PUBLIC HEALTH ASSESSMENT
EAST BETHEL SANITARY LANDFILL
(a/k/a EAST BETHEL SANITARY LANDFILL)
CEDAR, ANOKA COUNTY, MINNESOTA
The East Bethel Landfill National Priorities List (NPL) site, located in Anoka County, is about 40 miles north of the metropolitan area of Minneapolis and St. Paul, Minnesota. The area surrounding the landfill is primarily rural with scattered residential development. The population of the City of East Bethel is 8038.
The 60 acre landfill began operations in 1969, accepting demolition debris, mixed municipal waste and some industrial wastes. At present it continues to operate as a demolition debris landfill.
An analysis of groundwater samples from the site has found volatile organic compounds, heavy metals, polynuclear aromatic hydrocarbons and phenolics. These chemicals leached into the groundwater from wastes buried at the site. Extensive sampling indicates, however, the contaminants have not migrated far from their source in the landfill.
All the homes in this area use private wells for drinking water. The closest residential development area is about 0.5 miles from the landfill and includes 22 homes. They are separated from the site by a woods and an extensive wetlands area. A completed exposure pathway does not exist. All well samples have been clean. There are no other pathways for exposure to site contaminants.
To assure safe drinking water for the nearby residents, monitoring of the contaminant plume will continue during remediation of the site. At the present time, based on the information reviewed, the Minnesota Department of Health (MDH) has concluded this site presents no public health hazard, because no human exposure to contaminants is occurring, nor has it occurred in the past. However, the planned remediation of contaminated groundwater is necessary to clean up the environment and prevent any future public health concerns.
The MDH will continue to review the results of the groundwater monitoring for any public health implications. No additional health follow-up activities are planned at this time, however, if data become available MDH and ATSDR will re-evaluate this site for any indicated follow-up activities.
A. Site Description and History
The East Bethel Landfill is located in north central Anoka County, 1/2 mile east of Minnesota Highway 65 along 217th Ave., in East Bethel, Minnesota. East Bethel is 40 miles north of the metropolitan area of Minneapolis and St. Paul. The 60 acre site continues to operate as a commercial demolition debris landfill. Surrounding the landfill is an area consisting of wetlands, open water areas, and a mixture of woodlands and open fields.
Sylvester Brothers Development Company has owned the site since landfilling began in 1969. A permit for the landfill was issued in October of 1971 and amended in 1985 by the Minnesota Pollution Control Agency (MPCA).
The landfill has primarily accepted demolition debris and some mixed municipal waste. A limited amount of industrial waste was accepted between 1969 and 1976 (1).
Waste types reported to be deposited in the landfill include cleaning solvents, waste ink, caustics, paint, waste oils, thinner, dry cleaning solvents, liquids with strong chemical odor, small transformers and small cans of ether. Liquid wastes in pails and 55 gallon drums were buried at the site. Surplus eight ounce cans of ether were disposed of at least twice by the State of Minnesota.
In 1981 Anoka County initiated groundwater sampling requirements for landfills. In 1982 groundwater samples from the East Bethel landfill were tested for heavy metals, volatile organic compounds (VOC's), polynuclear aromatic hydrocarbons (PAH's), phenolic compounds, base neutral extractable compounds and pesticides. VOC's were found in the first set of samples and were confirmed in subsequent groundwater samples. The landfill was placed on the National Priorities List (NPL) in 1986 and a Remedial Investigation (RI) began April 15, 1988.
Two site visits have been conducted by staff from the Minnesota Department of Health (MDH) (Sept. 5 and Oct.20, 1990).
MDH Staff visited the site to determine the proximity of the residential areas, the woods and the wetlands to the landfill. No pathways for regular contact by local residents with the landfill were observed. The landfill is surrounded by a six foot fence and is posted no trespassing. It is isolated from residential areas by the surrounding woods and wetlands which provide a natural barrier to the site.
The housing development to the south is separated from the landfill by woods and a wetland area next to Neds Lake. The wetlands and the lake provide a considerable hydrologic barrier preventing leachate movement to residential wells. Neds Lake, to the southeast of the site, is reported to be a maximum of three feet deep. During the site visit wetland vegetation was growing out of the water almost to the center of the lake. There are no public access points.
The closest residence to the site is the Knode hog farm located on the west side near the entrance to the landfill property. The Knode well is one of the residential wells being regularly tested. No contamination has been found in any of the samples.
On October 20, 1990, the locations of monitoring wells and surface water sampling stations were inspected. The entire perimeter of the site was also inspected.
The landfill is located in a very sandy area. The side slopes of the landfill have good vegetative surface cover and the area where new fill is being placed is covered daily with soil. There was no evidence of gullying or leachate seeps on the side slopes of the landfill.
East of the landfill mound there is an area where lime sludge 
from a water treatment plant has been spread. Further south
grass clippings are being used to fill a borrow pit and there is
a small wetland area.
On the west side of the landfill is a machine shop building and the check-in point to enter the landfill. In this area equipment is stored and there is some salvage pipe and fencing material. As access to the landfill is restricted there do not appear to be any significant physical hazards to local residents. Next to the shop a pump-out well and air stripper have been installed. Although a pilot test of the system was run in the fall of 1990, no decision has been made regarding its use in remediation of the site.
C. Demographics, Land Use, and Natural Resource Use
The East Bethel Landfill is located in the city of East Bethel in northern Anoka County, Minnesota. According to 1990 estimated census data the population of East Bethel is 8038. Data from a 1988 Metropolitan Council survey indicate there are 2,430 households in East Bethel. Approximately 70 residences exist within 1 mile of the site. There are 22 residences about 0.5 miles south of the site.
Land use within one mile of the landfill includes transportation, residential, agricultural, recreational and commercial uses.
Residential uses are concentrated to the southwest of the landfill. Agricultural uses in the area include crop production and a hog farm located southwest of the landfill property.
About three-quarters of a mile southwest of the site is a small gas station/grocery store and a local bank. Sylvester Brothers' lumber yard is located one half mile northwest of the landfill.
Ninety acres of undeveloped land adjacent to the southern edge of the landfill property is owned by the Anoka County Park department. There are no developed accesses to this land and the area remains unused.
