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PUBLIC HEALTH ASSESSMENT

STOUGHTON CITY LANDFILL
STOUGHTON, DANE COUNTY, WISCONSIN


SUMMARY

The 27-acre Stoughton City Landfill operated between 1952 and 1982 as a disposal site formunicipal and industrial waste. The site is located on the northeastern edge of the City ofStoughton, Wisconsin, approximately 13 miles southeast of Madison. Between the mid-1950s andthe mid-1960s, the site was used for disposal of solvents and other wastes generated by a Stoughtonplastics manufacturer. Contamination at other disposal sites used by the manufacturer led toconcerns that this landfill may be affecting local groundwater and surface water and that a parkplanned for the site may not be safe.

Limited sampling data indicate that groundwater under the site is contaminated with tetrahydrofuranat levels exceeding Wisconsin Groundwater Enforcement Standards. However, this site-relatedcontaminant has not been detected in private and municipal wells in areas surrounding the site. Moreover, surface water and sediment on the site and in adjacent wetlands do not appear to becontaminated with chemicals at concentrations above levels of human health concern. However,methane gas appears to exceed explosive levels in a portion of the landfill.

Significant human exposure to site-related contaminants has not occurred to date. However, suchexposure could occur if the site is unremediated. Based on the lack of documented human exposureto site-related contaminants, the Division of Health has determined that this site poses no apparenthuman health hazard at the present time. The site would pose a public health hazard in the future iftetrahydrofuran in groundwater were to reach the municipal water supply at levels exceeding theWisconsin Groundwater Enforcement Standard.

The recommendations of this health assessment are further analysis of monitoring well samples andthe sandstone aquifer and to prevent methane migration into nearby buildings.

Since human exposure to contaminants is not likely, ATSDR's Health Activities RecommendationPanel has determined that no additional follow-up activities are need at this time.

The Division of Health will provide continuing public health education as new information relatedto public health issues becomes available, and will review and comment on public health aspects ofsampling and subsequent activities to be done pursuant to the Record of Decision.


BACKGROUND

Site Description and History

The Stoughton City Landfill is on the eastern edge of Stoughton, Dane County, Wisconsin, a city ofapproximately 8,000 located 12 miles southeast of Madison (see Appendix B). A suburban area ofStoughton begins about 1000 feet south of the landfill and further development is expected to thesouth and east (7). Immediately northwest of the landfill are the Yahara River and undevelopedwetlands owned by Dane County. Wetlands also border landfill to the northeast. Aerialphotographs indicate that farmland is about 1000 feet east of the wetland.

The 27-acre Stoughton City Landfill operated as an uncontrolled municipal waste dump from 1952to 1969. During this time, refuse was usually burned and occasionally covered with dirt. Somesolid and liquid waste may have been disposed of in bore-holes drilled in the western portion of thelandfill. Until 1962, the landfill accepted all types of wastes collected from homes and businesses inStoughton. Businesses using the landfill included dry cleaners, garages and other sources ofpotentially hazardous wastes (1). After 1962, the city disposed of refuse at another site but thelandfill continued to accept waste independently transported to the site (1). A survey conductedduring the Remedial Investigation (RI; see below) showed that many solvents, including methylethyl ketone, acetone, tetrahydrofuran, toluene and xylene mixtures, were disposed of at the landfill(2).

In 1969, the Wisconsin Department of Natural Resources (WDNR) licensed the site for disposal ofsolid waste. WDNR felt that the porous soil and relatively high water table made the locationunsuitable for a landfill and, between 1971 and 1977, negotiated with the city in an effort to closethe landfill. In 1977, the WDNR formally requested that the city submit an abandonment plan forthe landfill. Between 1978 and 1982, when the landfill officially closed, the site was used fordisposal of demolition and wood wastes only.

In the late 1950s and early 1960s, Uniroyal Plastics Inc. (then called U.S. Rubber Company)disposed of solid and liquid waste from their Stoughton plastics manufacturing plant at the site. Noinformation on the precise quantities or types of waste is available. However, the company hasprovided lists of solvents used at their plant during that time. The discovery that waste solvents hadcontaminated groundwater at two other Uniroyal disposal sites, the Hagen Farm and the EveryFarm, led the WDNR to request in March 1984 that the U.S. Environmental Protection Agency(USEPA) Exiting ATSDR Website consider placing the site on the National Priorities List (NPL). This action would makethe site eligible for further study and cleanup under the USEPA "Superfund" program. USEPAproposed placement on the NPL in October 1984 and placed it on the list in June 1986.

