PUBLIC HEALTH ASSESSMENT
LANSING TOWNSHIP, INGHAM COUNTY, MICHIGAN
The Motor Wheel Disposal Area site was placed on the U.S. Environmental Protection Agency (U.S. EPA)National Priorities List (NPL) in June 1986. The site, located in the City of Lansing, Ingham County, is a former waste disposal area used by the Motor Wheel Corporation and other area industries. After waste disposal ceased, portions of the site were mined for sand and gravel. On several occasions, Motor Wheel Corporation and the site owners, under regulatory agency supervision, have excavated and removed some of the waste material from the site for disposal elsewhere. Approximately 230,000 cubic feet of waste remains on the site. Groundwater at the site has been contaminated with several volatile organic chemicals and fluoride from the waste. Other adjacent industrial sites have contributed to the area's groundwater contamination. Contamination was detected in 1983 in a well on the site that was formerly used to wash gravel. No off-site potable water supplies are known to use the site-contaminated groundwater as a source. However, the City of Lansing has wells near the site, tapping a deeper aquifer. Preliminary results indicate that the contaminated groundwater is not hydraulically connected to the deeper aquifer. The site includes a large gravel pit that contains several ponds. The site perimeter is not fenced. The pit is fenced, but the capacity of the fence to restrict access has been diminished over time by vandalism and soil erosion. There are urban residential neighborhoods within walking distance beyond the industrial and commercial properties that surround the site perimeter. Trespassers have been seen swimming in one of the ponds. A Record of Decision for remediation of the site was signed in September 1991.
The site poses an indeterminate public health hazard. There are currently no known completed pathways of exposure associated with this site. Potential pathways include on-site exposure to contaminants in leachate, soil, fugitive dust and water and off-site exposure to contaminated groundwater in either of two aquifers. Investigations are under way to establish whether the groundwater used as a potable water supply in the area is threatened by contact with the contaminated groundwater in the site area.
The Motor Wheel Disposal Area site was placed on the U.S. Environmental Protection Agency (U.S. EPA) National Priorities List (NPL) in June 1986. The site occupies approximately 24 acres in northeast Lansing, Ingham County, Michigan, between Lake Lansing Road and an abandoned Penn Central Railroad right-of-way (see Figure 1). The site entrance is located at 1401 East Lake Lansing Road.
Motor Wheel Corporation purchased the site in 1938 and used it as a disposal site for industrial wastes, including fly ash, paints, solvents, liquid acids and caustics, and sludges . MDNR file records and aerial photographs indicate that most of the wastes were deposited in the west central section of the site. Records also indicate that several other firms, including W. R. Grace & Co., the Lansing Board of Water and Light, and CWC Castings Division of Textron, Inc., used the site for waste disposal. In 1971, Motor Wheel halted its disposal actions at the site, but other unauthorized dumping continued until 1979. In 1978, Motor Wheel sold the property to MSV Associates, who mined sand and gravel from the north half of the site. A 50-foot deep pit in the north half of the site and a 25-foot mound on the west side are remnants of the mining operations. In the process of mining, MSV Associates uncovered industrial wastes and contaminated soils. These wastes and soils were excavated, stockpiled on the west side of the site, and mostly covered with clay. Michigan Department of Natural Resources (MDNR) staff report that wastes have been found on the surface since then. MSV Associates installed a well on the site to use for washing the gravel, and later used water from ponds in the pit for the same purpose. Water from the well was found to be contaminated with trichloroethylene in 1983. MSV stopped mining operations on the site in 1987.
The pit on the north half of the site contains four small ponds. The current site owners have built a fence around the pit, though the fence was in poor repair and erosion had undercut it at the time of a Michigan Department of Public Health (MDPH) site visit. Piles of sand and debris are scattered around the site.
Geologically, the site area has approximately 100 feet of glacial drift material over bedrock. The area bedrock is part of the Saginaw Formation and consists of sandstone capped by shale. The glacial drift at the site contains two aquifers, a perched aquifer and a deeper glacial aquifer, which are separated by a clay layer. The sandstone of the Saginaw Formation also contains an aquifer, which is separated from the glacial aquifer by a layer of shale that is from 40 to 90 feet thick in the site area (1). The shale layer extends to about one-half mile south of the Motor Wheel Disposal Area site, where regional data suggest it tapers off.
Groundwater in the perched aquifer under the site flows northward and discharges as seeps into the pit at the north end of the site. Groundwater in the perched aquifer south of the site appears to flow southward. The groundwater divide, an area analogous to a ridge from which groundwater may flow either direction, appears to run underneath the south boundary of the waste disposal area. Mining operations on the site may have affected the location of the groundwater divide.
Groundwater in the glacial aquifer flows generally toward the south-southwest. Groundwater in the bedrock aquifer flows towards the west or northwest (1). The site lies within the drainage basin of the Grand River, which is approximately 1 mile southwest of the site. The river is probably the ultimate discharge point for groundwater from the two drift aquifers in the vicinity of the site.
Motor Wheel Corporation and MSV Associates have carried out waste removal operations at the site, but an estimated 230,000 cubic feet of waste material still remains. Groundwater in the perched and deeper glacial aquifers at the site has been found to be contaminated. Two other properties near the Motor Wheel Disposal Area site have contributed to the area groundwater contamination, and are being addressed by the State of Michigan under Public Act 307, the Michigan Environmental Response Act.
