PUBLIC HEALTH ASSESSMENT
BARKHAMSTED-NEW HARTFORD LANDFILL
BARKHAMSTED, LITCHFIELD COUNTY, CONNECTICUT
The sampling collected and compiled most recently was conducted by O'Brien and Gere as part of the remedial investigation (1). The sampling period was from 1992-1993. During this investigation, ground water, private wells, soil, surface water, leachate seep, sediment, landfill gases, soil gases, and air sampling were conducted. In April of 1988, the EPA also sampled private well water at nine residences and the Barkhamsted Town garage. Sampling of groundwater, surface water, sediment and leachate seeps quarterly by O'Brien and Gere began in August of 1995. Additional locations are also sampled quarterly by Fuss and O'Neill under a State of Connecticut Solid Waste Permit.
The discussion and tabulation of the results which follow present the contaminants of concern. Contaminants of concern are presented by media (i.e., water, soil, air, etc.) in which they were detected. The contaminants are also divided into on-site and off-site. The term on-site refers to sampling locations within the boundaries of the Barkhamsted Landfill property, and the term off-site refers to sampling locations outside the Barkhamsted Landfill property.
These contaminants will be examined in detail in sections which follow. This examination will be
done to determine if exposure to these contaminants have any public health significance. The
contaminants of concern were selected on the basis of the following characteristics:
| - | Concentrations of contaminants on-site and off-site. |
| - | Comparison of on-site and off-site concentrations with health comparison values(1) for non-carcinogenic and carcinogenic adverse health outcomes. |
| - | Community health concerns. |
| - | Data quality. |
The listing of one or more contaminant does not indicate that an adverse health outcome is likely to result from exposure. The list indicates which contaminants will be discussed in more detail in this public health assessment.
To further evaluate whether the contaminants will cause adverse health effects, the following are examined: concentration of the contaminant(s), route(s) and duration of exposure, and exposed population(s). This evaluation is presented in the Toxicological Evaluation Section on page 29.
The on-site sampling included the following media: groundwater from monitoring wells, groundwater from drinking water wells, surface water, surface soil, subsurface soil, ambient air, leachate seepage, landfill gases, and subsurface soil gases. In September of 1992, O'Brien and Gere identified twelve potential contaminant source areas for the site (1). The listing of the potential source areas is presented in Figure 2 below. (Appendix B depicts the locations of these potential source areas.)
Figure 2
Potential Waste Source Areas
| Potential Source Area |
| Former metal grindings area |
| Drum crushing area |
| Landfill disposal area |
| Liquid waste disposal area |
| Sedimentation basin #2 |
| Stained soil area |
| Metal grindings waste cell |
| Metal grindings waste interim storage |
| Southwestern slope of landfill |
| Access road |
| Potential landfill activity area |
| Leach field from building |
Ground Water
The BLS is located by the west branch of the Farmington River Basin (1). Ground water occurs in two aquifers(2): (overburden(3), and bedrock). The bedrock formations act as a single aquifer, however the RI examined the bedrock aquifer as three units (shallow, intermediate, and deep bedrock zones).
Ground water migrates vertically downward from the overburden aquifer to the bedrock in the area north of the landfill disposal area. The maximum downward flows occur by the northern section of the landfill (1). Contaminated ground water may therefore move in a downward direction from the overburden aquifer into the bedrock aquifer. The groundwater flow is toward the unnamed brook in a north easterly direction.
The ground water monitoring conducted on the site used fifteen monitoring wells installed in the bedrock aquifer and seven monitoring wells installed in the overburden aquifer. On-site ground water monitoring data from the RI, which encompasses the years of 1992 through 1993, were reviewed for this document.
Twenty-six contaminants were detected in monitoring wells located in the BLS property. Nine VOCs, five semivolatile organic compounds(4) (SVOCs), and eleven metals, and one pesticide were detected above health comparison values. The complete list including contaminant name, range of detected values, and health comparison values is presented in Table 1.
Table 1. On-Site Ground Water Monitoring Wells
| Contaminant | Concentration Minimum |
Range (ppb) Maximum |
Comparison Value ppb Source |
|
| 1,1,2,2-Tetrachloroethane | ND | 6 |
0.2 CREG
|
|
| 1,2-Dichloroethane | ND | 3 |
0.4 CREG
|
|
| 2,4-Dimethylphenol | ND | 3,100 |
700 RMEG
|
|
| 2-Butanone | ND | 30,000 |
20,000 RMEG
|
|
| 2-Methylphenol | ND | 2,600 |
2,000 RMEG
|
|
| Acetone | ND | 13,000 |
4,000 RMEG
|
|
| Antimony | ND | 35.8 |
3 LTHA
|
|
| Arsenic | ND | 37.6 |
0.02 CREG
|
|
| Barium | ND | 4,830 |
2,000 RMEG
|
|
| Benzene | ND | 21 |
1 CREG
|
|
| Beryllium | ND | 13.5 |
0.008 CREG
|
|
| Bis(2-ethylhexyl)phthalate | ND | 10,000 |
3 CREG
|
|
| Chromium total | ND | 466 |
100 LTHA
|
|
| cis-1,2-Dichloroethylene | ND | 190 |
70 LTHA
|
|
| Heptachlor Epoxide | ND | 0.026 |
0.004 CREG
|
|
| Lead | ND | 862 |
15 MCL
|
|
| Manganese | ND | 28,000 |
200 RMEG
|
|
| Nickel | ND | 449 |
100 LTHA
|
|
| Pentachlorophenol | ND | 4 |
0.3 CREG
|
|
| Phenol | ND | 6,900 |
4,000 LTHA
|
|
| Silver | ND | 110 |
100 LTHA
|
|
| Thallium | ND | 9.1 |
0.4 LTHA
|
|
| Toluene | ND | 11,000 |
700 EMEG
|
|
| Trichloroethylene | ND | 66 |
3 CREG
|
|
| Vanadium | ND | 811 |
100 EMEG
|
|
| Vinyl chloride | ND | 29 |
0.7 EMEG
|
|
| CREG | Cancer Risk Evaluation Guide |
| EMEG | Environmental Media Evaluation Guidelines |
| LTHA | Lifetime Health Advisory for drinking water |
| MCL | Maximum Contaminant Level |
| ND | None detected. The minimum concentration was below the detection limit. |
| ppb | parts per billion |
| RMEG | Reference Dose Media Evaluation Guide |
Ground water monitoring data indicate VOCs are present at the highest concentrations in the following areas: former metal grindings area, drum crushing area, landfill disposal area, and liquid waste disposal area. The ground water is migrating primarily to the northeast in the overburden and bedrock formations.
Ground Water - Landfill Office Well
The landfill office well was sampled on October 12, 1977, as part of a semi-annual sampling program (10). There were no volatile organic compounds detected in the water and the well water met all requirements for a potable water source. The landfill office well was sampled in November of 1980 by the Farmington Valley Health District (FVHD) (10). No volatile organic compounds were detected at that time and the well water continued to meet all requirements for a potable water source. Resampling conducted in September of 1982, by the FVHD, detected VOCs including the following: trichloroethylene (6.4 ug/L(5)), tetrachloroethylene (less than 1.0 ug/L), and benzene (less than 1.0 ug/L). The next sampling, also collected by the FVHD, was conducted in May of 1983, and indicated that the number of contaminants increased as did the concentrations (11). Four VOCs and one metal (manganese) were detected in the landfill office well at levels above health comparison values. Subsequent to this sampling, the landfill office well was closed in 1984. The contaminants detected above health comparison values are presented in Table 2.