Prior to 1988, limited sampling was performed by the WDNR, the Wisconsin Department of Healthand Social Services (WDHSS) and various contractors for the City of Stoughton. In 1988, inconformance with a Consent Order with USEPA, the City of Stoughton and Uniroyal contractedwith ERM-North Central of Deerfield, IL to perform a "Remedial Investigation/Feasibility Study"(RI/FS) on the Stoughton City Landfill. In 1989, a different contractor, ENSR Inc. of Chicago, IL,began work on the RI/FS, which was completed in January 1991. As stated in the Consent Order,the objectives of the RI were to determine the extent of hazardous contaminants released from thelandfill and, if necessary, to identify potential actions that could be taken at the site to mitigate anyhazards.

On September 30, 1991, USEPA signed a Record of Decision specifying a comprehensive cleanupplan for the site. The cleanup plan includes relocating waste from direct contact with thegroundwater and capping the site with a cap meeting current WDNR standards for landfills. Because of inadequate groundwater data, the potentially responsible parties are required to install anumber of new monitoring wells between the landfill and the municipal well. Based on the resultsof that sampling, the USEPA will decide whether or not to require a comprehensive groundwatercleanup of the site (4).

The northern third of the site, which was not used for waste disposal, is primarily composed ofwetlands (see Appendix A)(3). The waste, which is 0-12 feet deep over an area of approximately 15acres, is covered with approximately one foot of soil and seeded with grasses (5). About 200 feetbelow the ground surface is a layer of sandstone bedrock which is approximately 1000 feet thick (5). The soil between the waste and sandstone is comprised of glacial deposits containing fine grainedsands, silt, and clay which are moderately permeable. No naturally occurring surface soils remain atthe landfill (5).

Surface water runoff throughout the site is to ditches leading to the wetlands to the north and east. These wetlands drain into the Yahara River, which is 200 feet from the northwest boundary of thesite and 800 feet west of the disposal area. A pond and ditch in the northern portion of the site(about 100 feet from the disposal area) often contain standing water. Some site-related compoundswere found in these wetlands during the RI at concentrations exceeding Wisconsin Surface WaterQuality Criteria.

Two major aquifers underlie the site: one in the glacial outwash and the other in the sandstonebedrock. During wet weather, the water table may reach 0-1 feet below the ground's surface. Thetwo aquifers appear to be hydraulically connected (6).

Site Visit

Representatives from WDHSS visited the site on July 24, 1991. No physical hazards were evidentand a locked gate was installed at the Amundson Parkway entrance. The Sampling and AnalysisPlan for the Remedial Investigation indicated that another locked gate controlling vehicular accessexists but was not seen during the site visit.

The RI states that snow fencing has been installed along the southern property boundary andwarning signs placed every 200 feet along the western, northern and eastern boundaries. No snowfencing was visible during the site visit, although several signs were present. The site was coveredwith grasses widely scattered areas of bare soil and asphalt.

Demographics, Land Use and Natural Resource Use

The Stoughton City Landfill is on the eastern edge of Stoughton, a city of approximately 8,000located 12 miles southeast of Madison (see Appendix B). Two nursing homes which use municipalwater occupy land adjacent to landfill on the south. A suburban area of Stoughton begins about1000 feet south of the landfill and further development is expected to the south and east (7).

Census data from 1980 indicates that most of the 365 people living adjacent to the site are over 65years of age and very few are under 18. About 1/4 of the 289 people living between 1/8 and 1/4mile of the site are under age 18 and very few are over 65. No Blacks, Asians or persons of Spanishorigin live within 1/4 mile of the site. The Stoughton area has a population of 17,563 of which98.8% are white (8). The area is predominantly middle class and housing is comprised mostly ofsingle-family homes (8).

Immediately northwest of the landfill are the Yahara River and undeveloped wetlands owned byDane County. Wetlands also border landfill to the northeast. Aerial photographs indicate thatfarmland is about 1000 feet east of the wetland.

Health Outcome Data

No state or local health data are relevant since no exposure has been documented nor have community health concerns been expressed.


COMMUNITY HEALTH CONCERNS

At the time of the site visit, the WDHSS arranged a meeting with the local public health agency andelected officials. The mayor of Stoughton and a representative of the Dane County HealthDepartment attended. The WDHSS representative explained the purpose of public healthassessments and requested information about community health concerns. The officials were notaware of any community health concerns related to the landfill. Rather, the community is concernedabout the potential fiscal costs of the Superfund process and about the loss of a communityrecreational facility.

Anticipating potential concerns of the six users of private water supply wells located within 1500feet of the landfill, WDHSS analyzed water samples from these wells in July 1988. WDHSSnotified the well owners immediately that no contaminants were found in these samples. In addition,a representative of WDHSS presented its findings at a public meeting about the landfill inNovember 1988. At this meeting two citizens expressed concern that public officials were notproperly characterizing the contamination at the site. Most concerns, however, related to the costs ofthe Superfund process.

