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PUBLIC HEALTH ASSESSMENT

EAST BETHEL SANITARY LANDFILL
(a/k/a EAST BETHEL SANITARY LANDFILL)
CEDAR, ANOKA COUNTY, MINNESOTA

SUMMARY

The East Bethel Landfill National Priorities List (NPL) site,located in Anoka County, is about 40 miles north of themetropolitan area of Minneapolis and St. Paul, Minnesota. Thearea surrounding the landfill is primarily rural with scatteredresidential development. The population of the City of EastBethel is 8038.

The 60 acre landfill began operations in 1969, acceptingdemolition debris, mixed municipal waste and some industrialwastes. At present it continues to operate as a demolitiondebris landfill.

An analysis of groundwater samples from the site has foundvolatile organic compounds, heavy metals, polynuclear aromatichydrocarbons and phenolics. These chemicals leached into thegroundwater from wastes buried at the site. Extensive samplingindicates, however, the contaminants have not migrated far fromtheir 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 duringremediation of the site. At the present time, based on theinformation reviewed, the Minnesota Department of Health (MDH)has concluded this site presents no public health hazard, becauseno human exposure to contaminants is occurring, nor has itoccurred in the past. However, the planned remediation ofcontaminated groundwater is necessary to clean up the environmentand prevent any future public health concerns.

The MDH will continue to review the results of the groundwatermonitoring for any public health implications. No additionalhealth follow-up activities are planned at this time, however, ifdata become available MDH and ATSDR will re-evaluate this sitefor any indicated follow-up activities.

BACKGROUND

A. Site Description and History

The East Bethel Landfill is located in north central AnokaCounty, 1/2 mile east of Minnesota Highway 65 along 217th Ave.,in East Bethel, Minnesota. East Bethel is 40 miles north of themetropolitan area of Minneapolis and St. Paul. The 60 acre sitecontinues to operate as a commercial demolition debris landfill. Surrounding the landfill is an area consisting of wetlands, openwater areas, and a mixture of woodlands and open fields.

Sylvester Brothers Development Company has owned the site sincelandfilling began in 1969. A permit for the landfill was issuedin October of 1971 and amended in 1985 by the Minnesota PollutionControl Agency (MPCA).

The landfill has primarily accepted demolition debris and somemixed municipal waste. A limited amount of industrial waste wasaccepted between 1969 and 1976 (1).

Waste types reported to be deposited in the landfill includecleaning solvents, waste ink, caustics, paint, waste oils,thinner, dry cleaning solvents, liquids with strong chemicalodor, small transformers and small cans of ether. Liquid wastes in pails and 55 gallon drums were buried at the site. Surpluseight ounce cans of ether were disposed of at least twice by theState of Minnesota.

In 1981 Anoka County initiated groundwater sampling requirementsfor landfills. In 1982 groundwater samples from the East Bethellandfill were tested for heavy metals, volatile organic compounds(VOC's), polynuclear aromatic hydrocarbons (PAH's), phenoliccompounds, base neutral extractable compounds and pesticides. VOC's were found in the first set of samples and were confirmedin subsequent groundwater samples. The landfill was placed onthe National Priorities List (NPL) in 1986 and a RemedialInvestigation (RI) began April 15, 1988.

B. Site Visit

Two site visits have been conducted by staff from the MinnesotaDepartment of Health (MDH) (Sept. 5 and Oct.20, 1990).

MDH Staff visited the site to determine the proximity of theresidential areas, the woods and the wetlands to the landfill. No pathways for regular contact by local residents with thelandfill were observed. The landfill is surrounded by a six footfence and is posted no trespassing. It is isolated fromresidential areas by the surrounding woods and wetlands whichprovide a natural barrier to the site.

The housing development to the south is separated from thelandfill by woods and a wetland area next to Neds Lake. Thewetlands and the lake provide a considerable hydrologic barrier preventing leachate movement to residential wells. Neds Lake, tothe southeast of the site, is reported to be a maximum of threefeet deep. During the site visit wetland vegetation was growingout of the water almost to the center of the lake. There are nopublic 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 andsurface water sampling stations were inspected. The entireperimeter of the site was also inspected.

The landfill is located in a very sandy area. The side slopes ofthe landfill have good vegetative surface cover and the areawhere new fill is being placed is covered daily with soil. There was no evidence of gullying or leachate seeps on the sideslopes 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 isa small wetland area.