There are three Minnesota Department of Natural Resources (MDNR) protected waters and three protected wetlands within one mile of the site. The largest of these is Ned's Lake southeast of the site and consists of 212 acres of open water with 55 acres of associated wetlands. The maximum known depth is 3.5 feet. The bottom consists of muck with pond weeds, bulrushes, water lily and coon tail. There is no public access to this lake and it is not used for fishing. The RI reported there was duck hunting at Ned's Lake.
Groundwater is a utilized natural resource in this area. Drinking water is obtained from private wells in East Bethel. There are no municipal water supplies near the site.
Several sources of health outcome data for Minnesota populations are available. These include data taken from routinely collected Certificates of Live Birth, Certificates of Fetal Death, and Death Certificates. The primary and underlying causes of death are available from the two sets of mortality certificate data. Fetal anomalies diagnosed within the first days of neonatal observation are included in the birth certificate records.
In past years, Minnesota had no systematic method for monitoring cancer occurrence, so cancer incidence rates could not be calculated. As of January 1, 1988 the Minnesota Cancer Surveillance System began collecting data on cancer. This cancer surveillance system is a statewide system which collects information on all cancers confirmed by pathologists that have been diagnosed in Minnesota residents. No data is available for analysis at this time.
One resident in a development area south of the landfill, has expressed concern about the quality of their drinking water. This resident has a shallow sand point well in the upper sand aquifer about 20 feet deep. It is located about three-quarters of a mile from the southern edge of the site. A woods, an extensive wetlands and a pond separates the landfill property from this residential area. It is not located in the direction of the regional groundwater flow (southwest) from the site.
This well is very shallow, is not constructed to meet well code, is located in sandy soil and is in an area where septic tanks are used. As a result, it is subject to localized contamination.
Because of the resident's concern the well was sampled on January 11th and February 16th of 1990 by the Anoka County Community Health and Social Services Department. The samples were analyzed for VOC's by the MDH laboratory. The well was sampled in January and February of 1990 with very low levels of 1,1 dichloroethane (nd-0.3 ug/l) and 1,1,1 trichloroethane (3.1-4.1 ug/l) found in the samples. The source of these contaminants is not known.
In March 1990 samples from the well contained 10.6 mg/l nitrates. The resident has been contacted by the MPCA and advised of the problems of nitrates in drinking water and the options for mitigating the situation. The MDH will provide this resident with a copy of the Health Assessment and discuss any questions with them.
Because of the shallow depth of the well, poor construction, and it's location and distance from the site, it is the technical judgement of the MDH, the MPCA, Anoka County Community Health, and the responsible parties' consultants that there is no evidence this well is in any way impacted by contamination from the landfill.
This public health assessment was made available for public comment from August 13, through September 15, 1991. A summary of the comments received and responses is presented in appendix 2.
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
To identify possible facilities that could contribute to the contamination near the East Bethel Sanitary Landfill site, the Minnesota Department of Health has reviewed the most recent 1989 Toxic Chemical Release Inventory. TRI is developed by the U.S. Environmental Protection Agency (EPA) from the chemical release (air, water, and soil) information provided by certain industries. TRI did not contain information on toxic chemical release relevant to the East Bethel Sanitary landfill site.
Chemicals are included in this evaluation based on several considerations. These are as follows: 1) MDH has developed health based guidelines, Recommended Allowable Limits (RALS), for contaminants in private drinking water supplies. The RAL reflects the maximum concentration of a contaminant in drinking water that a person may ingest over a lifetime without risk of adverse health effects. Chemicals included on this list are those most frequently found in groundwater in Minnesota. RALs for non-carcinogens are often taken from the drinking water health advisories published by the EPA Office of Drinking Water (ODW). RALs for carcinogens are derived from the potency slopes from the EPA Carcinogen Assessment Group (CAG) and reflect an estimated lifetime excess cancer risk of 1 in 100,000. 2) Chemicals that do not exceed RALs may present a real or potential health hazard to the public based on site-specific information and professional judgement. In this case, the concern lies with the unknown health consequences of exposure to low concentrations of many chemicals simultaneously. Future research data on the adverse health effects of chemical mixtures may necessitate further evaluation of this site. 3) Concentrations of chemicals leaching from landfills are unpredictable. Chemicals are often released in pulses and monitoring may reflect either peak concentrations during pulses or lower concentrations found between pulses. In addition, the types of chemicals released either during or between the pulses may be highly variable. In addition, monitoring results may be impacted by the variability of glacial formations typical of Minnesota and the imprecise nature of hydrogeologic characterization.
A map of the area impacted by contamination from the landfill is presented as Figure 2 (RI Report, 1990). One striking feature of this map is the occurrence of two plumes, one heading to the west and the other heading south/southwest with a window of uncontaminated groundwater in between the two plumes directly to the southwest. Several factors may account for this. Based upon the soil gas sampling there appear to be significant sources of contaminants in the western and southern portions of the landfill. The fringe of the surrounding wetlands may influence the shape of the plume as well as the direction of groundwater flow which is different between the surficial and buried sand aquifers.
Groundwater data provided in the RI report was obtained from monitoring wells and residential wells. Prior to the RI there were 30 water table wells and four deep groundwater monitoring wells. Between June and October of 1988, 26 new monitoring wells were installed in the various aquifers beneath the site, (Refer to Figure 1, the Well Location Map). All of these wells were constructed in accordance with the MDH Water Well construction code.
Figure 1. Remedial Investigation Well Location Map
Several geophysical methods were used to determine the nature of the stratigraphy and leachate plume configuration including: resistivity, electromagnetic and seismic (both reflection and refractions methods). Based upon the survey conducted for the site and the correlations between groundwater levels and surface water levels the shallow groundwater system appears to be connected hydraulically with surface water. There is also evidence of mounding and localized movement of landfill leachate in a halo around the southern edge of the landfill. There was no evidence of leachate seeps beyond the toe of the landfill slopes.
Contaminants have been found in all of the aquifers beneath the site. The largest number of chemicals have been detected in the A horizon, the upper surficial water table aquifer. The chemicals that have been detected in the A horizon and the range of concentrations are listed in Table 1. The following chemicals have been found in the A horizon above the MDH health based guidelines for private water supply wells (RALs): tetrachloroethylene (N/D-12 ug/l), vinyl chloride (N/D-0.15 ug/l), 1,1 dichloroethane (4.4-3900 ug/l), 1,2-dichloroethane (N/D-6.8), 1,2-dichloropropane (10-24), benzene (19-1000 ug/l), toluene (12-2600 ug/l), xylene (12-2600 ug/l), tetrahydrofuran (10-280 ug/l), bis(2-chloroethyl)ether (10-19 ug/l) and arsenic (1.0-65 ug/l).
