PUBLIC HEALTH ASSESSMENT
MUSKEGO SANITARY LANDFILL
MUSKEGO, WAUKESHA COUNTY, WISCONSIN
The Muskego Sanitary Landfill site is situated within the City of Muskego, Waukesha County, in the State of Wisconsin. Muskego Sanitary Landfill is a former sand and gravel pit which received unspecified types and amounts of municipal and industrial wastes over a period of approximately 25 years. There are a three primary sources of contamination identified within the site. Excavations at the site revealed a large number of deteriorated drums containing organic solvents. Adjacent to the site is a former animal carcass rendering plant, which may have affected nearby groundwater quality.
Hazardous chemicals from the site are apparently contaminating local groundwater. Though groundwater generally moves across the site to the south and southeast, various geologic deposits under Muskego Sanitary Landfill complicates shallow groundwater movement away from the site. Samples collected from off-site groundwater monitoring wells have revealed organic and inorganic contamination.
Muskego Sanitary Landfill site is a public health hazard because in the past some nearby residents probably drank private well water containing site-related contamination. Water collected in 1982 from two nearby private wells revealed levels of lead which could affect the development of the nervous system in young children. It is unclear if this lead contamination was site-related. Currently no private wells near the site show signs of contamination.
The groundwater around the site might pose a future public health hazard if no further action were taken to clean up the site. Under such circumstances contaminated groundwater could continue to move away from the site and contaminate other private wells.
Ambient air near Muskego Sanitary Landfill is an indeterminate public health hazard. Ambient air sampled around the site was found to be contaminated with low levels of benzene and methylene chloride. Nearby residents could be breathing airborne contamination from the site, but information is not available to estimate the levels and duration of such potential exposures. People breathing this contaminated air over a lifetime could face a low-increased risk of cancer. Implementation of the U.S. EPA's proposed clean-up actions would minimize the release of VOCs from the site in to ambient air.
Wisconsin's Department of Health and Social Services, Division of Health (DOH)
recommends
the continued monitoring of groundwater in the vicinity of the site. Nearby residential wells
should also be tested regularly. Further air monitoring could provide a better understanding of
the extent of ambient air contamination around the site.
A. Site Description And History
The Muskego Sanitary Landfill Superfund site (subsequently referred to as the "site") is a former sand and gravel pit. It is situated within the City of Muskego, Waukesha County, in the State of Wisconsin. It is three miles southwest of the center of City of Muskego and approximately one mile east of the Village of Big Bend (see Figure 1). The site is located in the western half of Section 18, Township 5 North, Range 20 East. Muskego Sanitary Landfill site occupies approximately 56 acres and is bounded on the west by Crowbar Road, and on the south by Janesville Road.
The Muskego Sanitary Landfill Superfund site is owned by Carl Wauer and operated by Waste Management of Wisconsin, Inc (WMWI). The site is comprised of the three fill areas, which are: the Old Fill area; the Southeast Fill area; and the Non-Contiguous Fill area. The use of the term "On-Site" refers to locations found within one or more of these areas and all parts of the Anamax property. The approximate boundaries of these areas are described in Figure 2. The Old Fill area is the largest of the fill areas and is 36 acres in size. The Southeast Fill area is located directly east and southeast of the Old Fill, and covers approximately 16 acres. The Non-Contiguous Fill area measures 4.2 acres. The Non-Contiguous Fill area is comprised of four separate and distinct waste disposal zones: two elongated fill areas; the "L-shaped" fill area; and the drum trench area.
The inactive Stone Ridge landfill is owned and was operated by WMWI when it was active. This landfill is immediately north and northeast of the site. The former rendering plant (Anamax facility) is east of the Old Fill Area and bordered on the north and south by the Non-Contiguous Fill and Southeast Fill areas, respectively. The rendering plant contains a number of buildings and wastewater lagoons. Portions of the Anamax facility have been included within the Non-contiguous Fill boundaries. The Stone Ridge landfill have not been ranked as part of the site.
The 36-acre Old Fill area was in operation as a sand and gravel pit prior to 1950 (Figure 2). Refuse filling began when the owner received a permit in 1954 from the Town of Muskego to operate a dump on this site [34, p1]. There is no documentation providing details about the dumping of hazardous waste at the site, but in the late 1960s there were reports of waste oils and paints being present in the site [25, 34]. This area evolved into an open dump, and into a Wisconsin Department of Natural Resources (DNR) licensed sanitary landfill in 1971 [27]. The Old Fill area was closed and covered in 1977 [34, p7]. In 1980 and 1982 there were repair and maintenance fills to increase the site's surface grade, improve drainage, and reduce surface infiltration of water into the refuse [34, p12]. In 1984 a partial-active gas venting system (extraction wells, fans and blowers,and vents) was installed in and around the Old Fill Area to reduce methane gas migrating away from the area [34, p13].