On the west side of the landfill is a machine shop building andthe check-in point to enter the landfill. In this area equipmentis stored and there is some salvage pipe and fencing material. As access to the landfill is restricted there do not appear to beany significant physical hazards to local residents. Next to theshop 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 thesite.

C. Demographics, Land Use, and Natural Resource Use

The East Bethel Landfill is located in the city of East Bethel innorthern Anoka County, Minnesota. According to 1990 estimatedcensus data the population of East Bethel is 8038. Data from a1988 Metropolitan Council survey indicate there are 2,430households in East Bethel. Approximately 70 residences existwithin 1 mile of the site. There are 22 residences about 0.5miles 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 thelandfill. Agricultural uses in the area include crop productionand a hog farm located southwest of the landfill property.

About three-quarters of a mile southwest of the site is a smallgas 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 ofthe landfill property is owned by the Anoka County Parkdepartment. There are no developed accesses to this land and thearea remains unused.

There are three Minnesota Department of Natural Resources (MDNR)protected waters and three protected wetlands within one mile ofthe site. The largest of these is Ned's Lake southeast of thesite and consists of 212 acres of open water with 55 acres ofassociated wetlands. The maximum known depth is 3.5 feet. Thebottom consists of muck with pond weeds, bulrushes, water lilyand coon tail. There is no public access to this lake and it isnot used for fishing. The RI reported there was duck hunting atNed'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.

D. Health Outcome Data

Several sources of health outcome data for Minnesota populationsare available. These include data taken from routinely collectedCertificates of Live Birth, Certificates of Fetal Death, andDeath Certificates. The primary and underlying causes of deathare available from the two sets of mortality certificate data. Fetal anomalies diagnosed within the first days of neonatalobservation are included in the birth certificate records.

In past years, Minnesota had no systematic method for monitoringcancer occurrence, so cancer incidence rates could not becalculated. As of January 1, 1988 the Minnesota CancerSurveillance System began collecting data on cancer. This cancersurveillance system is a statewide system which collectsinformation on all cancers confirmed by pathologists that havebeen diagnosed in Minnesota residents. No data is available foranalysis at this time.

COMMUNITY HEALTH CONCERNS

One resident in a development area south of the landfill, hasexpressed concern about the quality of their drinking water. This resident has a shallow sand point well in the upper sandaquifer about 20 feet deep. It is located about three-quartersof a mile from the southern edge of the site. A woods, anextensive wetlands and a pond separates the landfill propertyfrom this residential area. It is not located in the directionof 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 areused. As a result, it is subject to localized contamination.

Because of the resident's concern the well was sampled on January11th and February 16th of 1990 by the Anoka County CommunityHealth and Social Services Department. The samples were analyzedfor VOC's by the MDH laboratory. The well was sampled inJanuary and February of 1990 with very low levels of 1,1dichloroethane (nd-0.3 ug/l) and 1,1,1 trichloroethane (3.1-4.1ug/l) found in the samples. The source of these contaminants isnot 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 theproblems of nitrates in drinking water and the options formitigating the situation. The MDH will provide this residentwith a copy of the Health Assessment and discuss any questionswith them.

Because of the shallow depth of the well, poor construction, andit's location and distance from the site, it is the technicaljudgement of the MDH, the MPCA, Anoka County Community Health,and the responsible parties' consultants that there is noevidence this well is in any way impacted by contamination fromthe landfill.

This public health assessment was made available for publiccomment from August 13, through September 15, 1991. A summary ofthe comments received and responses is presented in appendix 2.

ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

To identify possible facilities that could contribute to thecontamination near the East Bethel Sanitary Landfill site, theMinnesota Department of Health has reviewed the most recent 1989Toxic 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 certainindustries. TRI did not contain information on toxic chemicalrelease relevant to the East Bethel Sanitary landfill site.