WDHSS provided several opportunities for the community to identify health concerns associatedwith the landfill. A representative of WDHSS discussed the public health assessment at a publicmeeting in July 1991 and appeared at a public meeting in September 1991. A draft of this publichealth assessment was available locally for public comment in April 1992. Both meetings and therelease of the public health assessment were covered by local media. WDHSS received nocomments on the public health assessment.


ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS

This section describes contamination and other hazards associated with the Stoughton City Landfillsite. Contaminants of concern are selected for further analysis in following sections. Areasconsidered to be "on-site" are those areas on Stoughton City Landfill property. All other areas areconsidered to be "off-site". Environmental sample results are summarized in this section as theyapply to both on-site and off-site contamination.

The tables in this section list the contaminants of concern. We evaluate these contaminants in thesubsequent sections of the Public Health Assessment and determine whether exposure to them haspublic health significance. ATSDR and WDHSS selects and discusses these contaminants based upon the following factors:

  1. Concentrations of contaminants on and off the site.

  2. Field data quality, laboratory data quality, and sample design.

  3. Comparison of on-site and off-site concentrations with health assessment comparisonvalues for (1) noncarcinogenic endpoints and (2) carcinogenic endpoints.

  4. Community health concerns.

In the data tables that follow under the On-site Contamination subsection and the Off-siteContamination subsection, the listed contaminant does not mean that it will cause adverse healtheffects from exposures. Instead, the list indicates which contaminants will be evaluated further inthe Public Health Assessment. When selected as a contaminant of concern in one medium, thatcontaminant will be reported in all media.

A comparison value is a contaminant concentration level below which human exposure is likely tobe without harmful health effects. Comparison values are derived from toxicity data and exposuredose assumptions for specific media (e.g. soils, drinking water, etc.). These values are referred towhen possible to help select potential contaminants of concern from the results of samples takenfrom the site.

On-site Contamination

A summary of on-site sampling activities is presented in Table 1.

Table 1.

Summary of On-Site Sampling at Stoughton City Landfill
Medium Date Sampler Parameters
Soil Gas 1989 ERM+ VOC*, SVOC**, Some pest.***
Soils 1989 ERM VOC, SVOC, Metals
Air 1989 ERM Some VOC
Surface Water and Sediment 1989 ERM VOC, SVOC, Metals
Groundwater 1982-90
1984
1984
1989
Strand++
Strand/WDNR
Various Contractors
ERM
Indicators
VOC
VOC
VOC, SVOC, Metals, Pest.

+ ERM-North Central Inc. under contract to Uniroyal and the City of Stoughton.
++ Strand Associates Inc. under contract to the City of Stoughton
* Volatile organic compounds
** Semivolatile organic compounds
*** Pesticides

Soil Gas. During the RI, 74 soil gas samples were taken from different locations on the landfillproperty and 10 samples adjacent to the landfill. In general, chlorinated solvents (concentrationsnon-detected [ND]-9.3 parts per million [ppm]) and fluorocarbons (ND-100 ppm) are distributedthroughout the landfill. The highest levels of nonchlorinated solvents (2.5 ppm) and petroleumderivatives (3.2 ppm) were found in the west-central and northern portions of the landfill (seeAppendix A) (9). Since soil gas sampling is not designed to identify particular compounds, theresults of this sampling can only be used to identify areas where more sampling may be necessary.

Due to the detection of methane during installation of one of the monitoring wells, a comprehensivemethane survey was conducted by USEPA in May 1989. In this survey, methane was detected atlevels over the lower explosive limit in the west-central portion of the landfill and in the vicinity ofthe building (10).

Mixed soil/waste. Two mixed soil/waste samples were taken in conjunction with the installation ofmonitoring wells (MW) 2 and 6: one from 6 to 8 feet below the surface in the southwestern portionof the site (MW 2) (Appendix A) and one from 2 to 4 feet below the surface in the northeasternportion (MW 6). The samples were extracted and analyzed by gas chromatography. Benzene,chloroform and a number of polyaromatic hydrocarbons (PAHs) were identified in soil/waste fromthese locations but not quantified. The PAHs phenanthrene, fluoranthene, purene andbenzo(a)anthracene were detected at levels which are not of health concern. No polychlorinatedbiphenyls were detected and the only pesticide identified was 4,4'-DDD in one sample. Lead,cadmium and mercury were found at levels above background but not at levels of health concern. Other metals of potential concern such as arsenic, barium, chromium and silver were not found. Concentrations of compounds were quantified only in one of the two soil/waste samples.