The Southeast Fill area is located east and southeast of the Old Fill, and covers approximately 16 acres. The area is an engineered landfill, with a natural clay base and sidewalls, and a collection system for the removal of leachate from the landfill [34, p1]. It was brought into use as a DNR licensed landfill in 1977 when the Old Fill area was closed. Information is not available about the types of waste dumped at the Southeast Fill area. When the Southeast Fill area was closed in 1980 it was covered with two feet of clay, six inches of topsoil, and was planted with grass [34, p7].
The Non-contiguous Fill area received wastes from 1969 to 1977 [36]. There are no records about the types of wastes disposed at the Non-Contiguous Fill area. Test pit investigations conducted in 1981 by WMWI, under U.S. EPA supervision concluded that this area contained primarily municipal with some industrial wastes. Part of the Non-contiguous Fill area is on the Anamax Property.
Groundwater sampling in 1982 suggested that chemicals from the site were affecting off-site groundwater quality. WMWI sampled off-site private wells in 1981, 1982, and 1984 [39, Appendix K]. One private well contained 1,2-dichloroethane at 16 and 14 ug/L during the 1984 sampling [34, Appendix G], and the well was ultimately abandoned in 1990. In 1986 a municipal water supply line was extended to the edge of the property line of homes with private wells at risk of contamination.
In November 1988 test pits excavated during a geophysical survey revealed a small trench containing barrels. This area ultimately became the drum trench in the Non-contiguous Fill area. A total of 1,000 drums and 2,500 cubic yards of contaminated soils were removed from this trench. All drums and contaminated soils were removed from the trench by April 1991. Clean fill was placed on this area in May 1991 [27, p3]. Contaminated materials from the trench were sent out-of-state to three different sites capable of handling hazardous waste.
The Anamax facility was the site of an animal carcass rendering plant. Within the former facility are old waste water lagoons, which include an unlined treatment lagoon and a concrete-lined aeration pond. During normal operations, this facility handled an average of 170,000 to 200,000 pounds of animal carcasses per day and discharged 25,000 gallons per day of wastewater into the lagoons. In the early 1970s the DNR issued an air pollution order against Anamax, which resulted in the development and installation of four unlined seepage lagoons for use by the rendering plant [34, p4]. These seepage lagoons are found north of the Non-contiguous Fill area. In 1985 use of the seepage lagoons was halted [34, Appendix J]. In 1987 the treatment lagoons
Figure 1. Muskego Sanitary Landfill and Surrounding Vicinity
were closed, and liquids and sludge were removed from the seepage lagoons according to DNR guidelines. When the rendering plant seepage lagoons were taken out of service and the sludge removed, groundwater monitoring wells adjacent to the lagoons exhibited improved groundwater quality [34, p34]. Part of the Non-contiguous Fill area is on the Anamax Property. WMWI plans to demolish the Anamax buildings and fill the inactive lagoons with demolition debris.
An inactive landfill (Stone Ridge), operated by Waste Management of Wisconsin, Inc. (Muskego II, License No. 2985) [34, p1] borders the Non-contiguous area and the northern edge of the Old Fill site. It was one of the early clay-lined landfills licensed in Wisconsin. There is an active leachate collection system at the landfill. Leachate extraction is performed on a continuous basis and the collection lines are cleaned annually. The landfill is fenced along its north, east & west perimeter, with a gate and gatehouse at the entrance on Crowbar road.
The Muskego Sanitary Landfill site was evaluated and ranked by the United States Environmental Protection Agency (U.S. EPA), and placed on the National Priorities List on September 18, 1985. The inactive Stone Ridge landfill has not been ranked and is not are included on the National Priorities List.
The geologic deposits sampled from the site are of glacial origin and indicate a complicated geology. The regional direction of groundwater flow under the site is from the north to south. The geologic deposits at the site include glacial tills (silty brown and gray), lacustrine clay, outwash sand, and gravel deposits. Outwash sand and gravel deposits underlie most deposits at the site [34, p24]. These deposits vary in thickness and distribution and are underlain by a Niagara dolomite bedrock at a depth between 250 and 305 feet below the ground's surface [34, p19].
The original topography of the site has been greatly changed by the excavation of sand and gravel and subsequent refuse disposal, however the clay and till lenses complicate shallow groundwater movement. During the 1950 quarrying activities sandy brown outwash was mined from the many places down to either the lacustrine clay, gray till, or silty brown till. All of the Southeast Fill site and the majority of the Old Fill site is underlain by clay and gray till, which itself overlies outwash sand and gravel unit. Beyond the clay's western limits the site is underlain by sand and gravel. The lacustrine clay extends north-northwest from the Southeast Fill area partially into the Old Fill area, and up to the Non-contiguous Fill area. Groundwater does not flow well through the relatively impermeable lacustrine clays and glacial tills [34, p28]. Therefore shallow groundwater flowing from the site tends to flow to the north/northwest, up to the edge of clay, then cascades into the deeper and permeable outwash sand and gravel, and flows south. However, groundwater in some places does flow to the east from the Southeast Fill site. Refuse in the Old Fill area is found partially below the water table [34, p38].
Figure 2. Muskego Sanitary Landfill
DOH representatives conducted the first site visit on August 18, 1988. They reviewed the area from the perimeter by driving and walking around the entire site. Access to the site was not sought.