Chemicals are included in this evaluation based on severalconsiderations. These are as follows: 1) MDH has developedhealth based guidelines, Recommended Allowable Limits (RALS), forcontaminants in private drinking water supplies. The RALreflects the maximum concentration of a contaminant in drinkingwater that a person may ingest over a lifetime without risk ofadverse health effects. Chemicals included on this list arethose most frequently found in groundwater in Minnesota. RALsfor non-carcinogens are often taken from the drinking waterhealth advisories published by the EPA Office of Drinking Water(ODW). RALs for carcinogens are derived from the potency slopesfrom the EPA Carcinogen Assessment Group (CAG) and reflect anestimated lifetime excess cancer risk of 1 in 100,000. 2)Chemicals that do not exceed RALs may present a real or potentialhealth hazard to the public based on site-specific informationand professional judgement. In this case, the concern lies withthe unknown health consequences of exposure to low concentrationsof many chemicals simultaneously. Future research data on theadverse health effects of chemical mixtures may necessitatefurther evaluation of this site. 3) Concentrations of chemicalsleaching from landfills are unpredictable. Chemicals are oftenreleased in pulses and monitoring may reflect either peakconcentrations during pulses or lower concentrations foundbetween pulses. In addition, the types of chemicals releasedeither during or between the pulses may be highly variable. Inaddition, monitoring results may be impacted by the variabilityof glacial formations typical of Minnesota and the imprecisenature of hydrogeologic characterization.

A. On-site Contamination

A map of the area impacted by contamination from the landfill ispresented as Figure 2 (RI Report, 1990). One striking feature ofthis map is the occurrence of two plumes, one heading to the westand the other heading south/southwest with a window ofuncontaminated groundwater in between the two plumes directly tothe southwest. Several factors may account for this. Based uponthe soil gas sampling there appear to be significant sources ofcontaminants in the western and southern portions of thelandfill. The fringe of the surrounding wetlands may influencethe shape of the plume as well as the direction of groundwaterflow which is different between the surficial and buried sandaquifers.

Groundwater data provided in the RI report was obtained frommonitoring wells and residential wells. Prior to the RI therewere 30 water table wells and four deep groundwater monitoringwells. Between June and October of 1988, 26 new monitoring wellswere installed in the various aquifers beneath the site, (Referto Figure 1, the Well Location Map). All of these wells wereconstructed in accordance with the MDH Water Well constructioncode.

Remedial Investigation Well Location Map
Figure 1. Remedial Investigation Well Location Map

Area of Impact Map
Figure 2. Area of Impact Map

Several geophysical methods were used to determine the nature ofthe stratigraphy and leachate plume configuration including:resistivity, electromagnetic and seismic (both reflection andrefractions methods). Based upon the survey conducted for thesite and the correlations between groundwater levels and surfacewater levels the shallow groundwater system appears to beconnected hydraulically with surface water. There is alsoevidence of mounding and localized movement of landfill leachatein a halo around the southern edge of the landfill. There was noevidence of leachate seeps beyond the toe of the landfill slopes.

Contaminants have been found in all of the aquifers beneath thesite. The largest number of chemicals have been detected in theA horizon, the upper surficial water table aquifer. Thechemicals that have been detected in the A horizon and the rangeof concentrations are listed in Table 1. The following chemicalshave been found in the A horizon above the MDH health basedguidelines for private water supply wells (RALs): tetrachloroethylene (N/D-12 ug/l), vinyl chloride (N/D-0.15ug/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 surficialaquifer are listed in Table 2. The following chemicals have beenfound 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) andtetrahydrofuran (12-270 ug/l).

Chemicals found in the buried aquifer, the C horizon, are listedin Table 3. The following chemicals have been detected in the Chorizon 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 Dhorizon. They are listed in Table 4. No chemicals above theRALs were found in this bedrock aquifer. The RI reportindicated the phthalates found in the bedrock aquifer may be dueto laboratory contamination of samples. As it is not possible tomake an absolute determination as to the origin of thesecontaminants, the remediation of the groundwater is beingdesigned to remove any phthalates if they do exist.

B. Off-site Contamination

The contaminant plume drops off to nondetectable levels at adistance of about 800 feet from the site. This decrease inconcentration is greater than would be predicted by mostcontaminant transport models due to attenuation, dilution, decayand dispersion. Other site specific factors are also influencingthe contaminant plume. These factors may include downwardvertical gradients, contaminants heavier than water, and/orinteractions with the wetlands. The MPCA is requiring theinstallation of four additional monitoring wells to better definethe 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, 1to the west in the C horizon and 2 wells to the southwest in theB and C horizon.

Five surface water monitoring stations were sampled surroundingthe site, including 1 at Ned's Lake, southeast of the site. Nosignificant contamination attributable to the landfill was foundin the surface water sampling analyses.

Sediment samples were also taken at the surface water monitoringstations. The reported analytical levels for heavy metals(slightly above detection limits) and the general chemistryparameters for sediment samples do not indicate the presence ofcontamination from the landfill.

