PRELIMINARY PUBLIC HEALTH ASSESSMENT
BLACKBURN AND UNION PRIVILEGES
WALPOLE, NORFOLK COUNTY, MASSACHUSETTS
Blackburn Union Privileges Site Figures
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,
1600 Clifton Road NE, Atlanta, Georgia 30333
Information Booklet Preliminary Public Health Assessment for Executive Summary
Blackburn-Union Privileges (South St.) Site
Walpole Norfolk County, Massachusetts
The Agency for Toxic Substances and Disease Registry (ATSDR) was mandated by theComprehensive Environmental Response, Compensation, and Liability Act (CERCLA) asamended, to conduct Public Health Assessments for all National Priorities List (NPL) hazardouswaste 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 onthose NPL sites in the Commonwealth. This document is an executive summary of the finaldraft for public comment.
The Blackburn Union Privileges (South Street) site is situated in Walpole approximately 2,000feet southeast of the town center. In February of 1992, the site was proposed for listing on theNational Priorities List (NPL). In response to this proposed listing, the MDPH under itscooperative agreement with ATSDR conducted a preliminary public health assessment on theBlackburn Union Privileges site. Based on the findings of a community-wide survey, that wasconducted by MDPH in collaboration with the Walpole Board of Health, the site is characterizedas a past public health hazard. Since the characterization of the current contamination ofenvironmental media on or near the site is incomplete, the site is also characterized as anindeterminate 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 Streetapproximately 150 feet southwest of Common Street. The Neponset River flows under SouthStreet and through the site in a westerly fashion. Warehousing and foundry operations arecurrently ongoing on those land parcels east of South Street. A vacated factory is situated on thewestern land parcel. The site is situated in a residential area with the nearest residence locatedapproximately 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 thesite. From this time until 1935, raw asbestos materials were spun into yarn which was thenwoven to produce brake pads and clutch plates. Waste asbestos was piled behind the buildingthat currently houses offices of the foundry operation. In 1937, after asbestos manufacturingceased, 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 bleachedprior to fabric production. Waste solutions from the manufacturing process were discharged totwo 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 theMassachusetts Department of Environmental Quality Engineering [(MDEQE), currently theMassachusetts Department of Environmental Protection (MDEP)], received a complaint thatasbestos was present on the site; the asbestos pile was subsequently covered. In 1989, a siteassessment was conducted and environmental media were monitored for the presence of asbestosand other environmental contaminants. This preliminary public health assessment is largelybased on the findings of the site assessment.
An extensive asbestos removal action was completed in 1993. The Neponset River wastemporarily diverted while bedding material was placed and graded to match pre-existingriverbed elevations at the upstream and downstream ends of the culvert. A geotextile filter fabricwas laid on top of the bedding material and along the riverbed prior to placement of the 400-footlong aluminum culvert. After the culvert was in place the Neponset River was redirected throughthe aluminum culvert that lies in the Neponset riverbed. Asbestos-contaminated soils wereexcavated, consolidated, capped over the aluminum culvert with approximately 2 feet ofimported clean fill, and then vegetated. Mill Tail Race sediments were excavated, stabilized, andcapped in lagoon #2. Segregation of Tail Race sediments was necessary due to the presence ofother contaminants besides asbestos. Confirmatory monitoring of excavated soils for asbestoswas conducted during the removal action. The results of this monitoring are also evaluated in thepreliminary health assessment.
In 1986, ATSDR conducted a health consultation based on a bulk asbestos sample taken from thesite and concluded that since asbestos is a human carcinogen, its presence constitutes a healththreat. 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 sedimentsamples from specific areas of the site, determined that soils and sediments with asbestos contentof less than 1% did not pose a health threat.
Citizen concern over asbestos exposure and possible elevations of lung and kidney cancer ratesnear the site prompted investigations by MDPH into evaluating both the opportunities forasbestos exposure (March, 1988) and cancer incidence near the site (August, 1992). Theseconcerns and the results of MDPH investigations are assessed in the Preliminary HealthAssessment.