Table 2. Landfill Office Well Maximum Contaminant Concentration
| Contaminant | Maximum Concentration ppb |
Comparison Value
ppb Source |
|
| Benzene | 2 |
1 CREG
|
|
| Manganese | 14,000 |
200 RMEG
|
|
| Methyl chloride (chloromethane) | 180 |
3 LTHA
|
|
| Tetrachloroethylene | 1.0* |
0.7 CREG
|
|
| Trichloroethylene | 8.2 |
3 CREG
|
|
| * | This compound was detected at a concentration of less than 1 ug/L, however the concentration was not quantified. |
| CREG | Cancer Risk Evaluation Guide |
| LTHA | Lifetime Health Advisory for drinking water |
| ppb | parts per billion |
| RMEG | Reference Dose Media Evaluation Guide |
Sixteen surface water samples were collected from Beaver Pond, the unnamed brook, an unnamed pond, and two sedimentation basins. The surface water samples were collected in two phases. The first phase was conducted from October 29, 1992, through December 11, 1992. The second phase was conducted from September 29, 1993, through October 7, 1993. All samples were collected by O'Brien and Gere as part of the RI (1). The samples were selected to determine the concentrations in surface water located upgradient, adjacent, and downgradient of the landfill. The results of the surface water sampling indicates that there were no VOCs detected above health comparison values. Five metals and one SVOC were detected in surface waters at levels above health comparison values. The complete list including contaminant name, range of detected values, and health comparison values is displayed in Table 3.
| Contaminant |
Concentration Range
(ppb)
Minimum Maximum |
Comparison Value
ppb Source |
||
| Bis(2-ethylhexyl)phthalate |
ND 5
|
3 CREG
|
||
| Chromium * |
ND 50.9
|
3 CREG
|
||
| Lead |
ND 68.3
|
15 MCL
|
||
| Manganese |
ND 2,270
|
50 RMEG-Child
|
||
| Thallium |
ND 5.8
|
0.4 LTHA
|
||
| Vanadium |
ND 73
|
30 EMEG-Child
|
||
| * | The chromium(VI) health comparison value was used. |
| CREG | Cancer Risk Evaluation Guide |
| EMEG-Child | Environmental Media Evaluation Guidelines for a child |
| LTHA | Lifetime Health Advisory for drinking water |
| MCL | Maximum Contaminant Level |
| ND | None detected. The minimum concentration was below the detection limit. |
| ppb | parts per billion |
| RMEG-Child | Reference Dose Media Evaluation Guide for a child |
Twenty-four soil samples were collected and analyzed for VOCs, SVOCs, pesticides, polychlorinated biphenyls (PCBs), and metals (1). These samples were collected by O'Brien and Gere as part of the RI. Surface soil samples were collected on October 29, 1992, and three intervals in 1993: (October 30, November 3, and November 4). Two of the samples were taken from two off-site adjacent properties. (The off-site samples are discussed in the off-site contaminant section.) The samples were taken in the first six inches below the surface. The former metal grindings area contained soil with the most exceedences above health comparison values. There were no VOCs detected above comparison values in any surface soil sample. The contaminants detected in the surface soil included three metals, five pesticides, and two SVOCs. Tables 4a and 4b list the contaminant name, range of detected values, and health comparison values.
Table 4a. Surface Soil (non metals)
| Contaminant |
Concentration Range
(ppb)
Minimum Maximum |
Comparison Value
(ppb) Source |
||
| Aldrin |
ND 7.2
|
0.04 CREG
|
||
| Benzo(a)pyrene |
ND 2,100
|
0.1 CREG
|
||
| Bis(2-ethylhexyl)phthalate |
ND 920
|
50
CREG
|
||
| Dieldrin |
ND 0.97
|
0.04 CREG
|
||
| P,P`-dichlorodiphenyl dichloroethane (DDD) |
ND 26
|
3 CREG
|
||
| P,P`-dichlorodiphenyldichloroethylene (DDE) |
ND 25
|
2 CREG
|
||
| P,P`-dichlorodiphenyltrichloroethane (DDT) |
ND 6.1
|
2 CREG
|
||
| CREG | Cancer Risk Evaluation Guide |
| ND | None detected. The minimum concentration was below the detection limit |
| ppb | parts per billion |
Table 4b. Surface Soil (metals)
| Contaminant |
Concentration Range
(ppm)
Minimum Maximum |
Comparison Value
(ppm) Source |
||
| Arsenic |
ND 88
|
0.5 CREG
|
||
| Beryllium |
ND 51
|
0.2 CREG
|
||
| Chromium * |
6 5,620
|
60 CREG
|
||
| * | The chromium(VI) health comparison value was used. |
| CREG | Cancer Risk Evaluation Guide |
| ND | None detected. The minimum concentration was below the detection limit |
| ppm | parts per million |
Thirty-two subsurface soil samples were collected and analyzed for VOCs, SVOCs, PCBs, and metals (1). These samples were collected by O'Brien and Gere as part of the RI. Subsurface soil samples were collected from October 28, 1992, through December 11, 1992. The samples were taken at depths ranging from two to sixteen feet below the surface. The subsurface soil samples were collected from the following areas: former metal grindings area, drum crushing area, landfill disposal area, liquid waste disposal area, sedimentation basin number two, stained soil area, metal grindings waste cell, southwestern slope of landfill, access road, and the leach field from the landfill office. The metal grindings waste, interim storage location, as well as potential landfill activity area was not included in the subsurface sampling, since there were no indications from soil gas measurements that contamination was present.
Sedimentation basin number two contained two of the four samples that were detected above health comparison values. The subsurface soil analysis indicated that three metals and one SVOC were detected above health comparison values. Chromium was the highest detected metal, at 4,150 ppm. This contaminant may occur in many different forms, such as chromium(III) and chromium(VI). The most toxic form is chromium (VI). Since the report did not specify which form of chromium was detected, the most toxic form, chromium (VI), was assumed. There were no VOCs detected above health comparison values in any subsurface soil sample. Tables 5a and 5b list the contaminant name, range of detected values, and health comparison values.
Table 5a. Subsurface Soil (non metal)
| Contaminant |
Concentration Range
(ppb)
Minimum Maximum |
Comparison Value
ppb Source |
||
| Benzo(a)pyrene |
ND 0.74
|
0.1 CREG
|
||
| CREG | Cancer Risk Evaluation Guide |
| ND | None detected. The minimum concentration was below the detection limit |
| ppb | parts per billion |
Table 5b. Subsurface Soil (metals)
| Contaminant |
Concentration Range
(ppm)
Minimum Maximum |
Comparison Value
ppm Source |
||
| Arsenic |
ND 20.3
|
0.5 CREG
|
||
| Beryllium |
ND 0.47
|
0.2 CREG
|
||
| Chromium * |
6.4 4,150.0
|
60.0 CREG
|
||
| * | The chromium(VI) health comparison value was used. |
| CREG | Cancer Risk Evaluation Guide |
| ND | None detected. The minimum concentration was below the detection limit |
| ppm | parts per million |
Air sampling was conducted at two separate times. The first sampling occurred during October 23, 1992 through October 27, 1992. This occurred when there were no site activities. The second sampling was conducted during November 16, 1992 through November 17, 1992. This occurred at the same time as the installation of a monitoring well. These samples were all collected by O'Brien and Gere as part of the RI (1).
The average air temperature measured during the two samples obtained in October of 1992, was 50 degrees Fahrenheit (F), and the average temperature during the November of 1992, sampling was 32 degrees F. The ambient air sampling was conducted to determine the impact of the landfill on the ambient air both on-site and off-site. Sampling locations included: the landfill surface, seepage areas, and adjacent residential properties. Sampling of the ambient air was conducted over two day periods for eight hours per day. Seven sampling locations were selected. A brief description of the sampling locations is highlighted in Table 6.
Table 6. Air Sampling Locations
| Location | Purpose |
| Adjacent to residence north of site | Air quality impact determination at residential location |
| Adjacent to residence south-east of site | Air quality impact determination at residential location |
| Center of landfill | Air quality impacts from disposal area |
| Near monitoring well | Provide potential worst case, by proximity to potential point source |
| Near seepage area north-west of landfill | Determine air quality impacts from seepage area |
| Near seepage area west of landfill | Determine air quality impacts from seepage area |
| South side of landfill | Provide upwind and down wind air quality (based on wind direction) |
The only contaminants detected during the ambient air sampled during October and November of 1992, above health comparison values were three VOCs. The maximum concentration of benzene was detected at the center of the landfill. This location, however, may have had additional sources of benzene including a portable generator and one or more trucks running in the vicinity. Table 7 presents the contaminant name, range of detected values, and health comparison values. Contaminants detected above health comparison values were sampled from the center of the landfill and from two sections near the unnamed brook. There were no exceedences near adjacent residences.
| Contaminant |
Concentration Range
(ug/m3)
Minimum Maximum |
Comparison Value
ug/m3 Source |
||
| Benzene |
ND 16.0
|
0.1 CREG
|
||
| Carbon tetrachloride |
ND 1.9
|
0.07 CREG
|
||
| Trichloroethylene |
ND 1.1
|
0.6 CREG
|
||
| CREG | Cancer Risk Evaluation Guide |
| ND | None detected. The minimum concentration was below the detection limit. |
| ug/m3 | Micrograms of contaminant per cubic meter of air |
Leachate is a liquid that is produced when rain or surface water enters the landfill, contacts the buried waste, dissolves some of the contaminants, and exits through the soil. There were nine leachate seepage samples collected. These samples were all collected by O'Brien and Gere as part of the RI, and were collected in two phases. The first phase was conducted from October 29, 1992 through December 11, 1992. The second phase was conducted from September 29, 1993 through October 7, 1993. The leachate sampling was conducted to describe the contaminants in the leachate, as well as to ascertain possible impacts leachate may have on surface waters in the area.
