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PUBLIC HEALTH ASSESSMENT

METAMORA LANDFILL
METAMORA, LAPEER COUNTY, MICHIGAN


SUMMARY

The Metamora Landfill site was listed on the United States Environmental Protection Agency (U.S. EPA)National Priorities List (NPL) on September 21, 1984. The landfill, located 1 mile east of the Village of Metamora, in Metamora Township, Lapeer County, Michigan, operated from 1966 to 1980, accepting municipal and drummed industrial wastes. The landfill occupies the northern 25 acres of a total 160 acre site. The wastes were dumped into pits left from a former gravel mining operation. Limited gravel and aggregate mining continues in the southern portion of the site, and there is still a waste transfer station near the old landfill. The results of a series of studies, dating back to before the landfill was closed, led the U.S. EPA to place the site on the NPL in 1984.

Due to inadequate containment construction, the landfill has leachate seeps and a plume of organic and inorganic chemical contamination in the ground water. Thousands of drums have been discovered on the site, many have been excavated during remedial actions and removed from the site. Many packing containers of contaminated materials are staged on-site awaiting disposal. The U.S. EPA signed a Record of Decision addressing the ground-water operable unit in September 1990. The selected remedy consists of two measures: a groundwater purge and treat process; and placement of a clay cover that utilizes a passive gas collection system and gas flaring.

The site is considered to be an indeterminate public health hazard. The potential exists for future exposure to hazardous substances at concentrations that may result in adverse health effects. Although sampling of private wells downgradient of the site has not detected contamination, those wells draw from the affected aquifer and the leading edge of the plume has not been determined. This assessment recommends further characterization of the contaminant plume north of the site.

Since access to most of the site is not restricted, contact with and incidental ingestion of surface contaminants on the landfill and inhalation of fugitive dust are also potential health hazards. A number of physical hazards also remain on the site from the gravel mining operation, including steep banks, deep pits, and unguarded or abandoned equipment. During the current remediation, the working areas are fenced and guarded but there has been at least one incident of on-site trespass and vandalism. Since there is no available documentation of human exposure to the contaminants at levels of human health concern, no follow-up health activities are scheduled for this site at this time.


BACKGROUND

The Metamora Landfill site has been on the United States Environmental Protection Agency (U.S. EPA) National Priorities List (NPL) since September 21, 1984.

A. SITE DESCRIPTION AND HISTORY

The Metamora Landfill site covers approximately 160 acres, on the north side of Dryden Road approximately 1 mile east of the Village of Metamora, in Metamora Township, Lapeer County, Michigan. Figure 1 shows the site location and Figure 2 the major features of the site. Both Figures are taken from the E.C. Jordan Remedial Investigation Report. A landfill that accepted both municipal and industrial wastes operated from 1966 to 1980 on approximately 25 acres in the north-northeast section of the site. Much of the waste was reportedly deposited in unlined natural depressions or preexisting excavations, including former quarries or borrow pits from gravel mining operations on the site. After the landfill was closed, it was covered with a thin layer of sandy soil. As of this writing, it is estimated that 28,000 drums, many containing industrial chemical wastes, were dumped on the site in Drum Area 4, immediately west of the landfill, and Drum Area 1, south of the landfill (See Figure 2). A magnetometer survey carried out by the MDNR in 1982 found three other magnetic anomalies, which may indicate large concentrations of metal, possibly more drums, within the landfill and apparently buried deep under the waste. These three magnetic anomalies have not been further investigated because of their inaccessibility.

Currently, a solid waste transfer station operates in the northwest corner of the site, and a limited amount of aggregate is still mined from the site. There is an 8 acre gravel pit in the southeast corner of the site, and a 2 acre pond near the center of the site. Previous mining operations have left numerous steep excavation faces and borrow pits on the site. Elevations on the site range from 1,030 feet in the borrow pits to 1,150 feet at the rim of the gravel pit.

According to reports, there were frequent fires on the site during the landfill's operation.

