BLACKBURN AND UNION PRIVILEGES
WALPOLE, NORFOLK COUNTY, MASSACHUSETTS
APPENDICES
Chemical and Health Data Summary Tables
The following tables were not available in electronic format for conversion to HTML at the time of preparation of this document. To obtain a hard copy of the document, please contact:
Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Attn: Chief, Program Evaluation, Records, and Information Services Branch,
MS E-56
1600 Clifton Road NE, Atlanta, Georgia 30333
Information Booklet
Preliminary Public Health Assessment for
Blackburn-Union Privileges (South St.) Site
Walpole Norfolk County, Massachusetts
Executive Summary
BACKGROUND
The Agency for Toxic Substances and Disease Registry (ATSDR) was mandated by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) as amended, to conduct Public Health Assessments for all National Priorities List (NPL) hazardous waste sites in the country. In 1987, the Massachusetts Department of Public Health (MDPH) entered into a cooperative agreement with ATSDR to conduct Public Health Assessments on those NPL sites in the Commonwealth. This document is an executive summary of the final draft for public comment.
INTRODUCTION
The Blackburn Union Privileges (South Street) site is situated in Walpole approximately 2,000 feet southeast of the town center. In February of 1992, the site was proposed for listing on the National Priorities List (NPL). In response to this proposed listing, the MDPH under its cooperative agreement with ATSDR conducted a preliminary public health assessment on the Blackburn Union Privileges site. Based on the findings of a community-wide survey, that was conducted by MDPH in collaboration with the Walpole Board of Health, the site is characterized as a past public health hazard. Since the characterization of the current contamination of environmental media on or near the site is incomplete, the site is also characterized as an indeterminate present health hazard. On May 31, 1994, the site was officially placed on the NPL.
The site is irregularly shaped and consists of 30 acres of land parcels adjacent to South Street approximately 150 feet southwest of Common Street. The Neponset River flows under South Street and through the site in a westerly fashion. Warehousing and foundry operations are currently ongoing on those land parcels east of South Street. A vacated factory is situated on the western land parcel. The site is situated in a residential area with the nearest residence located approximately 25 feet north of the factory grounds.
Mill operations at the site date back to the 17th century and continued into the early 1900s. These activities included corn milling, fabric carding, wood working and hide tanning. In 1915, the Standard Woven Fabric Company (later the Multibestos Corporation) took ownership of the site. From this time until 1935, raw asbestos materials were spun into yarn which was then woven to produce brake pads and clutch plates. Waste asbestos was piled behind the building that currently houses offices of the foundry operation. In 1937, after asbestos manufacturing ceased, this plant, which is situated near the north bank of the Neponset and west of South Street, was converted to a cotton processing operation. In the factory, fibers were washed and bleached prior to fabric production. Waste solutions from the manufacturing process were discharged to two lagoons south and west of the factory's west wing, which runs parallel to the Neponset River. The factory is currently vacant.
The asbestos waste pile behind the foundry operation remained uncontained until 1986 when the Massachusetts Department of Environmental Quality Engineering [(MDEQE), currently the Massachusetts Department of Environmental Protection (MDEP)], received a complaint that asbestos was present on the site; the asbestos pile was subsequently covered. In 1989, a site assessment was conducted and environmental media were monitored for the presence of asbestos and other environmental contaminants. This preliminary public health assessment is largely based on the findings of the site assessment.
An extensive asbestos removal action was completed in 1993. The Neponset River was temporarily diverted while bedding material was placed and graded to match pre-existing riverbed elevations at the upstream and downstream ends of the culvert. A geotextile filter fabric was laid on top of the bedding material and along the riverbed prior to placement of the 400-foot long aluminum culvert. After the culvert was in place the Neponset River was redirected through the aluminum culvert that lies in the Neponset riverbed. Asbestos-contaminated soils were excavated, consolidated, capped over the aluminum culvert with approximately 2 feet of imported clean fill, and then vegetated. Mill Tail Race sediments were excavated, stabilized, and capped in lagoon #2. Segregation of Tail Race sediments was necessary due to the presence of other contaminants besides asbestos. Confirmatory monitoring of excavated soils for asbestos was conducted during the removal action. The results of this monitoring are also evaluated in the preliminary health assessment.
In 1986, ATSDR conducted a health consultation based on a bulk asbestos sample taken from the site and concluded that since asbestos is a human carcinogen, its presence constitutes a health threat. The health consultation recommended that the threat be removed or mitigated. In 1988, another health consultation was conducted at the site and, considering only soil and sediment samples from specific areas of the site, determined that soils and sediments with asbestos content of less than 1% did not pose a health threat.
