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PETITIONED PUBLIC HEALTH ASSESSMENT

GALLUP'S QUARRY
PLAINFIELD, WINDHAM COUNTY, CONNECTICUT


SUMMARY

The Plainfield community group, Peoples Rights in a Clean Environment (PRICE) petitioned the Agency for Toxic Substances and Disease Registry to determine whether the Gallup's Quarry site represents a public health hazard. Citizens were concerned with contaminants in surface water, groundwater, and soil, at the site, in private wells, and the Mill Creek area. A preliminary health assessment identified the site as a public health hazard and recommended further sampling. Two health consultations issued in 1993, addressed private wells and soil contamination. While contaminants identified were not at levels of health concern, further environmental sampling and site restrictions were recommended. In this health assessment, current environmental data were reviewed and evaluated. Results indicate that residents have not been exposed to contaminants at levels of health concern in soil, sediment, surface water, groundwater, and private well water. However, ATSDR recommends that monitoring wells continue to be sampled and residential wells should be resampled if long term monitoring on-site indicates that groundwater conditions have changed. Groundwater restrictions should also be imposed on future developments in areas of the contaminated groundwater plume. The draft health assessment was released on July 21, 1998 for public comment. The public comment period ended August 30, 1998; the comments received and ATSDR's response to these comments are provided in Appendix B.


PURPOSE AND HEALTH ISSUES

The citizens group, the Peoples Rights In a Clean Environment (PRICE), members of which live in Plainfield Connecticut, petitioned the Agency for Toxic Substances and Disease Registry (ATSDR), to determine whether exposure to contaminants identified at the Gallup's Quarry site represents a public health hazard and to make recommendations to reduce or prevent exposures. Citizens were concerned with contaminated 1) surface water runoff, 2) groundwater migrating to private drinking wells, and 3) soil that may expose people who access the site, Mill Creek, and adjacent marshes for recreational activities.


BACKGROUND

The town of Plainfield has a population of approximately 14,363 people as of the 1990 Census (1). Gallup's Quarry (a.k.a., Tarbox Road site), located on Tarbox Road in Plainfield Connecticut, is a 22 acre area initially used by the Connecticut Department of Transportation (CTDOT) as a source of gravel and a staging area during construction of highway Route 52 (Figure 1, Appendix A). The site is one mile south of Plainfield's central business area and rural residential areas are located close to the site. This site is located approximately 1800 ft. southeast of the Plainfield sewage treatment plant, which is situated at the confluence of Mill Brook and Fry Brook (2). An industrial park is located approximately 700 ft. north of the site on the opposite side of Mill Brook. Gallup's Quarry is bound by Mill Brook and associated wetlands to the north, Route 12 to the east, Tarbox Road and residential areas to the south, and an active railroad line and wetlands to the west. The property was purchased in 1977 for use as a gravel mining operation. From May 1977 to January 1978, approximately 1,600 barrels of chemical waste were illegally disposed of in three areas of the property, a 50 X 40 ft seepage bed, a 0.07 acre barrel pit and lagoon, and a 0.4 acre lagoon and barrel pit. Approximately 6500 people rely on wells located within 3 miles of the site, as a sole source of drinking water. The Gallup Water Company well field is located approximately 4,000 ft away from the site and serves approximately 2,200 people. The wells of the Brookside Water Company are located approximately one mile to the northeast, serving about 800 people. The Lillibridge Division wells of the Gallup Water Company are located on Tarbox Road, approximately 0.4 miles west of the southern end of the site. It serves about 144 people. Both well fields currently meet federal drinking water regulations and neither is located down gradient from the site (communications with the Connecticut Department of Environmental Protection (CTDEP)). There are approximately twenty-six private wells around the periphery of the site. The closest residential well is approximately 1,200 feet southeast of the site on Route 12.