The site lies on an approximately 300-foot-thick layer of sand and gravel above sandstone bedrock. There are scattered lenses of clayey and/or silty material throughout the upper sand and gravel layer. There are four identified aquifers in the site area: an upper aquifer, an intermediate aquifer, a perched aquifer, a the bedrock aquifer. The upper aquifer is an unconfined, water-table aquifer in the sand and gravel layer, with water level at around 1,005 feet. A large lens of up to forty feet of silt, clay, and gravel till is found between 925 and 990 feet under the northern part of the site, including the landfill and both drum areas. The till acts as an aquitard separating the upper aquifer from the intermediate aquifer. The exact extent and continuity of this till and how effectively it separates the aquifers is not known. The perched aquifer is small in extent, sitting on top of a clay lens located near the northwest corner of the landfill, with water level approximately 1,080 feet, 20 feet below grade, and 77 feet above the normal water table. The bedrock contains another aquifer which is separate from the higher ones.

In 1986, an Operable Unit Record of Decision was signed by the U.S. EPA Region V Administrator for removal of the drums and soils adjacent to them, with disposal in a RCRA-approved facility. The removal operation began in March 1989. The drums from the area west of the landfill have been excavated and some are still stored on the site, awaiting removal for disposal. That drum removal area has been backfilled and revegetated. Excavation continues south of the landfill. As of November 1990, 24,000 drums had been excavated and 11,000 drums and 8,600 tons of soil had been shipped off the site for disposal. E.C. Jordan Co. performed a Remedial Investigation/Feasibility Study (RI/FS) under contract from the Michigan Department of Natural Resources (MDNR). The Remedial Investigation (RI) work was done in 1987 and 1988, and the final report on the RI was issued in March 1989. The Feasibility Study was completed April 1990. In September 1990, the U.S. EPA signed a Record of Decision for capping the landfill and pumping and treating the contaminated ground water. A consent decree between the U.S. EPA and the settling parties for the second operable unit, and part of the first operable unit, was released for public comment between August 1, 1991 and September 31, 1991. The U.S. EPA, together with the U.S. Department of Justice, are currently preparing a responsiveness document to address the comments received.

B. SITE VISIT

Michigan Department of Public Health (MDPH) personnel, escorted by MDNR personnel, visited the site on June 28 and July 30, 1990. Since then, MDPH assessors have been kept informed of on-site activities by contacts with the U.S. EPA and MDNR and by having MDPH and ATSDR representatives present at site-related public meetings. Information obtained on the site visits and is reflected in the descriptions, conclusions and recommendations in this document.

C. DEMOGRAPHICS, LAND USE, AND NATURAL RESOURCE USE

The 1980 Census showed a population of 3,320 for Metamora Township and 552 for the Village of Metamora, 1 mile west of the site. Since 1980, fifteen homes have been built within 1 mile of the site. There is a residence less than 0.25 mile north of the site's northeast boundary. There are 13 homes and a Boy Scout camp within 0.5 mile of the site.

Land use around the site is primarily residential and agricultural. The area directly north of the landfill is heavily wooded, with limited accessibility. Residences are widely scattered in the wooded area north of the landfill. There are scattered parcels of heavy woodland to the east and west of the site, as well.

D. STATE AND LOCAL HEALTH DATA

MDPH assessors have consulted Lapeer County Health Department (LCHD) personnel to determine if there have been any unresolved health complaints relating to the site. They have also solicited information from the community regarding health concerns. Following a September 1991 public meeting, one concerned citizen reported a situation where two members of a family who lived a short distance from the site were diagnosed as having the same unusual form of cancer. The citizen who mentioned this disease incidence information contacted MDPH a short time later, saying that after consulting with the two people, and learning that they had no contact with the landfill, she no longer thought the site played any role in their condition. MDPH and the LCHD are willing to consider and investigate the plausibility of any health concerns associated with the site.


COMMUNITY HEALTH CONCERNS

As residential development increased near the site in the 1970s, owners and residents of land adjacent to the site lodged complaints about trash blowing off the landfill, odors, and hazards from steep slopes while the landfill was in operation. Residents expressed concerns about the ground water in the area, though at the time there was no indication of ground-water contamination. Local citizens continued to voice concerns during the closure and early investigation of the site. A Citizens' Information Committee for the site was established in 1984 to facilitate the exchange of information between the citizens of the community and the MDNR.

In 1984, the Detroit Area Council of the Boy Scouts of America (BSA) proposed to contract for gravel mining on the property owned by BSA, approximately 0.5 mile northeast of the Metamora Landfill. The proposal included subsequent flooding of the excavation for recreational use. Among the issues raised by local residents in opposition to the proposal was the proximity of the proposed new lake to the Metamora Landfill. Concerns were expressed that ground water could carry contaminants from the landfill to the lake. Consequently, the Metamora Township Planning Board refused permission for the project. The Boy Scout Council appealed the decision, without success, and filed suit against the township in Federal Court. The trial began in September 1989, and is still in process as of this writing.