A group of Potentially Responsible Parties (PRPs) for the Motor Wheel Disposal Area site entered into a Consent Order with the MDNR and the U.S. EPA to carry out a Remedial Investigation/Feasibility Study (RI/FS) under the agencies' oversight. An RI/FS is a combination of the investigative and analytical studies intended to gather the necessary data to determine the type and extent of contamination at a Superfund Site and develop several remedial alternatives for the site. Contractors began field work for the RI in January 1989, and a report on the first two phases of the RI was issued in February 1990 (2). A baseline Risk Assessment for the site was issued by the PRP's contractors in January 1991 (3). This risk assessment quantitatively evaluates health risks based upon exposure to contaminants present at the site and is considered in selecting a remedial option. Further environmental sampling was carried out at the site from July through November 1991 (1).
The MDPH, under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR), prepared a Preliminary Health Assessment for the site in March 1989 (4). The Preliminary Health Assessment concluded that the site was of potential public health concern because of the possible health threat due to exposure to volatile organic compounds via inhalation or dermal contact. The Preliminary Health Assessment recommended restriction of access to the site because of physical hazards present. The Preliminary Health Assessment identified no current exposures to contaminants, therefore no follow-up health studies were recommended.
In September 1991, the U.S. EPA signed a Record of Decision (ROD) for the remediation at the Motor Wheel Disposal Area site. The ROD called for installation of a new cap over the disposal area, extraction and treatment of contaminated groundwater, installation of a slurry wall to facilitate removal of contaminated water from the perched aquifer, groundwater monitoring, and deed restrictions on the site (5). Additional studies in conjunction with the design of the site remediation are in progress at the site as of this writing.
MDPH personnel visited the site on June 21, 1988. Brendan Boyle and John Filpus of MDPH and MDNR staff revisited the site on January 8, 1992. On each occasion observations were made on the status of the site restrictions, surface water on-site, evidence of trespass and vandalism, and the proximity of nearby businesses and residences. On the second visit it was noted that the ground beneath the fence around the pit had eroded enough in one place to permit access. Some segments of the fence had been broken from their supports and were on the ground at that time. Information received and observations made during obtained these visits have been included in this public health assessment and are referenced as such.
The population within 1 mile of the site is approximately 13,000 (Reference 2, p. 88). The population of the City of Lansing was approximately 122,700 at the time of the 1990 Census.
The properties adjacent to the site are primarily industrial or commercial. Across the railroad right-of-way to the west, approximately 200 feet from the site boundary, is a residential area. There are other residential areas to the south, approximately 500 feet from the site, beyond the industrial/commercial properties adjacent to the site. Several active or former landfills lie north of the site. The land northeast of the site, and north of the commercial properties along Lake Lansing Road has not been developed. A local utility company disposes of fly ash in a landfill approximately one-quarter mile southeast of the Motor Wheel Disposal Area site.
Three other areas within 0.25 mile north and northwest of the Motor Wheel Disposal Area site are listed on the Michigan Environmental Response Act (Act 307) priority list: the Friedland Iron and Metal Company to the northwest, the former Paulson Street Landfill also to the northwest, and the Granger North Lansing Landfill to the north. The Friedland property is listed because of contamination of surface soil with polychlorinated biphenyls (PCBs), and the two landfills are listed because of contamination of soil and groundwater with volatile organic compounds. The Barrels, Inc. NPL site is located approximately 1 mile southwest of the Motor Wheel Disposal Area site.
Most of the residences and businesses in the vicinity of the Motor Wheel Disposal Area site are currently supplied with Lansing municipal water. The RI states that there are at least 41 domestic wells, 8 commercial facility wells, and 22 public water supply wells within 2 miles of the site (2). It is possible that some undocumented private wells may remain in use in the area. The mining operation reportedly used a well on the site for washing gravel (6). The Lansing municipal water system obtains water from municipal wells that draw from the Saginaw Formation, including one that is 0.25 mile northwest of the Motor Wheel Disposal Area site and one that is 0.5 mile southwest of the site. These two wells are 450 and 446 feet deep, respectively. There is an industrial well 0.75 mile northeast of the site, and a public supply well (not a City of Lansing supply well) 0.5 mile to the east of the site.
From the evaluations performed for this public health assessment, there are no indications that humans have been exposed to site-related contaminants. However, community health concerns relating to the site have been reported, particularly with regard to cancer rates in the area. The health assessors have obtained from the MDPH Office of the State Registrar and Center for Health Statistics the latest cancer incidence and mortality records for the zip code areas most closely associated with this site (48906, 48912, and 48823). Evaluation of this data is reported later in the Health Outcome Data Evaluation section of this document.
Residents of the area are extremely concerned about the hazards posed by this site as well as the other toxic waste contamination sites in the area. They are concerned about air and groundwater pollution from the sites, and about their children gaining access to unfenced contaminated areas. In the past, citizens have expressed alarm at what they believe to be an unusually high incidence of leukemia and other cancers in the area.
The MDPH released a draft of this public health assessment for public comment on April 20, 1993, for a Public Comment period that lasted until May 20, 1993. One of the Potentially Responsible Parties for the site responded with an extensive critique of the document. This critique and MDPH's and ATSDR's responses to it are summarized in the Responsiveness Summary at the end of this document. A resident living approximately 0.5 mile northeast of the site wrote to MDPH describing a high incidence of various sorts of cancer among the people of her neighborhood. Her letter was forwarded to the appropriate section of the MDPH for further investigation.