Citizen concern over asbestos exposure and possible elevations of lung and kidney cancer rates near the site prompted investigations by MDPH into evaluating both the opportunities for asbestos exposure (March, 1988) and cancer incidence near the site (August, 1992). These concerns and the results of MDPH investigations are assessed in the Preliminary Health Assessment.
METHODS
Environmental data were evaluated according to ATSDR's methods, as indicated in the Public Health Assessment Guidance Manual, in order to determine contaminants of concern. Information on environmental data is presented in the Environmental Contamination and Other Hazards, Pathways Analysis, and Toxicological Evaluation sections. Health outcome data were evaluated using standard methods as outlined in the Health Outcome Data Evaluation section of the health assessment.
RESULTS
Extensive soil monitoring for asbestos was conducted on and around the site. Asbestos was detected in on and off site soils. Two residences in the area contained elevated soil asbestos levels. Asbestos-contaminated soil or sediment may have been taken from the site and used as fill at one of these residences. That residence is situated 2,000 feet downstream from the site. The source of asbestos at a residence immediately east of the site is not known.
Soil asbestos monitoring was also conducted during and after the emergency removal action in 1992, in which all soils known to contain greater than 1 percent asbestos were excavated. All excavations were back-filled with clean fill. It is possible that disturbance of the cap placed along the Neponset River may result in exposure to asbestos contamination underneath the cap if adequate containment measures are not taken beforehand.
Based on the results of the 1988 Walpole Asbestos Exposure Survey which was conducted by MDPH in collaboration with the Walpole Board of Health and a pulmonary specialist from the Massachusetts General Hospital, exposure to site-related asbestos was limited to a small percentage of those individuals either living in the same residence as those occupationally exposed to asbestos or those living within a half-mile radius of the site. Past generation of airborne asbestos particles may have been possible. Older children are reported to have played on the site and to have thrown asbestos-containing clutch plates that were discarded at the site. It is likely that inhalation of asbestos particles by these individuals occurred at that time.
Lead, arsenic and carcinogenic Polynuclear Aromatic Hydrocarbons (PAHs) were also detected in on-site soils at 18 to 48 inches BLS. Many of these contaminated areas were capped during the cap placement. There are, however, other areas where hazardous contaminant levels were detected below the soil surface. It is not known if exposure to contaminants in uncapped areas is occurring or has occurred in the past since monitoring of soils at 0 - 3 inches BLS was not conducted. ATSDR considers soils at this depth to be those most accessible to human contact and prone to becoming airborne if disturbed. It is also not known if the areas where soil contamination was detected can be accessed. The site was accessible to pedestrian traffic when visited in December of 1992. However, EPA reports that at the present time, all areas where the asbestos-contaminated soils were consolidated and capped and the building on the site are surrounded by a chain-link fence.
Asbestos and other contaminants were detected in surface waters, sediments and groundwater on or near the site. Asbestos was detected in ground water drawn from all monitoring wells on or near the site. The means by which asbestos entered the groundwater (e.g., via natural processes in the soil column, via soil disturbance during monitoring well installation) is not known. Benzene, arsenic and lead were detected in ground water near the lagoons south and west of the factory. Ground water is believed to flow toward the Neponset River. Ground water usage has not been completely characterized in the area. Two private wells have been identified one half mile north of the site. It is not known whether waters from these wells are contaminated with site-related contaminants. The use of these wells is also not yet known. Further hydrogeologic investigations may necessary in order to determine if private groundwater monitoring is warranted. Further characterization of on-site groundwater contamination is also necessary since bedrock groundwater on site was not monitored.
The town's drinking water needs are served by two groups of wells. One group is situated between three quarters of a mile and one and a half miles northwest of the site. The other is situated upgradient and approximately one mile southeast of the site. From March of 1988 through October of 1990, trichloroethylene (TCE) was detected consistently in one well in this group. A granulated activated carbon filtration system was installed and TCE has not been detected in waters drawn through the system since October of 1990. Since TCE has not yet been detected in significant levels in on-site groundwater, it is extremely unlikely that the site could have been a source for the contamination detected in the municipal well. Walpole residents were not exposed to high TCE levels for extended periods of time. It is therefore not likely that TCE contamination of municipal waters had a significant negative impact on the health of the Walpole community.
On-site groundwater is believed to discharge to the Neponset River. Neither the sediments nor the surface waters of the Neponset have been monitored for site-related contaminants other than asbestos. It is not certain whether exposure to benzene, carcinogenic PAHs, arsenic and lead, which have been detected in on-site soils and groundwater, is occurring through contact with the waters and sediments of the Neponset River. These contaminants, especially PAHs, can also accumulate in fish that may live in waters on or near the site. Asbestos has been detected in surface waters and sediments of the Neponset River, as far as 2,000 feet downstream of the site.