Environmental data were evaluated according to ATSDR's methods, as indicated in the PublicHealth Assessment Guidance Manual, in order to determine contaminants of concern. Information on environmental data is presented in the Environmental Contamination and OtherHazards, Pathways Analysis, and Toxicological Evaluation sections. Health outcome data wereevaluated using standard methods as outlined in the Health Outcome Data Evaluation section ofthe health assessment.
Extensive soil monitoring for asbestos was conducted on and around the site. Asbestos wasdetected in on and off site soils. Two residences in the area contained elevated soil asbestoslevels. Asbestos-contaminated soil or sediment may have been taken from the site and used asfill 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 in1992, in which all soils known to contain greater than 1 percent asbestos were excavated. Allexcavations were back-filled with clean fill. It is possible that disturbance of the cap placedalong the Neponset River may result in exposure to asbestos contamination underneath the cap ifadequate containment measures are not taken beforehand.
Based on the results of the 1988 Walpole Asbestos Exposure Survey which was conducted byMDPH in collaboration with the Walpole Board of Health and a pulmonary specialist from theMassachusetts General Hospital, exposure to site-related asbestos was limited to a smallpercentage of those individuals either living in the same residence as those occupationallyexposed to asbestos or those living within a half-mile radius of the site. Past generation ofairborne asbestos particles may have been possible. Older children are reported to have playedon the site and to have thrown asbestos-containing clutch plates that were discarded at the site. Itis likely that inhalation of asbestos particles by these individuals occurred at that time.
Lead, arsenic and carcinogenic Polynuclear Aromatic Hydrocarbons (PAHs) were also detectedin on-site soils at 18 to 48 inches BLS. Many of these contaminated areas were capped duringthe cap placement. There are, however, other areas where hazardous contaminant levels weredetected below the soil surface. It is not known if exposure to contaminants in uncapped areas isoccurring or has occurred in the past since monitoring of soils at 0 - 3 inches BLS was notconducted. ATSDR considers soils at this depth to be those most accessible to human contactand prone to becoming airborne if disturbed. It is also not known if the areas where soilcontamination was detected can be accessed. The site was accessible to pedestrian traffic whenvisited in December of 1992. However, EPA reports that at the present time, all areas where theasbestos-contaminated soils were consolidated and capped and the building on the site aresurrounded by a chain-link fence.
Asbestos and other contaminants were detected in surface waters, sediments and groundwater onor near the site. Asbestos was detected in ground water drawn from all monitoring wells on ornear the site. The means by which asbestos entered the groundwater (e.g., via natural processesin 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 thefactory. Ground water is believed to flow toward the Neponset River. Ground water usage hasnot been completely characterized in the area. Two private wells have been identified one halfmile north of the site. It is not known whether waters from these wells are contaminated withsite-related contaminants. The use of these wells is also not yet known. Further hydrogeologicinvestigations may necessary in order to determine if private groundwater monitoring iswarranted. Further characterization of on-site groundwater contamination is also necessary sincebedrock groundwater on site was not monitored.
The town's drinking water needs are served by two groups of wells. One group is situatedbetween three quarters of a mile and one and a half miles northwest of the site. The other issituated upgradient and approximately one mile southeast of the site. From March of 1988through October of 1990, trichloroethylene (TCE) was detected consistently in one well in thisgroup. A granulated activated carbon filtration system was installed and TCE has not beendetected in waters drawn through the system since October of 1990. Since TCE has not yet beendetected in significant levels in on-site groundwater, it is extremely unlikely that the site couldhave been a source for the contamination detected in the municipal well. Walpole residents werenot exposed to high TCE levels for extended periods of time. It is therefore not likely that TCEcontamination of municipal waters had a significant negative impact on the health of the Walpolecommunity.