C. Quality Assurance and Quality Control (QA/QC)

The data supplied are adequate to conduct a Health Assessment forthis site. Sample collection, chain-of-custody, laboratoryanalytical methods, calibration and preventive maintenance ofinstruments, internal quality control, data reduction andvalidation, audits and data-precision assessment were reviewed byMPCA QA/QC staff and found to be in accordance with the EPA-approved Quality Assurance Project Plan outlined in the RIWorkplan. Chemical analyses were conducted by EPA ContractLaboratory Program Laboratories.

D. Physical and other Hazards

The landfill site is fenced and access is restricted. It is also isolated and surrounded by a wetland and woods. Although thereis heavy equipment and some salvage materials at the site they donot appear to be a hazard to local residents. There was noevidence 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

PATHWAY ANALYSES

As previously discussed, wastes received in the past haveresulted in contamination of the groundwater beneath the site. The environmental and human exposure pathways associated with thesite 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 interspersedwith shallow wetlands. There are three aquifers underlying thesite; a surficial water table aquifer, a buried sand aquifer andthe Franconia formation bedrock aquifer consisting of sandstone.

The surficial aquifer varies in thickness from 34 feet to 64feet. It consists primarily of fine sand. In the northern andsouthern half of the site, the glacial till is missing and theupper and lower sand aquifer are continuous. The direction ofgroundwater flow in the surficial aquifer is to thewest/southwest.

The groundwater velocity is estimated to range from 13 to 240feet per year with a typical value of 115 feet per year. Thenearest receptor is the wetlands which are about 790 feet away. The time for groundwater to reach the wetland would be 3.5 yearsfor the typical case and 1.7 to 31 years for the range ofpossible velocities.

There appears to be evidence of a groundwater mound in a fringearound the landfill in the surficial aquifer. This may beenhanced by the lime sludge cover over much of the landfill whichwould increase runoff and direct it to the sandy soils at the toeof the landfill or it may be from deposition of waste in thewater table.

The buried sand aquifer is a brown to reddish brown fine to veryfine sand of about 60 to 100 feet in thickness. The direction ofgroundwater flow in the buried sand aquifer is to the west. Thegroundwater velocity is estimated to range from 15 to 145 feetper year with a typical value of 83 feet per year.

There is 1 residential well in the buried sand about 1400 feetwest of the landfill shop near the entrance road. This is theclosest well to the site and has been monitored for at least fiveyears. Although this well is in the direction of groundwaterflow no landfill contaminants have been found in the samples.

Beneath the buried sand aquifer is the Franconia sandstonebedrock. The direction of groundwater flow in the bedrockaquifer is to the south with a velocity of about 40 feet peryear. There is 1 residential bedrock well more than 2000 feetsouth of the landfill shop.

The groundwater beneath the landfill is contaminated with avariety of chemicals as previously noted. Contaminants have beenfound in the upper and lower surficial aquifers, the buried sandaquifer, and trace amounts have been found in the bedrockaquifer. The groundwater is a pathway for contaminants tomigrate off site. An additional four wells are being installedto further monitor the migration of the contaminant plume. Figure 1 contains a map of the monitoring well locations. Nocontaminants, however, have been found in any residential wellsin the direction of groundwater flow.

2. Air

No ambient air sampling data is available. However, the landfillhas an intact soil and vegetative cover over all but the activefill area which is covered daily. No excavation or disturbing ofthe cover is projected so the possibility of airbornecontaminants is minimized.

Emissions from the planned air stripper are a potential source ofcontaminants. The MPCA Division of Air Quality will be reviewingfor appropriate emission control equipment.

3. Soil

As the East Bethel Landfill has continued to operate as apermitted demolition landfill it has been routinely covered withsoil and is vegetated. The only unvegetated area is the activearea which is covered with soil as it is filled. Therefore thereis no direct exposure to any contaminated soils.

4. Surface water and sediments

The porous nature of the surface soils at the site eliminateproblems from runoff at the landfill. The wetland area to thesouth and west of the landfill, however, represent potentialdischarge points for contaminated groundwater.

The reported analytical levels for heavy metals and generalchemistry parameters for the sediment samples do not indicate thepresence of contamination from the landfill.

No significant contamination attributable to the landfill wasfound in any of the surface water sampling analyses. Nearbysurface waters and sediments are not contaminated and do notfunction as exposure pathways.