It is not possible to determine whether individuals were exposed to hazardous levels of airborne asbestos in the past. Asbestos exposure in occupational studies has been associated with an increased risk of lung cancer development. This risk is especially enhanced among cigarette smokers who are exposed to airborne asbestos. Asbestos inhalation is also highly associated with mesothelioma, a rare cancer of the membranes that line the internal organs. Mesothelioma is not yet known to be associated with cigarette smoking. It is not certain whether kidney and esophageal cancers are associated with asbestos inhalation since these findings have not been consistently replicated in occupational studies. High level asbestos exposure is associated with non-cancerous lung diseases such as asbestosis. It is, however, extremely unlikely that Walpole residents were exposed to those levels associated with this disease. Occupational studies have observed the development of corn-like benign skin lesions on those workers whose skin consistently comes in contact with asbestos. It is not certain whether or how frequently Walpole residents may have experienced such exposure.
Lung cancer incidence data from the Massachusetts Cancer Registry (MCR) was reviewed for purposes of this preliminary health assessment. Lung cancer rates between 1982 and 1989 were elevated among females residing in the census tract encompassing the site. There were 17 cases of lung cancers among females residing in the census tract and about 12 were expected based on the statewide experience. Kidney cancer was also elevated among females in this census tract. Between 1982 and 1989, 5 cases of kidney cancer were observed and approximately two were expected based on the statewide experience. Neither of these elevations among females was statistically significant (p < .05). Lung and kidney cancer rates among males residing in this census tract were near or below those that would be expected based on the statewide experience. There was one case of mesothelioma among males residing in the census tract encompassing the site. No females living within this area were diagnosed with mesothelioma. There were two cases of mesothelioma diagnosed among females who lived within the census tract west of that which encompasses the site. None of these cases, however, lived close to the site.
To obtain an information booklet summarizing the document, contact the MDPH, Bureau of Environmental Health Assessment, at the Massachusetts Department of Public Health, 7th Floor, 150 Tremont Street, Boston, MA 02111 (617-727-7170)
QUESTIONS ABOUT THE HEALTH ASSESSMENT
1. Q. What is a health assessment?
2. Q. Why was the health assessment done for the Blackburn-Union Privileges site?
3. Q. Why is the health assessment a "draft" document?
4. Q. Where is the Blackburn Union Privileges (South Street) site?
5. Q. What contaminants were detected at the site?
6. Q. How can I be exposed to contaminants at the site?
7. Q. What measures are regulatory agencies taking to reduce any potential health hazards associated with the site?
8. Q. Was the Walpole community extensively exposed to asbestos in the past?
9. Q. Are the cancer rates that are generally associated with asbestos exposure elevated in Walpole?
Summary of Written Correspondence
Received During the Public Comment Period
Blackburn and Union Privileges
Public Comment
| Information | ||
| Name and Address | Supplied Request | Comment |
| Susan M. Cooke, P.C. Goodwin, Proctor & Hoar Exchange Place Boston, Massachusetts 02109-2881 (on behalf of W.R. Grace & Co.) | X | |
| Kristine M. Laurmeyer
Remedial Project Manager United States Environmental Protection Agency 1 Congress Street Boston, MA 02203-2211 | X | |
Responsiveness Summary
SUMMARY OF PUBLIC COMMENTS
This responsiveness summary addresses comments on the preliminary Public Health Assessment (PHA) and Information Booklet that were received by the Massachusetts Department of Public Health (MDPH) or the Agency for Toxic Substances and Disease Registry (ATSDR) during the public comment period, from August 22 to September 21, 1994, and extended to September 21, 1994, for the Blackburn-Union Privileges Site in Walpole, Massachusetts. Susan M. Cooke of the law firm Goodwin, Proctor, and Hoar, representing W.R. Grace and Company, and Kristine M. Laumeyer, Remedial Project Manager for the site from the United States Environmental Protection Agency (USEPA), submitted comments.
The page numbers referred to in this responsiveness summary are based on the documents released for public review. Changed language in the revised documents may appear on pages with slightly different numbers.
W.R. Grace Comment 1: The site does not pose a past public health hazard and an indeterminate present health hazard, as concluded in the PHA. The ATSDR Health Assessment Guidance Manual (HAGM) focuses on current, not past, health conditions. The HAGM defines an indeterminate health hazard at a site as follows:
(t)he limited available data do not indicate that humans are being exposed or have been exposed to levels of contamination that would be expected to cause adverse health effects. However, data or information are not available for all environmental media to which humans may be exposed and there are insufficient or no community-specific health outcome data to indicate that the site has had an adverse impact on human health.