Soil. Four soil samples were taken in conjunction with the installation of monitoring wells, one from0-2 feet below ground surface (bgs), one from 2-4 feet bgs and one from 4-6 feet bgs (11). Like thewaste samples, analysis was performed by gas chromatography.

No specific solvents or polyaromatic hydrocarbons were identified in soil samples. Someunidentified hydrocarbons were detected. It is not clear if the 0-2 feet sample was taken from thesurface; otherwise, no surface soil samples were analyzed.

Soils from the west-central portion of the landfill (Appendix A), which the soil gas survey identifiedas contaminated with solvents, were not analyzed.

Surface Water and Sediment. Six surface water samples were taken on and adjacent to the landfillboundaries and analyzed for methylene chloride, acetone, dichlorofluoromethane and metals. Nosolvents were detected in these samples, nor were metals detected at levels over twice background. Eight sediment samples were analyzed for the compounds described above as well as for 2-butanone,PAHs and metals. Extremely low levels of PAHs were found in one sample (12).

Air. Air sampling by the WDNR in response to odor complaints in 1985 revealed no volatileorganic compounds (VOCs) in the vicinity of the landfill. During the RI, air samples were taken ontwo occasions from two upwind and seven downwind locations from the site. Trans-1,2-dichloroethene, ethyl benzene, toluene and xylenes were detected at 20-60 parts per billion at oneunspecified location. These levels are lower than the threshold limit values calculated for use inoccupational settings by a factor of approximately 10,000 (13) and are not of health concern.

Groundwater. Six monitoring wells were installed within the landfill in 1978 and have beensampled for indicator parameters (chemical oxygen demand, hardness, alkalinity, chloride, dissolvediron, field conductivity, field pH, and groundwater elevation) semiannually since 1982. Between1982 and 1984, WDNR and various contractors sampled these wells for some VOCs. The results ofthese sampling episodes are inconsistent with one another (14) (see QUALITY ASSURANCE ANDQUALITY CONTROL below), so the data are of limited value. However, the data do suggest thatthe groundwater under the landfill may contain benzene, ethylbenzene, 1,2-dichloroethylene (1,2-dichloroethene), tetrahydrofuran, toluene, and xylenes.

During the RI, six two-well clusters consisting of one shallow well (15 feet below the surface) andone deep well (60-80 feet) were installed. The deepest monitoring well was 75.6 feet, and no wellpenetrated the bedrock from which the City of Stoughton obtains its water (15). Samples werecollected during three sampling rounds in May, August and October, 1989. Analyses wereconducted for a standard list of VOCs, semi-volatile organic compounds (SVOCs) and some metalsduring the first sampling round. Those which were not found (except for methylene chloride andacetone) were not analyzed during the second round (16). The third sampling round was conductedbecause holding times were exceeded for some compounds in the samples taken during the secondround. A "background" water sample was taken from an unused residential well about 500 feet eastof the landfill boundary. The well water contained 65 micrograms per liter (µg/L) of lead, aconcentration exceeding Wisconsin's Groundwater Enforcement Standard of 50 µg/L. This wellwas installed with steel casing and is equipped with a hand-operated piston pump. Cadmium,copper, zinc and iron were also found in this well, suggesting to the authors of the RI that corrosionof the well casing and/or pump components may be the source of these compounds.

Results of groundwater testing during the RI are summarized in Table 2. Methylene chloride andacetone were also analyzed for but not detected.

From the available data, it appears that groundwater under the western section of the landfill iscontaminated at least with chlorofluorocarbons and tetrahydrofuran. Bis (2-ethylhexyl) phthalatewas also found in one sample at a level exceeding the Groundwater Enforcement Standard. Thecontaminants are present at all sampling depths in the two wells closest to this area. Monitoringwells south of the site do not contain any site-related contaminants. However, no data are availablefor the area of the landfill identified as the most contaminated from the soil gas samples (the west-central portion; Appendix A) or for the deeper aquifer.

Xylenes, 1,2-dichloroethene, arsenic, barium and lead were also found at levels below enforcementstandards in a small number of samples.

Table 2.

Chemicals of Potential Health Concern in On-Site Groundwater
Compound Concentrations Detected (µg/L)
Minimum Maximum
Frequency of Detection@ Standard
VOCs
Tetrahydrofuran (THF) 19 660* 6/25 50+
Trichlorofluoromethane 6.4* 16 6/25 None
SVOC
Bis(2-ethylhexyl)phthalate - 44* 1/23 3++

* Estimated value or below Contract Required Quantitation Limits. The highest verified value for THF was 492 g/L.
@ Number of detects/number of sampling events.
+ Wisconsin Groundwater Enforcement Standard
++ Wisconsin Proposed Groundwater Enforcement Standard

Source: Remedial Investigation Report, Table 4-12.