When the leachate seepage did not have sufficient flow rates for adequate sampling, a hole was dug to allow the leachate to aggregate. After the leachate pooled, a sample was then collected. Eleven contaminants detected in the leachate seepage were above health comparison values. Three VOCs, and seven metals, and one pesticide were detected above health comparison values.
Table 8 illustrates the contaminants present in the leachate seep that exceeded drinking water health comparison values. This table also lists the name and concentration range of the contaminants present in the leachate seeps.
Table 8. Leachate Seep On-Site
| Contaminant |
Concentration Range
(ppb)
Minimum Maximum |
|
| Antimony |
ND 16.1
|
|
| Arsenic |
ND 6.5
|
|
| Barium |
87.4 3,900
|
|
| Benzene |
ND 36
|
|
| Beryllium |
ND 1.3
|
|
| Chloromethane |
ND 9
|
|
| Dieldrin |
ND 0.087
|
|
| Lead |
ND 116
|
|
| Manganese |
292 10,300
|
|
| Thallium |
ND 24.7
|
|
| Toluene |
ND 4,700
|
|
| ND | None detected |
| ppb | parts per billion |
Sediment Sampling from Leachate Seeps
Sediment sampling was conducted at the six leachate seep locations. The sediments from the leachate seep were collected in two phases. The first phase was conducted from October 29, 1992 through December 11, 1992. The second phase was conducted from September 29, 1993 through October 7, 1993. All samples were collected by O'Brien and Gere as part of the RI (1). The samples were selected to determine the concentrations in the sediment at a leachate seep locations. The results of the sediment sampling from leachate seeps indicates that there were no VOCs detected above health comparison values. There were ten contaminants known as polycyclic aromatic hydrocarbons (PAHs) detected in the sediment. These contaminants were grouped by carcinogenic classification, (either probable human carcinogens or not classified). Two metals were detected in the sediment above health comparison values. Tables 9, 10, and 11 lists the range of contaminants detected in the sediment. Tables 9 and 10 depict PAHs stratified by their carcinogenic classification. Table 11 lists the two metals. Since there are few health comparison values for PAHs, the CT DPH combined the non-carcinogens, and carcinogens separately. The combined values listed in the tables were used in all subsequent risk estimation calculations.
Table 9. Non-Carcinogenic PAHs Detected in the Sediment From Leachate Seeps
| Chemical name |
Concentration Range
(ppm)
Minimum Maximum |
Comparison Value
ppm Source |
EPA Group | ||
| 2-methylnaphthalene |
ND 0.09
|
# #
|
not classified | ||
| Acenaphthylene |
ND 0.045
|
# #
|
not classified | ||
| Benzo(g,h,i)perylene |
ND 0.097
|
# #
|
not classified | ||
| Naphthalene |
ND 0.092
|
# #
|
not classified | ||
| Phenanthrene |
ND 0.42
|
# #
|
not classified | ||
| Total non-carcinogenic PAHs |
0.744
|
||||
| # | There are no health comparison values for these compounds |
| ND | None detected |
| ppm | parts per million |
Table 10. Carcinogenic PAHs Detected in the Sediment From
Leachate Seeps
| Chemical name |
Concentration Range
(ppm)
Minimum Maximum |
Comparison Value
ppm Source |
EPA Group |
||
| Benzo(a)anthracene |
ND 0.34
|
# #
|
B2 | ||
| Benzo(a)pyrene |
ND 0.27
|
0.1 CREG
|
B2 | ||
| Benzo(b)fluoranthene |
ND 0.77
|
# #
|
B2 | ||
| Chrysene |
ND 0.31
|
# #
|
B2 | ||
| Indeno(1,2,3,-c,d)pyrene |
ND 0.1
|
# #
|
B2 | ||
| # | There are no health comparison values for these compounds |
| B2 | Probable human carcinogen |
| CREG | Cancer Risk Evaluation Guideline |
| ND | None detected |
| ppm | parts per million |
Table 11. Metals Detected in Sediment from the Leachate
Seeps
| Chemical name |
Concentration Range
(ppm)
Minimum Maximum |
Comparison Value
ppm Source |
||
| Arsenic |
ND 3.3
|
0.5 CREG
|
||
| Beryllium |
ND 0.4
|
0.2 CREG
|
||
| CREG | Cancer Risk Evaluation Guideline |
| ND | None detected |
| ppm | parts per million |
A landfill gas survey was conducted during November and December of 1992. These samples were all collected by O'Brien and Gere as part of the RI. The landfill gas survey was done to determine the presence of landfill produced flammable gases (mainly methane). In addition, this sampling assisted in determining the potential off-site migration of these explosive gases. The landfill gas sampling was collected at 200 foot distances around the primary fill areas. The gases were sampled using soil probes driven into the soil three feet. Methane gas was sampled at eighteen locations around the periphery of the landfill excluding the west side. The western periphery was omitted based upon the assumption that the unnamed brook would act as a barrier for the migration of landfill gases. The sample locations were initially placed at two hundred foot intervals, however whenever methane was detected at greater than two percent, two more sample points were located one hundred feet on either side of the location where methane was detected. The eastern portion of the landfill, which is near several residences, indicated that there were no detectable levels of methane gas.
Sampling for combustible gases (i.e., methane) is conducted with one of several instruments. One commonly used measuring device is a combustible gas indicator. The combustible gas indicator is an instrument that measures the percentage of gases that can be burned in the atmosphere. The results are often presented as percentages of lower explosive limit (LEL) of methane. The LEL is the minimum amount of gas by volume required to sustain combustion in air. The Federal Occupational Safety and Health Administration (OSHA) has developed a set of guidelines designed to protect workers entering confined spaces where there is the potential to be exposed to explosive gases. Specifically, the OSHA guidelines state that confined spaces should not be entered, and if occupied, should be evacuated, if flammable gases reach or exceed 25 percent of the lower explosive limit. Therefore, the 25 percent lower explosive limit is considered a health comparison value for workplace as well as residential settings.
Combustible gases (principally methane) were detected in the northern portion of the landfill (west of the landfill office) at levels ranging from 10 percent to 90 percent by volume of methane in air. These values exceeded the health comparison values (25 percent LEL). This indicates that a condition of gas entrapment, methane migration or both is present beneath the ground surface. There was an elevated gas measurement near the landfill office.
A soil gas survey was conducted at 11 locations throughout the BLS site. These locations were from the areas landfill gases were collected. A soil gas survey is often used to determine the quantity of landfill produced gases present in the spaces between soil particles. Landfill produced gases often include methane, carbon dioxide, as well as other VOCs produced during the decomposition of buried landfill waste. The sampling was conducted using probes inserted into the soil and a pump to draw the sample. Multiple samples were collected from each of the 11 locations. This represented a total of 165 samples collected throughout the BLS site. These samples were all collected by O'Brien and Gere as part of the draft work plan limited field investigation in 1992 (12). Detectable VOCs were found within the BLS site in subsurface soils (1,12). Although the survey was conducted at eleven locations, only two locations contained contaminants above health comparison values. Within these two locations seven VOCs were detected above health comparison values. Four of these samples were collected from the area on the landfill on which liquid waste was disposed. The remaining samples were collected from the metal grindings waste cell. The results of the soil gas survey are presented in Table 12.
Table 12. Soil Gas Measurements (Maximum values)
| Contaminant | Maximum Concentration (ppmv) |
| Benzene | 15.8 |
| Methyl ethyl ketone | 11.6 |
| Methyl isobutyl ketone | 183.9 |
| Toluene | 115.7 |
| trans-1,2-Dichloroethylene | 16.3 |
| Trichloroethylene | 4.9 |
| Xylenes | 10.6 |
| ppmv | parts per million by volume |
The off-site contaminant sampling included groundwater from private drinking water wells (Town Garage and private residences), sediment from the unnamed brook, the gravel pit in the Town Garage, and surface soil from adjacent residences. There was one monitoring well located off-site that was found to be contaminated with trace amounts of VOCs in 1984. Subsequent sampling did not detect further contamination.
Ground water - Private Drinking Water Wells
In 1988, a domestic well sampling program was initiated for private wells located adjacent to the Barkhamsted landfill. The wells were selected to examine the potential impacts from the landfill (13). Domestic water samples were taken from ten private drinking water wells. This was implemented as part of the recommendations presented in the Interim PHA to evaluate the impacts on residential well water from ground water contamination by BLS. There were no VOCs detected in the private wells sampled in 1990 and 1993. The contaminants detected above health comparison values and the maximum concentrations are listed in Table 13. These samples were taken in January of 1993. Antimony, arsenic, and selenium were detected in three private wells. Lead was detected in the water from five homes, although only one sample exceeded the MCL of 15 ppb.