Response: MDPH and ATSDR disagree with W.R. Grace's interpretation of ATSDR guidance. The HAGM states on page 8-2 that in some instances, past exposures may have resulted in adverse health effects that have persisted to the present even though the site has been remediated and exposures are no longer occurring. Although available data indicate that asbestos exposure at the site is not likely occurring under current conditions, the 1988 exposure survey identified some residents who used the site for recreational activities (e.g., walking, playing) prior to remediation of the site; these residents could have been exposed to asbestos at the site.
MDPH and ATSDR believe that the site poses an indeterminate present health hazard because the site has not been completely characterized for several environmental media for several compounds (e.g., polynuclear aromatic hydrocarbons [PAHs] in river sediment or food chain components). Groundwater was not also not completely characterized because no deep groundwater samples were taken during any of the site investigations. Mobile compounds (e.g., benzene) were detected in shallow groundwater but their potential migration to deep groundwater is not known. In addition, because deep groundwater was not investigated, hydraulic properties (e.g., groundwater flow direction) in the deep zone are not characterized. Two private wells have been identified within one-half mile north of the site; the potential for migration of constituents from the site to these or other private wells is not known.
Finally, W.R. Grace states that no minimal risk level (MRL) has been exceeded at the site. However, no MRLs for asbestos have been established by ATSDR (ATSDR 1993; 1995).
W.R. Grace Comment 2 and USEPA Comment 1: W.R. Grace believes that a more detailed description of the remedial activities at the site are appropriate in the information booklet on page 2. In a similar comment, the USEPA suggested that more details on the emergency removal action at the site should be included in the Information Booklet.
Response: The description of past remedial activities currently in the Information Booklet was expanded, consistent with EPA's comments.
W.R. Grace Comment 3 and USEPA Comment 2: The language in the second paragraph of page 3 should be changed to reflect the uncertainty regarding the mechanisms for migration of asbestos-containing soil to a residential property.
Response: MDPH and ATSDR agree with this comment. The third sentence now reads: "Asbestos-contaminated soil or sediment may have been taken from the site and used as fill at one of these residences." The fifth sentence of this paragraph was changed to state "The source of asbestos at a residence immediately northeast of the site is not known."
W.R. Grace Comment 4 and USEPA Comment 4: Both W.R. Grace and EPA state that soils with asbestos levels greater than 1 percent were excavated and removed. Thus, the Information Booklet should not say on page 3 that two areas of the site (northwest corner and a residence 2,000 feet downstream of the site) had soil with asbestos levels greater than 1 percent.
Response: At the time the PHA and Information Booklet were prepared, MDPH and ATSDR only had draft tables (and no accompanying text) of data collected during or after excavation at the site. The tables showed some elevated asbestos levels in two excavated areas: the Orlando residential property and the Mill Tail Race; however, without any accompanying text, it was not clear whether any elevated levels remained after all excavation activities were completed. We have since received a copy of the July 1993 Draft Completion of Work Report: Removal Action, South Street Site, Walpole, Massachusetts, submitted to USEPA by Canonie Environmental Services. The report says that if soil samples taken after excavation showed elevated asbestos levels, more soil was excavated until the 1 percent cleanup level was achieved. For example, if a sample showed 11 percent asbestos after the initial excavation, excavation continued until the sample met the cleanup level. All sample results, including those that indicated further excavation was required, were reported in the tables to the draft report. The text of the document notes that the 1 percent cleanup level was achieved on both of the properties originally of concern. For example, sample MTR-B2-3G.2 at Mill Tail Race was said to be reexcavated 3 times before meeting the cleanup criterion (Canonie 1993, p. 24). Thus, the language on page 3 was changed to reflect this new information.
W.R. Grace Comment 5: The sentence in the third paragraph of page 3 of the Information Booklet cautioning against disturbance of the existing cap due to possible exposure to underlying asbestos should be deleted.
Response: MDPH and ATSDR believe that the sentence should remain because it does suggest that exposures could result if adequate containment measures are not taken (emphasis added).
W.R. Grace Comment 6 and USEPA Comment 5: On page 3, it says the site was accessible in December 1992. The site is now completely fenced and currently inaccessible to pedestrian or vehicular traffic.
Response: As noted by W.R. Grace, the western side of the site did not have fencing at the time of the site visit in December 1992 by federal and state health officials. EPA noted that the areas where the asbestos contaminated soils have been consolidated and capped and the building on the site are surrounded by a chain-link fence. The Information Booklet and the PHA were changed to reflect this updated information.
W.R. Grace Comment 7: The language in the first paragraph of page 4 regarding the presence of asbestos in groundwater inaccurately infers that it is migrating throughout the site via groundwater flow. The presence of asbestos in groundwater should be attributed to contamination of the sample during the installation of monitoring wells through asbestos-containing soils.
