to be a significant source of exposure at this site. Although no permanent health effects have been shown to occur at this estimated level of exposure, lead is generally believed to have potentially adverse health effects even at very low doses [2]. The MDPH has received no reports of health effects potentially related to lead exposure at the site, and exposure was effectively halted with the implementation of remedial activities at the site.

COPPER

Copper is an essential nutrient and the National Academy of Science (NAS) has recommended that 2 to 3 milligrams is an adequate daily intake for adults. Ingestion of excessive amounts of copper can result in gastrointestinal irritation which is manifested by symptoms such as vomiting, diarrhea, nausea, abdominal pain, and a metallic taste in the mouth. Liver and kidney damage can also occur as a result of the chronic ingestion of high levels of copper [2]. The ATSDR has no MRL and the EPA has no RfD for copper. Exposure to copper is not associated with the development of cancer in humans. No adverse health effects are expected to occur from the estimated doses of copper resulting from ingesting soil 0-12", subsurface soil, or sediment on or off-site; or the inhalation of contaminated dusts generated by ATV use or other activities. Dermal absorption of copper is essentially non-existent.

MANGANESE

Manganese is a nutrient which is needed to maintain good health. The normal diet contains between 2 and 9 milligrams of manganese per day [2]. Limited studies are available on the effect of oral exposure to manganese in humans. In one study, chronic ingestion of low levels of manganese (in addition to the normal dietary intake) resulted in mild neurological signs in an elderly population. It should be noted that limitations in the study design render the results of this study inconclusive. This was the only study found which measured doses at levels near to (but still five times higher than) the estimated doses for ingestion of on-site soil 0-12". Manganese is only a contaminant of concern in on-site soil 0-12".

The EPA has developed a chronic oral RfD of 0.005 mg/kg/day for manganese. Estimated doses for the ingestion of soil 0-12" is above this level. No adverse health effects have been reported at these doses. Also, no studies were found relating to the health effects of dermal exposure to manganese in humans. Dermal exposure and fugitive dust inhalation are not considered to be a significant route of exposure for manganese at this site.

THALLIUM

Acute ingestion of a large amount of thallium can affect the nervous system, lungs, health, liver, and kidney. Other effects of acute exposure are temporary hair loss, vomiting, and diarrhea. No information was available on health effects in humans after exposure to smaller, chronic doses. The EPA has no RfD for thallium. The ATSDR has an acute oral MRL of 8 x 10-5 mg/kg/day. No adverse health effects are expected to occur as a result of the ingestion of or dermal contact with contaminated soil 0-12", subsurface soil, or sediment on or off-site. The same is true for the inhalation of fugitive dusts generated by ATV use on-site. The development of cancer is not associated with oral or dermal exposure to thallium [2].

VANADIUM

Ingestion of vanadium can lead to intestinal cramping and diarrhea. No other health effects were reported regarding health effects in humans as a result of ingestion of vanadium. There were no information available on health effects due to dermal exposure. Oral exposure to vanadium has not been shown to increase the risk of cancer in humans.

The ATSDR has developed an intermediate oral MRL of 0.003 mg/kg/day for vanadium. The EPA has no RfD. Based on the estimated doses for exposure (via ingestion, dermal, or inhalation of fugitive dusts) to on-site soil 0-12" and subsurface soil, no adverse health effects are expected to occur due to exposure to vanadium at the site.

Organic Compounds

BENZENE

Oral exposure to large doses of benzene has caused death in humans. Other effects due to the ingestion of large doses includes a decrease in white blood cells and CNS toxicity. Dermal contact with benzene can produce skin irritation which may develop into scaly dermatitis. No studies were available on the risk of humans developing cancer as a result of ingesting benzene. The ATSDR has no MRLs and the EPA has no RfD for oral exposure to benzene. However, the EPA has developed an oral cancer slope factor.

All the doses estimated for ingestion of benzene contaminated soil 0-12", subsurface soil, and sediment were below those levels at which health effects were reported in humans. Similarly, the dose from dermal exposure and inhalation of fugitive dusts are not expected to cause adverse health effects in the exposed populations. Calculations based on the EPA's oral cancer slope factor did not show a significant increase in the risk of developing cancer as a result of exposure to contaminated soil or sediment.