To identify facilities that could contribute to the environmental contamination at and around the Motor Wheel Disposal Area site, the MDPH searched the Toxic Chemical Release Inventory (TRI) for 1987-1991. The TRI is maintained by the U.S. EPA from chemical release information provided by industries. No releases from the Motor Wheel Disposal Area site were listed. The TRI listed five facilities within the zip codes including and near the site (48906 and 48912) but three of them are located 0.75 miles or more south or southwest of the site, and are therefore unlikely to have an effect on the site. Two facilities listed in the TRI are located in the site vicinity -- the W. R. Grace plant that was formerly located at the south side of the Motor Wheel Disposal Area site and Environmental Marketing Services, Ltd., located a short distance east of the site. The TRI listed air releases of ammonia, ammonium nitrate solution, manganese compounds, phosphoric acid, sulfuric acid, and zinc compounds and a land release of sulfuric acid from the W. R. Grace facility. None of these chemicals appear to have affected the Motor Wheel Disposal Area site. There were no TRI reports for the W. R. Grace facility in the 1989, 1990, or 1991 databases. The W. R. Grace Company no longer operates a facility at that location. Environmental Marketing Services, Ltd., reported air releases of acrylamide (1 pound per year [lb./yr.]), formaldehyde (95 lbs./yr.), and sulfuric acid (1 lb./yr.), plus reports on disposal at other facilities of acrylic acid, diethanolamine, epichlorhydrin, hydrochloric acid, and sodium hydroxide solution, with no environmental releases cited of these chemicals.
Except where cited otherwise, environmental contamination data is taken from the Final Remedial Investigation (RI) report for the site (2).
Contaminants of concern were selected by comparing the maximum concentrations found on the site to comparison values for specific environmental media. Comparison values used included Environmental Media Evaluation Guides (EMEGs) developed by the ATSDR; Cancer Risk Evaluation Guides (CREGs) calculated to yield an estimated risk from lifetime adult exposure of one additional cancer case per 1,000,000 people exposed for possible, probable, or proven carcinogens; concentrations based on the U.S. EPA Reference Doses for chronic ingestion by a child; U.S. EPA lifetime Drinking Water Health Advisories; and U.S. EPA Safe Drinking Water Act Maximum Contaminant Levels. Comparison Values used are listed in Tables 2-7. Table 1 in Appendix B lists the chemicals found in water and soil samples in some medium at the Motor Wheel Disposal Area site at concentrations above the appropriate comparison value, and which are considered contaminants of concern for this public health assessment.
The highest concentrations of contaminants of concern found in soil samples collected during the RI are listed in Tables 2 (surface soil) and 3 (subsurface soil). In the Remedial Investigation surface soil samples were collected from the ground surface to 2 inches in depth. Subsurface soil was taken starting from below 2 feet below the ground surface.
The concentrations of polynuclear aromatic hydrocarbons (PAHs) found in soil on-site are listed in the Tables as they were reported in the RI report. The PAHs are listed by groups identified by the number of rings in the molecule.
The copper and lead concentrations found in surface soil are within the ranges commonly found in Eastern U.S. soils. The concentration of the 4-ring PAH found in the surface soil (fluoranthene) was on the low end of the range of background urban soil concentrations (Reference 7, p. 143, Table 5-5). The highest concentrations of antimony, silver, thallium, and zinc were from surface soil samples and are above background ranges.
In general, the maximum sub-surface soil concentrations listed in Table 3 represent samples collected from the waste disposal area on the site.
Aroclor-1254 and Aroclor-1260 are trade names for two commercial mixtures of polychlorinated biphenyls (PCBs). Most of the organic chemicals found on the site, including PCBs, pesticides, and volatile organic chemicals (VOCs) were only found in isolated samples. The VOCs detected in more than five soil samples (out of 60) were 1,2-dichloroethylene (1,2-DCE), trichloroethylene (TCE), ethylbenzene, toluene, and xylenes. Dibenzofuran was only detected twice.
The concentrations of arsenic, Aroclor-1254, and dieldrin in waste material on the site exceed soil EMEGs. The concentrations of most of the PAHs in the waste disposal area are within urban soil background levels. One sample from the waste, which yielded the levels for 1,2-DCE, TCE, ethylbenzene, toluene, and xylenes listed in Table 3, required considerable dilution before analysis. This dilution was necessary because the concentrations of these chemicals in the undiluted sample were higher than the analytical technique could accurately measure. This caused the effective detection levels for other organic chemicals to be far above normal values.
No elevated levels of contaminants were found in sediment samples collected from the ponds on the site during the RI (Table 4). The comparison values listed are for soil. The zinc concentration is within the range of surface soil concentrations found in the Eastern U.S.
Water samples from each of the four ponds on the site were collected during the RI and analyzed for metals, inorganic chemicals, VOCs, and other organic chemicals. Levels of metals and inorganic chemicals did not exceed comparison values or background concentrations. No organic chemicals were detected.