The most recent citizen concerns regarding the site center on the remedial alternatives contained in the record of decision. Originally, the U.S. EPA had planned to transport the contaminated media off the site in drums to be incinerated at an approved facility. Their inability to find a facility for processing the volume of wastes they were excavating and staging on-site prompted the U.S. EPA to change the remedial plan to include construction and use of an on-site waste incinerator. Some community residents are primarily opposed to on-site incineration. Other community residents are concerned about the adequacy of site characterization, the emergency preparedness for accidents during remedial actions, and the legality and level of assigned responsibility of the consent decree that is being developed with the settling partners. Two of the groups have applied for a U.S. EPA Technical Assistance Grant (TAG) in order to hire the services of their own technical consultants. The (TAG) award decision has not been made as of this writing.

This document was released for public comment from May 21, 1991 to June 20, 1991. Only one comment was received during this period. The comment and the response to the comment is attached to this Public Health Assessment in the Responsiveness Statement.


ENVIRONMENTAL CONTAMINANTS AND OTHER HAZARDS

To identify possible facilities that could contribute to the ground water, surface water, and soil contamination near the Metamora Landfill site, the MDPH searched the 1987, 1988, and 1989 Toxic Release Inventory (TRI). TRI is developed by the U.S. EPA from the chemical release information provided by certain industries. TRI did not contain information on toxic chemical release within the zip code area in which the site is located.

A. ON-SITE CONTAMINATION

During the 1987-88 RI work, volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), polynuclear aromatic hydrocarbons (PAHs), and metals were found at concentrations of concern at the site. Table 1 lists the chemicals found and the concentration ranges. The media sampled included ground water, surface water, leachate, soils, and sediments. Soil samples were taken from borings and from the surface at leachate break-outs.

Ground water contaminated with VOCs and metals was found in the upper aquifer, the shallow perched aquifer, and, to some extent, in the intermediate aquifer. Maximum concentrations in parts per billion (ppb) found in the upper aquifer were: arsenic, 260; barium, 2,170; benzene, 11; 1,1-dichloroethane, 55; 1,2-dichloroethane, 19; 1,1-dichloroethylene, 2.1; 1,2-dichloroethylene, 270; ethylbenzene, 2,800; iron, 12,700; trichloroethylene, 14; 1,1,2-trichloroethane, 6; vinyl chloride, 6; and xylene, 12,000.

The perched aquifer is believed to intercept leachate from the landfill and from one of the drum areas. Maximum concentrations (ppb) found in the perched aquifer were: arsenic, 183; barium, 338; benzene, 20 (est.); 1,1-dichloroethane, 29; 1,2-dichloroethylene, 9; ethylbenzene, 19; iron, 18,700; 4-methylphenol, 110; tetrachloroethylene, 2 (est.); vinyl chloride, 2 (est.); and xylene, 40.

Three monitoring wells on the site (MW-17I, MW-25I, and MW-31) tap the intermediate aquifer. All three showed contamination in the first sample, but the levels were much lower, to below detection limits, in later samples. MW-17I contained 1 ppb benzene, 9 ppb 1,1-dichloroethane (1,1-DCEA), 7 ppb 1,2-dichloroethane (1,2-DCEA), 97 ppb 1,2-dichloroethylene (1,2-DCE), 37 ppb styrene, 112 ppb 1,1,2-trichloroethane (1,1,2-TCEA), 44 ppb trichloroethylene (TCE), and 47 ppb vinyl chloride; MW-25I showed 1 ppb vinyl chloride (estimated); and MW-31 showed 160 ppb pentachlorophenol (PCP) and 17 ppb 4-chloro-3-methylphenol when first sampled. The specific chemicals identified in MW-17I were also found in a nearby well, MW-17S, which taps the upper aquifer. A third well in the same cluster, MW-17D, which taps the upper aquifer at a greater depth than MW-17S,(1) showed no site-related contamination. The rapid decrease of contaminant concentrations in the intermediate aquifer samples may indicate that the originally-detected contamination was due to short-lived cross-contamination that occurred during construction of the monitoring wells.

PCP was found at the site only in wells MW-17S and MW-31. None of the other chemicals detected in MW-17S were found in MW-31. The one MW-31 sampling represented the sole detection of 4-chloro-3-methylphenol in ground water at the site. There is not sufficient evidence to firmly establish that PCP and 4-chloro-3-methylphenol are site-related contaminants of concern.