POLYCYCLIC AROMATIC HYDROCARBONS

Polycyclic Aromatic Hydrocarbons (PAHs) are a group of compounds that have similar chemical structures and properties. Available data on the toxic effects of PAHs suggest that acute ingestion exposure results in irritation of the gastrointestinal tract (nausea, vomiting and diarrhea). PAHs are also associated with the development of stomach cancer in mice [2]. Benzo(a)pyrene is a PAH compound that is considered a probable human carcinogen by the EPA based on inadequate human data and sufficient animal data. Benzo(a)pyrene is one the more toxic components of PAH mixtures, therefore the health guidelines for PAHs has been established based on a worst case scenario for exposure to protect the public health. The majority of the data involves occupational exposure to more than one PAH. Therefore, it is difficult to associate an observed health effect with a specific compound. The EPA does not have a RfD for PAHs, but the ATSDR has established an acute oral MRL of 0.1 mg/kg/day for benzo(a)pyrene. The EPA has established an oral cancer slope factor for this compound.

The dose estimates for exposure to PAHs in soil 0-12", subsurface soil, and sediment were below the acute oral MRL for benzo(a)pyrene. Based on these doses, adverse health effects are not expected to occur as a result of ingestion of or dermal contact with PAH contaminated media at this site. The chance that a person would have an increased risk of developing cancer as a result of contact with contaminated media at the site are extremely small.

POLYCHLORINATED BIPHENYLS

Polychlorinated Biphenyls (PCBs) are a group of chemicals which have similar structures and properties called congergers. PCBs usually exist as a mixture of congergers. Few data are available about health effects related to ingestion of contaminated soil. PCBs are known to primarily affect liver and skin. Dermal exposure to PCBs could result in chloracne, hyperpigmentation, erythema, dryness and skin rashes [2]. Ingestion of contaminated soils could result in liver damage in children. Although certain PCB compounds have caused cancer in laboratory animals, there is no evidence to suggest that oral or dermal exposure to PCBs increases the risk of developing cancer in humans [2]. The ATSDR has set a chronic oral MRL of 2 x 10-5 mg/kg/day. The dose estimated for exposure to PCBs were below the MRL. No adverse health effects are expected to be seen at this level. EPA has developed an oral cancer slope factor for PCBs; there is no indication that PCB exposure at this site will significantly increase the risk of cancer to people accessing this site.

DIETHYLENE GLYCOL

Limited information is available regarding the human health effects from exposure to diethylene glycol. Diethylene glycol is moderately toxic to humans by ingestion. It is also and eye and skin irritant. No studies were found that associate exposure to diethylene glycol with an increase risk of cancer in humans [2]. The ATSDR has no MRL and the EPA has no RfD for diethylene glycol [2]. Based on the estimated doses, it is not expected that adverse health effects will occur as a result of dermal contact with or ingestion of diethylene glycol at this site.

1,1,1-TRICHLOROETHANE

The ingestion of 1,1,1-Trichloroethane (1,1,1-TCA) can result in vomiting and diarrhea. Extended dermal contact with large amounts of 1,1,1-TCA can produce skin irritations and burning sensations in humans. However, only a small amount is absorbed through the skin, so health effects are not expected via this exposure route. The ATSDR has not established an oral MRL for this compound, nor has the EPA established a RfD. Based on the estimated doses, no adverse health effects should occur as a result of ingestion of or dermal contact with 1,1,1-TCA in this media.

1,2-DICHLOROETHANE

Only limited data is available on the toxic effects of 1,2-dichloroethane (1,2-DCA) in humans. Ingestion of 1,2-DCA has been associated with bronchitis, hemorrhagic gastritis and colitis, hepatocellular damage, renal tubular necrosis, CNS depression, and histological depression in brain tissue [2]. No data was available on the effects of chronic exposure to low levels of this compound. There is little data regarding the carcinogenicity of 1,2-DCA in humans, however EPA has developed an oral cancer slope factor for 1,2-DCA. The ATSDR has established an oral MRL of 0.2 mg/kg/day for 1,2-DCA. The estimated doses for the incidental ingestion of or dermal contact with 1,2-DCA were minuscule. Therefore, it is extremely unlikely that adverse health effects will occur as a result of exposure to 1,2-DCA in surface water.

The compound 4-methyl-2-pentanone can be classified as a solvent, the general health effects of which are discussed below. The ATSDR does not have a MRL, nor the EPA an RfD. The estimated doses for the incidental ingestion of or dermal contact with 4-methyl-2-pentanone were minuscule. Therefore, it is extremely unlikely that adverse health effects will occur as a result of exposure to 4-methyl-2-pentanone in surface water.