In January 1978, the CTDEP sampled and confirmed the presence of hazardous waste including; metals, volatile organic compounds (VOCs), inorganic and organic compounds on-site in ground water, surface water, sediment and soil (3, 4). The CTDEP and State Police initiated removal activity in 1978, removing approximately 1600 barrels, 5,000 gallons of bulk liquid waste, and more than 3,470 tons of contaminated soil. Groundwater was determined to be contaminated with VOCs and the site was placed on the National Priorities List on October 4, 1989 (4). On May 24, 1989, ATSDR was requested by the Environmental Protection Agency (EPA) to review and comment on drinking water data collected from ten private wells (5). The EPA record of decision for this site was signed in October 1997 (6).

Previous ATSDR Actions for the Site

In 1991, a preliminary health assessment released by ATSDR identified the site as a potential health hazard and recommended further environmental characterization and sampling on-site (7). Two health consultations were prepared in February (8) and March (9) 1993. The health consultation completed in February 1993, assessed off-site private well data for site-related contamination (8). ATSDR concluded that the Gallup's Quarry site was an indeterminant health hazard. While there was no indication that residents were being exposed to contaminants from the site, there was insufficient environmental data to fully characterize the exposure risks. The March 1993 health consultation assessed the potential exposure to contaminated soil of person(s) who trespass on-site during recreational activity (9). It was recommended that barriers to roads and paths be erected to prevent use of the site for future recreational activity. The State of Connecticut Department of Public Health investigated community concerns regarding cancer in Plainfield and its surrounding community (March 24, 1993). Cancer incidence rates were obtained from the Connecticut Tumor Registry for the years 1971 to 1990. No increase in cancer incidence in Plainfield was reported.

The ATSDR and CTDEP conducted a site visit in April 1989, and the site was not fenced or posted with warning signs. Access to the site could be gained by an unpaved road or by walking onto the site. Another site visit was conducted by the CTDEP and the Connecticut Department of Public Health on September 27, 1993. At that time, the site was heavily vegetated and former disposal areas and lagoons were filled in with gravel. Visible signs of trespassing were observed including dirt bike trails, trash and debris. On November 19, 1996, ATSDR conducted another site visit and observed that the access roads to the site had gates, preventing vehicle access and the area was vegetated. No visible signs of activity at the site were observed.

This health assessment will address public health implications based on community concerns and a review of recent environmental data obtained during sampling of groundwater, residential wells, surface water and sediment from 1995 to 1997 (10).


DISCUSSION

ATSDR selects and discusses chemical contaminants based on several factors, including comparisons of concentrations with ATSDR comparison values for noncarcinogenic and carcinogenic endpoints, and community health concerns. Comparison values are maximum concentrations of contaminants in a specific medium (e.g., soil, sediment, surface water, groundwater, air) that are not expected to produce an adverse health effect in people who are exposed. Soil comparison values are used to determine safe values for sediment concentrations. When the concentration of a contaminant detected is above the comparison value it is selected for further evaluation to determine potential adverse health effects.

Groundwater

Previous groundwater sampling data indicated that VOCs were detected in the northwest area of the site in the former secondary disposal area and the former seepage bed area. VOCs were determined to be migrating as a plume off-site in groundwater to the northwest area of the quarry into Mill Brook and its wetlands (3).

Groundwater samples were obtained and analyzed for VOCs, semi-volatile organic compounds (SVOCs), metals, pesticides and polychlorinated biphenyl (PCB) compounds every 3 to 4 months from January 1995 to February 1997, under the Long Term Monitoring Program (9). Vinyl chloride (highest 1400 ppb) and 1,1,1-Trichloroethane (highest 390 ppb) were detected above ATSDR health based comparison values, in monitoring wells placed along the centerline of the contaminant plume located downgradient from the former primary disposal area. The highest concentrations were measured in a top-of-till (the till horizon ranges in thickness from approximately 10 to 20 feet) well, with low concentrations detected in shallow wells. The concentration of VOCs detected in monitoring wells beyond the boundaries of the plume were below comparison values. No SVOCs, pesticides, or PCB compounds were detected above health based comparison values. During the nine sampling periods, antimony (highest 28.7 ppb), arsenic (highest 18.2 ppb), manganese (highest 3250 ppb), lead (highest 93.5 ppb), and aluminum (highest 39,700 ppb) were detected above comparison values in monitoring wells placed in the plume located downgradient from the disposal site. It is unlikely that adverse health effects would result, since no municipal or residential wells are located downgradient from the site. However, ATSDR recommends restricting future use of groundwater on-site, continuing to monitor the migration of the VOC groundwater plume off-site, and deed restrictions on future land use in the area of the contaminated groundwater plume.