On-site groundwater is believed to discharge to the Neponset River. Neither the sediments northe surface waters of the Neponset have been monitored for site-related contaminants other thanasbestos. 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 thewaters and sediments of the Neponset River. These contaminants, especially PAHs, can alsoaccumulate in fish that may live in waters on or near the site. Asbestos has been detected insurface 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 airborneasbestos in the past. Asbestos exposure in occupational studies has been associated with anincreased risk of lung cancer development. This risk is especially enhanced among cigarettesmokers who are exposed to airborne asbestos. Asbestos inhalation is also highly associatedwith mesothelioma, a rare cancer of the membranes that line the internal organs. Mesotheliomais not yet known to be associated with cigarette smoking. It is not certain whether kidney andesophageal cancers are associated with asbestos inhalation since these findings have not beenconsistently replicated in occupational studies. High level asbestos exposure is associated withnon-cancerous lung diseases such as asbestosis. It is, however, extremely unlikely that Walpoleresidents were exposed to those levels associated with this disease. Occupational studies haveobserved the development of corn-like benign skin lesions on those workers whose skinconsistently comes in contact with asbestos. It is not certain whether or how frequently Walpoleresidents may have experienced such exposure.
Lung cancer incidence data from the Massachusetts Cancer Registry (MCR) was reviewed forpurposes of this preliminary health assessment. Lung cancer rates between 1982 and 1989 wereelevated among females residing in the census tract encompassing the site. There were 17 casesof lung cancers among females residing in the census tract and about 12 were expected based onthe 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 wereexpected based on the statewide experience. Neither of these elevations among females wasstatistically significant (p < .05). Lung and kidney cancer rates among males residing in thiscensus 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 thesite. No females living within this area were diagnosed with mesothelioma. There were twocases of mesothelioma diagnosed among females who lived within the census tract west of thatwhich 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 ofEnvironmental 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?
- A health assessment is a process used to determine the possibility of adverse public healthimpacts from past, current, and future exposures to contaminants from a Superfund site. Information about environmental exposure(s), toxicology of the contaminants, the availablehealth outcome data for the community (such as cancer incidence data), and the community'shealth concerns are used to determine the level of concern for the site. The types ofrecommendations for follow-up activities are based on the level of concern.
2. Q. Why was the health assessment done for the Blackburn-Union Privileges site?
- The federal Agency for Toxic Substances and Disease Registry (ATSDR) was mandated bythe Comprehensive Environmental Response, Compensation, and Liability Act of 1980(CERCLA), as amended, to conduct health assessments for all National Priorities List(Superfund) hazardous waste sites in the country. In 1987 the Massachusetts Department ofPublic Health (MDPH), Bureau of Environmental Health Assessment (BEHA) entered into acooperative agreement with the ATSDR to conduct these health assessments in Massachusetts. The workplan for FY-93 included the Blackburn-Union Privileges site as one that needed to becompleted and released for public comment during this year.
3. Q. Why is the health assessment a "draft" document?
- The Blackburn Union Privileges Preliminary Public Health Assessment was released as a draftdocument in order to solicit public comments. An important part of the health assessmentprocess is considering public health and environmental concerns about a Superfund site. Thepublic comment period allows more public involvement in the process, and ensures, to the extentpossible, that all public health concerns are addressed.
4. Q. Where is the Blackburn Union Privileges (South Street) site?
- The site is situated on South Street approximately 150 feet south of Common Street. SouthStreet runs through the land parcels that comprise the site. The area east of South Street currentlyhouses a metals foundry. The grounds where a vacant factory is situated is west of South Street. The Neponset River flows westerly through the site at its juncture with South Street.
5. Q. What contaminants were detected at the site?
- Asbestos, at this point, is the predominant contaminant and was detected in soil,groundwater, sediment and surface water on or near the site. Carcinogenic Polynuclear AromaticHydrocarbons (PAHs), arsenic, and lead, were detected in soils near the vacated factory buildingand near the metals foundry. Arsenic, lead, and benzene were also detected in groundwaterabove the bedrock table near the vacant factory building. Monitoring of the bedrock groundwaterhas not been conducted nor have river waters or sediments been monitored for environmentalcontaminants other than asbestos.