Other organic compounds of concern in soil 0-12", subsurface soil, and sediment on and off-site can be group into a class of chemicals generally known as solvents or vapors. These are mainly halogenated hydrocarbons: haloalkanes, haloalkenes, and aromatic hydrocarbons. There is limited information on the effects of these compounds on human health after ingestion or dermal contact. The ATSDR and EPA have developed health guidelines for some of these compounds, but, this section will address these compounds as by dividing them into groups with similar properties.

In general haloalkanes and haloalkenes have related mechanisms of toxic action. All of these have some effect on the central nervous system (CNS) and usually cause CNS disturbance at high doses. Some of these compounds are toxic to the liver and some are toxic to the kidney. Many of these have been shown to be carcinogenic in animal experiments, however, human data is limited [33]. Some aromatic hydrocarbons cause CNS effects at low doses. Some can also irritate the mucous membranes [33].

The estimated doses of these chemicals that would be obtained from ingestion of, dermal contact with, or inhalation of fugitive dust from this media are well below levels that would be expected to cause health effects in the exposed population.

Inhalation of Contaminants in Ambient Air or Bore Hole Air

Past exposure to metals and organic compounds via the inhalation of contaminated ambient air or bore hole air may have occurred to on-site workers, trespassers, residents and workers in the site area.

Metals

Data on the health effects of antimony is derived from the study of occupational exposures. These exposures are, in general, much higher than those experienced by populations around hazardous waste sites via ambient air. At high concentrations inhalation of antimony can cause respiratory tract irritation, chronic bronchitis and emphysema, alterations in pulmonary function, and altered EKG readings. Other effects are gastrointestinal tract irritation (abdominal pains, diarrhea, vomiting and ulcers), an increase in spontaneous abortions, and irregular menstrual cycle [2]. There is no evidence that inhalation of antimony causes an increase risk for the development of cancer in humans [2].

The ATSDR has not developed an inhalation MRL for antimony nor has the EPA developed an RfC. The Lowest Observed Adverse Effect Level (LOAEL) for humans via inhalation exposure was much higher than the estimated doses for the exposed population. Therefore, it is unlikely that there would be any adverse health effects related to antimony exposure due to inhalation of ambient air at this site.

As with antimony, most of the information available on the health effects of inhalation exposure to arsenic is gathered from studies done in an occupational setting with relatively high exposures. At these high levels irritation of the mucous membranes and throat have been noted. At extremely high levels perforation of the nasal septum can occur. Other effects following occupational exposure are gastrointestinal distress (nausea, vomiting, diarrhea) and peripheral neuropathy characterized by numbness, loss of reflexes, and muscle fatigue. The risk of developing lung cancer in humans is also increased due to the inhalation of large amounts of arsenic [2]. There is no MRL or RfC for inhalation of arsenic. However, the EPA has developed an inhalation cancer slope factor which can be used to the estimate risk of developing cancer as a result of exposure.

The No Observed Adverse Effect Level (NOAEL) for humans via inhalation is above the highest estimated dose for exposure to on-site and off-site ambient air. Similarly, there is no increase in the risk of developing cancer as a result of inhalation of arsenic at this site. No adverse health effects are expected to occur due to inhalation of arsenic in the ambient air at the site or in the site vicinity.

There is little information on the adverse health effects of exposure via inhalation to barium, and lead at levels below those which occur in the occupational setting [2]. No inhalation MRLs or RFCs have been developed for these contaminants. Inhalation of barium at high concentrations can cause gastrointestinal distress (abdominal cramps, nausea, and vomiting) and an increase in blood pressure. It is unlikely that exposure to barium in on or off-site ambient air will result in adverse health effects because of the very low doses involved. Inhalation of lead at high concentrations can impair the function of enzymes involved in hemoglobin synthesis [2]. The doses estimated for exposure to lead via ambient air are well below the LOAEL for inhalation of lead. No adverse health effects are expected as a result of inhalation of lead in contaminated ambient air in the site area. Finally, exposure to neither of these contaminants via inhalation has been linked to an increase in the incidence of cancer in humans [2].

The health effects resulting from low doses of vanadium are well documented. At levels far above the doses estimated for exposure at the Industriplex site humans experience respiratory irritation, coughing and an increase in mucous. Higher occupational exposures result in mild respiratory distress (cough, wheeze, chest pain, and runny nose), sore throat, eye irritation, and a greenish tint on the tongue. There is no evidence to suggest that inhalation of vanadium increases the risk of developing cancer in humans [2].