Off-site Contamination

Samples are defined "off-site" if taken outside the boundaries of the 27-acre parcel identified inAppendix A. The history of sampling for off-site contamination is summarized in Table 3.

Table 3.

Summary of Off-Site Sampling Results
Location Date Sampler Parameters
Yahara River 1984 WDNR VOC
Downwind air 1985 WDNR VOC
Municipal wells 1982
1983
1985
1986
1991
WDNR
WDNR
WDNR
WDNR
City of Stoughton
VOC
VOC
VOC
VOC
THF
Private wells 1988 WDHSS VOC

Soils. No off-site soil sampling has been performed. A methane gas survey in 36 unspecifiedresidences south of the landfill was performed by the USEPA Emergency Response Team. Nomethane gas was detected during the course of this survey (17).

Surface water. No VOCs were detected in a single surface water sample collected from the YaharaRiver at an unspecified location adjacent to the landfill. The sample was collected by StrandAssociates on behalf of the City of Stoughton in September 1984 (18).

Some surface water samples were taken from wetlands adjacent to the site but outside the siteboundary. Results from these samples are described in "on-site sampling" above.

Air. In response to complaints about odors emanating from the landfill, the WDNR collectedsamples downwind from the landfill in 1985. No VOCs were detected at that time (19). However,the conditions of sampling are not available so these data are of limited value (see QUALITYASSURANCE AND QUALITY CONTROL below).

Groundwater. Municipal wells for the City of Stoughton have been sampled for VOCs including thedichloroethene isomers, xylenes, trichlorofluoromethane, benzene and tetrahydrofuran four times bythe WDNR since 1982 as part of a statewide water quality investigation. No VOCs were detected inthese samples (20). In July, 1991, a private contractor hired by the City of Stoughton analyzedsamples from wells 3 and 6 for tetrahydrofuran, and none was found above the detection limit of 10g/L (21). In 1988, WDHSS analyzed water from five residential wells south of the site and from awater supply well at a cemetery approximately 1500 feet southeast of the landfill boundary. NoVOC contamination was detected in any of these wells.

No off-site groundwater sampling was performed during the RI.

A search of the Toxic Chemical Release Inventory for the zip code including Stoughton did notreveal any facilities releasing the chemicals of concern at this site. One rubber manufacturer islocated within the zip code.

Quality Assurance and Quality Control

Little or no quality assurance/quality control (QA/QC) information is available for pre-RIinvestigations. For example, well construction details, sample storage procedures or instrumentcalibration are not available for any of the WDNR or Strand Inc. sampling. Thus, inconsistencies inthe data are impossible to explain. These data can only be used as guidelines for further sampling.

QA/QC procedures are better documented in the RI, although some details such as the depth of soilgas samples are not specified. No samples were split between more than one laboratory, a commondata validation procedure. However, in accordance with USEPA-established procedures,Environmental Standards, Inc., of Valley Forge, Pennsylvania undertook a quality assurance reviewof all groundwater sampling data. The reviewers concluded that many of the data values could notbe used due to laboratory analysis problems. As a result, these data values were flagged in the finalreport. In addition, the USEPA "validated" the data for Round 1 (22).

Physical and Other Hazards

Methane gas is present at levels over the explosive limit in the southwestern section of the landfill(Appendix A) and under the building constructed on the site. The relatively permeable cap allowsmethane to escape, and, thus, pressure would probably not build up to explosive levels. Nevertheless, gas concentrations inside the building could potentially reach explosive levels.


PATHWAYS ANALYSES

People may be exposed to the chemicals of concern in a number of ways. The pathways analysislooks at five elements in two broad categories Environmental Pathways - the source of thechemicals, where they are found (soil, water, air), the ways the chemicals may move from the site;and Human Exposure Pathways- ways by which people could be exposed to the chemicals (touch,ingestion, inhalation), and the groups of people that might be exposed.

Exposure pathways are referred to as completed, potential, or eliminated. A completed pathway isone where there is a clear indication that people were exposed to chemicals from the site and whenthere is sufficient information to evaluate that exposure. All five of the elements must exist for acompleted pathway to exist. This includes exposures that occurred in the past and exposures that arecurrently happening.

A potential pathway exists when there is insufficient information to link a chemical to a known levelof exposure among an identified population. A potential pathway may refer to a past, present, orfuture exposure. An exposure pathway can be eliminated if one of the five elements is missing andwill never be present.

Environmental Pathways

Waste. Soil gas analysis revealed the presence of a number of solvents, most notably in the west-central portion of the landfill (see on site contamination above). These solvents are volatile andmay migrate off the site into nearby soils. However, the fact that no methane was found off the siteindicates that measurable levels of landfill gases are not likely to be migrating as far off-site as thelocation of the houses.