6. Q. How can I be exposed to contaminants at the site?
- The exposure assessment conducted by MDPH in 1988 showed that residents, for the mostpart, were not at high risk of exposure to site-related asbestos. Asbestos exposure occurred in thepast to some individuals residing within one half mile of the site, most likely to those individualstrespassing on the site. The asbestos contamination was capped in 1992 and if the cap andexcavations remain undisturbed, further exposure to asbestos contaminated soils is unlikely. Skin contact with asbestos in surface water and sediment may occur during wading activities inthe river as far as 2,000 feet downstream of the site. Since environmental contaminants have notbeen completely characterized for substances other than asbestos, other exposures to sitecontaminants cannot be determined at this time.
7. Q. What measures are regulatory agencies taking to reduce any potential health hazardsassociated with the site?
- The cap placed on the site in 1992, during the emergency removal action, as well as theexcavation of on-site and off-site asbestos contamination should largely prevent any furtherexposure to site-related asbestos. The state and federal environmental regulatory agencies arecurrently considering future plans to more completely characterize the environmentalcontamination on the site.
8. Q. Was the Walpole community extensively exposed to asbestos in the past?
- Based on the results of a community wide survey, only 22 of 346 respondents (6.3%) were atmoderate to high risk of asbestos exposure. Seven of these 22 individuals reported that they wereformer employees at the site, and the remaining 15 respondents reported that they either livedwith asbestos workers or within a one half mile radius of the site. Of the 187 respondents wholived within a half mile radius of the site or with an asbestos worker, 107 were at low risk ofasbestos exposure. According to the survey administered in 1988, the majority of the Walpolecitizenry who participated in the survey did not experience extensive asbestos exposure.
9. Q. Are the cancer rates that are generally associated with asbestos exposure elevated inWalpole?
- Lung cancer and mesothelioma are those cancers which have been consistently associatedwith asbestos exposure. It is not known what impact various risk factors may have played in thedevelopment of these cancers. Lung cancer incidence among males is below that which wouldbe expected based on the statewide experience. Lung cancer rates are elevated among females inWalpole but these elevations do not achieve statistical significance. The rates of cancers that arepotentially attributable to asbestos exposure are discussed in further detail in the Health OutcomeData Evaluation section.
Summary of Written Correspondence
Received During the Public Comment Period
|Name and Address||Supplied Request||Comment|
|Susan M. Cooke, P.C.|
Goodwin, Proctor & Hoar
Boston, Massachusetts 02109-2881
(on behalf of W.R. Grace & Co.)
|Kristine M. Laurmeyer |
Remedial Project Manager
United States Environmental Protection Agency
1 Congress Street
Boston, MA 02203-2211
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 PublicHealth (MDPH) or the Agency for Toxic Substances and Disease Registry (ATSDR) during thepublic 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 ofthe law firm Goodwin, Proctor, and Hoar, representing W.R. Grace and Company, and KristineM. Laumeyer, Remedial Project Manager for the site from the United States EnvironmentalProtection Agency (USEPA), submitted comments.
The page numbers referred to in this responsiveness summary are based on the documentsreleased for public review. Changed language in the revised documents may appear on pageswith slightly different numbers.