Response: The Dames and Moore report referred to in comment 7 states that the detection of asbestos throughout the site does not necessarily mean that it is migrating via groundwater flow. The report also noted that asbestos contamination of groundwater may have occurred during monitoring well installation. We agree that it is unlikely that asbestos is migrating via overburden groundwater flow; however, the mechanism for how asbestos entered the groundwater is not known. To clarify this point, we changed the subject language by deleting the sentence, "The mechanism for this migration is not known," and inserting the sentence, "The means by which asbestos entered the groundwater (e.g., via natural processes in the soil column, via soil disturbance during monitoring well installation) is not known."
W.R. Grace Comment 8: The PHA should not mention on page 4 that trichloroethylene (TCE) was detected in a municipal well upgradient from the site because it is extremely unlikely to be site-related.
Response: PHAs and Information Booklets include a brief discussion on the source and quality of municipal water supplies for the town in which the site under review is located. MDPH and ATSDR believe the paragraph in question clearly notes that the TCE found in the municipal well is "extremely unlikely" to be related to the site. The information, however, can be used by health officials to more accurately assess all possible environmental exposures occurring to town residents, regardless of whether the exposures are related to the site.
W.R. Grace Comment 9: Because no statistically significant elevation of asbestos-related cancer rates have been observed in the area near the site, the PHA on page 5 should state that no link between cancer incidence in the area and exposure to site-related asbestos can be made.
Response: The PHA examined cancer incidence data for several cancer types (e.g., mesothelioma) and found no statistically significant elevation in these cancers in residents of the census tract that includes the site. Such a descriptive analysis does not allow for any conclusions about possible links or lack thereof between environmental exposures or risk factors and health outcomes. Only more comprehensive studies (e.g., analytical epidemiology study) can address such associations. Thus, the PHA and Information Booklet were not changed.
W.R. Grace Comment 10: The reference on page 6 to a moving company near the site should be deleted because the company is no longer there.
Response: The reference to the moving company was deleted.
W.R. Grace Comment 11: The second sentence of question 6 on page 7 infers that some residents living within a one-half-mile radius of the site were definitely exposed to asbestos. This sentence should be changed to indicate that living within a one-half-mile radius of the site does not necessarily mean that exposures actually occurred.
Response: The original language on page 7 clearly states that exposure occurred most likely to those individuals trespassing on the site; hence, W.R. Grace's concerns that the answer to question 6 infers that living within a one-half-mile radius of the site resulted in definite exposure is unfounded. As suggested in the comment, the article "a" was deleted.
W.R. Grace Comment 12: Question 8 on page 7 should ask only about potential exposure to asbestos from the site. Because approximately 94 percent of the survey respondents did not experience high level asbestos exposure, the word "majority" overrepresents the community's degree of asbestos exposure. Although the term "majority" may be technically correct, it implies a level of 50 percent of the people who were not exposed compared with the actual 94 percent. Finally, the answer to the question should say whether the seven individuals who reported that they had worked with asbestos did so at the Blackburn-Union Privileges site.
Response: The 1988 exposure survey was not limited to potential exposures to the site, but rather included questions about probable exposures to asbestos in the workplace and in the home. Thus, it is not appropriate that question 6 be limited to potential exposures to the site itself. The PHA and Information Booklet presented the actual proportions of those surveyed who were at risk of asbestos exposure. The PHA and Information Booklet were changed, however, in that the description of asbestos exposure from the 1988 survey was inaccurate. The PHA originally noted that "high asbestos exposure" occurred in some people, based on the survey. It is more accurate, however, to say that some survey respondents were at a "high risk of exposure to asbestos," and this change was made throughout the PHA and the Information Booklet (see page 7 of the Information Booklet, and pages 14, 15, and 23 of the PHA). The use of the word majority is appropriate. The exposure survey reported that seven individuals were former employees at the site.
W.R. Grace Comment 13: The word "but" should be substituted for "and" in the sentence on page 8 regarding elevated lung cancer rates among women of Walpole that were not statistically significant.
Response: The suggested change was incorporated.
W.R. Grace Comment 1 : W.R. Grace suggests more detailed language in the PHA summary regarding the emergency removal action begun in 1992.
Response: This section is designed to give the reader a brief overview of the PHA contents. The remedial actions are described in greater detail on pages 4, 5, and 6 of the PHA.
W.R. Grace Comment 2: The description of the asbestos detected near the southern border of the site, which is referred to in the third paragraph of page 1, should be clarified to indicate that this contamination was removed during the emergency removal action.