In April 1980, MDNR and Ingham County Health Department personnel observed that the cap on the waste disposal area showed cracks in places. Water was seeping out of the breaks, running to a low spot, and seeping back into the sand (8). Analysis of two samples of this leachate detected as much as 13,000 ppb toluene and 610 ppb TCE (9). In 1982, groundwater from the site contained up to 67 ppb 1,1-dichloroethane, 310 ppb chloroethane, 390 ppb 1,1-DCE, 15 ppb toluene, and 76 ppb pentachlorophenol (10).(1) Water from the well on the site, that was used for washing newly-mined gravel, in 1982 contained 101 ppb TCE, 5 ppb cis-1,2-DCE, 12,000 ppb nitrates, 2,800 ppb fluoride, and 350,000 ppb sulfates (12).
The maximum concentrations of contaminants of concern detected in the groundwater in monitoring wells on the site during the RI in 1989, by aquifer, are listed in Table 5. The locations of the wells sampled are shown in Figure 2 in Appendix A (Reference 2, Figure 4.4). Wells MW-1, -3, -4, -5, -6, -7, -8, -9, -10, -14, -19, and -20 were drilled into the glacial aquifer, wells MW-15, -16, -17, and -18 were drilled into the perched aquifer, and wells MW-2, -11, -12, and -13 are well clusters, with a shallow well (S) into the perched aquifer and a deeper well (D) into the glacial aquifer. The bedrock aquifer was investigated in Phase III of the RI, between July and November 1991. Four wells were constructed into the Saginaw aquifer, and water samples analyzed. The only volatile organic chemical detected was 2-butanone, in one well at 10 ppb, at the limit of detection. Di(2-ethylhexyl)phthalate (DEHP) was found in all samples, including the method blank and the field blank, with levels as high as 320 ppb. DEHP is a common laboratory contaminant. The unfiltered samples were analyzed for inorganic chemicals. The concentrations of metals found that exceed comparison values are listed in Table 6 (1). The levels of metals detected were likely heavily influenced by particles in the unfiltered water. From the profile of chemicals detected and the great difference between concentrations of zinc found in the upper aquifer versus the bedrock aquifer, there does not appear to be an impact from the site on the bedrock aquifer. The MDNR is planning to analyze additional samples from these wells for dissolved metals (13).
Mapping the concentrations of the chemicals in the glacial aquifer shows a plume of 1,2-DCE, vinyl chloride, TCE, benzene, and 1,1-DCE (in order of concentration) extending south to south-southeast from the major waste disposal area on the site. The groundwater concentrations of 1,2-DCE in the glacial aquifer at the site are plotted on Figure 2 (Reference 2, Fig. 4.4). The highest fluoride concentration was in MW-2D (in the glacial aquifer) with other high concentrations (in order of decreasing concentration) in MW-6, -2S, -16, -3, -17, and -18 (see Figure 2 for well locations). The high chloride and sulfate concentrations listed in Table 5 were found in MW-6, and the high zinc concentration in MW-7, neither of which is in the core of the plume of organic chemicals.
The contamination in the perched aquifer was mainly found north and northeast of the main waste disposal area, between the disposal area and the gravel pit. The highest detected concentrations of nitrate, chloride, sulfate, and zinc in the perched aquifer were from MW-16 (see Figure 2), which is upgradient of the waste disposal area.
The detected concentrations of benzene, 1,2-DCE, vinyl chloride, sulfates, fluoride, and nitrates exceed comparison values.
Monitoring wells located on the perimeter of the site and near the site, in the glacial aquifer, show some chemical contamination. The maximum concentrations of chemicals of potential concern found in off-site or upgradient wells are listed in Table 7. Monitoring wells (MW-1 et al) referred to in the following paragraphs are shown in Figure 2 in Appendix A.
The plume of 1,2-DCE, vinyl chloride, TCE, and benzene extends beyond the site boundaries to the south, at least as far as MW-13D. Trichloroethylene, 1,2-dichloroethane, 2-hexanone, chloroethane, 1,1-dichloroethane, and sulfate were found in wells which are probably not hydraulically connected to the waste disposal area. That is, wells in the glacial aquifer northeast (upgradient) of the waste disposal area and beyond the gravel pit which serves as a terminus for the perched aquifer. Trichloroethylene was also found in MW-19, northwest of the gravel pit. Sulfate was found in MW-9, MW-19, and MW-20, northwest of the gravel pit, and in MW-11D, MW-12D, and MW-13D, downgradient of the waste disposal area. 1,2-Dichloroethane was found in MW-4, and 2-hexanone was found in MW-8, both east of the pit. Chloroethane and 1,1-dichloroethane were only found in MW-1, in the glacial aquifer north of the gravel pit. Fluoride concentrations above the comparison values were found in wells MW-4, (upgradient of the disposal area), -12D, and -13D, the last two south of the site on the W. R. Grace property.
The maximum concentration of DEHP exceeds the EMEG for the water pathway. The maximum level was found in MW-12D, southwest of the waste disposal area. This is downgradient, though the well is outside the plume of contamination mentioned above. Water from MW-8, east of the gravel pit, contained 64 ppb of DEHP. DEHP was also found (15 ppb) in water from a MW-12S, a shallow well, tapping the perched aquifer, south of the site. This well is south of the divide in the perched aquifer, however, and no other chemicals found in the perched aquifer north and northeast of the disposal area were found in this well.