Water discharges from the air stripper are a potential source ofsurface water contamination. The MPCA Water Quality Divisionwill be evaluating the discharge, recommending appropriatecontrol technology and reviewing necessary permit requirements.

B. Human Exposure Pathways

1. Groundwater

There are no completed human exposure pathways through thegroundwater. As outlined in the on-site contamination sectionabove, a variety of contaminants have been found, however theyhave not migrated off the landfill site. At present a plume hasbeen detected on site west and southwest of the landfill sourceas shown in Figure 2.

Fortunately, no contamination has been found in any residentialwells. It appears the wetlands surrounding the landfill act as ahydrological barrier to prevent the spread of contamination. Sampling of both monitoring and residential wells will continueduring the planned remediation of the groundwater to prevent anyhuman 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 inoperation and no decision has been made as to its future use. Ifit is used the MPCA Division of Air Quality will require theappropriate emission control equipment.

3. Soil

The landfill has an intact vegetative cover over all but thecurrent fill area which is covered daily. There are no exposedcontaminated soils on the site and therefore no completed humanexposure pathway.

4. Surface water and sediments

No contamination attributable to the landfill has been found inany surface water or sediment samples analyzed. No humanexposure pathway exists through surface water or sediments.

Water discharges from the air stripper are a potential source ofsurface water contamination. The MPCA Water Quality Divisionwill evaluate the discharge, recommend appropriate controltechnology and review necessary permit requirements.

5. Biota

No contamination attributable to the landfill has been found inthe surface water or sediments surrounding the site. As a resultno 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 exposureto the livestock at this farm.

PUBLIC HEALTH IMPLICATIONS

A. Toxicological Evaluation

Because of the large number of compounds detected beneath thelandfill it is necessary to choose contaminants of concern thatrepresent the major hazards. As there are no completed humanexposure pathways at this site, basic toxicological informationon the chemicals of concern is included. These contaminants werechosen for this summary because of their toxicity, volume anddistribution at the site and environmental fate characteristics. The absorption, metabolism, distribution, and toxicology of eachof these chemicals are discussed below.

1. Benzene

Benzene is a neutral, low molecular weight, lipid-solublechemical. Animal studies indicate that virtually all of aningested dose will be absorbed (2) while data from humans showabout 50% absorption from inhalation exposure (3). Benzene canbe absorbed through the skin but at a much lower rate (4). Afraction (estimates from 12 to 50%) is exhaled unchanged. Theabsorbed portion is distributed mostly to liver, bone marrow andfat. Benzene metabolism occurs primarily in the liver andsecondarily in the bone marrow. It is believed that one or morebenzene metabolites are responsible for benzene-induced toxicitydemonstrated to date. Benzene is metabolized by mixed-functionoxidases to hydroxylated benzenes (primarily phenol andhydroquinone), catechol, and 1,2,4-trihydroxybenzene. These canbe metabolized further to quinones or semiquinones (5). Chemicals which increase mixed-function oxidase activity (e.g.,ethanol) will increase benzene metabolism. Conversely, chemicalswhich decrease mixed-function oxidase activity (e.g., toluene,carbon monoxide, PCBs) will decrease benzene metabolism. Benzenemetabolites covalently bind to cellular macromolecules, which maybe the mechanism of toxicity. Urinary excretion of metabolitesis rapid, and can be used as an indicator of benzene exposure.

Bone marrow is a target organ for benzene, and exposure resultsin changes in the circulating formed blood elements. There arenumerous examples of benzene-induced hematological toxicity inhumans occupationally exposed. One investigator estimates thatchronic exposure to as little as 10 ppm may cause depressedlymphocyte levels and lymphocytopenia (6). In addition, there isevidence that there may be a positive association betweenpancytopenia 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 benzeneexposure, including "antibody formation against leukocytes,platelets, and red cells" (7).

Studies consistently show structural and numerical chromosomalaberrations in human lymphocytes exposed to benzene (5). Epidemiological and case studies also show a link between benzeneexposure and leukemia. Based on human epidemiological studies inoccupational settings by Rinsky (8), Ott (9), and Wong (10), theEPA Carcinogen Assessment Group (CAG) designates benzene as groupA (human carcinogen). EPA CAG has estimated that lifetimeingestion of water (2 liters/day) containing 7.0 ug benzene perliter of water would present an increased cancer risk of oneexcess cancer per population of one hundred thousand (11, D.Bayliss, pers. comm). The Occupational Safety and HealthAdministration has established a permissible exposure limit of 1ppm as an 8 hour time-weighted-average concentration, and a shortterm (15 minute) exposure limit of 5 ppm, for inhalation ofbenzene in the occupational environment (29CFR 1910.1028).