Table 13. Private Residential Drinking Water Wells
| Contaminant | Maximum Concentration (ppb) |
Comparison Value
ppb Source |
|
| Antimony | 16.3 |
3.0 LTHA
|
|
| Arsenic | 1.4 |
0.02 CREG
|
|
| Lead | 29.2 |
15.0 MCL
|
|
| Selenium | 38.0 |
20.0 EMEG-
Child
|
|
| CREG | Cancer Risk Evaluation Guide |
| EMEG-Child | Environmental Media Evaluation Guide for Children |
| LTHA | Lifetime Health Advisory for drinking water |
| MCL | Maximum Contaminant Level |
| ppb | parts per billion |
Ground water - Barkhamsted Town Garage Well
The Barkhamsted Town Garage well was sampled by EPA (13,14) in April of 1988. Two VOCs were detected above health comparison values. The VOCs are cis-1,2-dichloroethylene and trichloroethylene. The two contaminants detected and their respective health comparison values, along with their maximum concentrations, are highlighted in Table 14.
Table 14. Barkhamsted Town Garage Well Maximum Contaminant Concentrations
| Contaminant | Maximum Concentration (ppb) |
Comparison Value
ppb Source |
|
| cis-1,2-dichloroethylene | 160 |
70 LTHA
|
|
| trichloroethylene | 52 |
3 CREG
|
|
| CREG | Cancer Risk Evaluation Guide |
| LTHA | Lifetime Health Advisory for drinking water |
| ppb | parts per billion |
Two residential properties adjacent to the site, were included in the surface soil sampling conducted at BLS. This sampling was conducted by O'Brien and Gere as part of the RI (1). The surface soil from these residences was analyzed for VOCs, SVOCs, pesticides, and metals (1). The samples were collected from the first six inches below the surface. This sample was only analyzed for VOCs. Metals, SVOCs, PCBs, and pesticides were analyzed from a sample that included the first twelve inches of soil(6). There were no VOCs, SVOCs, or pesticides detected above health comparison values in any off-site surface soil samples. Five metals were detected above health comparison values. Table 15 displays all five contaminants detected during these sampling events above health comparison values, along with the range of detected values.
Table 15. Surface soil (residential)
| Contaminant |
Concentration Range
(ppm)
Minimum Maximum |
Comparison Value
ppm Source |
||
| Arsenic |
1.5 2.5
|
0.5 CREG
|
||
| Beryllium |
0.58 0.62
|
0.2 CREG
|
||
| Chromium * |
19.2 29.4
|
10.0 RMEG-Pica
|
||
| Manganese |
379.0 387.0
|
300.0 RMEG-Pica
|
||
| Vanadium |
36.2 38.8
|
6.0 Int
EMEG-Pica
|
||
| * | Chromium(VI) health comparison values were used. |
| CREG | Cancer Risk Evaluation Guide |
| Int EMEG-Pica | Reference Dose Media Evaluation Guidelines for young children who exhibit pica behavior (placing objects in their mouth). |
| ppm | parts per million |
| RMEG-Pica | Environmental Media Evaluation Guidelines for young children who exhibit pica behavior (placing objects in their mouth). |
One leachate seep sample was collected from the gravel pit at the Town Garage. This sample was collected by O'Brien and Gere as part of the RI. Seven contaminants detected in the leachate seepage were above health comparison values. All contaminants are metals.
Table 16 illustrates the contaminants present in the leachate seep that exceeded drinking water health comparison values. This table also lists the name and concentration range of the contaminants present in the leachate seeps.
Table 16. Leachate seep (Town Garage)
| Contaminant |
Concentration Range
(ppb)
Minimum Maximum |
|
| Arsenic |
ND 5.5
|
|
| Barium |
2,790 3,620
|
|
| Lead |
111 197
|
|
| Manganese |
27,300 52,900
|
|
| Silver |
ND 127
|
|
| Thallium |
ND 55.4
|
|
| Vanadium |
182 242
|
|
| ND | None detected |
| ppb | parts per billion |
Sediment Sampling from the Unnamed Brook
Sediment sampling was conducted at each surface water location. A total of sixteen sediment samples were collected from Beaver Pond, the unnamed brook, an unnamed pond, and two sedimentation basins. The samples were collected in two phases. The first phase was conducted from October 29, 1992 through December 11, 1992. The second phase was conducted from September 29, 1993 through October 7, 1993. All samples were collected by O'Brien and Gere as part of the RI (1). The samples were selected to determine the concentrations in the sediment below the surface water located upgradient, adjacent, and downgradient of the landfill. The results of the sediment sampling indicates that there were no VOCs detected above health comparison values. There were nine contaminants known as PAHs detected in the sediment. These contaminants were grouped by carcinogenic classification, (either probable human carcinogens or not classified). Three metals were detected in the sediment above health comparison values. Tables 17, 18, and 19 lists the range of contaminants detected in the sediment.
Table 17. Non-Carcinogenic PAHs Detected in Sediment from the Unnamed Brook
| Chemical name |
Concentration Range
(ppm)
Minimum Maximum |
Comparison Value
ppm Source |
EPA Group | ||
| Acenaphthylene |
ND 0.17
|
# #
|
not classified | ||
| Benzo(g,h,i)perylene |
ND 0.34
|
# #
|
not classified | ||
| Naphthalene |
ND 0.019
|
# #
|
not classified | ||
| Phenanthrene |
ND 0.73
|
# #
|
not classified | ||
| Total non-carcinogenic PAHs |
1.26
|
|
|||
| # | There are no health comparison values for these compounds |
| ND | None detected |
| ppm | parts per million |
Table 18. Carcinogenic PAHs Detected in Sediment from the
Unnamed Brook
| Chemical name |
Concentration Range
(ppm)
Minimum Maximum |
Comparison Value
ppm Source |
EPA Group |
||
| Benzo(a)anthracene |
ND 0.67
|
# #
|
B2 | ||
| Benzo(a)pyrene |
ND 0.85
|
0.1 CREG
|
B2 | ||
| Benzo(b)fluoranthene |
ND 2.1
|
# #
|
B2 | ||
| Chrysene |
ND 0.68
|
# #
|
B2 | ||
| Indeno(1,2,3,-c,d)pyrene |
ND 0.33
|
# #
|
B2 | ||
| # | There are no health comparison values for these compounds |
| B2 | Probable human carcinogen |
| CREG | Cancer Risk Evaluation Guideline |
| ND | None detected |
| ppm | parts per million |
Table 19. Metals Detected in Sediment from the Unnamed
Brook
| Chemical name |
Concentration Range
(ppm)
Minimum Maximum |
Comparison Value
ppm Source |
||
| Arsenic |
ND 5.8
|
0.5 CREG
|
||
| Beryllium |
ND 2
|
0.2 CREG
|
||
| Manganese |
53.3 9,450
|
7,000 RMEG-Child
|
||
| CREG | Cancer Risk Evaluation Guideline |
| ND | None detected |
| ppm | parts per million |
| RMEG-Child | Reference Dose Media Evaluation Guide for Children |
C. QUALITY ASSURANCE AND QUALITY CONTROL
The consulting firm conducting the RI was monitored by EPA oversight personnel, both in field and laboratory procedures. However, the procedures used by these firms or other consultants who have conducted historic sampling at the site were not evaluated by the Connecticut Department of Public Health. Therefore, the conclusions drawn for this health assessment were determined by the availability and reliability of the referenced information and it is assumed that adequate quality assurance and quality control measures were followed with regard to chain of custody, laboratory procedures and data reporting.
To identify possible facilities that could contribute to contamination near the site, the Toxic Release Inventory (TRI) was searched for the years: 1987 - 1994. The toxics release inventory contains information on total releases of certain chemicals from certain industries. The toxics release inventory does not identify all facilities which may have in the past or may currently be contributing to contamination near the site. There were no releases reported in Barkhamsted, CT, for the years 1987 - 1994.
To determine whether nearby residents have been or are being exposed to contaminants migrating from the site, the CT DPH and the ATSDR evaluate the environmental contamination and human exposure and an exposed population. The pathway analysis consists of five elements: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population. The exposure pathways discussed here are air, ground water, soil, and sediment. The ATSDR categorizes exposure pathways as either completed or potential pathways. For an exposure pathway to be completed all five elements of the pathway must be present. Potential pathways are those where there is not sufficient evidence to show that all the elements are present now, could be present in the future, or were present in the past.