W.R. Grace Comment 1: The site does not pose a past public health hazard and an indeterminatepresent health hazard, as concluded in the PHA. The ATSDR Health Assessment GuidanceManual (HAGM) focuses on current, not past, health conditions. The HAGM defines anindeterminate health hazard at a site as follows:
(t)he limited available data do not indicate that humans are being exposed or have been exposedto levels of contamination that would be expected to cause adverse health effects. However, dataor information are not available for all environmental media to which humans may be exposedand there are insufficient or no community-specific health outcome data to indicate that the sitehas 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 inadverse health effects that have persisted to the present even though the site has been remediatedand exposures are no longer occurring. Although available data indicate that asbestos exposureat the site is not likely occurring under current conditions, the 1988 exposure survey identifiedsome residents who used the site for recreational activities (e.g., walking, playing) prior toremediation 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 becausethe site has not been completely characterized for several environmental media for severalcompounds (e.g., polynuclear aromatic hydrocarbons [PAHs] in river sediment or food chaincomponents). Groundwater was not also not completely characterized because no deepgroundwater 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 groundwateris 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 havebeen identified within one-half mile north of the site; the potential for migration of constituentsfrom 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 detaileddescription of the remedial activities at the site are appropriate in the information booklet onpage 2. In a similar comment, the USEPA suggested that more details on the emergency removalaction at the site should be included in the Information Booklet.
Response: The description of past remedial activities currently in the Information Booklet wasexpanded, consistent with EPA's comments.
W.R. Grace Comment 3 and USEPA Comment 2: The language in the second paragraph of page3 should be changed to reflect the uncertainty regarding the mechanisms for migration ofasbestos-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 atone of these residences." The fifth sentence of this paragraph was changed to state "The sourceof 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 soilswith asbestos levels greater than 1 percent were excavated and removed. Thus, the InformationBooklet should not say on page 3 that two areas of the site (northwest corner and a residence2,000 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 ATSDRonly had draft tables (and no accompanying text) of data collected during or after excavation atthe site. The tables showed some elevated asbestos levels in two excavated areas: the Orlandoresidential property and the Mill Tail Race; however, without any accompanying text, it was notclear whether any elevated levels remained after all excavation activities were completed. Wehave 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 EnvironmentalServices. The report says that if soil samples taken after excavation showed elevated asbestoslevels, more soil was excavated until the 1 percent cleanup level was achieved. For example, if asample showed 11 percent asbestos after the initial excavation, excavation continued until thesample met the cleanup level. All sample results, including those that indicated furtherexcavation was required, were reported in the tables to the draft report. The text of the documentnotes that the 1 percent cleanup level was achieved on both of the properties originally ofconcern. For example, sample MTR-B2-3G.2 at Mill Tail Race was said to be reexcavated 3times before meeting the cleanup criterion (Canonie 1993, p. 24). Thus, the language on page 3was changed to reflect this new information.
W.R. Grace Comment 5: The sentence in the third paragraph of page 3 of the InformationBooklet cautioning against disturbance of the existing cap due to possible exposure to underlyingasbestos should be deleted.
Response: MDPH and ATSDR believe that the sentence should remain because it does suggestthat 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 inDecember 1992. The site is now completely fenced and currently inaccessible to pedestrian orvehicular traffic.
Response: As noted by W.R. Grace, the western side of the site did not have fencing at the timeof the site visit in December 1992 by federal and state health officials. EPA noted that the areaswhere the asbestos contaminated soils have been consolidated and capped and the building on thesite are surrounded by a chain-link fence. The Information Booklet and the PHA were changedto reflect this updated information.
W.R. Grace Comment 7: The language in the first paragraph of page 4 regarding the presence ofasbestos in groundwater inaccurately infers that it is migrating throughout the site viagroundwater flow. The presence of asbestos in groundwater should be attributed tocontamination 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 ofasbestos 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 duringmonitoring well installation. We agree that it is unlikely that asbestos is migrating viaoverburden groundwater flow; however, the mechanism for how asbestos entered thegroundwater is not known. To clarify this point, we changed the subject language by deleting thesentence, "The mechanism for this migration is not known," and inserting the sentence, "Themeans 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 besite-related.
Response: PHAs and Information Booklets include a brief discussion on the source and qualityof municipal water supplies for the town in which the site under review is located. MDPH andATSDR believe the paragraph in question clearly notes that the TCE found in the municipal wellis "extremely unlikely" to be related to the site. The information, however, can be used by healthofficials to more accurately assess all possible environmental exposures occurring to townresidents, regardless of whether the exposures are related to the site.
