PUBLIC HEALTH ASSESSMENT
WILLOW RUN SLUDGE LAGOON
YPSILANTI, WASHTENAW COUNTY, MICHIGAN
The Willow Run Sludge Lagoon (WRSL) site, also called the Ford Motor Company Sludge Lagoon site, is located in Ypsilanti Township, Washtenaw County, Michigan, on property belonging to Willow Run Airport. The site was proposed for the U.S. Environmental Protection Agency (U.S. EPA) National Priority List (NPL) in January 1987, but a 1990 reevaluation of the site indicated that it did not qualify for the NPL. In 1988, the U.S. EPA and two Potentially Responsible Parties (PRPs) for the site signed a Consent Agreement under which the PRPs are remediating the WRSL site under Michigan Department of Environmental Quality (MDEQ) supervision. The PRPs have begun construction on a hazardous waste landfill near the lagoon to receive sludge from the lagoon and contaminated sediments from two nearby ponds.
The lagoon was a ravine that was dammed in 1942 to serve as a settling basin for effluent from a wastewater treatment plant serving a nearby Ford Motor Company aircraft factory. The wastewater treatment plant also accepted wastes from other plants and nearby communities, and effluent was discharged to the lagoon until 1964. Overflow from the lagoon discharged to a nearby open drain, and thence to Willow Run Creek. At the present time, the lagoon contains approximately 15 feet of sludge, covered by 2 feet of sediment. The sludge is contaminated with polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals. Sediment in the lagoon, its outlet, and Willow Run Creek is also contaminated with the same contaminants. There are several other potential sources for the contamination in Willow Run Creek, including closed landfills and factories in its watershed. There is some organic chemical contamination in the groundwater near the WRSL, upgradient of the lagoon and attributed to a nearby closed landfill.
Residents of the site area have expressed concerns about the safety of consuming fish from a nearby lake, potential health effects from airborne chemicals and dust from the lagoons, and the physical hazards posed by ponds and other lagoons near the WRSL site. The health hazards involved in these pathways are considered relatively minor. Allegations that people were fishing in Willow Run Creek have been investigated but were not verifiable. One area resident asked whether his current health problems could be related to his frequent visits to the creek area as an adolescent. The Michigan Department of Community Health (MDCH) has offered to consult with the resident and his physician about his health problems. Adverse health effects from environmental exposures to PCBs have not been reported to the MDCH from cases of exposures to soils containing much higher concentrations of PCBs than are present in the WRSL vicinity.
The WRSL site is considered an indeterminate public health hazard. Trespassers in the site vicinity might have been exposed to contaminated soil and sediments, but insufficient information on surface soil composition is available. Fish living in Belleville Lake, the outlet for Willow Run Creek, may have ingested PCBs from sediments carried by the creek into the lake. The assessment recommends collection of samples of surface soil from the site vicinity, collection of fish from Belleville Lake at the outlet from the creek, and a health education program for people in the vicinity.
The Willow Run Sludge Lagoon site was proposed for the United States Environmental Protection Agency (U.S. EPA) National Priorities List (NPL) in January 1987, but a 1990 reevaluation of the site indicated that it did not qualify for the NPL.
The Willow Run Sludge Lagoon (WRSL) site (also known as the Ford Motor Company Sludge Lagoon) is located on Willow Run Airport property in Ypsilanti Township, Washtenaw County, Michigan, southeast of the city of Ypsilanti. The site is 1,500 feet east of McGregor Road, approximately 0.5 mile north of Exit 187 on Interstate Highway 94 (Figure 1).
The WRSL site includes a lagoon and outlet originally constructed in 1942 to serve an aircraft manufacturing plant, operated by Ford Motor Co., at what is now Willow Run Airport. The lagoon, covering approximately 3 acres, held wastewater sludge from the plant's wastewater treatment plant. Overflow from the lagoon flowed into Ypsilanti Drain No. 8, an open drain south of the lagoon that flows east into Willow Run Creek. The wastewater treatment plant also serviced other industrial facilities and municipalities in the area. Documented discharge to the lagoon ceased in 1964. The lagoon remains seasonally flooded by water runoff from the surrounding area.