2. Tetrahydrofuran

Tetrahydrofuran (THF) is a low molecular weight, water solublechemical. The primary use of tetrahydrofuran is as a solvent todissolve synthetic resins, particularly polyvinyl chloride, andvinylidene chloride copolymers. It is also used as a solvent inthe production of tetraethyl and tetramethyl lead. No naturalsources of THF exist.

Because of its high vapor pressure and water solubility,significant amounts of THF can be released to the environmentwhen used as a solvent. Once it is released to the environmentlittle monitoring data exists. In the atmosphere THF shoulddegrade very rapidly and should be removed by rain. In water itmay biodegrade. Spills on soil are expected to evaporate rapidlyand leach into the groundwater. It is not expected tobioconcentrate in aquatic organisms (12).

THF can be absorbed through inhalation across the alveolarmembrane and from the digestive tract. Absorption can also occurthrough the skin (13). THF has also been found in mothers milk(14).

Reports of animal studies indicate irritation of the skin andmucous membranes including the eyes, nose and respiratory tractas the primary effect from exposures of 100 to 200 ppm (15). High acute doses (25,000 ppm) produced anesthesia, a fall inblood pressure and strong respiratory stimulation. Afterprolonged exposures to levels greater than 1000 ppm damage to theliver, kidneys and lungs has been observed in laboratory animals(16).

Daily 6 hour exposures of dogs to 200 ppm THF resulted in anobservable effect on pulse pressure within 3 or 4 weeks. Theroute of exposure was not specified. No demonstratablehistopathologic changes occurred in critical organs of theanimals despite exposure for 9 weeks followed by an additional 3week exposure at nearly twice this level (16).

THF was negative in the Ames test for mutagenicity (17). In acytogenicity test using Chinese hamster ovary cells THF testedpositive for chromosome aberrations and negative for sisterchromatid exchanges. THF tested negative for mutagenicity in thestandard National Toxicology Program Salmonella/microsomepreincubation assay (18). THF has been tested forcarcinogenicity in mice. A test for skin tumors was conducted inwhich THF was applied to the skin of mice twice per week for 25exposures and observed for 17.5 months. No carcinogenic effectwas observed (19).

Data on toxicity of THF in humans is limited, however, there havebeen health complaints from workers exposed to THF. A report hasbeen published on two workers who were exposed to a gluecontaining THF in a confined space. They both had signs ofirritation of the mucous membranes, mild effects on the centralnervous system and cytolytic hepatitis. After removal from theexposure all clinical signs in both workers were gone within twodays and liver enzymes returned to normal within two weeks (13). Severe occipital headaches have been reported in technicianstesting for pharmacological properties of THF.

The probable lethal dose in humans is estimated to be 50-500mg/kg. The National Institute of Occupational Safety and Healthhas established an eight hour time-weighted average thresholdlimit value of 200 ppm for the protection of workers (20). Adrinking water MDH RAL has been set at 154 ug/l based on the EPASummary of Acceptable Daily Intakes for Oral Exposures.

B. Health Outcome Data Evaluation

The available data sources provide descriptive information on thecrude incidence of selected outcomes and may be used in attemptsto detect trends or associations. However, because the number ofpeople potentially exposed to the site is very small asignificant change in disease rate among the site populationwould not be detected. County-based incidence rates do notinclude an accurate measure of exposure and therefore, are notspecific enough to be representative of the small populationpotentially exposed to the site.

From the available county-based data alone, it would not bepossible to conclude that the site has, or has not, impacted thehealth of the 23 residences surrounding the site. Actualsampling data from the site indicates there has been no humanexposure to contaminants. If health outcome data on thispopulation becomes available, it will be evaluated in an attemptto detect any causal relationship.

C. Commounity Health Concerns Evaluation

One resident in a development area south of the landfill, hasexpressed concern about the quality of their drinking water. This resident has a shallow sand point well in the upper sandaquifer about 20 feet deep. It is located about three-quartersof 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 theproblems of nitrates in drinking water and the options formitigating the situation. The MDH will provide this residentwith a copy of the Health Assessment and discuss any questionswith them.