A water sample collected in December 1987 from the municipal well nearest to the site (0.25 miles northwest) contained 4 ppb 1,1-DCE and 14 ppb methylene chloride. Later sampling has found no contamination. A June 1989 water sampling of the other municipal well near the site found no VOCs.
Water from 5 private wells between 0.25 and 0.5 miles to the east and southeast of the site and 1 private well approximately 0.5 miles to the northwest of the site was sampled by the Ingham County Health Department (ICHD) in October 1982. No hydrocarbons were detected in any of these wells. The only parameters that exceeded drinking water standards were iron (up to 800 ppb) and hardness (up to 339 ppm CaCO3). These levels were not considered to be of health concern, so the ICHD only alerted the well owners to the potential problems of scale formation in their water systems. Depth data are available for only three of the wells, which were from 275 to 300 feet deep, indicating that they were bedrock wells (14).
Three of the 5 private wells east and southeast of the site were resampled by ICHD in April 1987. One of the other two was noted as no longer in use, as was the private well northwest of the site (15). No organic chemicals were detected in any of the samples. One of the 3 private wells contained 75 ppb lead, which ICHD staff attributed to the household plumbing not being used for most of the year. A coliform bacterial analysis on water from the same well was positive, attributed to a dirty tap. The well in question is not used for drinking water. The ICHD reported elevated levels of iron, hardness, and alkalinity in all three wells, and of manganese in the well cited above, exceeding drinking water standards based on aesthetics, such as odor, taste, and color, but posing no health concern (16).
In preparing this public health assessment, the MDPH relied on the information provided in the referenced documents and assumed that adequate quality assurance and quality control measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analysis and conclusions drawn for this public health assessment is determined by the reliability of the referenced information.
One soil sample, mentioned above, contained such high concentrations of certain chemicals that the levels could not be reliably measured except after repeated dilution of the sample. This dilution also raised the limit of detection for all chemicals. Analysis of such a diluted sample could fail to detect other contaminants of concern that might have been present at levels found elsewhere on the site. The potential for laboratory contamination accounting for the presence in phthalates and 2-butanone in bedrock aquifer samples and phthalates in the perched aquifer in areas thought to be outside the plume needs to be further examined.
The side slopes of the gravel pit and the mound are steep in some locations, creating a possible hazard for people trespassing on the site. The pit is fenced, but MDPH personnel observed on a visit to the site that the ground beneath the fence had eroded enough in one place to permit access. They also observed that some segments of the fence had been broken from their supports and were on the ground at that time.
To determine whether nearby residents are exposed to contaminants migrating from the site, ATSDR evaluates the environmental and human components that lead to human exposure. An exposure pathway contains five major elements: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population.
An exposure pathway is considered a completed pathway if there is evidence that all five of these elements are or have in the past been present. A pathway is considered a potential pathway if one or more of these elements is not known to be or have been present, but could be or have been. An exposure pathway can be eliminated from consideration if one of the elements is not present and could never be present. The following sections discuss the most important exposure pathways at this site.
There are no pathways for human exposure to the contaminants at this site that are known to be complete. There are several possible pathways which may be complete under certain conditions. However, it is not known whether, or how often, these conditions actually do occur.
The waste mass is in contact with the groundwater in the perched aquifer. Groundwater flowing through the aquifer and infiltrating rain water may leach contaminants out of the waste mass into the aquifer. The aquifer discharges in seeps on the walls of the gravel pit. Any person on the site who walks over one of the seeps may come into contact with the contaminants by contact with the leachate or soils contaminated by the leachate at the seeps. Exposure may come about through dermal contact with or incidental ingestion of water or sediments. Trespassers have been seen on the site, swimming in one of the ponds, though it is not known whether they encountered the areas of the seeps.
The seeps also feed the ponds in the pit, and may carry contaminants into the surface water and sediments in the ponds. Exposure may come about through dermal contact with or incidental ingestion of water or sediments. As of yet, however, no contaminants have been found in the water or sediments of the pond.
Surface soil on the site can become contaminated by erosion of the cover that exposes the waste, by leachate seeping onto the surface, or by chemicals diffusing through the cover. The cover is as little as one foot thick in places, according to soil boring logs from the RI (2). The contaminants may enter the body through incidental ingestion, or through dermal absorption when contaminated soil is in contact with the skin. The majority of the site, including the waste disposal area, is not fenced. While the pit is fenced, the fence has been undermined by erosion and has fallen down in places.
Under appropriate conditions, wind is able to pick up fine surface soils or exposed waste materials, and carry it as dust a distance away. This dust can transport contaminants from contaminated areas or exposed waste off the site to neighboring properties. People on the site, workers or patrons off-site at nearby commercial and industrial establishments, and residents of the site vicinity could be exposed to the dust by inhalation, dermal contact, or incidental ingestion.
Volatile chemicals may evaporate from contaminated surface soil, exposed wastes, leachate at the seeps, or contaminated surface water. Workers and trespassers on the site or on neighboring property may be exposed to the chemicals by inhalation. Based on available information, it is not known if anyone would be close enough to the contaminated areas to be exposed.