The chemicals detected in the B horizon, the lower surficial aquifer are listed in Table 2. The following chemicals have been found in the B horizon above the MDH RALs: tetrachloroethylene (250-560), vinyl chloride (6.3-57), cis-1,2-dichloroethylene (6.3-360 ug/l), methylene chloride (82-150 ug/l), 1,2-dichloroethane (12-20), 1,2-dichloropropane (3-30), trichloroethylene (160-200 ug/l), benzene (8.5-180 ug/l) and tetrahydrofuran (12-270 ug/l).
Chemicals found in the buried aquifer, the C horizon, are listed in Table 3. The following chemicals have been detected in the C horizon above the RALs: tetrachloroethylene (N/D-8.4), 1,1-Dichloroethane (5.6-1600 ug/l), 1,2-dichloroethane (N/D-18), benzene 13 ug/l) and tetrahydrofuran (11-210 ug/l).
Only three chemicals were detected in the bedrock aquifer, the D horizon. They are listed in Table 4. No chemicals above the RALs were found in this bedrock aquifer. The RI report indicated the phthalates found in the bedrock aquifer may be due to laboratory contamination of samples. As it is not possible to make an absolute determination as to the origin of these contaminants, the remediation of the groundwater is being designed to remove any phthalates if they do exist.
The contaminant plume drops off to nondetectable levels at a distance of about 800 feet from the site. This decrease in concentration is greater than would be predicted by most contaminant transport models due to attenuation, dilution, decay and dispersion. Other site specific factors are also influencing the contaminant plume. These factors may include downward vertical gradients, contaminants heavier than water, and/or interactions with the wetlands. The MPCA is requiring the installation of four additional monitoring wells to better define the plume and act as guardian wells for the residential wells. There will be 1 well to the south of the site in the C horizon, 1 to the west in the C horizon and 2 wells to the southwest in the B and C horizon.
Five surface water monitoring stations were sampled surrounding the site, including 1 at Ned's Lake, southeast of the site. No significant contamination attributable to the landfill was found in the surface water sampling analyses.
Sediment samples were also taken at the surface water monitoring stations. The reported analytical levels for heavy metals (slightly above detection limits) and the general chemistry parameters for sediment samples do not indicate the presence of contamination from the landfill.
C. Quality Assurance and Quality Control (QA/QC)
The data supplied are adequate to conduct a Health Assessment for this site. Sample collection, chain-of-custody, laboratory analytical methods, calibration and preventive maintenance of instruments, internal quality control, data reduction and validation, audits and data-precision assessment were reviewed by MPCA QA/QC staff and found to be in accordance with the EPA-approved Quality Assurance Project Plan outlined in the RI Workplan. Chemical analyses were conducted by EPA Contract Laboratory Program Laboratories.
The landfill site is fenced and access is restricted. It is also isolated and surrounded by a wetland and woods. Although there is heavy equipment and some salvage materials at the site they do not appear to be a hazard to local residents. There was no evidence children had access to the site.
TABLE 1. EAST BETHEL GROUNDWATER SAMPLING RESULTS
Surficial Aquifer - A horizon
| Concentration Range ug/l | |
| Halogenated VOC's | |
|
Chloroethane |
33-5600 |
| Tetrachloroethylene | ND-12* |
| Vinyl Chloride | 7.6-12* |
| cis-1,2-Dichloroethylene | 33-41 |
| Methylene Chloride | 10-18 |
| trans-1,2-Dichloroethylene | 3.7-4.4 |
| 1,1-Dichloroethane | 4.4-3900* |
| 1,2-Dichloroethane | ND-6.8* |
| 1,2-Dichloropropane | 10-24* |
| Dichlorofluoromethane | 5-18 |
| Chloroform | ND-5.1 |
| Trichloroethylene | ND-7.5 |
| Non-chlorinated VOC'S | |
|
Benzene |
19-1000* |
| Ethyl Benzene | 24-360 |
| Toluene | 12-2600* |
| m-p Xylene | 40-1300* |
| o-Xylene | 19-510* |
| Tetrahydrofuran | 10-280* |
| Ethyl Ether | 27-540 |
| Methyl Ethyl Ketone | 11-120 |
| Methyl Isobutyl Ketone | ND-30 |
| Acetone | 10-300 |
| Other Compounds | |
| bis(2-chloroethyl)ether | 10-19* |
| Naphthalene | ND-11 |
| bis(2-ethylhexyl)Phthalate | 12-3400* |
| di-n-octyl phthalate | 24-1100 |
| di-n-butyl phthalate | ND-200 |
| diethyl phthalate | 10-20 |
| d-BHC | ND-0.020 |
| g-BHC | ND-0.0310 |
| b-BHC | ND-0.082 |
| 2,4-Diethylphenol | 1.3-24 |
| PCB-1254 | ND-0.6 |
| Arsenic | 1.0-65* |
* Above the MDH RAL for drinking water
ND = not detected
See Appendix 3 for a complete list of RALs
TABLE 2. EAST BETHEL GROUNDWATER SAMPLING RESULTS
Surficial Aquifer - B horizon
| Concentration Range ug/l | |
| Halogenated VOC's | |
|
Chloroethane |
6-4500 |
| Tetrachloroethylene | 250-560* |
| Vinyl Chloride | 6.3-57* |
| cis-1,2-Dichloroethylene | 6.3-360* |
| Methylene Chloride | 82-150* |
| trans-1,2-Dichloroethylene | 8-37 |
| 1,1-Dichloroethane | 10-13 |
| 1,2-Dichloroethane | 12-20* |
| 1,2-Dichloropropane | 3-30* |
| Dichlorofluoromethane | 5-37 |
| Trichloroethylene | 160-200* |
| Non-chlorinated VOC'S | |
|
Benzene |
8.5-180* |
| Ethyl Benzene | 31-130 |
| Toluene | 480-1100 |
| m-p Xylene | 130-180 |
| o-Xylene | 90-160 |
| Tetrahydrofuran | 12-270* |
| Ethyl Ether | 66-870 |
| Methyl Isobutyl Ketone | ND-65 |
| Other Compounds | |
| bis(2-ethylhexyl)Phthalate | 190-780 |
| di-n-octyl phthalate | 20-30 |
| diethyl phthalate | 11-17 |
| d-BHC | ND-0.0170 |
| 2,4-Diethylphenol | ND-2.1 |
* Above the MDH RAL for Drinking Water.