The exposure pathways are presented in Table 20. This table lists the pathway name, source of contamination, environmental media, point of exposure, route of exposure, population at risk of exposure and pathway status and time frame.
| Pathway Name | Exposure Pathway Elements | Pathway Status and Time Frame | ||||
| Source | Environmental Media | Point of Exposure | Route of Exposure | Population at risk of Exposure | ||
| Groundwater landfill office well | BLS | water | landfill office well | ingestion | workers | completed past |
| Groundwater Town Garage well | BLS | water | Town Garage well | ingestion | workers | completed past |
| Groundwater As, Sb, Se: private residential wells | BLS or naturally occurring | water | private well | ingestion (As, Sb, Se) dermal |
residents children adults |
completed past present potential future |
| Groundwater Pb: private residential wells |
Plumbing | water | private well | ingestion | residents children adults |
completed past present potential future |
| Surface soil: off-site Private yards |
Contaminants on BLS were also present on the off-site residences | soil | off-site exposed surface soil residential yards |
ingestion dermal |
pica children children adults |
completed past present potential future |
| Surface soil: on-site | BLS | soil | on-site exposed surface soil | ingestion dermal |
workers trespassers |
potential past present future |
| Sediment: off-site |
BLS | sediment | off-site sediment | ingestion dermal |
children adults |
potential past present future |
| Sediment: on-site |
BLS | sediment | on-site sediment | ingestion dermal |
workers trespassers |
potential past |
| Ambient Air: on-site |
BLS | air | on-site- center of landfill | inhalation | workers trespassers |
potential present future |
| Indoor Air of Landfill Office | BLS | air | landfill office | explosion hazard | workers | potential present future |
| Subsurface soil Surface soil in Town Garage Gravel Pit | BLS | soil | Town Garage gravel pit | ingestion dermal |
workers trespassers |
potential present future |
A. COMPLETED EXPOSURE PATHWAYS
Ground Water - Landfill Office
People who drank or used water from the contaminated well servicing the landfill office were exposed to volatile organic compounds and metals. These exposures ceased after the contaminated well was shut down. The exposures may have included ingestion, dermal absorption and/or inhalation of VOCs, and ingestion of metals. People drank or used water from the landfill office well were exposed to contaminated water for up to four years from 1980 to 1984.
Ground Water - Town Garage Well
People who drank or used water from the Barkhamsted Town Garage well were exposed to contaminated water for up to four years from 1986 to 1990. The Barkhamsted Town Garage well water was contaminated with volatile organic compounds. The exposures may have included ingestion, dermal absorption and/or inhalation of VOCs.
Ground Water - Off-Site Private Wells
People who drink or use water from three private residential wells are currently exposed to antinomy, arsenic, and selenium. Exposures may occur through ingestion and skin contact (arsenic) with contaminated water.
Ground Water - Off-Site Private Wells (continued)
People who drink or use water from five private residential wells are currently exposed to lead. Exposures may occur through ingestion of the contaminated water.
Surficial Soil -Off-Site Private Residences
Residents of two properties adjacent to the landfill may have in the past and may now be receiving
exposure to contaminated soil via ingestion and dermal absorption. Inhalation of airborne soil
particles is a possible route of exposure, however, the CT DPH lacks sufficient information to
characterize this exposure scenario. The CT DPH does not know whether there are any young
children who often place objects in their mouths (pica behavior) living at either residence.
However, these sensitive populations were examined in detail in the Toxicological Evaluation Section.
B. POTENTIAL EXPOSURE PATHWAYS
Exposures to contaminated soils may occur to individuals who work at the landfill. The exposures may include ingestion and dermal absorption of contaminants from soil. These exposure routes may occur particularly if the soil is disturbed during excavation for landscaping, construction, or road work purposes. Trespassers may gain access to areas within the Barkhamsted Landfill that are contaminated. Inhalation of airborne soil particles is also a possible route of exposure, however, the CT DPH lacks sufficient information to characterize this exposure scenario.
Surficial Soil - Off-site Town Garage
Workers at the Town Garage gravel pit may have in the past, and may now be receiving exposure to contaminated soil via ingestion and dermal absorption. Inhalation of airborne soil particles is a possible route of exposure, however, the CT DPH lacks sufficient information to characterize this exposure scenario.
One seepage location was identified in the gravel pit during the remedial investigation. However, during the 1994 site visit representatives of the CT DPH and CT DEP identified another area of discoloration that may indicate a seepage zone that was inactive during the identification phase of the remedial investigation. Because this is an active sand and gravel pit, the CT DPH considers exposure to surface soil possible. Moreover, the CT DEP expressed concerns about leachate contaminated soil in the gravel pit in a correspondence (15) to the First Selectman of the Town of Barkhamsted. This concern is also shared by the CT DPH as a potential exposure route to leachate contaminated surface soil in the gravel pit. Specifically, excavation activities at the gravel pit may expose workers as well as trespassers who enter the gravel pit. Sand and gravel at the gravel pit adjacent to the BLS have been excavated since 1981 (16). Apparently, this activity will continue, and areas excavated may include those currently contaminated with leachate.
Sediment -Unnamed Brook (sections of this brook are both on-site and off-site)
Exposure to sediment may occur to older children and adults who come in contact with the sediment of the Unnamed Brook. Older children may wade in water and contact the contaminated sediment. However, in order for an older child or adults to access the Unnamed Brook, one would have to travel across a busy high speed road (Route 44), walk down a steep gradient (thirty feet), and then travel through a heavily wooded area. These three factors suggest that access and exposure are unlikely. Children may, however, access the discharge point of the Unnamed Brook located directly east of Route 44 after passing underneath the road.
Exposure to leachate and sediment may occur to workers and older children who trespass on the site. Exposure may occur through direct skin contact, and potential incidental ingestion.
Physical Hazard - On-site Landfill Office: Methane Gas
Present and future physical hazard exposures are possible for methane gas on-site. Methane gas may accumulate in enclosed structures on-site and lead to an explosion or fire hazard.
Present and future inhalation exposures are possible to landfill workers and trespassers who enter the center of the landfill where elevated VOCs were measured.
Completed and potential exposure pathways have been identified for the groundwater, and soil pathways. In this section, the potential health effects associated with exposure to contaminants of concern will be discussed.
To evaluate health effects, the ATSDR has developed Minimal Risk Levels (MRLs) for contaminants commonly detected at hazardous waste sites. The MRL is an estimate of daily human exposure to a contaminant below which non-cancerous, adverse health effects are unlikely to occur. MRLs are developed for each route of exposure such as ingestion, inhalation, and dermal absorption. MRLs are also developed for the length of exposure, such as acute (less than 15 days), intermediate (15 to 364 days), and chronic (greater than 364 days).
We used ATSDR Toxicological Profiles in our review of the potential health effects associated with site contaminants. The ATSDR Toxicological Profiles are chemical-specific reports that provide information on health effects, environmental transport and human exposures (17, 18, 19, 20, 21, 23, 25, 27).
Exposure Assumptions
The exposure pathways examined in the following section include the incidental ingestion of contaminated soil for young children, ages 1 to 3 years old, who often place objects in their mouth (5,000 mg soil per day), older children over 3 years old, who do not place objects in their mouth (200 mg soil per day), and adults (100 mg soil per day). Additionally, dermal absorption of contaminants from soil adhering to the skin was examined for children.
The exposure pathways also included ingestion of drinking water. The daily drinking water consumption rates are one liter (about one quart) for children, and two liters (about two quarts) for adults.
An exposure dose calculated for adults and children is commonly represented as an amount of contaminant per body weight per day. The contaminant is often listed in milligrams(8) (mg). The body weight is often listed as kilograms(9) (kg). The quantity of contaminant per quantity of body weight per day is thus written as follows: mg/kg/day. This number is defined as an ingestion exposure. These values are then compared to a minimal risk level (MRL). When an MRL is unavailable the comparison is often to a reference dose (RfD). The RfD is an estimated daily intake of a chemical that is likely to be without an appreciable risk of health effects, and has been developed by the EPA.
Residential Soil Exposure Route:
Since the soil collected from the residences adjacent to the landfill was analyzed for metals,
pesticides, and PCBs from a combined sample of the first twelve inches below the surface, the
concentrations may have underestimated the actual contaminant concentrations. This
underestimation would have occurred if contaminants were located in the first three or six inches of soil.
Non-cancerous Effects - Residential Well
Non-cancerous health effects determination was based on the highest antimony concentration.
We assume that adults drink two liters (about two quarts) of tap water each day, and weigh 70 kg
(154 pounds) and children drink one liter (about one quart) of tap water each day, and weigh 10
kg (22 pounds). Using the highest antimony concentration detected (16.3 ppb) the ingestion
exposures were calculated for adults (0.00047 mg/kg/day) and children (0.0016 mg/kg/day).