One waste sample of two analyzed during monitoring well installation appeared to be contaminatedwith PAHs, one pesticide, cadmium and low levels of lead and mercury. Because these compoundsbind tightly to organic matter and soil particles, they are not likely to migrate into groundwater (23,24, 25, 26, 27).

Soil. Soil gas results indicate that soil in a wide area may be contaminated with solvents. The mostpervasive compounds include trans-1,2-dichloroethene, trichloroethene and fluorocarbons. Whilethese compounds may volatilize from soil into the air, limited air sampling data do not indicate thatsuch volatilization is occurring.

Food Chain. Potential chemical exposure through the food chain may occur through consumption ofcontaminated wildlife. The area is surrounded by wetlands which may be inhabited by waterfowland fish taken from the Yahara River may be consumed. Limited sampling data from surface waterboth on site and in the Yahara River indicate that contaminant releases occurring from the landfillinto surface water are too low to concentrate in the food chain to levels of human health concern. Inaddition, no or low levels of contaminants are apparently present in the wetland sediments. Therefore, contaminant exposure through consumption of wildlife is not expected to be significant.

Groundwater. Tetrahydrofuran, trichlorofluoromethane and bis(2-ethylhexyl)phthalate weredetected at levels potentially of health concern in the shallow aquifer. Limited evidence in the RIreport indicates that the shallow aquifer flows radially from high points in the landfill (Appendix A). The shallow aquifer discharges into the Yahara River to the west and the wetlands to the east.

The wetlands to the east are owned by Dane County and do not contain any private wells. To thesouth, six homes southeast of the site use well water drawn from the shallow aquifer. WDHSSsampling in 1988 for VOCs including those found in the landfill indicated that well water in thesehomes did not contain VOCs. In addition, monitoring wells south of the site do not appear to becontaminated Apparently, contaminants are not flowing toward these homes.

Two of the four municipal wells serving the City of Stoughton are located within one mile west ofthe landfill. Flow in the bedrock aquifer, which is the source of water for the Stoughton municipalwells, appears to be northwest toward the Yahara River in the direction of these wells (28). One ofthese wells, Well 6, located approximately 3000 feet west of the site and is cased to a depth of 210feet and is an open hole to a total depth of 950 feet (29). In July 1991, neither of the two wellscontained THF at a level above the detection limit.

Surface Water. Limited sampling data indicate that surface water near the site contains some metalsand organic compounds at levels exceeding Wisconsin Surface Water Quality Standards and may behazardous to aquatic life (see "on-site contamination" above). Any contaminated groundwaterflowing into the Yahara River will be greatly diluted in river water.

Air. VOCs in the air above the site reported in the RI are the same as those found in the landfill. Therefore, VOCs originating from the landfill may be contaminating air above the landfill. Thecompounds were present at levels marginally exceeding their detection limits.

Concentrations at any populated areas downwind of the landfill would likely be well belowdetectable levels.

Similarly, any potential releases of methane into outdoor air would likely be diluted before reachingnearby homes. However, methane could reach potentially explosive levels inside enclosed structuresbuilt over the landfill.

Human Exposure Pathways

Ingestion. Possible routes of ingestion of chemicals from the Stoughton City Landfill are throughingestion of contaminated groundwater or soil. The available evidence also indicates thatcontaminated groundwater is not reaching nearby wells or the Stoughton municipal wells. However,more information on concentrations of contaminants in the sandstone aquifer between the site andthe municipal wells is needed before final conclusions can be made about future exposures. Soilingestion may be significant if the area is used for a park and children are allowed to play onpotentially contaminated soils. The extent of surface soil contamination is not known since surfacesoils have not been analyzed.

Inhalation. Inhalation is not expected to be a significant exposure route at residences located nearthe landfill. While VOCs were detected in the air above the landfill and individuals may be exposedto these compounds if the area is used as a park, levels of exposure would be extremely low. Sincethe surface soil is planted with grasses, it is not likely to be eroded by wind.

Dermal Absorption. While access to the site is essentially unrestricted, there are no signs of frequentuse. Dermal absorption of landfill contaminants at the site is unlikely due to the current usage of thearea and the low levels of contaminants present. However, the lack of surface soil analysis,especially in areas identified by the soil gas survey as contaminated, makes precise estimation ofexposure by dermal absorption difficult.

In summary, exposure to site-related contaminants is not expected through ingestion or inhalation. Dermal exposure has not been reported in the past and probably will not occur in the future since only low levels of contaminants have been found.