ND = not detected
See Appendix 3 for a complete list of RALs
TABLE 3. EAST BETHEL GROUNDWATER SAMPLING RESULTS
Buried Aquifer - C horizon
| Concentration Range ug/l | |
| Halogenated VOC's | |
|
Chloroethane |
200-210 |
| Tetrachloroethylene | ND-8.4* |
| 1,1-Dichloroethane | 5.6-1600* |
| 1,2-Dichloroethane | ND-18* |
| Dichlorofluoromethane | 33-54 |
| Trichloroethylene | ND-4.1 |
| Dichlorodifluoromethane | ND-13 |
| Non-chlorinated VOC'S | |
| Benzene | ND-13* |
| Toluene | ND-160 |
| Tetrahydrofuran | 11-210* |
| Ethyl Ether | 15-62 |
| Methyl Isobutyl Ketone | ND-12 |
| Acetone | 12-130 |
| Other Compounds | |
| bis(2-ethylhexyl)Phthalate | 11-140 |
| di-n-octyl phthalate | 15-190 |
| 2,4-Dimethylphenol | 1.6-3.7 |
| Endrin | ND-0.0130 |
| 44 DDE | ND-0.0190 |
* Above the MDH Recommended Allowable Limit for Drinking Water.
ND = not detected
See Appendix 3 for a complete list of RALs
TABLE 4. EAST BETHEL GROUNDWATER SAMPLING RESULTS
Bedrock Aquifer - D horizon
| Concentration Range ug/l | |
| Non-chlorinated VOC'S | ND |
| Other Compounds | |
| bis(2-ethylhexyl)Phthalate | <10-120 |
| di-n-octyl phthalate | <10-150 |
| 2,4-Dimethylphenol | ND-1.8 |
ND = not detected
As previously discussed, wastes received in the past have resulted in contamination of the groundwater beneath the site. The environmental and human exposure pathways associated with the site are discussed in the following subsections.
A. Environmental Pathways (Fate and Transport)
1. Groundwater
The East Bethel Landfill site is located on the Anoka Sand plain, a broad relatively flat plain of glacial outwash interspersed with shallow wetlands. There are three aquifers underlying the site; a surficial water table aquifer, a buried sand aquifer and the Franconia formation bedrock aquifer consisting of sandstone.
The surficial aquifer varies in thickness from 34 feet to 64 feet. It consists primarily of fine sand. In the northern and southern half of the site, the glacial till is missing and the upper and lower sand aquifer are continuous. The direction of groundwater flow in the surficial aquifer is to the west/southwest.
The groundwater velocity is estimated to range from 13 to 240 feet per year with a typical value of 115 feet per year. The nearest receptor is the wetlands which are about 790 feet away. The time for groundwater to reach the wetland would be 3.5 years for the typical case and 1.7 to 31 years for the range of possible velocities.
There appears to be evidence of a groundwater mound in a fringe around the landfill in the surficial aquifer. This may be enhanced by the lime sludge cover over much of the landfill which would increase runoff and direct it to the sandy soils at the toe of the landfill or it may be from deposition of waste in the water table.
The buried sand aquifer is a brown to reddish brown fine to very fine sand of about 60 to 100 feet in thickness. The direction of groundwater flow in the buried sand aquifer is to the west. The groundwater velocity is estimated to range from 15 to 145 feet per year with a typical value of 83 feet per year.
There is 1 residential well in the buried sand about 1400 feet west of the landfill shop near the entrance road. This is the closest well to the site and has been monitored for at least five years. Although this well is in the direction of groundwater flow no landfill contaminants have been found in the samples.
Beneath the buried sand aquifer is the Franconia sandstone bedrock. The direction of groundwater flow in the bedrock aquifer is to the south with a velocity of about 40 feet per year. There is 1 residential bedrock well more than 2000 feet south of the landfill shop.
The groundwater beneath the landfill is contaminated with a variety of chemicals as previously noted. Contaminants have been found in the upper and lower surficial aquifers, the buried sand aquifer, and trace amounts have been found in the bedrock aquifer. The groundwater is a pathway for contaminants to migrate off site. An additional four wells are being installed to further monitor the migration of the contaminant plume. Figure 1 contains a map of the monitoring well locations. No contaminants, however, have been found in any residential wells in the direction of groundwater flow.
2. Air
No ambient air sampling data is available. However, the landfill has an intact soil and vegetative cover over all but the active fill area which is covered daily. No excavation or disturbing of the cover is projected so the possibility of airborne contaminants is minimized.
Emissions from the planned air stripper are a potential source of contaminants. The MPCA Division of Air Quality will be reviewing for appropriate emission control equipment.
3. Soil
As the East Bethel Landfill has continued to operate as a permitted demolition landfill it has been routinely covered with soil and is vegetated. The only unvegetated area is the active area which is covered with soil as it is filled. Therefore there is no direct exposure to any contaminated soils.
4. Surface water and sediments
The porous nature of the surface soils at the site eliminate problems from runoff at the landfill. The wetland area to the south and west of the landfill, however, represent potential discharge points for contaminated groundwater.
The reported analytical levels for heavy metals and general chemistry parameters for the sediment samples do not indicate the presence of contamination from the landfill.
No significant contamination attributable to the landfill was found in any of the surface water sampling analyses. Nearby surface waters and sediments are not contaminated and do not function as exposure pathways.
Water discharges from the air stripper are a potential source of surface water contamination. The MPCA Water Quality Division will be evaluating the discharge, recommending appropriate control technology and reviewing necessary permit requirements.
1. Groundwater
There are no completed human exposure pathways through the groundwater. As outlined in the on-site contamination section above, a variety of contaminants have been found, however they have not migrated off the landfill site. At present a plume has been detected on site west and southwest of the landfill source as shown in Figure 2.
Fortunately, no contamination has been found in any residential wells. It appears the wetlands surrounding the landfill act as a hydrological barrier to prevent the spread of contamination. Sampling of both monitoring and residential wells will continue during the planned remediation of the groundwater to prevent any human exposure to contaminants.