Response: The third paragraph refers to possible current or future exposure pathways. Because MDPH and ATSDR now have the Draft Completion of Work Report, which documents that the 1 percent asbestos-in-soil cleanup level was achieved at the site, the PHA was changed to reflect the result of the emergency removal action (see response to comment 4). The phrase, ". . .in offsite soils sampled near the southern border of the site as well as. . .," in the third paragraph was deleted. All soils known to contain asbestos greater than 1 percent were excavated.
W.R. Grace Comment 3: The statement on page 1 stating that the 1988 exposure survey "demonstrated that a completed exposure pathway to asbestos existed in the past," should delete the word "demonstrated" and insert the word "suggests." The survey may not have distinguished between site- and nonsite-related asbestos exposure.
Response: The MDPH and ATSDR retained the original language with the word "demonstrated." A complete exposure pathway comprises the following five elements: 1) a source, 2) presence in a medium and mechanism of transport, 3) point of exposure, 4) route of exposure, and 5) receptors. The 1988 exposure survey asked respondents whether they worked on the site or whether they played, walked, or swam on the site. The survey results indicated that some individuals did work on the site or use the site for recreational activities. Thus, the survey demonstrated that a complete exposure pathway existed in the past. An example of a complete exposure pathway would be as follows: soils containing asbestos were on the site (source); some surface soils, which could be directly contacted by individuals, contained asbestos (medium, transport mechanism, and point of contact); some soil could be incidentally ingested while walking or playing (route of exposure); and the survey indicated that the site did have recreational users (receptor population).
W.R. Grace Comment 4: The site should not be classified as a past public health hazard and an indeterminate present public health hazard.
Response: See response to W.R. Grace comment 1 on the Information Booklet.
W.R.Grace Comments 5 and 34, and USEPA Comment 5: The site is currently completely fenced, and the statement on page 3 of a partially fenced site is no longer accurate.
Response: See response to W.R. Grace comment 6 on the Information Booklet. In addition, the phrase, "enhance site security," on page 2 was deleted. Also, Recommendation 1 on page 25 was changed to: "The present security of the site, for which EPA reports all capped areas, which contain the consolidated and asbestos-contaminated soils, are completely fenced, should be maintained."
W.R. Grace Comment 6: The description on page 4 of the emergency removal action completed in 1993 should be reworded, per EPA comments (see response to W.R. Grace comment 2 on the Information Booklet).
Response: The descriptions on pages 4, 5, and 6 were supplemented with additional information on the emergency removal action.
W.R. Grace Comment 7: The text on page 5 that describes the 1986 ATSDR health consultations should be clarified and a new sentence should be inserted describing the 1987 health consultation.
Response: As requested by W.R. Grace, "constitutes" was changed to "constituted." In addition, two clarifying phrases were added to the first full paragraph.
W.R. Grace Comment 8: Several conditions present during the December 1992 site visit are no longer applicable (the 1992 site visit is discussed on page 5). The conditions included organic odors, a dark brown flow into the Neponset River, and fencing.
Response: See response to W.R. Grace comment 19 (below) regarding organic odors and to W.R. Grace comment 6 on the Information Booklet regarding fencing at the site. None of the language was changed because the paragraph accurately described conditions at the time of the site visit.
W.R. Grace Comment 9: Clark Street is northwest of the site and not northeast as described on page 6. Gleason Court is northeast of the site and not southeast of the site as stated on page 6 of the PHA.
Response: These changes were incorporated into the PHA. Gleason Court appears to be due east of the site.
W.R. Grace Comment 10: The sentence on page 9 stating the absence of comparison values for asbestos levels in soil is confusing because cleanup levels for the site were set at 1 percent soil asbestos.
Response: MDPH and ATSDR changed the PHA to say that the term, "comparison values," is an ATSDR term that refers to several values used by ATSDR (e.g., environmental media evaluation guide [EMEG]). These comparison values are not cleanup levels, which are established by state and federal environmental regulatory agencies. One ATSDR comparison value, the EMEG, is used to select chemicals of potential concern at hazardous waste sites. The EMEG is based on the level at which no adverse health effect is expected (i.e., the MRL) and on the potential exposure to the chemical via a specific medium (e.g., soil). Thus, EMEGs exist for specific media; no EMEG exists for asbestos in any medium.
However, as noted on page 5 of the PHA, the 1988 ATSDR health consultation concluded that "1 percent asbestos levels in soil is not likely to contribute significantly as a public health threat via air to the residents in that area" (House 1988).
W.R. Grace Comments 11, 18: The statements on pages 9 and 15 that most of the soils with asbestos levels of greater than 1 percent were excavated and removed should be changed to say that all soils greater than 1 percent asbestos were excavated and removed.
Response: The PHA was changed to reflect the fact all soil greater than 1 percent asbestos was removed during excavation of the site. See also response to W.R. Grace comment 4 on the Information Booklet.