Residential Wells

Residential wells were sampled for VOCs, SVOCs, metals, pesticides and PCB compounds on January 1995, July 1995, February 1996, and August 1996 (9). No VOCs, SVOCs, pesticides, or PCB compounds were detected above comparison values. Antimony was the only metal detected above ATSDR's comparison value. It was only detected one time at 26.3 ppb (DW113) and 29.5 ppb (DW106) in two of the thirteen private wells tested during the four sampling periods (Figure 3, Appendix A). Both of these private wells are located upgradient from the site groundwater contamination. The concentration of antimony detected in both private wells was about 2 times greater than the EPA Region III Risk Based Concentration of 15 ppb. However, because antimony was not detected in three of the four sampling periods, it is unlikely that people are being exposed to levels of antimony above the comparison value for long periods of time. In addition, the comparison values are conservative and health effects would be unlikely if people were exposed to levels of antimony slightly greater than the comparison value. Little data is available on the absorption of antimony from the gastrointestinal tract in humans. However, results of studies in animals have estimated a 2% to 7% absorption of certain antimony salts, suggesting that less than 10% is probably absorbed in humans (11). The International Commission on Radiological Protection has recommended a reference value for gastrointestinal absorption in humans of 10% for antimony tartrate and 1% for all other forms of antimony (12). Residents intermittently exposed to the maximum concentration measured (29.5 ppb) at 1% to 10% absorption, would be receiving a dose below the EPA chronic oral RfD of 0.0004 mg/kg/da. EPA's ambient water criterion established for the protection of human health from the toxic properties of antimony ingested through water and contaminated aquatic organisms is 146 ppb (13 ). The maximum concentration measured in private wells was five times lower than EPA's ambient water criterion. Therefore, based on the environmental data reviewed and toxicological information on antimony, it is unlikely that health effects would be expected to occur from adults or children using private well water.

Surface Water and Sediment Sampled in Mill Brook and Wetland Soils

Surface water bodies located near the site are Mill Brook, Fry Brook, and Packers Pond (Figure 2, Appendix A). Mill Brook flows from east to west-southwest along the northern and western edges of the site. Mill Brook and Fry Brook ultimately discharge to Packers Pond. The State of Connecticut classifies the section of Mill Brook that is north of the site as B/A which indicates that these water bodies may not be meeting Class A water quality criteria. The water quality goal for the lower portion of Mill Brook, below its confluence with Fry Brook is classified as B, indicating that the water should meet Class B guidelines and be suitable for cold water fisheries (4). Surface water, sediment, and wetland soils that were upstream, adjacent to, and downstream of the Gallup's Quarry site were sampled and analyzed for potential migration of contaminants from the site. Samples were obtained on September 1994, April and November 1995, and May and November 1996 and were analyzed for VOCs, SVOCs, and metals (9). Sediment concentrations were compared to ATSDR comparison values for soil. No SVOCs or VOCs were detected above comparison values. In Mill Brook and the unnamed tributaries, manganese (highest 2520 ppb, UB-SW-2), arsenic (highest 29.6 ppb, UB-SW-5), and aluminum (46,400 ppb, UB-SW-5) were detected in surface water. In Packers Pond, only lead (highest 62.1 ppb, PP-SW-1) and arsenic (24.9 ppb, PP-SW-3) were detected in surface water. The highest concentrations of metals were detected at locations sampled upstream from the site and may be due to run-off from developed areas (streets, highways, residences, agricultural, or industrial property). No adverse health effects are likely to occur since these concentrations are below comparison values and people would not routinely visit these areas.