2. Air
The landfill site is too isolated and distant from residential areas for air contaminants from the site to be a health concern. Landfill workers could potentially be exposed to volatilized contaminants, however, excavation of the site is not planned and contact would be minimal.
Although an air stripper is in place, it is not currently in operation and no decision has been made as to its future use. If it is used the MPCA Division of Air Quality will require the appropriate emission control equipment.
3. Soil
The landfill has an intact vegetative cover over all but the current fill area which is covered daily. There are no exposed contaminated soils on the site and therefore no completed human exposure pathway.
4. Surface water and sediments
No contamination attributable to the landfill has been found in any surface water or sediment samples analyzed. No human exposure pathway exists through surface water or sediments.
Water discharges from the air stripper are a potential source of surface water contamination. The MPCA Water Quality Division will evaluate the discharge, recommend appropriate control technology and review necessary permit requirements.
5. Biota
No contamination attributable to the landfill has been found in the surface water or sediments surrounding the site. As a result no exposure pathway to the local wildlife exists.
No contamination has been found in the well of the closest farm (and residence) to the landfill. Therefore there is no exposure to the livestock at this farm.
Because of the large number of compounds detected beneath the landfill it is necessary to choose contaminants of concern that represent the major hazards. As there are no completed human exposure pathways at this site, basic toxicological information on the chemicals of concern is included. These contaminants were chosen for this summary because of their toxicity, volume and distribution at the site and environmental fate characteristics. The absorption, metabolism, distribution, and toxicology of each of these chemicals are discussed below.
1. Benzene
Benzene is a neutral, low molecular weight, lipid-soluble chemical. Animal studies indicate that virtually all of an ingested dose will be absorbed (2) while data from humans show about 50% absorption from inhalation exposure (3). Benzene can be absorbed through the skin but at a much lower rate (4). A fraction (estimates from 12 to 50%) is exhaled unchanged. The absorbed portion is distributed mostly to liver, bone marrow and fat. Benzene metabolism occurs primarily in the liver and secondarily in the bone marrow. It is believed that one or more benzene metabolites are responsible for benzene-induced toxicity demonstrated to date. Benzene is metabolized by mixed-function oxidases to hydroxylated benzenes (primarily phenol and hydroquinone), catechol, and 1,2,4-trihydroxybenzene. These can be metabolized further to quinones or semiquinones (5). Chemicals which increase mixed-function oxidase activity (e.g., ethanol) will increase benzene metabolism. Conversely, chemicals which decrease mixed-function oxidase activity (e.g., toluene, carbon monoxide, PCBs) will decrease benzene metabolism. Benzene metabolites covalently bind to cellular macromolecules, which may be the mechanism of toxicity. Urinary excretion of metabolites is rapid, and can be used as an indicator of benzene exposure.
Bone marrow is a target organ for benzene, and exposure results in changes in the circulating formed blood elements. There are numerous examples of benzene-induced hematological toxicity in humans occupationally exposed. One investigator estimates that chronic exposure to as little as 10 ppm may cause depressed lymphocyte levels and lymphocytopenia (6). In addition, there is evidence that there may be a positive association between pancytopenia or aplastic anemia and later development of leukemia (3).
Exposure to benzene can also cause immune system depression. Many aspects of the hematological system are altered by benzene exposure, including "antibody formation against leukocytes, platelets, and red cells" (7).
Studies consistently show structural and numerical chromosomal aberrations in human lymphocytes exposed to benzene (5). Epidemiological and case studies also show a link between benzene exposure and leukemia. Based on human epidemiological studies in occupational settings by Rinsky (8), Ott (9), and Wong (10), the EPA Carcinogen Assessment Group (CAG) designates benzene as group A (human carcinogen). EPA CAG has estimated that lifetime ingestion of water (2 liters/day) containing 7.0 ug benzene per liter of water would present an increased cancer risk of one excess cancer per population of one hundred thousand (11, D. Bayliss, pers. comm). The Occupational Safety and Health Administration has established a permissible exposure limit of 1 ppm as an 8 hour time-weighted-average concentration, and a short term (15 minute) exposure limit of 5 ppm, for inhalation of benzene in the occupational environment (29CFR 1910.1028).
2. Tetrahydrofuran
Tetrahydrofuran (THF) is a low molecular weight, water soluble chemical. The primary use of tetrahydrofuran is as a solvent to dissolve synthetic resins, particularly polyvinyl chloride, and vinylidene chloride copolymers. It is also used as a solvent in the production of tetraethyl and tetramethyl lead. No natural sources of THF exist.
Because of its high vapor pressure and water solubility, significant amounts of THF can be released to the environment when used as a solvent. Once it is released to the environment little monitoring data exists. In the atmosphere THF should degrade very rapidly and should be removed by rain. In water it may biodegrade. Spills on soil are expected to evaporate rapidly and leach into the groundwater. It is not expected to bioconcentrate in aquatic organisms (12).
THF can be absorbed through inhalation across the alveolar membrane and from the digestive tract. Absorption can also occur through the skin (13). THF has also been found in mothers milk (14).
Reports of animal studies indicate irritation of the skin and mucous membranes including the eyes, nose and respiratory tract as the primary effect from exposures of 100 to 200 ppm (15). High acute doses (25,000 ppm) produced anesthesia, a fall in blood pressure and strong respiratory stimulation. After prolonged exposures to levels greater than 1000 ppm damage to the liver, kidneys and lungs has been observed in laboratory animals (16).
Daily 6 hour exposures of dogs to 200 ppm THF resulted in an observable effect on pulse pressure within 3 or 4 weeks. The route of exposure was not specified. No demonstratable histopathologic changes occurred in critical organs of the animals despite exposure for 9 weeks followed by an additional 3 week exposure at nearly twice this level (16).
THF was negative in the Ames test for mutagenicity (17). In a cytogenicity test using Chinese hamster ovary cells THF tested positive for chromosome aberrations and negative for sister chromatid exchanges. THF tested negative for mutagenicity in the standard National Toxicology Program Salmonella/microsome preincubation assay (18). THF has been tested for carcinogenicity in mice. A test for skin tumors was conducted in which THF was applied to the skin of mice twice per week for 25 exposures and observed for 17.5 months. No carcinogenic effect was observed (19).