Soil at the leachate seeps contained various VOCs and PAHs, with maximum concentrations (in ppb) as follows: 1,1-dichloroethylene, 12(est.); trans-1,2-dichloroethylene, 20; 2-butanone, 920 (est.); trichloroethylene, 2 (est.); tetrachloroethylene, 12 (est.); toluene, 46 (est.), ethylbenzene, 13; phenanthrene, 900; fluoranthene, 1,500; and pyrene, 1,300.

The wastes in the drums are believed to be primarily paints and solvents. Analysis of the wastes showed VOCs, SVOCs, PAHs, and metals, at concentrations as high as 15 per cent. Polychlorinated biphenyls (PCBs) were found at as much as 1,200,000 ppb. Soils adjacent to the drums contained low levels (to 700 ppb) of organic chemicals and inorganic chemicals comparable to background levels, indicating little lateral migration of contaminants. Soils beneath the wastes, which are likely to be contaminated, will be investigated after the removal action is completed. Some of the wastes had been burned, and samples of the burned wastes were analyzed for chlorinated dioxins and dibenzofurans. The total concentrations of such compounds, reported in the RI report as 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD) equivalents, ranged from 0.0013 to 0.105 ppb.

The air at four locations near the site perimeter, one upwind and three downwind, is monitored for organic chemicals each day during remedial activity on the site. The locations are not fixed, but are chosen each day corresponding to current weather conditions. The maximum concentrations of selected chemicals found during two recent periods, in June/July and October/November 1990, are listed in Table 2. Detection of contaminants has been sporadic, with highest levels corresponding to excavation and soil packing periods. Benzene has been frequently detected in upwind samples, but at lower levels than downwind. Trichloroethylene was occasionally detected at up to 1.7 ppb in upwind samples. Off-site sources or short-term shifts of the wind during collection periods may account for these anomalies.

B. OFF-SITE CONTAMINATION

Water from monitoring wells in the shallow aquifer as far as 500 feet north of the landfill has been found to contain organic chemical contaminants. Maximum contaminant levels in these wells include 3 ppb chloroethane, 28 ppb 1,1-dichloroethane, 9 ppb 1,2-dichloroethane, 25 ppb 1,2-dichloroethylene, 42 ppb 1,1,1-trichloroethane, 5.9 ppb 1,1,2-trichloroethane, 3.3 ppb trichloroethylene, 2.9 ppb phenol, and 2 ppb vinyl chloride. The extent of the contamination plume in the upper aquifer is not known, because no monitoring wells have been installed north (downgradient) of those mentioned above. Mathematical modelling of the ground-water flow indicates that the plume of contamination may reach as far as 3,000 feet north of the site.

Sampling of private wells north of the site has shown no contamination. However, the majority of these wells tap the bedrock aquifer, which has not shown contamination at on-site monitoring wells. There are two older shallow residential wells (reportedly 80 to 90 feet deep) approximately 0.5 mile directly north of the site. At the most recent sampling, in October 1990, the water in these wells showed no contaminants.

C. QUALITY ASSURANCE AND QUALITY CONTROL

In preparing this Public Health Assessment, MDPH relied on the data 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. Information on laboratory quality control cited in this Assessment was taken from the referenced documents. The validity of the analysis and conclusions drawn for this Public Health Assessment is dependent upon the reliability of the referenced information.

D. PHYSICAL AND OTHER HAZARDS

Access to much of the site is unrestricted, though selected areas have been fenced. The working areas have been fenced and posted during the remediation currently in progress, and the contractors maintain a twenty-four hour security guard. The transfer station area is fenced. There are remnants of much older fences elsewhere on the site, probably dating from the gravel mining operation. There are a number of physical hazards on the site outside of the currently fenced-in areas. The gravel pits have steep banks and there are a number of pieces of abandoned machinery on the site which might be dangerous but attractive for climbing by unauthorized visitors.


PATHWAYS ANALYSES

A. ENVIRONMENTAL PATHWAYS (FATE AND TRANSPORT)

Ground water at the site flows generally to the north or north-northwest, at a rate estimated at 0.1 to 0.3 ft/day in the upper aquifer, and 0.6 to 1.0 ft/day in the bedrock aquifer. The contaminants have been primarily found in the upper aquifer. This aquifer is rarely used for drinking water supplies. Most wells in the area draw on the much deeper bedrock aquifer.