Sediment was sampled for VOCs, SVOCs, metals, pesticides, and PCB compounds. Soil comparison values were used to evaluate sediment concentrations. No VOCs, SVOCs, pesticides, or PCBs were detected above health based comparison values.

Air Monitoring

A baseline air quality survey was conducted on-site (9). Air samples were taken at eight locations across the site, at three known former disposal areas, upwind, and downwind. Samples were taken at breathing level (approximately 3 to 6 feet above ground surface) and measured for total VOCs and respirable dust. No VOC or respirable dust concentrations sampled at any of the eight locations were at levels of health concern.

During the initial EPA field investigations, ambient air was monitored at the eight locations for VOCs and respirable dust. In addition, continuous air monitoring was conducted at discrete locations (microwell, soil boring, etc.) where on-site workers were located. No readings above EPA's action levels were detected at the perimeter of the site, but VOCs were detected at two soil boring locations on-site. During later EPA investigations, air monitoring in the vicinity of the former primary disposal area tested for the presence of toluene, ethyl benzene, total xylene, tetrachloroethene, and PCB, previously found in shallow soil excavations during the initial sampling. None of these compounds were detected over an eight hour sampling period during later investigations.


ATSDR CHILD HEALTH INITIATIVE

Infants and children are more sensitive to environmental exposures than adults in communities with contaminated water, soil, air, or food, since 1) children play outside and are likely to be more exposed to soil or surface water, 2) children are shorter and closer to dust, soil and vapors near the ground, and 3) children have a higher metabolic rate than adults, resulting in a higher dose per body weight. Since exposures to children may affect development and growth, ATSDR is committed to evaluating potential exposures to children as part of the Child Health Initiative. ATSDR evaluated the potential for children living near the Gallup's Quarry site to be exposed to contaminants at levels of health concern. ATSDR did not identify any exposures to children that are likely to result in adverse health effects.


CONCLUSIONS

1. The Gallup's Quarry site represents no public health hazard in the past or present. Some VOCs and metals were detected in groundwater above ATSDR comparison values but only in monitoring wells located in the contaminated groundwater plume, downgradient from the former primary disposal area. Since municipal and private wells in the area are not located downgradient of the contaminated groundwater plume, it is unlikely that these wells would be affected by the migration of contaminants.

However, Gallup's Quarry could potentially be of health concern in the future if new sources of groundwater use are installed in the area of the plume off-site and to future workers on-site who may use the groundwater.

2. No volatile organic compounds, semi-volatile organic compounds, metals, pesticides, or polychlorinated biphenyls were detected at levels of health concern in the residential wells sampled.

3. Volatile organic compounds, semi-volatile organic compounds, and pesticides were not detected at levels of health concern in groundwater, surface water or sediment sampled off-site in Mill Brook, Packers Pond, and adjacent marshes.

4. Antimony was inconsistently detected (once out of four sampling periods) above the drinking water comparison value in two private wells located upgradient of the site. Adults and children drinking the water would not likely experience adverse health effects since these levels are slightly above the comparison value and the duration of exposure would be limited.

5. On-site air monitoring results indicated that volatile organic compounds were not detected at the perimeter of the site, but were detected at two soil boring locations during remedial activity at the former primary disposal area.


RECOMMENDATIONS

1. Sample residential wells for site related contaminants if long term monitoring at the site indicates that the conditions of the contaminated groundwater plume has changed.

2. Continue the Long Term Monitoring Program to determine the extent and migration of the VOC groundwater plume off-site.

3. Impose groundwater restrictions on-site and restrict future development of private wells of-site in the areas of the contaminated groundwater plume.