PUBLIC HEALTH IMPLICATIONS

Toxicological Evaluation

Significant exposure to landfill contaminants does not appear to have occurred to date. Soil and aircontaminant concentrations are below levels of health concern and no wells which are presentlybeing used for human water consumption contain site-related contaminants. However,tetrahydrofuran, which has been found in the shallow aquifer under the site, may flow toward thecity well. Although health data on tetrahydrofuran is not extensive, one study of rats was locatedwhich indicate that ingestion of the chemical at high doses may be associated with alterations in liverenzymes or blood cell counts (30). Inhalation of the chemical has also been found to causerespiratory irritation and liver damage (31). Bis-(2-ethylhexyl)phthalate is classified as a probablehuman carcinogen by the USEPA (32) and ingestion of the chemical may increase cancer risks.

Health Outcome Data Evaluation

"Health outcome data" is a phrase referring to records of death and disease. When there is evidencethat people near a site have been exposed to contaminants at levels that could lead to an increase inrates of death or disease, a review of health outcome data may be appropriate. A review also may beappropriate if there are reports of unusual clusters of diseases near a site. There is no evidence ofsignificant public exposure to chemicals from the landfill, and WDHSS is not aware of any reportsof clusters of chronic disease near this site.

Community Health Concerns Evaluation

As discussed earlier, no health concerns related to the site have been expressed by the community todate. Concerns about the proper characterization of the site are being addressed through the Recordof Decision and additional sampling. Additional groundwater monitoring is designed to determinethe precise extent of contamination.

Most concerns expressed thus far involve the costs of the Superfund process. The public healthassessment is not intended or authorized to examine costs associated with the Superfund process.


CONCLUSIONS

  1. The Stoughton City Landfill poses no apparent public health hazard under currentconditions. However, if the site is unremediated and contaminants continue to be releasedfrom the site, the water of the Stoughton municipal supply may become impacted and thesite would pose a public health hazard.

  2. Local residents have not expressed concern that the landfill is affecting their health. Whilegroundwater in the upper aquifer appears to flow primarily into the Yahara River, it mayalso be flowing to the south toward private residences. At present, these wells do not appearto be at risk for contamination since the southernmost monitoring wells on the site do not contain any site-related contaminants.

  3. Air over the site does not appear to contain site-related contaminants.

  4. No information concerning contaminant concentrations in the sandstone aquifer between thelandfill and the Stoughton municipal wells is available. Therefore, the extent of thecontaminant plume and the potential for contamination of the municipal wells cannot beprecisely defined.

  5. Potential methane buildup in enclosed structures may present an explosive hazard.

RECOMMENDATIONS

  1. Private wells in the area do not appear to be in the path of contamination and do not need tobe sampled further. However, the two monitoring wells on the southern site boundary (MW-1 and MW-2) should be continue to be monitored to insure that contaminants are notflowing in this direction.

  2. The sandstone aquifer between the site and the Stoughton municipal wells should be tested for chemicals found in monitoring wells at the site.

  3. Take steps to prevent methane from migrating into buildings where it could explode.

Need For Follow-Up Health Activities

According to federal law, public health assessments of "Superfund" sites should help agencies decideif more actions to address health-related concerns is appropriate. Such action might include carryingout more detailed studies on cases of disease near a site or arranging for educational programs aboutexposure to toxic chemicals at a site (33). WDHSS and ATSDR's Health ActivitiesRecommendation Panel reviewed the information about the Stoughton City Landfill to determine theneed for follow-up activities. Since human exposure to contaminants is not likely to have occurredat this site, no additional health activities are needed at the site. WDHSS and ATSDR willdetermine the need for more health activities if high levels of contamination are released when thesite is cleaned up or if new information shows that public exposure is greater than expected.


PUBLIC HEALTH ACTIONS

The Department of Health and Social Services, in cooperation with ATSDR, will conduct thefollowing activities to respond to the recommendations of this public health assessment:

  1. Provide continuing public health education as new information related to public health issues becomes available;

  2. Review and comment on public health aspects of sampling and subsequent activities to bedone pursuant to the Record of Decision, after the lead agency overseeing the investigation provides copies of the plans to the Department of Health and Social Services;

  3. Advise and consult with the Wisconsin Department of Natural Resources and the USEPA on public health concerns that may arise as new information about the site becomes available.

PREPARER OF REPORT

Jay Goldring, Ph.D.
Research Scientist-Toxicologist
Division of Health
Wisconsin Department of Health and Social Services

ATSDR REGIONAL REPRESENTATIVES

Louise Fabinski, Region V
Regional Services, Office of the Assistant Administrator

Denise Jordan-Izaguirre, Region V
Regional Services, Office of the Assistant Administrator

ATSDR TECHNICAL PROJECT OFFICER

William Greim
State Programs Section, Remedial Programs Branch
Division of Health Assessment and Consultation


CERTIFICATION

This Stoughton City Landfill Public Health Assessment was prepared by the Wisconsin Departmentof Health and Social Services under a cooperative agreement with the Agency for Toxic Substancesand Disease Registry (ATSDR). It is in accordance with approved methodology and proceduresexisting at the time the public health assessment was begun.