W.R. Grace Comment 9: Because no statistically significant elevation of asbestos-related cancerrates have been observed in the area near the site, the PHA on page 5 should state that no linkbetween 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 thecensus tract that includes the site. Such a descriptive analysis does not allow for any conclusionsabout possible links or lack thereof between environmental exposures or risk factors and healthoutcomes. Only more comprehensive studies (e.g., analytical epidemiology study) can addresssuch 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 bedeleted 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 residentsliving within a one-half-mile radius of the site were definitely exposed to asbestos. This sentenceshould be changed to indicate that living within a one-half-mile radius of the site does notnecessarily mean that exposures actually occurred.
Response: The original language on page 7 clearly states that exposure occurred most likely tothose individuals trespassing on the site; hence, W.R. Grace's concerns that the answer toquestion 6 infers that living within a one-half-mile radius of the site resulted in definite exposureis 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 toasbestos from the site. Because approximately 94 percent of the survey respondents did notexperience high level asbestos exposure, the word "majority" overrepresents the community'sdegree of asbestos exposure. Although the term "majority" may be technically correct, it impliesa 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 thatthey 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, butrather 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. ThePHA and Information Booklet presented the actual proportions of those surveyed who were atrisk of asbestos exposure. The PHA and Information Booklet were changed, however, in that thedescription of asbestos exposure from the 1988 survey was inaccurate. The PHA originallynoted that "high asbestos exposure" occurred in some people, based on the survey. It is moreaccurate, however, to say that some survey respondents were at a "high risk of exposure toasbestos," and this change was made throughout the PHA and the Information Booklet (see page7 of the Information Booklet, and pages 14, 15, and 23 of the PHA). The use of the wordmajority is appropriate. The exposure survey reported that seven individuals were formeremployees at the site.
W.R. Grace Comment 13: The word "but" should be substituted for "and" in the sentence onpage 8 regarding elevated lung cancer rates among women of Walpole that were not statisticallysignificant.
Response: The suggested change was incorporated.
W.R. Grace Comment 1 : W.R. Grace suggests more detailed language in the PHA summaryregarding the emergency removal action begun in 1992.
Response: This section is designed to give the reader a brief overview of the PHA contents. Theremedial 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 thesite, which is referred to in the third paragraph of page 1, should be clarified to indicate that thiscontamination was removed during the emergency removal action.
Response: The third paragraph refers to possible current or future exposure pathways. BecauseMDPH and ATSDR now have the Draft Completion of Work Report, which documents that the1 percent asbestos-in-soil cleanup level was achieved at the site, the PHA was changed to reflectthe result of the emergency removal action (see response to comment 4). The phrase, ". . .inoffsite soils sampled near the southern border of the site as well as. . .," in the third paragraphwas 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 deletethe word "demonstrated" and insert the word "suggests." The survey may not have distinguishedbetween 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) asource, 2) presence in a medium and mechanism of transport, 3) point of exposure, 4) route ofexposure, and 5) receptors. The 1988 exposure survey asked respondents whether they workedon the site or whether they played, walked, or swam on the site. The survey results indicated thatsome individuals did work on the site or use the site for recreational activities. Thus, the surveydemonstrated that a complete exposure pathway existed in the past. An example of a completeexposure pathway would be as follows: soils containing asbestos were on the site (source); somesurface soils, which could be directly contacted by individuals, contained asbestos (medium,transport mechanism, and point of contact); some soil could be incidentally ingested whilewalking or playing (route of exposure); and the survey indicated that the site did haverecreational users (receptor population).
W.R. Grace Comment 4: The site should not be classified as a past public health hazard and anindeterminate 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 completelyfenced, 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, thephrase, "enhance site security," on page 2 was deleted. Also, Recommendation 1 on page 25 waschanged to: "The present security of the site, for which EPA reports all capped areas, whichcontain the consolidated and asbestos-contaminated soils, are completely fenced, should bemaintained."