Contaminants have leached out of the waste mass into the perched aquifer. Contaminants from the site and from off-site sources have been found in the glacial aquifer. If any wells for domestic use tap these aquifers in the contamination zone, users of water from the wells could be exposed to the chemicals through ingestion, dermal exposure, and inhalation of volatile chemicals secondary to such use as showers and dishwashing. All wells on record in the site vicinity draw on the bedrock aquifer, and none are known to draw on the glacial or perched aquifer. There has been no confirmed report of site-related contamination in the bedrock aquifer, and preliminary indications are that the glacial and bedrock aquifers are not significantly connected in the site area. Use of water from the well on the site for washing gravel may have exposed the workers doing the washing to contaminants in the water by contact and inhalation of volatilized contaminants. Operations on the site have ceased, and the well is no longer in use. Therefore, these pathways are not known to be complete at this time. It is also possible that some unrecorded wells may be using the glacial or perched aquifer.
Groundwater contamination at the Motor Wheel Disposal Area site is not likely to have an impact on the Grand River because of the distance to the river, dispersion in the aquifers, and dilution in the river.
There is no indication from any sampling of municipal or residential wells in the area that any significant exposure to contaminants has occurred. Under the routine monitoring program applied to the municipal wells, any well which is found to contain contaminants will be taken out of service. The extremely high concentrations of various metals found in unfiltered water samples from the Saginaw Formation aquifer are being investigated further by the MDNR.
There are no pathways for human exposure to site-related contaminants that are known to be complete. The most likely of the potential exposure pathways is that of a trespasser on the site. Trespassers have been seen on the site, though details of how often and how long they spend on the site are not known. This evaluation assumes a young trespasser, weighing 35 kilograms, goes onto the site once a week for 3 hours, for 6 months out of the year. Based on the upper end of the typical range of total rate for incidental ingestion of soil of 250 milligrams per day, a year-round average ingestion of 3.5 milligrams of soil per day would be attributed to the site. The concentrations in the soil the trespasser would be exposed to are assumed to be the maximums found in the surface soil.
The risk of experiencing non-cancer adverse health effects is evaluated by comparing the estimated doses the modeled individual would be exposed to with the Minimal Risk Levels (MRLs) developed by the ATSDR and to the Reference Doses (RfDs) developed by the U.S. EPA. A person who experiences a dose of a chemical below the MRLs or RfDs is generally expected not to experience adverse non-cancer health effects. The risk of developing cancer as a result of the exposure are evaluated separately, with no significant risk considered to be less than an estimate of 1 additional cancer case per 1,000,000 people exposed.
A trespasser is not likely to incidentally ingest enough di(2-ethylhexyl)phthalate (DEHP) from the soil on the site to exceed the RfD for non-cancer health effects or to incur a significant cancer risk. The U.S. EPA has classified the chemical as a probable human carcinogen (U.S. EPA Class B2) due to evidence that laboratory animals exposed to the chemical developed cancer of the liver (17).
There are no MRLs or RfDs available for ingestion of zinc. Ingestion of large amounts of zinc has been known to cause digestive problems, problems with the immune system, and anemia. Zinc is also an essential nutrient in the diet. A trespasser is not likely to incidentally ingest enough zinc from the soil on the site to reach the Recommended Daily Allowance for zinc in the diet, nor would he or she attain the doses at which adverse effects have been observed in animal and human studies. There is no evidence that zinc causes cancer (18).
Exposure to lead can cause brain and kidney damage and developmental problems, especially in children and the unborn. Lead tends to accumulate in the body, compounding the effects of small exposures. Animal testing has linked lead exposure to cancer, while human cancer studies are inconclusive. The U.S. EPA has classified lead as a probable human carcinogen (U.S. EPA Class B2). It is difficult to predict health effects from a given exposure to lead, due in part to the chemical's tendency to accumulate in the body. However, it is very unlikely a trespasser would ingest enough lead from the soil on the site to cause adverse health effects. The surface concentrations are below the U.S. EPA's level of concern (500 ppb). Wastes containing high lead levels are buried and not available for human exposure though the cap could erode and expose the wastes (19).
A trespasser is not likely to incidentally ingest enough chromium or antimony from the soil on the site to exceed any RfD for non-cancer health effects. There is no evidence that ingestion of any chromium compound or antimony causes cancer (20, 21).
A trespasser is not likely to incidentally ingest enough cadmium from the soil on the site to exceed the MRL for non-cancer health effects. There is no evidence that ingestion of cadmium causes cancer (22).
A trespasser is not likely to incidentally ingest enough selenium from the soil on the site to exceed the MRL for non-cancer health effects. There is no evidence that selenium causes cancer (23).
A trespasser is not likely to incidentally ingest enough fluoranthene (the only 4-Ring PAH identified in surface soil samples) from the soil on the site to exceed the RfD for non-cancer health effects. There is no evidence that fluoranthene causes cancer (7).
A trespasser is not likely to incidentally ingest enough aldrin from the soils on the site to exceed the RfD for non-cancer health effects or to incur a significantly increased risk of cancer. The U.S. EPA has classified aldrin as a probable human carcinogen (U.S. EPA Class B2) because of evidence linking exposure to the chemical with liver cancer in laboratory animals (24).
A trespasser is not likely to incidentally ingest enough dieldrin from the soil on the site to exceed the MRL for non-cancer health effects or to incur a significantly increased risk of cancer. The U.S. EPA has classified dieldrin as a probable human carcinogen (U.S. EPA Class B2) because of evidence linking exposure to the chemical with liver cancer in laboratory animals (24).