William Greim
Technical Project Officer
Remedial Programs Branch
Division of Health Assessment and Consultation (DHAC)
ATSDR


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

Robert C. Williams, P.E., DEE
Director, DHAC, ATSDR


REFERENCES

1. ENSR Consulting and Engineering, Inc., under contract to the Stoughton City Landfill SteeringCommittee. Final Remedial Investigation Report, Revision 3, ENSR Document No. 6885-002-531,Westmont, IL: ENSR Inc., Jan. 17, 1991, p. 1-2.

2. Remedial Investigation Report, p. 4-3.

3. Remedial Investigation Report, p. 3-2.

4. U.S. Environmental Protection Agency. Record of Decision for the Stoughton City Landfill. September 30, 1991.

5. Remedial Investigation Report, pp. 3-10 to 3-17.

6. Remedial Investigation Report, p. 3-18.

7. CACI Marketing Services, Inc. The Sourcebook of Demographics and Buying Power for EveryZIP Code in the USA. Fairfax, VA, 1989.

8. Remedial Investigation Report, Figures 4-2, 4-2, 4-4 and 4-5.

9. Remedial Investigation Report, p. 4-5.

10. ENSR Consulting and Engineering Inc. under contract to Stoughton City Landfill SteeringCommittee. Stoughton City Landfill, Final Remedial Investigation, Technical Memorandum 1,Westmont, IL: ENSR Inc., Jan. 17, 1991, Appendix A.

11. Remedial Investigation Report, Tables 4-9 and 4-10.

12. Remedial Investigation Report, Tables 4-4 to 4-8.

13. American Council of Government Industrial Hygienists. Threshold Limit Values for ChemicalSubstances and Physical Agents. Cincinnati, OH, 1990.

14. Remedial Investigation Report, Table 1-3.

15. Remedial Investigation Report, p. 2-10.

16. Remedial Investigation Report, p. 4-23.

17. Remedial Investigation Report, p. 4-11.

18. Remedial Investigation Report, p. 1-19.

19. Remedial Investigation Report, p. 4-32.

20. Wisconsin Department of Natural Resources, Southern District. Volatile organic waterchemistry report, City of Stoughton Municipal Well. Madison, WI, 7/23/86.

21. Carroll, Jenny, Strand Assoc., Madison, WI. Personal Communication. 9/23/91.

22. Remedial Investigation Report, p. 4-1.

23. U.S. Environmental Protection Agency. Ambient water quality criteria for polynuclear aromatichydrocarbons, EPA 440/5-80-069. Washington, D.C., Office of water regulations and standards:criteria and standards division, 1980.

24. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Cadmium. Atlanta, GA, 1989.

25. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Lead. Atlanta,GA, 1989.

26. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Mercury. Atlanta, GA, 1989.

27. Agency for Toxic Substances and Disease Registry. Toxicological Profile for p,p'-DDT, DDEand DDD. Atlanta, GA, 1989.

28. Remedial Investigation Report, p. 1-17.

29. Remedial Investigation Report, p. 3-19.

30. Katahira, T. 1982. [Experimental studies on the toxicity of tetrahydrofuran]. Osaka ShiritsuDaugaku Igaku Zasshi 31:221-239. In Japanese, cited in a memorandum from Pei-Fung Hurst,Biologist, Chemical Mixtures Assessment Branch, USEPA, to W. Bruce Peirano, Acting Chief,Chemical Mixtures Assessment Branch, USEPA, June 22, 1990.

31. Grumbein, S. 1988. 13-week subchronic toxicity test by inhalation of tetrahydrofuran in Fisher344 rats and B6C3F1 mice. Pathology Working Group Chairperson's Report. Submitted to NationalToxicology Program, Research Triangle Park, NC. Cited in a memorandum from Pei-Fung Hurst,Biologist, Chemical Mixtures Assessment Branch, USEPA, to W. Bruce Peirano, Acting Chief,Chemical Mixtures Assessment Branch, USEPA, June 22, 1990.

32. US Environmental Protection Agency. Drinking water regulations and health advisories. Washington, DC, Office of Drinking Water, April 1990.

33. Comprehensive Environmental Response and Liability Act as amended, 42 U.S. Code 9604 (i).


LIST OF APPENDICES

Ground Water Flow and Well Locations
Appendix A. Groundwater Flow and Well Locations.

Site Location
Appendix B. Site Location.


Table of Contents

  
 
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