The nearest surface water body downgradient of the site is Reed Lake, 1.5 miles to the northwest (see Figure 1). Beaver Lake is 1 mile to the northeast, but the site is in the Reed Lake drainage basin topographically and hydrogeologically. Hunters Creek, which drains both Reed and Beaver Lakes, crosses east to west two miles north of the site and eventually flows northward into the South Branch of the Flint River. The ground water from the site probably discharges into Reed Lake or Hunters Creek. There is no record of either surface water body having been tested for site-related contaminants. However, mathematical modelling of the ground-water flow at the site predicts that the contamination would not have migrated as far as either water body.

The pond near the center of the site is fed by rainwater and surface runoff and has no outlet. It is located south of the landfill and the drum areas. The pond is upgradient to both ground-water flow and surface runoff from the landfill and drum area. At an elevation of approximately 1,100 feet, the pond probably supplies water to the upper aquifer rather than being fed by it. The pond is located above buried drums in Drum Area 1, and water infiltrating through the pond bed may leach contaminants into the ground water. A number of other ponded water areas can be found on the site after heavy rains.

Volatilization of volatile contaminants and air transport via fugitive dust are also potential transport pathways for contaminants from the site. Volatile contaminants and contaminated dust may be washed out of the air by rain into the surface water bodies on the site. Excavation of source areas as part of remediation activities may increase the potential for volatilization of chemicals and fugitive dust.

B. HUMAN EXPOSURE PATHWAYS

Potential pathways for human exposure to the contaminants associated with the site involve ground water, surface water, soil and sediment. For the pathways involving water, exposure may occur through ingestion, dermal contact, and inhalation secondary to household use. Dermal contact and ingestion are routes of exposure to soils and sediments on the site.

As mentioned earlier, most private wells in the area do not use the contaminated aquifer at this time. Those downgradient wells that do tap the shallow aquifer are being monitored to detect any encroaching contamination. New wells constructed north of the site may also tap the impacted aquifer.

There is no outlet for the surface water from the pond on the site and the water is not used for consumption or recreation. The groundwater contamination plume may, if not treated or naturally dispersed, reach Hunters Creek or Reed Lake, and users of these water bodies may be exposed to the contaminants.

Access to the majority of the site, including much of the landfill cap, is unrestricted, raising the possibility of exposure to contaminated soil on the site through dermal contact, inhalation of dust, and ingestion. The site is sufficiently far from residences that it is unlikely that very young children would reach the site without supervision. Hence, deliberate ingestion of soils on the site, through pica behavior, is much less likely than incidental ingestion. Portions of the site, such as the gravel pit, are attractive areas for dirt bike riding and other recreational activities. The Boy Scout camp located within 0.5 mile of the site hosts a seasonal population of pre-teens and teenagers. On-site contractor personnel have reported nearby residents riding horses into the site area from the north, through the woods. During the remediation in progress as of this writing, most of the contaminated areas of the site have been fenced and are under 24-hour security guard. In September 1991, there was an incident of vandalism on the site that produced a spill of fuel used for remedial work equipment.

Inhalation of volatile contaminants and of contaminated dust from the site are potential pathways of human exposure for nearby residents and workers, visitors, and trespassers on the site. As mentioned above, excavation during remedial actions may expose fresh waste, increasing the likelihood of volatilization and fugitive dust. Workers and authorized visitors at the site are required to wear protective clothing in the working areas. The workers in the excavation activity wear breathing masks, air tanks, hard hats, and protective coveralls. Air in the excavation area is monitored for organic vapors. Appropriate precautions to reduce organic vapor emission are implemented when excessive levels are reported.

The air at the perimeter of the site is also monitored for chemical contamination during working periods. When the monitor records the presence of excessive levels of organic vapors during excavation or other operations, precautions are implemented to reduce emissions from the source area.


PUBLIC HEALTH IMPLICATIONS

A. TOXICOLOGICAL IMPLICATIONS

The concentrations of various chemicals found in site-related environmental media have been compared with the Minimal Risk Levels (MRLs) published in the ATSDR Toxicological Profiles for the chemicals. A person who drank only water containing the maximum concentration of arsenic found in the ground water at the site would ingest a dose of the metal in excess of the MRL for non-cancer endpoints. The air concentration of methylene chloride on the site has exceeded the MRL for non-cancer endpoints based on intermediate-term exposure (15 days to one year). The air concentration of methylene chloride has exceeded its MRL for non-carcinogenic endpoints. There have been instances where naturally occurring arsenic has been found in groundwater in Lapeer County and in this general geographic area of the state. In this particular location the landfill is considered the primary source of arsenic in the groundwater.