Since there is no chronic MRL, the calculated dose has been compared to a reference dose. Using
the RfD (0.0004 mg/kg/day) as a comparison the non-carcinogenic health risks for an adult
exposed to antimony may be characterized as minimal. Although the exposure dose for children
exceeded the RfD, the EPA has established a longer-term health advisory for children. The
longer-term health advisory is a concentration that children could be exposed to for up to seven
years without any adverse health effects. Since the EPA longer-term health advisory was not
exceeded, non-cancerous adverse health effects are also considered minimal for children who
drank water contaminated with antimony at the maximum concentration for up to seven years.
Exposures beyond seven years may represent a low increased risk of non-carcinogenic health
effects in children.
Carcinogenicity Classification:
Antimony has not been classified by the EPA regarding its carcinogenicity. Consequently, we
were unable to estimate cancer risks for children or adults.
Brief Description of Chemical:
Antimony is a naturally-occurring metal that is silvery white. Antimony is present in small
quantities in the earth's crust. This element is mixed with other metals such as lead and zinc to
increase the strength of the resultant metal alloy. These alloys have many uses including: lead
storage batteries, solder, sheet metal, castings, and pewter. Antimony oxide is mixed with textiles and plastics as a fire retardant (17).
Non-cancerous Effects - Drinking Water
Using the highest arsenic concentration detected in private well water (1.4 ppb) the ingestion
exposures were calculated for adults (0.00004 mg/kg/day) and children (0.00014 mg/kg/day).
These exposure levels are below the chronic MRL of 0.0003 mg/kg/day. Consequently,
non-cancerous adverse health effects may be characterized as minimal for persons who consumed arsenic contaminated water for more than one year at this concentration.
Non-cancerous Effects - Soil (Pica Children(10))
Exposures to arsenic may have occurred in the past and could be occurring presently to residents
who contact and ingest arsenic contaminated surface soil in two off-site residential locations.
Using the highest arsenic concentration detected off-site in surface soil (2.5 ppm) the ingestion
exposure was calculated for pica children. Pica children are children one to three years old who
often place objects in their mouth. They represent the population of greatest risk of exposure to
contaminated surface soil. The exposure dose calculated for pica children was 0.0013 mg/kg/day
and exceeds the chronic MRL of 0.0003 mg/kg/day. Chronic ingestion studies in humans exposed
to arsenic identified skin effects at elevated levels. Those levels were higher than the levels found
here at the off-site residential locations. Consequently, the occurance of non-cancerous health
effects in the pica child is low. Since non-cancerous health effects are characterized as low for
pica children, they are minimal for older children and adults.
Non-cancerous Effects - Sediment from Unnamed Brook & Leachate Seeps (Older
Children and Adults)
Exposures to arsenic may have occurred in the past, and could be occurring presently to older
children and adults who come in contact with arsenic contaminated sediment in either the
Unnamed Brook or the leachate seeps. Using the highest arsenic concentration detected in the
sediment (5.8 ppm) the ingestion exposure was calculated for older children (0.0000038
mg/kg/day) and adults (0.0000022 mg/kg/day). Both are below the chronic MRL of 0.0003
mg/kg/day. Consequently, non-cancerous adverse health effects may be characterized as minimal
for older children and adults who are exposed to arsenic contaminated sediment in the Unnamed
Brook at this concentration.
Carcinogenicity Classification: drinking water
Arsenic has been classified by the EPA as a known human carcinogen (EPA group A). When
people are exposed to high levels of arsenic through drinking water over extended durations
(many years), there is an increased risk for developing skin cancer. The cancer risk estimates
using the highest arsenic concentration detected off-site (1.4 ppb) for children and adults for a 20 year period indicate that there is no apparent increased risk for developing skin cancer.
Carcinogenicity Classification: Soil
The cancer risk estimates using the highest arsenic concentration detected in the surface soil of
off-site residential locations (2.5 ppm) for pica children, older children, and adults for a 20 year
period indicate that there is an insignificant risk for developing skin cancer.
Background Levels Measured in Soil
The average background level of arsenic in soils located in the eastern United States is 4.8 ppm
(29). Although the residential soil samples were obtained from the first twelve inches of soil, and
therefore may have underestimated the actual arsenic concentration if the arsenic was in the first
six inches of soil, a comparison with the background level indicates that the detected
concentrations (1.5 ppm to 2.5 ppm) may be within normal background levels in eastern United
States.
Carcinogenicity Classification: combined estimation for soil and drinking water
Cancer risk estimates were calculated using the highest arsenic concentration detected in the
surface soil of off-site residential locations (2.5 ppm) and the highest detected level in a private
drinking water well (1.4 ppb). The CT DPH calculated a combined cancer risk estimation for a
child exposed to arsenic in the drinking water year round, and exposed to arsenic in the surface
soil for a maximum of 20 years. The results indicate that there is no apparent risk for developing
skin cancer from the combined exposure to water and surface soil.
Carcinogenicity Classification: Sediment from the Unnamed Brook and Leachate Seeps
The cancer risk estimates using the highest arsenic concentration detected in the sediment (5.8
ppm) for older children for a 15 year period indicate that there is no apparent increased risk for
developing skin cancer.
Brief Description of Chemical:
Inorganic arsenic is used mainly to preserve wood and formulating insecticides and weed killers.
Inorganic arsenic is a naturally-occurring element found in higher concentrations in the bedrock in some areas within Connecticut.
Carcinogenicity Classification:
Benzene has been classified by the EPA as a known human carcinogen (EPA group A). The
cancer risks were calculated for employees who drank from the landfill office well contaminated
with benzene. We used the maximum benzene concentration (2 ppb), and conclude that there is an insignificant risk for developing cancer for the four years of potential exposure.
Brief Description of Chemical:
Benzene is a colorless liquid with a sweet odor. This compound dissolves in water easily and
evaporates readily into the air. Benzene is a highly flammable liquid and is a component of gasoline (18).
Non-cancerous Effects - Soil (Pica Children)
Exposures to beryllium may have occurred in the past, and could be occurring presently to
residents who contact and ingest beryllium contaminated surface soil in two off-site residential
locations. Using the highest beryllium concentration detected off-site in surface soil (0.62 ppm)
the ingestion exposure was calculated for pica children (0.0003 mg/kg/day). Pica children are at greatest risk of exposure to contaminated surface soil. Since there is no chronic MRL, the
calculated dose from the maximal concentration of 0.62 ppm has been compared to a reference
dose. Using the RfD (0.005 mg/kg/day) as a comparison the non-carcinogenic health risks for
pica children exposed to beryllium may be characterized as minimal. Since non-cancerous health
effects are minimal for pica children, they are also minimal for older children and adults.
Non-cancerous Effects - Sediment from Unnamed Brook & Leachate Seeps (Older
Children and Adults)
Exposures to beryllium may have occurred in the past, and could be occurring presently to older
children and adults who contact contaminated sediment. Using the highest beryllium concentration
detected (2 ppm) the ingestion exposure was calculated for children (0.0000013 mg/kg/day), and
adults (0.0000007 mg/kg/day). Using the RfD (0.005 mg/kg/day) as a comparison the
non-carcinogenic health risks for older children and adults exposed to beryllium in the sediment of
the Unnamed Brook may be characterized as minimal.
Carcinogenicity Classification - Soil
Beryllium has been classified by the EPA as a probable human carcinogen (EPA group B2). The
cancer risk estimates using the highest beryllium concentration detected in off-site surface soil
(0.62 ppm) for pica children, older children, and adults for a 20 year period indicate that there is
no apparent risk for developing cancer.
Carcinogenicity Classification: Sediment from the Unnamed Brook and Leachate Seeps
The cancer risk estimates using the highest beryllium concentration detected in the sediment (2
ppm) for older children for a 15 year period indicate that there is no apparent risk for developing
cancer.
Background Levels Measured in Soil
The average background level of beryllium in soils located in the eastern United States is 0.55
ppm (29). Although the residential soil samples were obtained from the first twelve inches of soil,
and therefore may have underestimated the actual beryllium concentration if the beryllium was in
the first six inches of soil, a comparison with the background level indicates that the detected
concentrations (0.58 ppm to 0.62 ppm) may be within normal background levels in eastern
United States.
Brief Description of Chemical
Beryllium is a mineral that is found in rocks, coal, oil, soil, and volcanic dust (19). Beryllium is
found in the gemstone quality mineral known as beryl. Beryllium does not have any particular
odor. Combustion of coal and fuel oil releases compounds containing beryllium into the
atmosphere (19).