Data on toxicity of THF in humans is limited, however, there have been health complaints from workers exposed to THF. A report has been published on two workers who were exposed to a glue containing THF in a confined space. They both had signs of irritation of the mucous membranes, mild effects on the central nervous system and cytolytic hepatitis. After removal from the exposure all clinical signs in both workers were gone within two days and liver enzymes returned to normal within two weeks (13). Severe occipital headaches have been reported in technicians testing for pharmacological properties of THF.
The probable lethal dose in humans is estimated to be 50-500 mg/kg. The National Institute of Occupational Safety and Health has established an eight hour time-weighted average threshold limit value of 200 ppm for the protection of workers (20). A drinking water MDH RAL has been set at 154 ug/l based on the EPA Summary of Acceptable Daily Intakes for Oral Exposures.
B. Health Outcome Data Evaluation
The available data sources provide descriptive information on the crude incidence of selected outcomes and may be used in attempts to detect trends or associations. However, because the number of people potentially exposed to the site is very small a significant change in disease rate among the site population would not be detected. County-based incidence rates do not include an accurate measure of exposure and therefore, are not specific enough to be representative of the small population potentially exposed to the site.
From the available county-based data alone, it would not be possible to conclude that the site has, or has not, impacted the health of the 23 residences surrounding the site. Actual sampling data from the site indicates there has been no human exposure to contaminants. If health outcome data on this population becomes available, it will be evaluated in an attempt to detect any causal relationship.
C. Commounity Health Concerns Evaluation
One resident in a development area south of the landfill, has expressed concern about the quality of their drinking water. This resident has a shallow sand point well in the upper sand aquifer about 20 feet deep. It is located about three-quarters of a mile from the southern edge of the site.
In March 1990 samples from the well contained 10.6 mg/l nitrates. The resident has been contacted by the MPCA and advised of the problems of nitrates in drinking water and the options for mitigating the situation. The MDH will provide this resident with a copy of the Health Assessment and discuss any questions with them.
Because of the shallow depth of the well, poor construction, and it's location and distance from the site, it is the technical judgement of the MDH, the MPCA, Anoka County Community Health, and the responsible parties' consultants that there is no evidence this well is in any way impacted by contamination from the landfill.
This public health assessment was made available for public comment from August 13, through September 15, 1991. A summary of the comments received and responses is presented in appendix 2.
At the present time, based on the information reviewed, the MDH has concluded there are no public health hazards from this site, because no human exposure to contaminants is occurring, nor has it occurred in the past. Remediation, however, is necessary to prevent any possibility of contaminants moving into areas where human exposure could occur.
The planned monitoring of the groundwater both on and off site should continue to prevent any human exposures to contaminants through ingestion of contaminated drinking water.
Remediation of the contaminated groundwater underneath the site will begin as soon as the feasibility study is completed and a method is chosen. The review of the feasibility study is being conducted by the MPCA. At present there is no human exposure to contaminants from the landfill. To assure this situation continues the planned monitoring and clean-up should proceed.
HEALTH ACTIVITIES RECOMMENDATION PANEL (HARP) RECOMMENDATIONS
In accordance with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERLA) as amended, the East Bethel Landfill site has been evaluated for appropriate follow-up with respect to health activities. Based on the information and data reviewed during the preparation of this Health Assessment no human exposure to contaminants at concentrations of public health concern is occurring or is believed to have occurred in the past. Therefore, this site is not being considered for follow-up health activities at this time. However, if data become available suggesting that human exposure to hazardous substances at levels of public health concern is occurring, ATSDR and the Minnesota Department of Health will re-evaluate this site for any indicated follow-up activities. A community education effort related to this site was initiated. Public meetings have been held by the MPCA to exchange information with members of the community.
The MDH along with the Agency for Toxic Substances and Disease Registry (ATSDR) will monitor the progress of the above recommendations. The MPCA will continue to require quarterly groundwater sampling. MDH will review the results of the groundwater sampling to monitor for any public health implications.
The MPCA is reviewing the Feasibility Study/Detailed Analysis report which outlines the proposed remedial actions. The MDH will also review this report to determine if the proposed remediation will be protective of public health. MDH will make additional recommendations if necessary. MDH will monitor the remedial actions with the MPCA and will make additions to this assessment if warranted. Additional conclusions or recommendations will be communicated to the local residents through fact sheets, mailings or meetings as necessary.
Susan A. Welsh
Environmental Research Scientist
Minnesota Department of Health
Forest Arnold
Hydrogeologist
Minnesota Department of Health (No longer with the MDH)
ATSDR Regional Representative
Louise Fabinski
Office of Regional Operations
Region V
Office of the Assistant Administrator
ATSDR Technical Project Officer
Burt J. Cooper
Environmental Health Scientist
Remedial Programs Branch
Division of Health Assessment and Consultation
This public health assessment was prepared by the Minnesota Department of Health under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health assessment was initiated.
Burt J. Cooper
Technical Project Officer, SPS, RPB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this health assessment and concurs with its findings.
Director, DHAC, ATSDR
APPENDIX 1: SUMMARY OF COMMUNITY OUTREACH ACTIVITIES BY THE MINNESOTA DEPARTMENT OF HEALTH REGARDING THE EAST BETHEL LANDFILL HEALTH ASSESSMENT
Summary
A fact sheet was issued August 21, 1991 by the Minnesota Department of Health entitled "Superfund Site Health Facts - Information for Citizens about East Bethel Landfill". It has been sent to interested local residents (See attachment 1). It includes a summary of the site history and a question and answer section about health risks. Names and phone numbers of people to contact for further information are listed on the fact sheet. A press release was sent to local media announcing the public comment period.
APPENDIX 2: SUMMARY OF THE PUBLIC COMMENTS RECEIVED BY THE MINNESOTA DEPARTMENT OF HEALTH
(August 13, 1991 to September 15, 1991)
REGARDING THE EAST BETHEL LANDFILL HEALTH ASSESSMENT
A mailing list of interested citizens and government officials was obtained from the Minnesota Pollution Control Agency Office of Public Information. A copy of the draft Health Assessment, a citizen's fact sheet about the site and a letter explaining how to respond during the 30-day comment period was sent to the people on this list.
During the 30-day comment period (August 13 - September 15, 1991), we received two letters. Each of the concerns raised in the letters were investigated and some of the information provided resulted in additions to the assessment. A letter has been sent to the interested citizens responding to their concerns. The following is a summary of the concerns and the responses to them.
Response: This has been corrected to read four.