Many scientists believe there is no safe level of exposure to any chemical suspected of causing cancer. A conservative stand on matters of public health concern would be that any exposure to any carcinogen is hazardous. Of the major chemicals of concern at this site, arsenic, benzene, and vinyl chloride are classified as proven human carcinogens (U.S. EPA Class A). 1,2-DCEA and TCE are classified as probable human carcinogens (U.S. EPA Class B2). A number of PAHs are classified as probable human carcinogens (U.S. EPA Class B2), and many other PAHs are suspected carcinogens based on chemical and structural similarity. A number of PCB congeners have been classified in U.S. EPA Class B2. 1,1-DCE and 1,1,2-TCEA are considered potential human carcinogens (U.S. EPA Class C).

Exposure to chlorinated solvents can cause liver and kidney damage. Exposure to high levels of other VOCs can lead to depression of the nervous system. Chronic exposure to low levels of benzene can interfere with blood production. Exposure to barium can cause difficulty in breathing, increased blood pressure, changes in nerve reflexes, and damage to the liver, kidney, heart, and spleen. Exposure to arsenic can produce changes in the skin, decreased blood production, depressed nerve function, and liver and kidney damage.

The air concentration of methylene chloride exceeded the MRL for non-cancer endpoints during excavation of the drums at the site. Workplace safety procedures in place during excavation call for continuous monitoring of the air and appropriate actions to reduce such emissions whenever excessive levels are reported. Workers in the most hazardous area of the site wear full protective equipment. Dilution and dispersion reduce the concentration of such emissions before they reach the nearest residences. The health hazard from this exposure is likely to be minimal.

Based on considerations of concentration and toxicity, arsenic, barium, benzene, 1,2-DCEA, 1,2-DCE, ethylbenzene, TCE, vinyl chloride, and xylenes are the primary chemicals of concern in the ground water at the site. E.C. Jordan Co., in the Risk Assessment section of the RI final report, also considers 1,1-DCE and 1,1,2-TCEA as ground-water contaminants of concern due to their potential carcinogenicity (U.S. EPA Class C), though the concentrations found are within drinking water standards. They include 1,1-DCEA as a chemical of concern, as a carcinogen. The U.S. EPA has not announced its classification for the chemical, however.(2) No Federal drinking water standard for the chemical is available.(3) The MDPH concurs with the Risk Assessment conclusion that ingestion of ground water at the site would present a hazard to public health due to the presence of a number of proven and probable human carcinogens as site-related contaminants in the water. In addition, the barium in the ground water may pose a hazard to human health through other mechanisms than cancer.

E.C. Jordan Co. also assessed the health risk from contact and incidental ingestion of leachate-contaminated soil, with 2-butanone (MEK), 1,1-DCE, PCE, and TCE as contaminants of concern, and concluded that the risk was within acceptable limits. Their analysis did not include the potential risk from several polynuclear aromatic hydrocarbons (PAHs) in the leachate-contaminated soil: fluoranthene, phenanthrene, and pyrene. Ingestion of the leachate-contaminated soil, either incidental or in pica behavior, would not result in a dose of PAHs above the MRL for non-cancer endpoints based on acute (less than 14 days) exposure by ingestion. MRLs based on longer-term ingestion exposure or for dermal exposure have not been established. At the PAH concentrations found in the leachate-contaminated soil, normal amounts of dirt adhering to the skin would contain much less of the chemicals than has produced adverse non-cancer health effects in animal experiments. PAHs that are adsorbed to soil are not as likely to be absorbed through dermal exposure than the same chemical in a "free", for example liquid, form. Certain PAHs have been shown to cause cancer on dermal exposure. It is impossible to evaluate the cancer risk from this route at this site because of limited health data on the compounds. Fluoranthene, phenanthrene, and pyrene have not caused cancer in animal tests. The chemicals have caused genetic damage to cells in experiments, which is an indication of potential carcinogenicity. There is also limited evidence that pyrene and fluoranthene may enhance the cancer-causing potential of other PAHs.

The levels of dioxins found in the soil at the site are not considered to be of human health concern.