W.R. Grace Comment 6: The description on page 4 of the emergency removal action completedin 1993 should be reworded, per EPA comments (see response to W.R. Grace comment 2 on theInformation Booklet).
Response: The descriptions on pages 4, 5, and 6 were supplemented with additional informationon the emergency removal action.
W.R. Grace Comment 7: The text on page 5 that describes the 1986 ATSDR healthconsultations should be clarified and a new sentence should be inserted describing the 1987health 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 nolonger applicable (the 1992 site visit is discussed on page 5). The conditions included organicodors, a dark brown flow into the Neponset River, and fencing.
Response: See response to W.R. Grace comment 19 (below) regarding organic odors and toW.R. Grace comment 6 on the Information Booklet regarding fencing at the site. None of thelanguage was changed because the paragraph accurately described conditions at the time of thesite visit.
W.R. Grace Comment 9: Clark Street is northwest of the site and not northeast as described onpage 6. Gleason Court is northeast of the site and not southeast of the site as stated on page 6 ofthe PHA.
Response: These changes were incorporated into the PHA. Gleason Court appears to be due eastof the site.
W.R. Grace Comment 10: The sentence on page 9 stating the absence of comparison values forasbestos levels in soil is confusing because cleanup levels for the site were set at 1 percent soilasbestos.
Response: MDPH and ATSDR changed the PHA to say that the term, "comparison values," is anATSDR term that refers to several values used by ATSDR (e.g., environmental media evaluationguide [EMEG]). These comparison values are not cleanup levels, which are established by stateand federal environmental regulatory agencies. One ATSDR comparison value, the EMEG, isused to select chemicals of potential concern at hazardous waste sites. The EMEG is based onthe level at which no adverse health effect is expected (i.e., the MRL) and on the potentialexposure to the chemical via a specific medium (e.g., soil). Thus, EMEGs exist for specificmedia; no EMEG exists for asbestos in any medium.
However, as noted on page 5 of the PHA, the 1988 ATSDR health consultation concluded that "1percent asbestos levels in soil is not likely to contribute significantly as a public health threat viaair 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 withasbestos levels of greater than 1 percent were excavated and removed should be changed to saythat 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 wasremoved during excavation of the site. See also response to W.R. Grace comment 4 on theInformation Booklet.
W.R. Grace Comment 12: Asbestos was detected in groundwater sampled from all but one ofthe 14 monitoring wells drilled onsite and not in all of the monitoring wells as was reported inthe 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, andasbestos in Mill Tail Race sediment. A sentence should be added to say that these sedimentswere remediated during the asbestos removal action.
Response: The description on page 11 summarizes data prior to the removal action. Thus, thedescription on page 11 stands. However, on page 17, the PHA was amended to includeremediation 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. TheEPA-required analytical method for asbestos in soil was used for the site. The appropriate forumfor 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 uncertaintyarising from analytical methods because uncertainty in estimated concentrations results inuncertainty in estimated health risks. EPA Region I has developed a protocol for screening soiland 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 anystandard 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 identifyfibers 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 thetechnician. The reliability of such estimates depends on the technician's experience, and theresulting percent values are uncertain. In addition, because the method only identifies fibersgreater than 250 µm, the method may also under- or overestimate percent asbestos in the entiresample if the distribution of fibers in the smaller-sized fraction (i.e., less than 250 µm) isdifferent 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 withthe above information. Conclusion 5 on page 24 was changed to reflect uncertainty in thepercent values used with the EPA protocol. Recommendation 2 on page 25 was deleted becausethe EPA Region I protocol used at the site appears to be as appropriate and practical as anycurrently available method to determine attainment of a soil cleanup level of 1 percent asbestosin soil.