The Stone Ridge landfill was observed to be in use. The Old Fill and Southeast Fill areas were mounded and covered with grass. No leachate ponds were seen and the area appeared to be dry (this was at the end of an extremely dry summer).
A second DOH site visit was conducted on October 9, 1991. Also present were representatives from Waste Management of Wisconsin, the U.S. Environmental Protection Agency (Region V), and the Waukesha County Health Department. During the site visit, the following activities were observed [14]:
Private homes were observed in the vicinity of the site. The WMWI Muskego Site Manager pointed out the private wells which were selected for ongoing water testing, and indicated those homes which continued to use well water exclusively for all domestic uses. Some homes with active wells are also connected to the municipal water supply. The municipal water supply to affected homes on Hillendale, Janesville, and Crowbar roads was installed in 1986. Only a portion of these homes are connected to Muskego municipal sewage lines. Also noted was an operating restaurant/tavern on Janesville Road that obtains all of its water from a well. (Note: One year after the site visit this restaurant/tavern connected to City water and no longer uses the well for consumption purposes.)
A third DOH site visit was conducted on June 6, 1994 [17]. Also present were representatives of Waste Management of Wisconsin and the U.S. EPA. The following observations were made during the site visit:
C. Demographics, Land Use, And Natural Resource Use
The area around the site is semi-rural, with limited agriculture. There are approximately 130 homes within one-half mile of the site. This converts to a population of 325, assuming 2.5 persons live in each home. The Southeastern Wisconsin Regional Planning Commission estimates a population of within one mile of the site to be 2,991 [39, p3-8]. Recently constructed homes were observed during the October 1991 site visit to be approximately one-half mile north and northeast of the site. Most new residential developments are to the northeast, north, and northwest of the site. There are no schools or retirement communities within a one-mile radius.
Demographic information about persons living adjacent to the Muskego Sanitary Landfill site is from the 1990 census, which is defined by zip code. The City of Muskego (over 99 percent caucasian) is a middle to upper-middle income community at the southwestern edge of the Milwaukee metropolitan area. The median age is 30.5 years. According to the 1990 Census, there are 304,715 persons living within Waukesha County, Wisconsin. Big Bend has a population of 1,299 and 16,813 persons reside within the City of Muskego. The annual population growth rate for Muskego is approximately 0.9% [12][13].
The land surrounding the site is a mixture of private homes, small-scale agriculture, medium-sized farming, and industrial use. Homes and farms are to the immediate east and south of the site. Homes are also found along Hillendale road to the immediate northeast of the site. Agricultural activities are interspersed with private homes. Some residents raise livestock, such as horses and sheep. Local residents obtain domestic water from either private wells or the municipal water supply.
An apple orchard, harvested annually, is found on the eastern end of the Anamax property. A small corn field was observed immediately southwest of the site. There are very few nearby bodies of water. However, one nearby resident uses water from a wetland to irrigate their orchard. There are no other reports of people or businesses using surface water.
An active sand and gravel quarry is located to the west of the site. Blasting at the quarry has been observed by the site manager and active gravel removal was seen at the time of the 1991 DOH site visit. Approximately one-half mile east of the site is a spring-water bottling plant, which bottles water from a source in the Village of Big Bend. Immediately south of the site is a restaurant .
"Health outcome data" is a phrase referring to records of death and disease. When there is evidence that people near a site have been exposed to contaminants at levels which could lead to an increase in rates of death or disease, a review of health outcome data may be appropriate. A review also may be appropriate if there are reports of unusual clusters of diseases near a site.
As discussed in the Pathways Analysis section (page 21), three nearby households probably used groundwater containing two site-related contaminants. Also it is possible that nearby residents breathed air contaminated with chemicals which originate from the site. However, there is not enough information to determine if any people were exposed, much less what might be the duration and level of such exposures.
Some of the chemicals detected in ambient air are known to be cancer-causing. Based on
the possibility of human exposures, the DOH will evaluate the appropriateness of
examining cancer incidence data for the Muskego area.
Quarterly monitoring of private wells was initiated because of concern about private well contamination. Additionally, in 1986 municipal water lines were installed by WMWI within five feet of homes with wells which were at risk of contamination. These homes are on Hillendale, Janesville, and Crowbar roads. Not all buildings adjacent to the site are connected to the public water supply [34, p13].
Division of Health staff met with the Mayor of Muskego and two community members, on October 9, 1991, to discuss any health concerns that they have related to the Muskego Sanitary Landfill Superfund site. Also present were representatives of Waste Management, a representative of State Senator Adelman, and the Waukesha County Health Department Sanitarian [16].
The community health concerns expressed at the meeting related to:
The Mayor stated that "there would be more concerns if municipal water wasn't available" to residents adjacent to the site. WMWI has covered the cost of bringing municipal water up to residences adjacent to the site.
During the June 6, 1994 site visit, the U.S. EPA Remedial Project Manager said they continue to receive citizen concerns about the potential for dust generated during site remediation, particularly since it was a dry spring. No other community concerns were reported.
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