There are no MRLs or RfDs available for exposure to copper. A trespasser is not likely to incidentally ingest enough copper from the soil on the site to attain a dose that has been observed to cause adverse health effects. There is no evidence available that copper causes cancer (25).
There are no MRLs or RfDs available for exposure to nickel in general. There is an RfD for the soluble salts of nickel, equivalent to a comparison value in soils of 40 ppm. A trespasser is not likely to incidentally ingest enough nickel from the soils on the site to exceed this RfD, nor to attain any dose at which adverse health effects have been observed. There is no evidence available that ingesting nickel causes cancer (26).
There are no MRLs or RfDs available for long-term exposure to thallium. A trespasser is not likely to incidentally ingest enough thallium from the soil on the site to attain a dose that has been observed to cause adverse health effects. There is no evidence available that thallium causes cancer (27).
When detected, contaminants of concern in the water and sediments of the on-site ponds were found at concentrations comparable to background levels. Exposure to these chemicals at these levels is not expected to cause adverse health effects.
Data were obtained on cancer incidence and mortality for zip code 48906 in which the site is located. Because the site is near the southeast boundary of the zip code area, data were also evaluated for zip code 48912 (Lansing, immediately south of the site) and zip code 48823 (East Lansing, east of the site). The available cancer incidence data covers the years 1985 through 1990. Mortality data were evaluated for the period of 1989 through 1991. Mortality records were not available by zip code prior to 1989 (28).
Ratios of observed to expected cases and deaths were calculated for each of the selected zip codes for each year from 1985-1990 for cancer of all sites and for cancer of the lung and bronchus (Table 8, Table 9, Table 10, Table 11). The number of "expected" cases were calculated by applying the age- and sex-specific cancer rates for Michigan to the age- and sex-specific zip code area population estimates. When the number of observed vs. expected cancer cases are identical, the ratio is 1.0. When there are more cases observed than expected the ratio is greater than 1.0. Conversely, when there are fewer cases than expected, the ratio is less than 1.0. The magnitude of the difference (higher or lower) is checked to see if it is statistically different from 1.0 taking into consideration factors such as sample size and degree of variation from year to year.
None of the three zip codes showed a significantly higher than expected cancer incidence. Cancer incidence and mortality (deaths) for zip code 48823 (East Lansing) tended to be significantly lower than expected for all cancer sites combined and cancer of the lung and bronchus (Table 8, Table 9). Observed cancer deaths for the zip code 48912 were significantly higher than expected for 1989. In both 1990 and 1991, there were fewer deaths observed than expected (Table 10).
The age-adjusted incidence and death rates for each of the zip codes were compared to the rates for Ingham County excluding those zip codes, and to the State (Table 12). Rates that were statistically different than either reference area are noted in the table with a superscript and footnote. As with the observed vs expected data discussed above, the cancer incidence rates (All sites combined and lung and bronchus cancer) for zip code 48823 (East Lansing) was significantly lower than both the State and the remainder of Ingham County. Although the age-adjusted death rate for zip code 48906 during years 1989-1991 was higher than both the Ingham County and State rates, the difference was not statistically significant.
The cancer data above do not indicate any consistent pattern of excess cancer incidence or mortality for the residents of the zip codes areas in which the Motor Wheel Disposal Area site is located or those adjacent to the site as compared to the rest of Ingham County or to the State. However, this does not rule out the possibility that subpopulations in smaller areas near the site experienced excesses. Data do not allow a more localized assessment.
The community concerns regarding this site have been primarily with the dangers of exposure and physical hazards on the site. MDPH and ATSDR continue to recommend effective site restrictions and maintenance of those restrictions until site remediations are completed. In response to the concerns citizens have expressed about cancer, MDPH has evaluated the latest cancer incidence and mortality data from the site area, as described in the preceding section.
- From the information reviewed, the Motor Wheel Disposal Area site is judged to be an indeterminate public health hazard. The levels of di(2-ethylhexyl)phthalate, 1,2-dichloroethylene, and vinyl chloride in the groundwater at the site would pose significant risks of adverse health effects to anyone drinking the water for long periods, but there is no evidence that the contaminated aquifer is currently being used. The contaminated aquifer does not appear to be connected to a deeper aquifer, which is used as a drinking water source in the site area. However, there needs to be more study to determine how well the two aquifers are separated.
- Though surface soil contaminant levels do not pose significant exposure hazards to trespassers on the site, the danger of injury from falling into excavations or drowning in the on-site pit warrants maintaining restrictions to prevent public access.
- There is a large deposit of wastes, including volatile organic chemicals, on the site that could release hazardous vapors when it is disturbed.
- The bedrock aquifer needs to be studied further to define the hydraulic connection, if any, between it and the glacial aquifer.
- Access to the entire site should be better restricted.
- Site remediation workers should follow appropriate safety practices. Precautions to minimize off-gassing should be implemented during any on-site work that exposes wastes.
The Health Activities Recommendation Panel has evaluated the data and information developed in the Motor Wheel Disposal Area public health assessment for appropriate follow-up health actions. The panel determined that, although there is no indication that human exposure to contaminants at levels of public health concern is occurring or has occurred, the community has concerns regarding cancer associated with the site. MDPH has previously conducted a cluster investigation of cancer incidence in the site area. In response to these concerns and as a follow-up to the cluster investigation, the panel recommends MDPH conduct a health statistics review to determine if an increase in cancer incidence may be associated with site contamination.