Non-cancerous Effects - Soil (Pica Children)
Exposures to chromium in soil may have occurred in the past, and could be occurring presently to
residents who contact and ingest chromium contaminated surface soil in two off-site residential
locations. Using the highest chromium concentration detected (29.4 ppm) the ingestion exposure
was calculated for pica children (0.015 mg/kg/day). Since there is no chronic MRL, the calculated
dose has been compared to a reference dose. The RfD is 0.005 mg/kg/day. This value was
exceeded. However, at this exposure level it is not expected that health effects would occur. The
occurance of non-carcinogenic health effects would be characterized a low. This was based upon
a continuous daily exposure. However, if the exposure were not continuous, perhaps twice a
week, the ingestion exposure would then be 0.004 mg/kg/day. In addition, we assumed the most
toxic form of chromium was present making the estimate even more conservative. The risks of
non-carcinogenic health effects would then be characterized a minimal. Pica children are the most sensitive population potentially exposed. Since non-cancerous health effects are minimal for pica children, they are also minimal for older children and adults.
Carcinogenicity Classification:
Chromium(VI) has been classified by the EPA as a known human carcinogen (EPA group A) only via inhalation. However, there is insufficient information to determine cancer risk estimations for individual's exposure through inhalation of chromium in contaminated soil.
Background Levels Measured in Soil
The average background level of chromium in soils located in the eastern United States is 33 ppm
(29). Although the residential soil samples were obtained from the first twelve inches of soil, and
therefore may have underestimated the actual chromium concentration if the chromium was only
in the first six inches of soil, a comparison with the background level indicates that detected
concentrations (19.2 ppm to 29.4 ppm) may be within normal background levels in eastern
United States.
Brief description:
Chromium is an element that occurs naturally in rocks and soil. This element exists in several different forms, chromium(0), chromium(III), and chromium(VI). None of these forms have any known taste or odor. Chromium compounds are used for chrome plating, the manufacture of dyes, and in wood preservatives (20).
Carcinogenicity Classification:
There is insufficient information regarding human carcinogenicity for cis-1,2-dichloroethylene.
Brief Description of Chemical:
cis-1,2-Dichloroethylene is a flammable, colorless liquid with a pungent odor. This compound is
man-made, and has no natural sources. cis-1,2-Dichloroethylene is a breakdown product of trichloroethylene and tetrachloroethylene.
The lead detected in the private drinking water is probably due to lead plumbing fixtures in individual homes and is unlikely to be site-related. Although not likely to cause adverse health effects alone, long term exposure to lead in drinking water could contribute significantly to the overall body burden of lead. This could increase the lead exposure in individuals at risk for lead toxicity due to other sources (lead-based paint, food, and soil). Children under the age of six are at greatest risk for lead poisoning.
Studies indicate that long term exposure to low levels of lead can cause brain damage and lowered Intelligence Quotient (I.Q.). Lead exposure can increase blood pressure in middle-aged men. If a pregnant women is exposed to lead in drinking water it can be carried to the unborn child and may have an adverse effect on the mental development of the fetus.
Carcinogenicity Classification:
Lead has been classified by the EPA as a probable human carcinogen (EPA group B2). There is
insufficient information to calculate cancer risk estimates for individuals potentially exposed to lead in contaminated drinking water.
Brief Description of Chemical:
Lead is a naturally occurring gray metal detected in small quantities in the earth's crust. This
compound has no taste or odor. Lead is used in the manufacture of batteries and in lead solder.
However, as of 1986, the U.S. Congress banned the use of lead solder containing more than 0.2
percent lead. When water stays in pipes containing lead or lead containing plumbing systems for
several hours the lead in the pipes or solder may dissolve into the drinking water(11).
Non-cancerous effects- Landfill Office Drinking Water Well
Exposure to manganese occurred in the past to persons who drank from the contaminated landfill
office well for as long as four years. The maximum concentration detected was 14,000 ppb. Since
there is no chronic MRL, the calculated dose from the maximal concentration of 14,000 ppb has
been compared to a reference dose. Using the highest manganese concentration detected in the
landfill office well (14,000 ppb), an ingestion exposure was calculated for adults (0.27
mg/kg/day). The risks of developing health effects for adults may be characterized as low.
Non-cancerous Effects - Surface Soil
Exposures to manganese may have occurred in the past, and could be occurring presently to
residents who contact and ingest manganese contaminated surface soil in two off-site residential
locations. The maximum concentration detected was 387 ppm. Since there is no chronic MRL,
the calculated dose from the maximal concentration of 387 ppm has been compared to a reference
dose. Using the highest manganese concentration detected in the surface soil (387 ppm), the
ingestion exposures were calculated for pica children (0.194 mg/kg/day). Pica children are the
most sensitive population potentially exposed. The RfD for manganese is 0.14 mg/kg/day.
Although this value exceeds the RfD, the occurance of non-cancerous effects may be
characterized as low in pica children exposed to manganese contaminated surface soil. Since the
occurance of non-cancerous health effects are low for pica children, they may be classified as
minimal for older children and adults.
Non-cancerous Effects - Sediment from the Unnamed Brook (Older Children and Adults)
Exposures to manganese may have occurred in the past, and could be occurring presently to older
children and adults who contact manganese contaminated sediment in the Unnamed Brook. Using
the highest manganese concentration detected (9,450 ppm) the ingestion exposure was calculated
for older children (0.0062 mg/kg/day), and adults (0.0035 mg/kg/day). Using the RfD (0.14
mg/kg/day) as a comparison, the non-carcinogenic health risks for older children and adults
exposed to manganese in the surface soil may be characterized as minimal.
Background Levels Measured in Soil
The average background level of manganese in soils located in the eastern United States is 260
ppm (29). Since the residential soil samples were obtained from the first twelve inches of soil, the
actual manganese concentration may have been underestimated. The concentration of manganese
was slightly higher than background levels measured in the eastern United States.
Carcinogenicity Classification:
Manganese is not currently classified by the EPA regarding its carcinogenicity.
Brief Description of Chemical:
Manganese is a naturally occurring compound detected in many rock formations. This element is
similar in chemical and physical properties to iron. Manganese has numerous industrial uses
including the formation of batteries and ceramics (21).
Methyl chloride (chloromethane)
Carcinogenicity Classification:
Methyl chloride is not currently classified by the EPA regarding its carcinogenicity.
Brief Description of Chemical:
Methyl chloride is a colorless gas, that has a faintly sweet odor. This naturally occurring chemical
is produced in large quantities in the ocean. This is also produced by rotting wood and by some
plants. When grass, wood, charcoal, or coal are burnt this chemical is produced. Methyl chloride
is used in industry to make other compounds such as: agricultural chemicals, butyl rubber, and silicones (23).
Non-cancerous Effects - Sediment from Unnamed Brook & Leachate Seeps (Older
Children and Adults)
Using the combined non-carcinogenic PAH concentration (1.26 ppm), the ingestion exposure was
calculated for older children (0.00003 mg/kg/day) and adults (0.00002 mg/kg/day).
Non-carcinogenic PAHs do not have a health comparison value. However, naphthalene, one of
the non-carcinogenic PAHs does have an RfD. Consequently, the non-carcinogenic PAHs were
compared as an aggregate to that RfD. The combined value does not exceed the RfD for
naphthalene (0.004 mg/kg/day). Therefore non-carcinogenic health effects for older children or
adults exposed to non-carcinogenic PAHs in sediment may be characterized as minimal.
Carcinogenicity Classification:
Benzo(a)pyrene (BaP) has been classified by the EPA as a possible human carcinogen. This was
the only PAH detected in any sediment sample. BaP is the only carcinogenic PAH for which there
is carcinogenic risk information. Since BaP is also the most toxic PAH, the remaining
carcinogenic PAHs were converted into BaP equivalents. To reach the BaP equivalent values,
each concentration was multiplied by a value. This value incorporates the potency of each
compound relative to BaP. For example, if one compound is ten times less toxic than BaP, then
the concentration of that compound was multiplied by 0.10.
Carcinogenicity Classification: Sediment from the Unnamed Brook and Leachate Seeps
Cancer risk estimations were based on the combined maximum carcinogenic sediment PAH
concentration from table 21 (1.15 ppm). The cancer risk estimations indicate that there is a low
increased risk of developing cancer among children or adults who contact the contaminated
sediment over a period of 15 years. The CT DPH does not consider this a likely exposure
scenario. Cancer risk estimations were based on worst case exposure scenarios. The actual cancer risk is likely to be lower.
Table 21. Calculations for Carcinogenic PAHs Detected in Sediment From the Unnamed Brook
| Chemical name |
Concentration Range
(ppm)
Minimum Maximum |
BaP relative potency |
Concentration based
on BaP relative potency (ppm) |
|
| Benzo(a)anthracene |
ND 0.67
|
0.1
|
0.067 | |
| Benzo(a)pyrene |
ND 0.85
|
1.0
|
0.85 | |
| Benzo(b)fluoranthene |
ND 2.1
|
0.1
|
0.2 | |
| Chrysene |
ND 0.68
|
0.001
|
0.0007 | |
| Indeno(1,2,3,-c,d)pyrene |
ND 0.33
|
0.1
|
0.0330 | |
|
Total carcinogenic PAHs
(equivalent to BaP)
|
1.1507 | |||
| ND | None detected |
| ppm | parts per million |
Carcinogenicity Classification:
Selenium has not been classified as a human carcinogen.