The ATSDR has developed an acute inhalation MRL for vanadium of 0.2 ug/m3. The EPA has not developed a RfC. The doses estimated for inhalation exposure via ambient air at the site are below the MRL and the LOAEL for inhalation of vanadium. No adverse health effects are expected to occur due to the inhalation of vanadium in the ambient air at the site.

Organic Compounds

Inhalation of Methyl Ethyl Ketone (MEK, also known as 2-butanone) at low levels may cause irritation of the nose and throat. Exposure to high concentrations can cause mild respiratory effects and eye irritation. Inhalation of MEK has not been shown to increase the risk of developing cancer in humans [2]. The ATSDR has no inhalation MRL for MEK, but the EPA has established an intermediate RfC of 1000 ug/m3. The doses estimated for inhalation of MEK in the ambient air on and off-site are below the RfC, the LOAEL for respiratory effects in humans, and the NOAEL for neurological effects in humans. No adverse health effects are expected as a result of exposure to MEK in the ambient air at the site.

1,1,1 - trichloroethane (1,1,1-TCA) is a common industrial solvent. Most of the information on the adverse health effects due to the inhalation of 1,1,1-TCA comes from studies of occupational or intentional exposures. Exposure to high levels of this compound can cause respiratory depression, cardiac arrhythmias, mild eye irritation, and CNS depression resulting in neurobehavioral effects and possibly death [2]. The ATSDR has established an intermediate inhalation MRL of 700 ppb (3.82 ug/m3). There is no RfC. The estimated doses for inhalation of MEK in the ambient air at the site is well below the RfC and NOAEL for humans via this route of exposure. Therefore, it is unlikely that health effects will occur due to exposure to 1,1,1-TCA in ambient air on and off-site.

Although several compounds of concern were found in bore hole air, only the most toxic will be discussed here. Hydrogen sulfide is a human poison by inhalation. Exposure to hydrogen sulfide at the levels detected in bore hole air results in death from asphyxiation, so the effects of the other bore hole air contaminants are of no significance. Exposure to low concentration of hydrogen sulfide causes eye irritation; slightly higher concentrations cause respiratory tract irritation and pulmonary edema. Chronic poisoning results in headache, conjunctivitis, photophobia, tearing, pain and blurred vision, inflammation of the eyelids and digestive disturbances leading to weight loss and general debility. No studies were located that showed an association between inhalation of hydrogen sulfide and an increase in the risk of developing cancer [2]. The ATSDR has no MRL nor does the EPA have an RfC.

The bore hole air does not migrate into the ambient air on the site. The levels detected in bore hole air will cause immediate death to anyone exposed to this media without the proper personal protective equipment (PPE). It is highly unlikely that anyone who accessed the site was actually exposed to these levels. The MDPH has received no reports of death associated with exposure to bore hole air on the site.

B. Health Outcome Data Evaluation

The human health impact of the Woburn environment has been of great concern since the late 1970's. A number of investigations have been conducted by the Massachusetts Department of Public Health (MDPH), the Center for Disease Control (CDC), and Harvard University. The initial health problems suspected of being related to environmental exposures are the serious elevations in both total and male childhood leukemia incidence (the rate of occurrence of leukemia). For the period 1969-1978, childhood (aged 0-14 years) leukemia incidence was significantly elevated for males (9 observed, 3.1 expected), but not for females (3 observed, 2.2 expected). The ratio of male to female incidence was three to one. For the area of Woburn that received the greatest proportion of water from Wells G and H (census tract #3334), childhood leukemia incidence in males was 12 times higher than expected (5 observed, 0.4 expected, p < 0.001). A p value less than 0.001 means that the probability that the difference between the observed and expected values was due to chance is less than 0.1 chances in 100. The remaining census tracts in Woburn did not have a significant increase in childhood leukemia incidence for either sex. During the period 1979-1981, three cases of childhood leukemia were diagnosed in males. Childhood leukemia was not diagnosed in females during this same period. For the period 1982-1990, seven additional cases of childhood leukemia occurred in Woburn, from which the ratio of male (5 cases) to female (2 cases) incidence is 2.5 to 1. Five of the seven cases were diagnosed during the period 1982 - 1983. No additional cases of childhood leukemia were diagnosed between 1987 and 1990.

Although the focus of the cancer concerns has been childhood leukemia, kidney cancer mortality is also significantly elevated (Standard Mortality Ratio = 145, 21.3 expected cases, 31 observed cases, p = 0.05) for the period 1969-1986. No association has been established between cancer incidence or mortality and the Woburn environment. This has partly been due to the small number of cancer cases as well as difficulty in trying to characterize past exposures [1].