Because of the shallow depth of the well, poor construction, andit's location and distance from the site, it is the technicaljudgement of the MDH, the MPCA, Anoka County Community Health,and the responsible parties' consultants that there is noevidence this well is in any way impacted by contamination fromthe landfill.

This public health assessment was made available for publiccomment from August 13, through September 15, 1991. A summary ofthe comments received and responses is presented in appendix 2.

CONCLUSIONS

At the present time, based on the information reviewed, the MDHhas concluded there are no public health hazards from this site,because no human exposure to contaminants is occurring, nor hasit occurred in the past. Remediation, however, is necessary toprevent any possibility of contaminants moving into areas wherehuman exposure could occur.

RECOMMENDATIONS

The planned monitoring of the groundwater both on and off siteshould continue to prevent any human exposures to contaminantsthrough ingestion of contaminated drinking water.

Remediation of the contaminated groundwater underneath the sitewill begin as soon as the feasibility study is completed and amethod is chosen. The review of the feasibility study is beingconducted by the MPCA. At present there is no human exposure tocontaminants from the landfill. To assure this situationcontinues 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, theEast Bethel Landfill site has been evaluated for appropriatefollow-up with respect to health activities. Based on theinformation and data reviewed during the preparation of thisHealth Assessment no human exposure to contaminants atconcentrations of public health concern is occurring or isbelieved to have occurred in the past. Therefore, this site isnot being considered for follow-up health activities at thistime. However, if data become available suggesting that humanexposure to hazardous substances at levels of public healthconcern is occurring, ATSDR and the Minnesota Department ofHealth will re-evaluate this site for any indicated follow-upactivities. A community education effort related to this sitewas initiated. Public meetings have been held by the MPCA toexchange information with members of the community.

PUBLIC HEALTH ACTIONS

The MDH along with the Agency for Toxic Substances and DiseaseRegistry (ATSDR) will monitor the progress of the aboverecommendations. The MPCA will continue to require quarterlygroundwater sampling. MDH will review the results of thegroundwater sampling to monitor for any public healthimplications.

The MPCA is reviewing the Feasibility Study/Detailed Analysisreport which outlines the proposed remedial actions. The MDHwill also review this report to determine if the proposedremediation will be protective of public health. MDH will makeadditional recommendations if necessary. MDH will monitor theremedial actions with the MPCA and will make additions to thisassessment if warranted. Additional conclusions orrecommendations will be communicated to the local residentsthrough fact sheets, mailings or meetings as necessary.

PREPARERS OF REPORT

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

CERTIFICATION

This public health assessment was prepared by the MinnesotaDepartment of Health under a cooperative agreement with theAgency for Toxic Substances and Disease Registry (ATSDR). It isin accordance with approved methodology and procedures existingat the time the health assessment was initiated.

Burt J. Cooper
Technical Project Officer, SPS, RPB, DHAC

The Division of Health Assessment and Consultation, ATSDR, hasreviewed this health assessment and concurs with its findings.

Director, DHAC, ATSDR

REFERENCES

  1. Final Report Remedial Investigation - East Bethel Landfill February 16, 1990
    Prepared by Bruce A. Liesch Associates, Inc.
    3020 Harbor Lane, Minneapolis, Minnesota, 55447
    and
    Environmental Resources Management-North Central, Inc.
    102 Wilmot Road
    Suite 300
    Deerfield, IL., 60015

  2. Sabourin, P., B. Chen, R. Henderson, G. Lucier and L. Birnbaum. 1986. Effect of dose on absorption and excretion of 14C benzene administered orally or by inhalation. The Toxicologist 6:163.

  3. ATSDR (Agency for Toxic Substance and Disease Registry). 1987. Toxicological Profile for Benzene. Draft for public comment. U.S. Public Health Service.

  4. Blank, I. H. and D. J. McAuliffe. 1985. Penetration of benzene through human skin. J. Invest. Dermatol. 85:522-526

  5. Snyder, C. A. 1987. Benzene. In: Snyder, R. (ed.) Ethyl Browning's toxicity and metabolism of industrial solvents, 2nd ed., V.1: Hydrocarbons.

  6. Chang, I. . 1972. Study on the threshold limit value of benzene and early diagnosis of benzene poisoning. J. Cath. Med. Coll. 23:429-434.