Response: The term sanitary landfill has been changed to demolition landfill.
Response: The assessment has been changed from 60 to 95 acres.
Response: The assessment has been changed to explain yard waste is being used to fill a borrow pit.
Response: The assessment has been changed to reflect the various reasons for a groundwater mound.
Response: Figure 1 has been eliminated.
Response: According to the sampling results from monitoring wells, the contaminant concentrations drop off to nondetectable at 800 feet from the site. Figure 1, showing the area of impact is designed to give a visual image of the contamination area. I have added an arrow to the figure to better illustrate the edge of the plume.
APPENDIX 3: RECOMMENDED ALLOWABLE LIMITS FOR DRINKING WATER CONTAMINANTS
Prepared by the
Minnesota Department of Health
Section of Health Risk Assessment
| Compound |
Ral (µg/L)
|
Endpoint
|
|
|
||
|
Acenapthene |
4,000.0
|
S
|
| Acetone |
700.0
|
S
|
| Acifluorfen (Acid) |
9.00
|
S
|
| Acrylamide |
0.08
|
C
|
| Acrylonitrile |
0.6
|
C
|
| Alachlor*** |
4.0
|
C
|
| Aldicarb*** |
9.0
|
S
|
| Aldrin |
0.02
|
C
|
| Allyl Chloride (3 chloropropene) |
1.0
|
S
|
| Ametryn |
60.00
|
S
|
|
Ammonium Sulfamate |
1,000.0
|
S
|
| Anthracene |
2,000.0
|
S
|
| Antimony |
1.0
|
S
|
| Arsenic |
0.2
|
C
|
| Asbestos |
70,000,000*
|
C
|
| Atrazine |
3.0
|
S
|
| Barium, Barium Sulfate and Chloride |
2,000.0
|
S
|
|
Baygon (Propoxur)*** |
3.0
|
C
|
| Bentazon (Basagran) |
20.0
|
S
|
| Benzene |
10.0
|
C
|
| Benzidine |
0.002
|
C
|
| Benzoic acid |
30,000.0
|
S
|
| Beryllium |
0.08
|
C
|
| 1,1-biphenyl (diphenyl) |
300.0
|
S
|
| Bis (2-chloroethyl) ether |
0.3
|
C
|
| Bis (2-chloroisopropyl) ether |
300.0
|
S
|
| Bis (chloromethyl) ether |
0.002
|
C
|
|
Boron |
300.0
|
S
|
| Bromacil |
80.0
|
S
|
| Bromodichloromethane |
3.0
|
C
|
| Bromoform |
40.0
|
C
|
| Bromomethane |
0.10
|
S
|
| n-Butanol |
700.0
|
S
|
| Butylate |
400.0
|
S
|
| Butylbenzyl phthalate |
100.0
|
S
|
| Butylphthalyl butylglycolate |
7,000.0
|
S
|
| Cadmium |
4.0
|
S
|
|
Carbaryl |
700.0
|
S
|
| Carbofuran |
40.0
|
S
|
| Carbon disulfide |
700.0
|
S
|
| Carbon Tetrachloride |
3.0
|
C
|
| Carboxin |
700.0
|
S
|
| Chloramben |
100.0
|
S
|
| Chlordane |
0.3
|
C
|
| Chlorobenzene (Monochlorobenzene) |
100.0
|
S
|
| Chlorodibromomethane (Dibromochloromethane |
10.0
|
S
|
| Chloroform |
60.0
|
C
|
|
2-Chlorophenol |
30.0
|
S
|
| Chlorothalonil*** |
100.0
|
C
|
| Chlorpyrifos |
20.0
|
S
|
| Chromium (Total), Chromium VI |
100.0
|
S
|
| Chromium III |
20,000.0
|
S
|
| Cobalt |
1.0
|
S
|
| Copper |
1,000.0
|
S
|
| m, o, p-Cresol |
30.0
|
S
|
| Cyanazine |
10.0
|
S
|
| Cranide, free |
100.0
|
S
|
| Dacthal |
3,000.0
|
S
|
| Dalapon |
200.0
|
S
|
|
DDT |
1.0
|
C
|
| Diazinon |
0.6
|
S
|
| 1,4-Dibromobenzene |
70.0
|
S
|
| Dibromochloromethane |
10.0
|
S
|
| 1,2-Dibromoethane (Ethylene dibromide, EDB) |
0.004
|
C
|
| 1,2-Dibromo-3-chloropropane (DBCP) |
0.3
|
C
|
| Dibutyl phthalate |
700.0
|
S
|
| Dicamba |
200.0
|
S
|
| 1,2-Dichlorobenzene (ortho-) |
600.0
|
S
|
| 1,3-Dichlorobenzene (meta- |
600.0
|
S
|
|
1,4-Dichlorobenzene (para-) |
10.0
|
C
|
| 3,3-Dichlorobenzidine |
0.8
|
C
|
| Dichlorodifluormethane |
1,000.0
|
S
|
| 1, 1-Dichloroethane |
70.0
|
S
|
| 1, 2-Dichloroethane |
4.0
|
C
|
| 1, 1-Dichloroethene |
6.0
|
S
|
| 1,2-Dichloroethene (cis) |
70.0
|
S
|
| 1, 2-Dichloroethene (trans) |
100.0
|
S
|
| Dichloromethane |
50.0
|
C
|
| 2,4-Dichlorophenol |
20.0
|
S
|
| 2,4-Dichlorophenoxyacetic acid (2,4-D) |
70.0
|
S
|
| 1,2-Dichloropropane |
5.0
|
C
|
| 1,3-Dichloropropene (cis-, trans-, mixture)*** |
2.0
|
C
|
|
Dieldrin |
0.02
|
C
|
| Diethylphtalate |
6,000.0
|
S
|
| Di(2-ethylhexyl)phthalate (bis--)(DEHP) |
20.0
|
C
|
| Dimethrin |
2,000.0
|
S
|
| 2,4-Dimethylphenol |
600.0
|