The Public Health Action Plan (PHAP) for the Motor Wheel Disposal Area site contains a description of actions to be taken by ATSDR and/or the Michigan Department of Public Health (MDPH) at and in the vicinity of the site subsequent to the completion of this Public Health Assessment. The purpose of the PHAP is to ensure that this Public Health Assessment not only identifies public health hazards, but also provides a plan of action designed to mitigate and prevent adverse human health effects resulting from exposure to hazardous substances in the environment. Included is a commitment on the part of ATSDR and MDPH to follow up on this plan to ensure that it is implemented. The public health actions to be implemented by ATSDR and/or MDPH are as follows:
Health Actions Planned
ATSDR and MDPH will continue the informational and educational activities included in the normal health assessment process at this site to address community health concerns as appropriate.
MDPH, in cooperation with ATSDR, will conduct a health statistics review of cancer incidence in the site area.
ATSDR and MDPH will coordinate with federal and state environmental agencies to carry out the recommendations made in this assessment.
ATSDR will reevaluate and expand the Public Health Action Plan when needed. New environmental, toxicological, or health outcome data, or the results of implementing the above proposed actions and recommendations may determine the need for additional actions at this site.
Michigan Department of Public Health
John W. Filpus
Health Assessment Coordinator
John L. Hesse
ATSDR Regional Representative
Regional Services, Region V
Office of the Assistant Administrator
ATSDR Technical Project Officer
Environmental Health Scientist
Division of Health Assessment and Consultation
The Motor Wheel Disposal Area public health assessment was prepared by the Michigan Department of Public Health under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health assessment was initiated.
Technical Project Officer, SPS, RPB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this health assessment and concurs with its findings.
Director, DHAC, ATSDR
- ENSR Consulting and Engineering. Saginaw Aquifer Investigation Report for the Motor Wheel Disposal Site, Lansing, Michigan. April 1992.
- Hunter/Keck Environmental Services. Remedial Investigation Report: Motor Wheel Disposal Site: Lansing, Michigan. February 8, 1990.
- ENSR Consulting and Engineering. Risk Assessment for the Motor Wheel Disposal Site. January 1991.
- Michigan Department of Public Health, for ATSDR. Preliminary Health Assessment for Motor Wheel Incorporated. March 1989.
- U.S. Environmental Protection Agency. Declaration for the Record of Decision, Motor Wheel Disposal site. September 30, 1991.
- U.S. Environmental Protection Agency. Site Inspection Report. August 27, 1983.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Polycyclic Aromatic Hydrocarbons. ATSDR/TP-90/20. December 1990.
- Rowe, G., Ingham County Health Department. File Summary of Motor Wheel Landfill Site. June 30, 1983.
- Ruskin, J., Ingham County Health Department. Memo to F. Robert Godbold. May 19, 1980.
- Michigan Department of Natural Resources, Water Quality Division. Former Motor Wheel Disposal Site. October 22, 1982.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Pentachlorophenol, Update, Draft for Public Comment. October 1992.
- Ceru, R., Ingham County Health Department. Letter to D. Schlegel. December 21, 1982.
- Adelman, M., MDNR Project Manager. Personal communications. April 1992.
- Ceru, R., Ingham County Health Department. Letter to G. Klepper, MDNR. December 21, 1982.
- Feltwer, M., Ingham County Health Department. Memo re: Well Monitoring Program, Old Motor Wheel Dump Site. March 26, 1987.
- Rowe, G., Ingham County Health Department. Letters to well owners. June 18, 1987.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Di(2-ethylhexyl)phthalate, Update, Draft for Public Comment. October 1991.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Zinc, Update, Draft for Public Comment. October 1992.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Lead, Update, Draft for Public Comment. October 1991.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Antimony, Draft for Public Comment, October 1990.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Chromium, Update, Draft for Public Comment. October 1991.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Cadmium, Update, Draft for Public Comment. October 1991.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Selenium. ATSDR/TP-89/21. December 1989.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Aldrin/Dieldrin, Update, Draft for Public Comment. October 1991.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Copper. ATSDR/TP-90/08. December 1990.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Nickel, Update, Draft for Public Comment. October 1991.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Thallium, Draft for Public Comment. October 1990.
- Spivak, G., Michigan Department of Public Health, OSRCHS. Memo to D. Dolanski, BEOH/DHRA. January 21, 1993.
OTHER INFORMATION SOURCES NOT CITED IN TEXT
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Benzene, Update, Draft for Public Comment. October 1991.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for Vinyl Chloride, Update, Draft for Public Comment. October 1991.
- Agency for Toxic Substances and Disease Registry. Toxicological Profile for 1,1-Dichloroethane. ATSDR/TP-90/12. December 1990.
- Agency for Toxic Substances and Disease Registry, Toxicological Profile for 1,2-Dichloroethene. ATSDR/TP-90/13. December 1990.
1. Comparison values for pentachlorophenol in water: 30 ppb based on a Minimal Risk Level for non-cancer health effects through intermediate term exposure, U.S. EPA lifetime Drinking Water Health Advisory of 200 ppb, 0.3 ppb CREG (11). Comparison Values for other chemicals listed in Table 5.