W.R. Grace Comment 17: Page 15 of the PHA may overstate the possibility of asbestosexposure to children playing on the site.
Response: As stated in the PHA, the 1988 exposure assessment revealed that at least some olderchildren played on the site (e.g., playing frisbee with brake linings or clutch plates). The PHAthen said that it is "likely that inhalation of airborne asbestos particles occurred at this time." Webelieve this statement is appropriate; ambient air monitoring at the site is not likely to capture thepotential 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 odordetected during the site visit should not be mentioned in the PHA; the odor was from asphaltinstalled at about the time of the site visit. EPA, however, attributes the tar-like odor to dieselequipment that was operating at the time.
Response: As previously stated, the report of the site visit routinely incorporated in the PHAspresents 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 twocomments. 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 asbestosbut did not eliminate potential future exposures. Lack of future exposure depends on theintegrity of the cap and lack of future soil disturbance, which could result in the release offugitive dust containing asbestos.
W.R. Grace Comments 21, 33: Should the cap be disrupted for monitoring purposes, properprotective procedures will prevent any exposure during the process. The use of proper protectiveprocedures should be mentioned in the PHA.
Response: On page 17, the phrase, "if proper protective and containment procedures are notstrictly followed," was added at the end of the first (incomplete) paragraph. The suggestedwording in the eighth recommendation appearing on page 26 supports the use of properprotective procedures should any cap disturbance occur.
W.R. Grace Comment 22: No evidence exists that the river has run dry in the past; hence thePHA concern on page 17 for river sediment containing asbestos to become airborne in the eventof the river running dry during summer months is unwarranted.
Response: MDPH and ATSDR maintain that the potential for the river to run dry remainsunknown. However, the PHA was changed to indicate that no evidence exists that the river hasever dried up.
W.R. Grace Comment 24: The statement on page 19 that asbestos exposure is likely to haveoccurred 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 atthe 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-relatedcancer rates have been observed in the area near the site, the PHA should state on pages 23 and24 that there is no association between exposure to site-related contamination and cancer rates inthe 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 notexperience high level asbestos exposure, the word "majority" on page 23 overrepresents thecommunity'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 inconclusion 8 on page 25, it may be more useful to determine private well usage in the vicinity ofthe 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" thesite 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 alreadyregularly 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 soilgreater than 1 percent asbestos was removed.
Response: This recommendation was deleted (see response to W.R. Grace comment 4 on theInformation Booklet).
W.R. Grace Comments on the References and Appendix A: The Health Consultations and theDraft 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 DraftCompletion of Work Report was received by the MDPH in March 1995. The PHA corrected thespelling of "Canonie" on Figure 3 of Appendix A. In addition, all references in the PHA wererearranged and placed in alphabetical order.
USEPA Comment 1: This comment, part of which was addressed earlier in this responsivenesssummary, also questioned the use of "onsite" versus "offsite" terms in the PHA and InformationBooklet. 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 ofthe study area. Because these terms were already defined in a manner consistent with EPA'scomment, the terminology of "onsite" and "offsite" was not changed.
USEPA Comment 6: Because smoking is a risk factor for lung cancer, the PHA should includediscussion of the percentage of lung cancer cases who smoked cigarettes. Such a statementwould inform the reader of other causes of lung cancer in the site area, thereby reducing thelikelihood 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 cigarettesmoking have a synergistic effect on the risk of contracting lung cancer. That is, exposure toasbestos and smoking cigarettes results in greater risk of lung cancer than would be expected bysimply adding the risks of each together. Thus, asbestos exposure has a larger effect on lungcancer 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 sampledat 0 to 3 inches below land surface (BLS). The sampling conducted at zero to six inches wasadequate to assess health risks associate with soil contaminants at the site.
Response: MDPH and ATSDR recognize that many federal and state agencies have differentdefinitions of "surface soil." ATSDR, however, has defined surface soil as 0 to 3 inches BLSbecause 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 higherconcentrations than results from more shallow samples.