The Michigan Department of Natural Resources (MDNR) investigated the WRSL in 1978, 1979, and 1981 (cited in References 1 and 2). A Field Investigation Team (FIT) from a U.S. EPA contractor investigated the Willow Run Creek vicinity, including the WRSL site and adjacent areas, in 1982 (1). Willow Run Creek flows through four former or existing impoundments, the North and South G.M. Ponds and Tyler Pond, upstream from the WRSL, and Edison Pond downstream from the WRSL near the creek's entry into Belleville Lake, an impoundment on the Huron River (Figure 1). The South G.M. Pond was drained sometime in the late 1970s (based on a notation on Figure 9 in Reference 1, compared with a U.S.G.S. Ypsilanti East Quadrangle topographic map, latest revision 1973).
The lagoon was fenced in 1986. The fence also enclosed a Willow Run Airport runway light, located on the east bank of the lagoon, and a gate was provided for access to maintain the light. In 1990, the outflow area between the lagoon and Ypsilanti Drain No. 8 was fenced, and additional fencing was constructed between the lagoon proper and the runway light within the original fence ("Proposed" fencing on Figure 2, taken from Reference 2, Figure 7.1).
The WRSL site was originally proposed for the United States Environmental Protection Agency (U.S. EPA) National Priorities List (NPL) as part of a larger site including the entire Willow Run Creek. In August 1988, the U.S. EPA and two of the Potentially Responsible Parties (PRPs) for the WRSL site signed a Consent Agreement under which the PRPs would carry out a RI/FS for the site and ultimately conduct the site remediation, under U.S. EPA and Michigan Department of Natural Resources (MDNR) supervision. A contractor for the PRPs began field work for the RI in 1989. The final report on the RI was issued in December 1992 (2).
In May 1990, the Hazard Ranking System (HRS) score for the WRSL site was reevaluated, and the revised score did not meet the minimum needed for placement on the NPL. The WRSL site has therefore not been placed on the NPL, however, under the 1988 Consent Agreement, the Michigan Department of Environmental Quality (MDEQ)(1) continues to supervise the PRPs' remediation of the WRSL site.
On September 30, 1988, the Agency for Toxic Substances and Disease Registry (ATSDR) prepared a Preliminary Health Assessment for the Ford Motor (Willow Run) Sludge Lagoon Site. ATSDR concluded that the site was of potential public health concern because of the possibility of exposure to hazardous substances via contaminated groundwater, surface soil, surface water, air, and biota, with exposure potentially occurring through ingestion, inhalation, and dermal contact. The assessors recommended that the Remedial Investigation and Feasibility Study (RI/FS) be designed to produce the information needed to fully assess the health impacts from these exposure pathways (3).
In April 1991, the MDNR conducted an Expanded Site Inspection (ESI) of the Willow Run Creek Area site, including the WRSL site. The report on the ESI was issued on June 1, 1993 (4).
The U.S. EPA investigated Willow Run Creek and its vicinity under the Superfund Accelerated Clean-up Model in 1993 and 1994. In October 1993, the Michigan Department of Public Health (MDPH)(2) prepared a consultation on the potential health hazards from the contamination in and near the creek. The consultation concluded that the contaminant levels in the sediments in the creek and the WRSL pose a public health threat through direct contact, that the individuals who may have been exposed to these sediments cannot be identified, and that there is insufficient data available to evaluate health threats through consumption of fish or contact with other surface materials on the site. The consultation recommended that the lower Willow Run Creek and Edison Pond be investigated to determine whether fish are resident in these waters, that fish from these waters and from Belleville Lake be sampled and analyzed for contamination, that access to the sludge lagoon and creek sediments be restricted, and that surface soil from trails and bare ground in the site area be sampled and analyzed for contaminants. The consultation also said that it would be prudent health policy to restrict access to the entire Willow Run Creek site (5).
From January through March 1994, a contractor for the U.S. EPA conducted field work for an Engineering Evaluation/Cost Analysis (EE/CA) for the Willow Run Creek Site (6).