W.R. Grace Comment 12: Asbestos was detected in groundwater sampled from all but one of the 14 monitoring wells drilled onsite and not in all of the monitoring wells as was reported in the PHA on page 10.
Response: The correction was made.
W.R. Grace Comment 13: The top of page 11 refers to elevated levels of PAHs, lead, and asbestos in Mill Tail Race sediment. A sentence should be added to say that these sediments were remediated during the asbestos removal action.
Response: The description on page 11 summarizes data prior to the removal action. Thus, the description on page 11 stands. However, on page 17, the PHA was amended to include remediation of Mill Tail Race sediments. The changed language appears in the section, "Sediment - Past, Present, and Future," in the first paragraph.
W.R. Grace Comments 14, 23, 26, 32: Mention of TCE in municipal water supplies on pages 12, 18, 22, and 25 in the PHA is inappropriate.
Response: See response to W.R. Grace comment 8 on the Information Booklet.
W.R. Grace Comment 15: A grammatical error appears in the first paragraph of page 13.
Response: The error was corrected.
W.R. Grace Comments 16, 30, 35: It is not appropriate to comment in the PHA (pages 13, 24, and 25) on the validity of the analytical methods used to determine asbestos levels in soil. The EPA-required analytical method for asbestos in soil was used for the site. The appropriate forum for debate on the analytical techniques for determining asbestos in soil is not in a PHA.
Response: MDPH and ATSDR believe that it is appropriate to include discussions of uncertainty arising from analytical methods because uncertainty in estimated concentrations results in uncertainty in estimated health risks. EPA Region I has developed a protocol for screening soil and sediment samples for asbestos content (U.S. EPA 1994); this protocol was required for analyses of site soils and was indeed used at the site. The protocol was necessitated because no standard method exists for analyzing asbestos in soil or sediment. Reflecting the lack of any standard method for asbestos in soil, ATSDR (1993) provided no discussion of analytical methods for asbestos in soil. The protocol uses polarized light microscopy (PLM) to identify fibers found in the sample, but EPA states that the protocol is not meant to be used as a quantitative method; rather it is useful to determine whether or not soil or sediment contains significant amounts (e.g., greater than 1 percent) of asbestos. The protocol calls for sieving soil samples through a 250 µm sieve, and the material remaining on the sieve is analyzed. Hence the method initially detects fibers or bundles of fibers greater than 250 µm size. Identification of fibers as asbestos fibers is unequivocal with this analysis (U.S. EPA 1994; Cook 1995). The determination of the percent asbestos in the sample is based on a visual estimate made by the technician. The reliability of such estimates depends on the technician's experience, and the resulting percent values are uncertain. In addition, because the method only identifies fibers greater than 250 µm, the method may also under- or overestimate percent asbestos in the entire sample if the distribution of fibers in the smaller-sized fraction (i.e., less than 250 µm) is different than in the larger-sized fraction (i.e., greater than 250 µm).
For purposes of this PHA, the discussion on asbestos analysis on page 13 was supplemented with the above information. Conclusion 5 on page 24 was changed to reflect uncertainty in the percent values used with the EPA protocol. Recommendation 2 on page 25 was deleted because the EPA Region I protocol used at the site appears to be as appropriate and practical as any currently available method to determine attainment of a soil cleanup level of 1 percent asbestos in soil.
W.R. Grace Comment 17: Page 15 of the PHA may overstate the possibility of asbestos exposure to children playing on the site.
Response: As stated in the PHA, the 1988 exposure assessment revealed that at least some older children played on the site (e.g., playing frisbee with brake linings or clutch plates). The PHA then said that it is "likely that inhalation of airborne asbestos particles occurred at this time." We believe this statement is appropriate; ambient air monitoring at the site is not likely to capture the potential for inhalation of asbestos during these types of activities.
W.R. Grace Comment 19 and USEPA Comment 7: W.R. Grace contends that the organic odor detected during the site visit should not be mentioned in the PHA; the odor was from asphalt installed at about the time of the site visit. EPA, however, attributes the tar-like odor to diesel equipment that was operating at the time.
Response: As previously stated, the report of the site visit routinely incorporated in the PHAs presents site conditions at the time of the visit. Organic odors were present during the site visit. The source of the odors is not certain, as evidenced by the different opinions presented in the two comments. No paving operations appeared to be ongoing at the time of the site visit.
W.R. Grace Comment 20: The emergency asbestos removal completed in 1993 resulted in the "elimination" and not "reduction" of asbestos exposure, as stated on page 16.
Response: The emergency removal action greatly reduced the risk of future exposure to asbestos but did not eliminate potential future exposures. Lack of future exposure depends on the integrity of the cap and lack of future soil disturbance, which could result in the release of fugitive dust containing asbestos.