Brief Description of Chemical:
Selenium is a naturally occurring element distributed throughout the earth's crust. Selenium is an essential nutrient for both humans and animals.
Carcinogenicity Classification:
PCE was classified as a probable human carcinogen (EPA group B2). Currently, however, this
classification has been withdrawn, and a review of this compound is being conducted by the EPA
(24). Although the review is not yet complete, cancer risks were calculated for adults using
available information from the Environmental Criteria and Assessment Office of the U.S. EPA
(Superfund Technical Support Center). The longest exposure duration to PCE was four years.
Consequently, this value was utilized in cancer risk calculations.
The estimated cancer risks were calculated using the highest PCE concentration detected (1 ppb). The cancer risk estimates calculated for a four year period indicate that there is an insignificant risk for developing cancer.
Brief Description of Chemical:
PCE is a synthetic compound used as a metal degreaser and fabric dry cleaner. PCE is a
nonflammable liquid with a sweet odor. There are no natural sources of PCE.
Carcinogenicity Classification:
TCE was classified as a probable human carcinogen (EPA group B2). Currently, however, this
classification has been withdrawn, and a review of this compound is being conducted by the EPA
(24). Although the review is not yet complete, we calculated cancer risks for adults using
available information from the Environmental Criteria and Assessment Office of the U.S. EPA
(Superfund Technical Support Center). The longest period of time adults may have been exposed
to TCE is four years. Consequently, we utilized this value in our estimates. The cancer risks
listed below, were based on worst case scenarios.
These calculations were based on the maximum concentration of TCE detected, 52 ppb. On the basis of our conservative estimates, persons who drank water containing TCE at the maximum concentration detected in the Barkhamsted Town Garage well of 52 ppb for up to four years, have an insignificant increased risk for developing cancer.
Brief Description of Chemical:
TCE is a non-flammable liquid that has a sweet odor. This man-made compound is not detected
naturally in the environment. TCE is used as a metal degreaser, paint thinner, spot remover and in the manufacture of adhesives.
Non-cancerous Effects - Surface Soil
Exposures to vanadium may have occurred in the past, and could be occurring presently to
residents who contact and ingest vanadium contaminated surface soil in two off-site residential
locations. The maximum concentration detected was 38.8 ppm. Since there is no chronic MRL,
the calculated dose from the maximal concentration of 38.8 ppm has been compared to the
intermediate MRL (0.003 mg/kg/day). Using the highest vanadium concentration detected in the
surface soil (38.8 ppm), the ingestion exposure was calculated for pica children (0.02 mg/kg/day).
This value exceeded the intermediate MRL. However, the highest value reported in the scientific
literature at which there were no adverse health effects for an intermediate human exposures was
1.3 mg/kg/day. Consequently, non-cancerous effects are characterized as minimal in pica children
exposed to vanadium contaminated surface soil for up to one year. Since non-cancerous health
effects are minimal for pica children, they are also minimal for older children and adults.
Background Levels Measured in Soil
The average background level of vanadium in soils located in the eastern United States is 43 ppm
(28). Although the residential soil samples were obtained from the first twelve inches of soil, and
therefore may have underestimated the actual vanadium concentration if the vanadium was in the
first six inches of soil, a comparison with the background level indicates that the detected
concentrations (36.2 ppm to 38.8 ppm) may be within normal background levels in eastern
United States.
Carcinogenicity Classification:
Vanadium is not currently classified by the EPA regarding its carcinogenicity. Consequently, no
cancer risk estimations were calculated.
Brief Description of Chemical:
Vanadium is a naturally occurring element and is found in the earth's crust. This metal is white or
gray, and is often found in crystal formations. Vanadium is released into the environment when
fuel is burned. In addition, when rocks that contain vanadium are weathered, some vanadium dust
may enter the air. Vanadium is used in the production of rubber, plastics, and ceramics (25).
B. EVALUATION OF COMMUNITY HEALTH CONCERNS
| Area residents had complained of odors in the past. |
Evaluation of the contaminants present in the ambient air indicated that the only contaminants detected above health comparison values were sampled from the center of the landfill and from two sections near the Unnamed Brook. There were no exceedences near adjacent residences. There is no historical air data to assess what may have caused the odor complaints in the past.
| A resident complained of contaminants migrating off the site causing damage to his fruit trees. |
We are unable to determine whether contaminants present in the soil would harm fruit trees or other vegetation. However, the contaminants detected in the soil of the two residences indicated that the soil pathway represents no apparent public health hazard to people who come in contact with the soil.
| One citizen expressed concern that the contaminated plume may reach a school. |
There is no indication that the contaminated plume has reached any nearby school (approximately 2 miles north of the landfill). The private well monitoring program is designed to detect plume migration.
| Concern was raised about runoff coming through a resident's property and a resident was distressed about a cancer diagnosis. |
We examined the soil contamination on the two residences adjacent to the landfill. The levels of contaminants measured in the soil represent no apparent public health hazard. In addition, there were no carcinogenic contaminants detected above a level of concern in the adjacent residences' soil or well water.
| One resident reported dizziness and loss of balance in their spouse. In addition, that resident reported having occasional severe diarrhea. The diarrhea was also noted in the spouse and an in-law. |
The concentrations of contaminants detected in either the residential surface soil or private well water are not anticipated to lead to the reported illnesses.
1. Comparison values for health assessments are contaminant concentrations in specific media that are used to select contaminants for further evaluation. These values include Environmental Media Evaluation Guides (EMEGs), Cancer Risk Evaluation Guides (CREGs), and other relevant guidelines. EMEGs are calculated from Minimal Risk Levels (MRLs). An MRL is an estimate of daily human exposure to a chemical that is likely to be without appreciable risk of an adverse, non-carcinogenic risk. CREGs are estimated contaminant concentrations based on one excess cancer in a million people similarly exposed over a lifetime. Reference Dose Media Evaluation Guides (RMEGs) are used when EMEGs or CREGs are not available for a specific medium. RMEGs are calculated from the EPA Reference Dose (RfD) which are estimates of the daily exposure to a contaminant that is unlikely to cause adverse health effects. A concentration is calculated from RfDs making certain assumptions about human intake of water or ambient air. Maximum Contaminant Levels (MCLs) represent concentrations that the EPA deems protective of public health (considering the availability and economics of water treatment technology) over a 70 year period of exposure drinking two liters (0.53 gallons) of water per day. A Lifetime Health Advisory (LTHA) is a concentration the EPA has determined to be without public health risk over a lifetime at an exposure rate of two liters of water per day.
2. Aquifers are water bearing geologic features such as rock formations and areas of unconsolidated soils.
3. Overburden consists of loose material including rock fragments, clay, sand, and other materials above the more solid bedrock formations.
4. SVOCs are like volatile organic compounds in their chemical composition, but SVOCs do not evaporate as fast at common temperatures we encounter every day. These compounds are therefore less mobile.
5. ug/L represents a concentration of a compound in micrograms (one millionth of a gram) per liter of liquid.
6. If non-VOC contaminants were located near the surface (from 0 to 3 inches), then this analysis of the first twelve inches of soil would have underestimated the actual concentrations of contaminants.
7. The groundwater plume which contains VOCs has been characterized, and does not extend to these wells. The groundwater plume which contains metals has not been characterized. Consequently, the metals detected in the private wells may be the result of landfill contamination or a natural source unrelated to the landfill.
8. There are one thousand milligrams in one gram.
9. One kg equals one thousand grams.
10. Children one to three years old who often place objects in their mouths are referred to as pica children.
11. Lead enters drinking water primarily as a result of the corrosion (i.e., wearing away) of lead-containing materials in the household plumbing. These materials include lead-based solders used to connect copper pipe and brass and chrome-plated brass faucets. In 1986, the U.S. Congress banned the use of lead solder containing greater than 0.2% lead, and restricted the lead content of faucets, pipes and other plumbing materials to 8%. You may reduce the concentration of lead in your water by flushing your household plumbing. To flush, let the water run until the water gets noticeably colder, usually about 15 to 30 seconds. You may want to repeat this procedure any time the water in a faucet has gone unused for more than six hours. Additionally, you may want to avoid cooking with, or drinking water from the hot water tap. Hot water dissolves more lead more quickly than cold water. If you need hot water, draw water from the cold tap and then heat it on the stove.
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