  7. Goldstein, B. D. 1977. Hematotoxicity in humans. J. Toxicol. Environ. Health. Suppl. 2:69-105.

  8. Rinsky, R. A., R. J. Young and R. B. Smith. 1981. Leukemia in benzene workers. Am. J. Ind. Med. 2:217-245.

  9. Ott, M. G., J. C. Townsend, W. A. Fishbeck and R. A. Langer. 1978. Mortality among workers occupationally exposed to benzene. Arch. Environ. Health. 33:3-10.

  10. Wong, O., R. W. Morgab and M. D. Whorton. 1983. Comments on the NIOSH study of leukemia in benzene workers. Technical report submitted to Gulf Canada Ltd, by Environmental Health Associates, as seen in EPA, 1986.

  11. EPA (U. S. Environmental Protection Agency). 1985. Drinking water criteria document on benzene. PB86-118122.

  12. Howard, P.H., Handbook of Environmental Fate and Exposure Data for Organic Chemicals, Vol.II, solvents, 1990, pp.430- 434.

  13. R. Garnier, N. Rosenberg, J.M. Puissant, J.P. Chauvet, M.L. Efthymiou, Tetrahydrofuran poisoning after occupational exposure. British Journal of Industrial Medicine 1989; 46:677-678.

  14. Pellizzari Ed., et al., Purgeable Organic Compounds In Mother's Milk; Bull Environmental Contamination and Toxicology 28: 322 (1982)

  15. Katahira T. et al, Sangyo Igaku 24 (4): 373-378 (1982).

  16. American Conference of Governmental Industrial Hygienists (ACGIH), Documentation of TLVS 5th Edition, 1986, p.564.

  17. Mortelmans K et al; Environ Mutagen 8:1-119 (1986)

  18. NTP; Fiscal Year 1984 Annual Plan p.75 (1984) NTP-84-023

  19. McMahon R.E., Cancer Research 39 (3): 682 (1979)

  20. NIOSH OSHA Occupational Health Guide Chem. Hazards. 1990, p.210.

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 MinnesotaDepartment of Health entitled "Superfund Site Health Facts -Information for Citizens about East Bethel Landfill". It hasbeen sent to interested local residents (See attachment 1). Itincludes a summary of the site history and a question and answersection about health risks. Names and phone numbers of people tocontact for further information are listed on the fact sheet. Apress release was sent to local media announcing the publiccomment period.

Fact Sheet page 1

Fact Sheet page 2

info tagline

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 officialswas obtained from the Minnesota Pollution Control Agency Officeof Public Information. A copy of the draft Health Assessment, acitizen's fact sheet about the site and a letter explaining howto respond during the 30-day comment period was sent to thepeople on this list.

During the 30-day comment period (August 13 - September 15,1991), we received two letters. Each of the concerns raised inthe letters were investigated and some of the informationprovided resulted in additions to the assessment. A letter hasbeen sent to the interested citizens responding to theirconcerns. The following is a summary of the concerns and theresponses to them.

  1. Concern: Four new wells are being installed, not five as theassessment originally stated.
  2. Response: This has been corrected to read four.

  3. Concern: The term sanitary landfill was used to describe thelandfill. It is actually a demolition landfill.
  4. Response: The term sanitary landfill has been changed todemolition landfill.

  5. Concern: The total site includes 95 acres.
  6. Response: The assessment has been changed from 60 to 95 acres.

  7. Concern: Composting of yard waste is not being done at thesite.
  8. Response: The assessment has been changed to explain yardwaste is being used to fill a borrow pit.

  9. Concern: About the possible reasons for a groundwater moundat the edge of the landfill.
  10. Response: The assessment has been changed to reflect thevarious reasons for a groundwater mound.

  11. Concern: Figure 1. was difficult to read.
  12. Response: Figure 1 has been eliminated.

  13. Concern: What does figure 1 showing the area of impact mean?
  14. Response: According to the sampling results from monitoringwells, the contaminant concentrations drop off to nondetectableat 800 feet from the site. Figure 1, showing the area of impactis designed to give a visual image of the contamination area. Ihave added an arrow to the figure to better illustrate the edgeof the plume.


Prepared by the
Minnesota Department of Health
Section of Health Risk Assessment

APPENDIX 3:

RECOMMENDED ALLOWABLE LIMITS FOR DRINKING WATER CONTAMINANTS
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.


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