In December 1994, a group of PRPs for the Willow Run Creek and Willow Run Sludge Lagoon sites proposed a remedial action for the creek and lagoon in which contaminated sediments and sludges would be excavated from the lagoon, Tyler Pond, and Edison Pond, and contained in an on-site hazardous waste landfill. The landfill would be designed to meet the requirements of the U.S. Toxic Substances Control Act and the Michigan Hazardous Waste Management Act (Public Act 64 of 1979). The proposed site for the landfill is approximately 1,500 feet east of the WRSL, east of Willow Run Creek and between the creek and the airport facilities (7). The initial site preparation for the remedial action was carried out from September through December 1995. Construction of the landfill and remediation of the creek, ponds, and lagoons is scheduled to begin in the spring of 1996 (8).
The lagoon consists of a ravine closed by a rolled-clay-core earthen dam at the southern end, with a concrete overflow structure and sluice gate. Now, it contains 10 to 15 feet of sludge, overlain by 1 to 2 feet of surface sediments. The surface is now thickly vegetated. It is covered with water during wet seasons, but may dry out completely during dry summers. The overflow outlet from the lagoon drains to Ypsilanti Drain No. 8 approximately 200 feet south of the lagoon. Drain No. 8 flows to the east into Willow Run Creek, approximately 1,000 feet southeast of the site. Willow Run Creek flows south into Belleville Lake, an impoundment of the Huron River, approximately 1 mile southeast of the site. The Huron River flows to the southeast, eventually draining into Lake Erie.
At the time of the RI, there were two seeps of groundwater within the fence, northwest of the lagoon. These are presumed to be leachate from the Fons Landfill, north of the site. One of these seeps flows overland for a short distance and recharges back into the ground still northwest of the lagoon proper. The other seep flows immediately into a culvert, which was built to carry stormwater around the lagoon and into the lagoon outlet. An underground stormwater drain flows into Ypsilanti Drain No. 8 from the northwest approximately 600 feet upstream from the WRSL site.
The site lies on a bed of glacial deposits atop bedrock. The surficial deposits in the site area are 10 to 20 feet of sand and gravel from an ancient river delta. Under the surficial deposits are 75 feet of glacial tills and clays, then a second sand layer, 5 to 10 feet thick, then 30 to 40 feet of clay, down to bedrock. The bedrock in the site area is the Antrim Shale, found at a depth of approximately 125 feet below ground level. The Antrim Shale is expected to be between 50 and 100 feet thick in the site area, underlain by carbonate rock of the Traverse Formation.
There are at least three aquifers in the site area, an unconfined upper aquifer in the surficial sand, a confined lower aquifer in the second sand layer, and a bedrock aquifer in the carbonate rock of the Traverse Formation. These aquifers are separated effectively by the clay and till in the glacial deposits and the non-water-bearing Antrim Shale. Water in the upper aquifer in the site area flows to the southeast, discharging to Ypsilanti Drain No. 8 and to Willow Run Creek. There is a groundwater mound under the lagoon, suggesting that the aquifer is recharged from the lagoon. Water in the lower sand aquifer flows to the east-southeast. There is no information available on water flow in the bedrock aquifer.
On January 26, 1993, John Filpus of the MDPH drove around the site area before he attended a U.S. EPA public meeting regarding the site at the Ypsilanti Township Hall. He did not get closer to the site than the McGregor Road end of the site access road, which was closed with a locked gate. He noted various industrial and commercial establishments along McGregor Road.
On June 4, 1993, Manna Muroya of ATSDR, James Bedford of MDPH, and U.S. EPA personnel toured the vicinity of the site in connection with an ATSDR/MDPH health consultation on the Willow Run Creek SACM investigation. They saw a trail-bike rider using the area and a significant amount of litter from picnickers (5).
On April 6, 1994, Brendan Boyle and John Filpus of the MDPH and personnel from the U.S. EPA, the Washtenaw County Health Department, the Wayne County Health Department, and a contractor for the PRPs visited the WRSL site. They examined the site, noting the state of access restrictions and proximity to other features, then moved to a conference room at a near-by publicly-owned sewage treatment facility for further discussions.