The MDPH convened a panel of experts from throughout the United States to assist in determining if a link exists between environmental contamination originating from this site and health problems in the vicinity of the site. The panel's strongest recommendations included more studies of the environment and the development of a system of non-invasive watchfulness focused on reproductive outcomes. It was hoped that reproductive outcomes would serve as a more sensitive indicator of an environmental problem and, in addition, would allow for an environmental association to be detected statistically.

ATSDR awarded funds to the State of Massachusetts in support of the Woburn Environment and Birth Study (WEBS) which was designed to address the concerns of the panel. This investigation began in the fall of 1988, and the results were released in August 1994. WEBS studied reproductive outcomes both prospectively (i.e., those events occurring from today and into the future) and retrospectively (i.e., those events that occurred in the past) in relation to consumption of water from the Wells G and H NPL site. MDPH is also analyzing birth outcome data in Woburn in relation to further or current tannery and greenhouse sites to complete all analyses as outlined in the WEBS analytical protocol. This analysis should completed at the end of 1995. The MDPH also conducted an expanded case control study of childhood leukemia utilizing exposure data generated as part of the WEBS. This type of study compares individuals with a given disease to a comparison group of identical age, sex, etc. to demonstrate differences between the two that may be associated with development of the disease. Final peer review comments on the Woburn Childhood Leukemia Follow-Up Study are expected this month. The results of the WEBS study are summarized below in the Community Health Concerns Evaluation section of this health assessment.

C. Community Health Concerns Evaluation

Community health concerns were addressed as follows:

  1. Could exposure of children or their parents to chemicals from the site be responsible for the excess of leukemia cases?

    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 excess of leukemia cases. The most predominant chemicals detected on-site at concentrations at which human health effects are known to occur were arsenic, chromium, and lead. Exposure to these chemicals has not been associated with the occurrence of leukemia.


  2. Is the incidence of adverse reproductive outcomes in the site vicinity elevated when compared to the normal or average population?

    The Woburn Environment and Birth Study (WEBS) was designed to establish (1) whether the occurrence of certain adverse reproductive outcomes was different between residents of Woburn and selected local and regional comparison populations; and (2) whether the occurrence of these outcomes was different between Woburn residents classified as "exposed" and those classified to "unexposed" to contaminated drinking water. The study examined the occurrence of adverse reproductive outcomes for two time periods: the Retrospective Study period (1969-1988) and the Prospective Surveillance Study period (1989-1991). Maternal exposure to contaminated water was assessed on the basis of an estimate of the proportion of contaminated water that reached each birth residence location during pregnancy.

    No differences in the rates of most of the outcomes evaluated between Woburn and the twelve surrounding communities were indicated. Some types of birth defects were higher in Woburn than in these surrounding communities; however, the discrepancies appeared to be more likely due to methodologic differences rather than real differences in the occurrence of birth defects. Furthermore, comparisons between groups within Woburn identified as "exposed" and "unexposed" did not indicate significant differences in rates of most adverse reproductive outcomes evaluated. The results of WEBS with regard to Wells G and H exposure were made public in August, 1994 and are currently available at the Woburn Public Library. More information regarding opportunities for exposure other than well water and reproductive outcomes will be available in the near future.


  3. Are the chemicals at the site posing a current health risk?

    Chemicals at the site do not pose a current health risk for several reasons: (1) the presence of a fence and 24 hour security prevents access to the site by unauthorized personnel; (2) on going remediation has reduced the migration of contaminants off-site and the release of contaminants into the ambient air; and (3) the use of Hall's Brook Holding Area for recreational purposes is highly unlikely due to it's location in an undesirable area.


  4. Could the odorous gases emanating from the site during the excavation of hide piles have affected the public health?

    Elevated levels of hydrogen sulfide soil gas (or bore hole gas) occurred in the past; however, hydrogen sulfide has not been detected in ambient air at the site. Currently, the risk of exposure to hydrogen sulfide in soil gas has been effectively reduced by stabilization of the hide piles and thermal oxidation of the soil gas. Past elevations of hydrogen sulfide in soil gas were such that anyone exposed without personal protective equipment were at risk of severe health effects.

    The Record of Decision for the site was influenced by these community concerns. Moving the on-site hide piles increases these odors; therefore it was decided that they should be capped in place in order to limit odors. One pile that is actively producing odors, as of May 1995, has been covered by an impermeable cap, and a gas extraction system will soon be installed. The risk of exposure to soil gas has been effectively reduced by this stabilization of the hide piles and thermal oxidation of the soil gas.



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