PUBLIC HEALTH ACTION PLAN

No public health action plan is provided since residents' concerns have been addressed in this and previous health assessments. In addition, while potential exposures to contaminants do exist, they are not at levels of health concern and no adverse health effects are likely to occur.


PREPARERS OF REPORT

Adele M. Childress, Ph.D., MSPH
Environmental Health Scientist
Exposure Investigation and Consultation Branch/Petition Response Section
Division of Health Assessment and Consultation, ATSDR


Technical Review

Susan Moore
Toxicologist
Exposure Investigation and Consultation Branch
Division of Health Assessment and Consultation, ATSDR

Louise House
ATSDR Senior Regional Representative, Region I


REFERENCES

1. Census Sample Count, Part A, Connecticut Population and Housing Characteristics, August 1991.

2. Environmental Protection Agency, New England Region (USEPA). Declaration of the Record of Decision: Gallup's Quarry Superfund Project, Plainfield, CT. September 30, 1997.

3. Fuss & O'Neill, Evaluation of a Chemical Waste Disposal Area, Tarbox Road Site, Plainfield, CT. January 29, 1979.

4. NUS Corporation, final HRS Documentation Package, Gallup's Quarry, Plainfield, CT. TDD No. F1-8706-01, NUS Job No. CT40HR, EPA Site No. CTD1089660972. Contract No. 68-01-7346. September 15, 1987.

5. Preliminary Health Assessment for Gallup's Quarry (a.k.a. Tarbox Road) Proposed National Priorities List site. Plainfield, CT. Cerclis No. CTD108960972. February 1990.

6. Environmental Protection Agency, New England Region (USEPA). Record of Decision: Gallup's Quarry Superfund Project, Plainfield, CT. October, 1997.

7. Agency for Toxic Substances and Disease Registry (ATSDR). Atlanta: U.S. Dept. of Health & Human Services, Public Health Service. Preliminary Health Assessment for Gallup's Quarry. Plainfield, Windham County, CT. January 30, 1991.

8. Agency for Toxic Substances and Disease Registry (ATSDR. Atlanta: U.S. Dept. of Health & Human Services, Public Health Service. Health consultation on private drinking water wells for Gallup's Quarry. February 25, 1993.

9. Agency for Toxic Substances and Disease Registry (ATSDR). Atlanta: U.S. Dept. of Health & Human Services, Public Health Service. Health consultation on surface soil for Gallup's Quarry. March 25, 1993.

10. Environmental Protection Agency, New England Region (USEPA). Remedial Investigation Report: Gallup's Quarry Superfund Project. Plainfield CT. Vol. 1 (Text and Figures) and Vol. 2 (Tables). (QST Environmental: Nashua, NH). Final. June 1997.

11. Agency for Toxic Substances and Disease Registry. Toxicological profile for antimony. Atlanta, GA: Agency for Toxic Substances and Disease Registry. September 1992.

12. International Commission on Radiological Protection (ICRP) 1981.Limits of intakes of radionuclides by workers. Metabolic data for antimony. Annals of the ICRP. ICRP Publication 30, part 3.

13. Environmental Protection Agency; Ambient water quality criteria for antimony. EPA-440/5-80-020: 1980; 113 p. Internet address: http://130.14.32.43/cgi-bin/Version-B


APPENDIX A: FIGURE

Gallup's Quarry Gravel Pit
Figure 1. Gallup's Quarry Gravel Pit


APPENDIX B: RESPONSE TO COMMENTS

The Connecticut Department of Public Health provided additional comments and corrections to the health assessment during the public comment period.

Comments 1- 10. Editorial suggestions.

ATSDR Response: Suggested editorial changes were adopted, thank you for your suggestions.

Comment 11: Page 7, Conclusions, Please consider the inclusion of antimony detected above the CV, and discuss the implications of the maximum concentration which exceeds the child long term health advisory of 10 ppb.

ATSDR Response: The conclusion and health implications regarding the concentration of antimony found in two private wells have been added to the conclusion section of the document.



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