On June 14, 1995, John Filpus and John Hesse of the MDPH visited the vicinity of the Willow Run Sludge Lagoon site before a U.S. EPA-called public meeting concerning the Willow Run Creek remediation. They observed that Tyler Pond was fenced and surrounded by industrial properties. The gate at the end of the road past the WRSL site was open, but Filpus and Hesse did not visit the lagoon. They visited Edison Pond, driving through the park between the Pond and Belleville Lake. They did not notice any restriction of access to the pond beyond the steep, wooded banks, taller on the north side than on the south. At the outlet from the Pond to Belleville Lake, there was a short length of tall fence with a gate separating the private property on the north from the public park on the south. However, the gate was askew so that passage on foot was possible. There, Hesse and Filpus interviewed two men who were fishing in Belleville Lake and catching snakes along the lakeshore.
Information and observations obtained on these site visits are included in the appropriate sections of this assessment.
In 1985, the U.S. EPA estimated that 2,200 people lived within 1 mile of the site and 24,000 people within 3 miles. The lagoon is located approximately 750 feet west of the boundary between Ypsilanti Township, Washtenaw County, and Van Buren Township, Wayne County. In the 1990 U.S. Census, Ypsilanti Township had a population of 45,307, and Van Buren Township had a population of 21,010. The population of Washtenaw County was primarily non-Hispanic white, with 11.2% African-American, 4.1% Asian or Pacific Islanders, 2% Hispanic, 0.4% Native American, and 0.7% other races. Of the County's population, 21.6% were under 18, and 7.5% were 65 or older (9). Washtenaw County Health Department staff report that the population in a neighborhood approximately 0.75 mile west of the site is approximately 50% African-American (10). The population of Wayne County, excluding the City of Detroit, was 6.6% African-American, 2% Hispanic, 1.2% Asian or Pacific Islanders, 0.4% Native American, and 0.5% other races, the residual being non-Hispanic white, with 24.7% under 18 and 12.9% 65 or older (9).
Immediately northwest of the WRSL is the closed Fons Landfill. South of the WRSL, immediately south of Ypsilanti County Drain No. 8, is the closed Wayne Disposal Landfill No. 1. The Airport Landfill, a closed landfill approximately 10 acres in size, is approximately 0.5 mile southeast of the lagoon, east of Willow Run Creek.(3) The active Wayne Disposal Landfill No. 2 is approximately 1 mile southeast of the WRSL. The area within 0.5 mile of the site is lightly developed, with primarily commercial and industrial establishments. The Ypsilanti Wastewater Treatment Plant is approximately 0.5 mile west of the lagoons, and a General Motors plant is approximately 0.75 mile to the northwest. Willow Run Airport facilities are 0.5 mile east and 0.6 mile north of the site. The lagoon is approximately 2,000 feet from the end of one of the airport runways, in a direct line. There is a runway approach light unit at the edge of the lagoon, within the original site fence. Much of the area within 0.5 mile of the site, especially north and east of the site, is Willow Run Airport property. Willow Run Airport is currently used primarily for cargo traffic. Hangars and terminal buildings for the airport are located approximately 0.5 mile east and 0.75 mile north of the site. There is evidence of unauthorized recreational use of the Airport property around the site.
The nearest residential area to the WRSL is 0.5 mile south of the site, across Interstate 94. The nearest residence to the site is approximately 2,200 feet southwest of the site, on McGregor Road. This residence is connected to the Ypsilanti Township municipal water supply system (2). Willow Run Creek flows through industrial and airport properties north of Interstate 94. South of I-94, the creek flows through suburban residential and recreational properties the rest of its length, through Edison Pond into Belleville Lake.