B. HEALTH OUTCOME DATA EVALUATION

Local health authorities have reported that they have received no complaints of adverse health effects that can be plausibly connected with this site. As the analysis of the potential for human exposure to chemicals on the site does not indicate that adverse health effects are likely, no further investigation of health outcome data has been done regarding this site.


CONCLUSIONS

Based upon information reviewed, this site is an indeterminate public health hazard. Although no current exposure has been documented, there is a potential future exposure to hazardous substances at concentrations that may result in adverse health effects. As noted in the ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS and PATHWAYS ANALYSES SECTIONS above, human exposure to volatile and semi-volatile organic chemicals and metals may occur via ground-water use (ingestion, contact, or inhalation secondary to use) if water supplies eventually become impacted.


RECOMMENDATIONS

  1. Further analysis of ground water north of the site is recommended. Monitoring wells should be placed and monitored to establish the extent and migration of ground-water contamination plume. Provision should be made within the remediation plan for continued monitoring of the private wells downgradient of the site. Monitoring of those wells within the estimated plume area or in the shallow aquifer is especially important in order to detect movement of the plume and cross-contamination of other aquifers. Future use of the aquifer within the affected area should be restricted by zoning, deed restriction, or other institutional mechanisms. MDPH concurs with E.C. Jordan's recommendation for further testing of water from the intermediate aquifer to better characterize any contamination of that aquifer.

  2. The remediation of the old landfill, as part of the U.S. EPA Record of Decision of September 1990, must address the leaching of materials from the fill in order to reduce the source of further contamination of the ground water.

  3. Access to the entire site should be restricted to reduce physical hazards as well as contact with contaminants. The landfill will be fenced in the remediation prescribed in the Record of Decision.

  4. The Metamora Landfill site has been evaluated by the ATSDR Health Activities Recommendation Panel for appropriate follow-up with respect to health activities. Because there is no indication in the information and data reviewed for this Public Health Assessment that human exposure to contaminants at levels of public health concern is occurring or has occurred, this site is not being considered for follow-up health activities at this time. However, if data become available suggesting that human exposure to significant levels to hazardous substances is currently occurring or has occurred in the past, this site will be reevaluated for any indicated follow-up.

  5. If future ATSDR evaluations indicate that a substantive completed exposure pathway exists or that the community has expressed specific health concerns, then health outcome data bases should be evaluated in future assessments for this site.

PREPARERS OF REPORT

John W. Filpus
Environmental Engineer
Michigan Department of Public Health

James Bedford
Environmental Toxicologist
Michigan Department of Public Health

John L. Hesse
Principal Investigator
Michigan Department of Public Health

Brendan Boyle
Health Assessment Coordinator
Michigan Department of Public Health


ATSDR Regional Representative

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


ATSDR Technical Project Officer

Richard E. Gillig
Technical Project Officer
Division of Health Assessment and Consultation
Remedial Programs Branch


CERTIFICATION

This 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.

Richard E. Gillig
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


REFERENCES

ATSDR, Preliminary Health Assessment, Metamora Landfill Site, January 25, 1989.

E.C. Jordan Co., Metamora Landfill Site, Remedial Investigation, Final Report, March 1989.

E.C. Jordan Co., Metamora Landfill Site, Feasibility Study, Final Report (Draft), November 1989.

Gary Hoffmaster, MDNR Site Manager.

MDPH Site Visits, June 28 and July 31, 1990.

U.S. EPA, Record of Decision: Summary of Remedial Alternative Selection for the Metamora Landfill Site, Metamora Township, Metamora, Michigan, September 28, 1990

GZA-Donohue, Weekly Summaries of Activities at the Metamora Landfill Site, for weeks ending June 1, June 8, June 15, June 22, June 29, November 9, November 16, and November 23, 1990.

ATSDR, Toxicological Profile for Arsenic, ATSDR/TP-88/02, 1988.

ATSDR, Toxicological Profile for Barium, Draft for Public Comment, October 1990.

ATSDR, Toxicological Profile for Benzene, ATSDR/TP-88/03, 1988.

ATSDR, Toxicological Profile for 2-Butanone, Draft for Public Comment, October 1990.

ATSDR, Toxicological Profile for Carbon Tetrachloride, ATSDR/TP-89/05, 1989.

ATSDR, Toxicological Profile for Chloroethane, ATSDR/TP-89/06, 1989.

ATSDR, Toxicological Profile for Chloroform, ATSDR/TP-88/09, 1989.