W.R. Grace Comments 21, 33: Should the cap be disrupted for monitoring purposes, proper protective procedures will prevent any exposure during the process. The use of proper protective procedures should be mentioned in the PHA.
Response: On page 17, the phrase, "if proper protective and containment procedures are not strictly followed," was added at the end of the first (incomplete) paragraph. The suggested wording in the eighth recommendation appearing on page 26 supports the use of proper protective procedures should any cap disturbance occur.
W.R. Grace Comment 22: No evidence exists that the river has run dry in the past; hence the PHA concern on page 17 for river sediment containing asbestos to become airborne in the event of the river running dry during summer months is unwarranted.
Response: MDPH and ATSDR maintain that the potential for the river to run dry remains unknown. However, the PHA was changed to indicate that no evidence exists that the river has ever dried up.
W.R. Grace Comment 24: The statement on page 19 that asbestos exposure is likely to have occurred on the site in the past is incorrect.
Response: See response to W.R. Grace comment 17 on the PHA.
W.R. Grace Comment 25: On page 21, the PHA should say that benzene-contaminated waters at the site are not currently being used.
Response: The PHA was changed to include this information.
W.R. Grace Comments 27, 29: Because no statistically significant elevation of asbestos-related cancer rates have been observed in the area near the site, the PHA should state on pages 23 and 24 that there is no association between exposure to site-related contamination and cancer rates in the area.
Response: See response to W.R. Grace comment 9 on the Information Booklet.
W.R. Grace Comment 28: Because approximately 94 percent of the survey respondents did not experience high level asbestos exposure, the word "majority" on page 23 overrepresents the community's degree of asbestos exposure.
Response: See response to W.R. Grace comment 12 on the Information Booklet.
W.R. Grace Comment 31: Instead of determining private well usage in Walpole, as suggested in conclusion 8 on page 25, it may be more useful to determine private well usage in the vicinity of the site.
Response: This comment refers to a conclusion, not a recommendation. The conclusion stands. Recommendation 5 on page 25 states the use and quality of water from private wells "near" the site should be determined. This recommendation is consistent with W.R. Grace's comment.
W.R. Grace Comment 36: Because the cap over the asbestos containment area is already regularly inspected, the recommendation on page 25 for such monitoring is not necessary.
Response: The recommendation supports the regular monitoring and was retained in the PHA.
W.R. Grace Comment 37: Recommendation 9 on page 26 should be deleted because all soil greater than 1 percent asbestos was removed.
Response: This recommendation was deleted (see response to W.R. Grace comment 4 on the Information Booklet).
W.R. Grace Comments on the References and Appendix A: The Health Consultations and the Draft Completion of Work Report should be included in the references.
Response: These citations and others are now cited in the PHA. The text of the Draft Completion of Work Report was received by the MDPH in March 1995. The PHA corrected the spelling of "Canonie" on Figure 3 of Appendix A. In addition, all references in the PHA were rearranged and placed in alphabetical order.
USEPA Comment 1: This comment, part of which was addressed earlier in this responsiveness summary, also questioned the use of "onsite" versus "offsite" terms in the PHA and Information Booklet. The terms "on-facility" and "off-facility" should be used instead.
Response: On page 3 the PHA defined "onsite" as on-facility, and "offsite" as the remainder of the study area. Because these terms were already defined in a manner consistent with EPA's comment, the terminology of "onsite" and "offsite" was not changed.
USEPA Comment 6: Because smoking is a risk factor for lung cancer, the PHA should include discussion of the percentage of lung cancer cases who smoked cigarettes. Such a statement would inform the reader of other causes of lung cancer in the site area, thereby reducing the likelihood that asbestos exposure affected the rates of lung cancer in the area.
Response: While smoking is a risk factor for lung cancer, asbestos exposure and cigarette smoking have a synergistic effect on the risk of contracting lung cancer. That is, exposure to asbestos and smoking cigarettes results in greater risk of lung cancer than would be expected by simply adding the risks of each together. Thus, asbestos exposure has a larger effect on lung cancer rates in those populations where smoking is prevalent, thereby affecting lung cancer rates.
USEPA Comment 8: EPA disagrees with the recommendation on page 25 that soils be sampled at 0 to 3 inches below land surface (BLS). The sampling conducted at zero to six inches was adequate to assess health risks associate with soil contaminants at the site.
Response: MDPH and ATSDR recognize that many federal and state agencies have different
definitions of "surface soil." ATSDR, however, has defined surface soil as 0 to 3 inches BLS
because this is the depth to which individuals are most likely to be exposed to chemicals in soil.
Sample results from greater depths (e.g., 0-6 inches, 0-2 feet) may show lower or higher
concentrations than results from more shallow samples.