S
|
| Dimethylphthalate |
7,000.0
|
S
|
| Di-N-butylphthalate |
700.0
|
S
|
| 2,4-Dinitrophenol |
10.0
|
S
|
| 2,4-Dinitrotoluene |
1.0
|
C
|
| Dinoseb |
10.0
|
S
|
| p-Dioxane (1,4-Dioxane |
30.0
|
C
|
|
Diphenamid |
200.0
|
S
|
| 1,2-Diphenylhydrazine |
0.5
|
C
|
| Disulfoton |
0.3
|
S
|
| Diuron |
10.0
|
S
|
| Endothall |
100.0
|
S
|
| Endrin |
2.0
|
S
|
| Epichlorohydrin |
30.0
|
C
|
| Ethylbenzene |
700.0
|
S
|
| s-Ethyldipropylthiocarbamate (EPTC) |
200.0
|
S
|
| Ethyl ether |
1,000.0
|
S
|
| Ethylene Glycol |
10,000.0
|
S
|
|
Ethylene Thiourea (ETU) |
2.0
|
C
|
| Ethylphthlylethyglycolate |
20,000.0
|
S
|
| Fenamiphos |
2.0
|
S
|
| Fluometuron |
90.0
|
S
|
| Fluoranthene |
300.0
|
S
|
| Fluorene (9H-Fluorene) |
300.0
|
S
|
| Fonofos |
10.0
|
S
|
| Glyphosate |
700.0
|
S
|
| Heptachlor |
0.08
|
C
|
| Heptachlor Epoxide |
0.04
|
C
|
| Hexachlorobenzene*** |
0.2
|
C
|
|
Hexachlorobutadiene (1,3-butadiene) |
1.0
|
S
|
| Hexachlorocyclohexane (HCH, alpha-) |
0.06
|
C
|
| HCH (beta-) |
0.2
|
C
|
| HCH (gamma-) (Lindane)*** |
0.3
|
C
|
| Hexachlorocyclopentadine |
50.0
|
S
|
| Hexachlorodibenzo-p-dioxin (HXCDD) |
0.0001
|
C
|
| Hexachloroethane |
1.0
|
S
|
| Hexane (n-hexane) |
4,000.0
|
S
|
| Hexazinone |
200.0
|
S
|
| Isophorone |
100.0
|
S
|
| Isopropylbenzene (cumene) |
300.0
|
S
|
|
Lead |
20.0
|
S
|
| Linuron |
1.0
|
S
|
| Maleic Hydrazide |
3,000.0
|
S
|
| Manganese |
300.0
|
S
|
| Mercury, Mercury Chloride or Sulfate*** |
1.0
|
S
|
| Methomyl |
200.0
|
S
|
| Methoxychlor |
30.0
|
S
|
| Methyl Ethyl Ketone (MEK, 2-butanone) |
300.0
|
S
|
| Methyl Isobutyl Ketone (MIBK) |
300.0
|
S
|
| Methyl Parathion |
2.0
|
S
|
| Methylene Chloride (Dichloromethane) |
50.0
|
C
|
|
(MCPA) (4-Chloro-2-Methylphenoxyl)-Acetic Acid |
4.0
|
S
|
| Metoachlor |
100.0
|
S
|
| Metribuzin |
200.0
|
S
|
| Molybdenum |
20.0
|
S
|
| Naphthalene |
30.0
|
S
|
| Nickel |
70.0
|
S
|
| Nitrate |
10,000.0
|
S
|
| Nitrite |
1,000.0
|
S
|
| Nitrobenzene |
3.0
|
S
|
| N-Nitrosodiethylamine |
0.002
|
C
|
| N-Nitrosodimethylamine |
0.007
|
C
|
|
N-Nitrosodi-N-butylamine |
0.06
|
C
|
| N-Nitrosodiphenylamine |
70.0
|
C
|
| Oxamyl |
200.0
|
S
|
| PAHS (total carcinogenic) |
0.03
|
C
|
| PAHS (total noncarcinogenic) |
0.3
|
S
|
| Paraquat (dichloride salt) |
3.0
|
S
|
| Pentachlorobenzene |
6.0
|
S
|
| Pentachlorophenol (PCP) |
200.0
|
S
|
| Phenol |
4,000.0
|
S
|
| Picloram |
500.0
|
S
|
| Prometon |
100.0
|
S
|
|
Pronomide |
50.0
|
S
|
| Propachlor |
90.0
|
S
|
| Propazine |
10.0
|
S
|
| Propham |
100.0
|
S
|
| Pyrene |
200.0
|
S
|
| Selenium |
10.0
|
S
|
| Silver |
10.0
|
S
|
| Simazine |
10.0
|
S
|
| Styrene |
10.0
|
C
|
| Tebuthiuron |
500.0
|
S
|
| Terbacil |
100.0
|
S
|
|
Terbufos |
1.0
|
S
|
| 1,2,4,5-Tetrachlorobenzene |
2.0
|
S
|
| 1,1,1,2-Tetrochloroethane |
20.0
|
C
|
| 1,1,2,2-Tetrachloroethane |
2.0
|
C
|
| 1,1,2,2-Tetrachloroethene*** |
7.0
|
C
|
| 2,3,4,6-Tetrachlorophenol |
200.0
|
S
|
| Tetrahydrofuran |
100.0
|
S
|
| Thallium |
0.3
|
S
|
| Tin |
2,000.0
|
S
|
| Toluene |
1,000.0
|
S
|
| Toxaphene |
0.3
|
C
|
|
1,1,1-Trichloroethane |
600.0
|
S
|
| 1,1,2-Trichloroethane |
3.0
|
S
|
| 1,1,2-Trichloroethene (TCE)*** |
30.0
|
C
|
| Trichlorofluoromethane |
2,000.0
|
S
|
| 2,4,6-Trichlorophenol |
30.0
|
C
|
| 2,4,5-Trichlorophenoxyacetic Acid (2,4,5-T) |
70.0
|
S
|
| 2,4,5-Trichlorophenoxypropionic Acid (Silvex) |
60.0
|
S
|
| 1,2,3-Trichloropropane |
40.0
|
S
|
| 1,1,2-Trichloro-1,2,2-trifluorethane |
200,000.0
|
S
|
| Trifluralin |
6.0
|
S
|
| 1,3,5-Trinitrobenzene |
0.3
|
S
|
| Vanadium |
20.0
|
S
|
| Vinyl Chloride |
0.10
|
C
|
| Xylene (total m, p and o) |
10,000.0
|
S
|
| Zinc |
700.0
|
S
|
* long fibers/liter
** S=systemic; C=carcinogenic
*** indicates Rfd or potency slope used as basis for RAL has been withdrawn
from IRIS by EPA.