Most of the area west of the site is served by the Ypsilanti Township municipal water system. The Township municipal water system takes its water from 9 wells, located approximately 2 miles south-southwest of the WRSL site, south of the Huron River and upstream of Belleville Lake. The Township also buys water from the City of Detroit municipal water system, which uses water from Lake Huron and the Detroit River. According to MDPH/MDEQ(4) staff, the Township closed its water plant on September 4, 1994. They also decommissioned their wells and arranged to buy City of Detroit water exclusively, for economic reasons (11, 12). Van Buren Township, Wayne County, covering the area east of the WRSL site, also buys water from the City of Detroit municipal water system, and its pipelines reach to the township/county line in the WRSL site vicinity (13). Appendix E to the RI report includes well logs for 7 wells within 1.7 miles of the site. The two closest wells included were located approximately 0.4 mile from the site, one to the west (upgradient) and one to the southeast (downgradient). These were both described as domestic wells, and were screened at approximately 90 feet below ground level. The other wells on the list were 3 wells 1.2 miles south of the site, beyond the Huron River, and 2 wells 1.6 miles northwest (upgradient) of the site (2). The FIT report listed the well 0.4 mile southeast of the site, a "domestic" well approximately 0.5 mile north of the WRSL site, and another 0.75 mile southeast of the site. The well 0.4 mile southeast of the site was described in the FIT report as an industrial well and its owner said it was not used for drinking (1). This well has since been capped and the facility connected to the municipal water system (14). Water from Tyler Pond, on Willow Run Creek upstream of the site, was formerly used by the airport to supply their fire suppression system. People living on the shores of Edison Pond, on Willow Run Creek downstream of the site near Belleville Lake, reportedly pumped water from the Pond in the past to water their lawns (10).
The Ypsilanti Community Utility Authority (YCUA) operates a sewage disposal plant approximately 0.5 mile west of the WRSL site. Until July 1995, the treated discharge from this plant released into Willow Run Creek at Tyler Road, approximately 0.5 mile north of the WRSL site. This discharge reportedly made up approximately 75% of the flow in the creek. The YCUA has constructed a new discharge on the Lower Branch of the River Rouge,(5) and in July 1995, they stopped their discharge into Willow Run Creek (10, 15).
There is a school 0.9 mile south of the site (south of I-94), another school 1.2 miles west of the site, and a third 1.3 miles north-northwest of the site.
Local health department personnel report signs that local residents hunt and trap in the site area. Shotgun shells and the bodies of foxes with their tails cut off have been found. Other signs seen in the area indicate that people play "paintball", a simulated combat in which plastic projectiles containing paint are used for bullets, in the area around the site (10). There is a public beach on Lake Belleville near the outlet from Edison Pond and Willow Run Creek, approximately 2 miles southeast of the WRSL site.
There have been no community health concerns expressed that can be related to any specific health outcome, nor is there any means for identifying the people exposed to the site. Therefore, no health outcome data have been consulted for this assessment.
On January 26, 1993, John Filpus of the MDPH attended a U.S. EPA public meeting in Ypsilanti Township to discuss the RI results for the WRSL site. The attendees expressed the following health-related concerns:
1. What impact has the WRSL site had on fish from Willow Run Creek and Belleville Lake? What are the health effects from consumption of fish containing the levels of contamination found in Belleville Lake?
2. Are there hazards in the air coming off the lagoon?
3. Is there a need to restrict access to other lagoons and ponds near the site because of physical hazards?
On January 12, 1995, Brendan Boyle and John Filpus of the MDPH attended a public meeting in Van Buren Township called by the MDNR to elicit public comment on the proposed remedial action plan for the Willow Run Creek site. Comments and questions from the public primarily addressed the proposed remediation, expressing the opinion that the action might not be sufficiently protective. One member of the public referred to people in the area eating fish that were contaminated.
More recently, a resident of the site area has contacted the MDNR, saying that he had recreated in the Willow Run Creek area frequently 15 years previously, frequently coming into contact with the water and sediments. He has since developed health problems, described as lumps on his side, neck, and one testicle and ringing in his ears. He was concerned that these problems might be connected to his exposure to the sediments along Willow Run Creek. MDNR referred his questions to the MDCH (16).
The Michigan Department of Public Health released a draft of this Public Health Assessment for public comment on January 31, 1996. The public comment period lasted until March 1, 1996. No comments were received in this period.