ATSDR, Toxicological Profile for Cresols, Draft for Public Comment, October 1990.

ATSDR, Toxicological Profile for 1,2-Dichloroethane, ATSDR/TP-89/10, 1989.

ATSDR, Toxicological Profile for 1,1-Dichloroethene, ATSDR/TP-89/11, 1989.

ATSDR, Toxicological Profile for Methylene Chloride, ATSDR/TP-88/18, 1988.

ATSDR, Toxicological Profile for Pentachlorophenol, ATSDR/TP-89/19, 1989.

ATSDR, Toxicological Profile for Phenol, ATSDR/TP-89/20, 1989.

ATSDR, Toxicological Profile for 2,3,7,8-Tetrachlorodibenzo-p-dioxin, ATSDR/TP-88/23, 1988.

ATSDR, Toxicological Profile for Tetrachloroethylene, ATSDR/TP-88/22, 1988.

ATSDR, Toxicological Profile for Toluene, ATSDR/TP-89/23, 1989.

ATSDR, Toxicological Profile for Trichloroethylene, ATSDR/TP-88/24, 1988.

ATSDR, Toxicological Profile for Vinyl Chloride, ATSDR/TP-88/25, 1988.

ATSDR, Toxicological Profile for Zinc, ATSDR/TP-89/25, 1989.

ATSDR, Toxicological Profile for Polycyclic Aromatic Hydrocarbons, ATSDR/TP-90/20, 1990.

Raphael Gaynier, Environmental Health Director, Lapeer County Health Department, personal communications.

MDPH Files.

MDNR Files


FIGURES

Site Location Map
Figure 1. Site Location Map

Site Features
Figure 2. Site Features


TABLES

Table 1. Chemical Contaminants Found at the Metamora Landfill Site. (From the E.C. Jordan Co. RI Report [1989]. Samples taken 1987-1988)

Chemical Medium

Concentration Range (ppb)

arsenic ground water 2.1-260
barium ground water 63-2,170
benzene ground water 1.9-12
benzoic acid ground water 11-240
2-butanone leachate/soil(4) 240-710
chlorobenzene ground water 1-2
chloroethane ground water 1-17
chloroform soil 5
4-chloro-3-methylphenol ground water
soil
17
510
1,1-dichloroethane ground water 1.3-55
1,2-dichloroethane ground water 7-24
1,1-dichloroethylene ground water
leachate/soil
2.1
12
1,2-dichloroethylene ground water
soil
leachate/soil
1.2-270
11
20
2,4-dimethylphenol ground water 13-23
dioxins (2,3,7,8-TCDD equivalent) soil 0.0013-0.105
ethylbenzene ground water
soil
leachate/soil
5-2,800
19-43
13
fluoranthene leachate/soil 700-1,500
4-methyl-2-pentanone soil 49-55
2-methylphenol ground water 8-16
4-methylphenol ground water 12-110
naphthalene ground water
soil
2-2.6
81
pentachlorophenol ground water 5-160
phenanthrene leachate/soil 400-420
phenol ground water 2.6-3.9
pyrene leachate/soil 980-1,300
tetrachloroethylene ground water
soil
leachate/soil
2
11-88
12
toluene ground water
soil
leachate/soil
560-670
5-27
35-46
1,1,1-trichloroethane ground water
soil
2.8-42
5-28
1,1,2-trichloroethane ground water
soil
1-6
4-17
trichloroethylene ground water
soil
leachate/soil
3.3-14
2-16
2
vinyl chloride ground water 1-6
xylenes ground water
soil
5,900-12,000
4-700
zinc leachate/soil 333

Note: Non-detect results omitted. Soil concentrations of inorganic chemicals within background ranges omitted.

a. Soil from leachate seeps.


Table 2. Air Sampling Results, from May/June and October/November 1990 (from GZA-Donohue Weekly Summaries)

Chemical Maximum Concentration (ppb)
benzene 1.10
carbon tetrachloride 0.13
chloroform 0.05
1,2-dichloroethane 0.11
methylene chloride 61.50
tetrachloroethylene 0.10
trichloroethylene 3.30

RESPONSIVENESS STATEMENT

The Public Comment Draft of the Metamora Landfill was released for comments from May 21, 1991 to June 20, 1991. During that time, one comment was received from a Lapeer County public health professional. In response to the comment regarding naturally occurring arsenic in groundwater in the general geographic area, the public health assessment was revised to reflect this circumstance.

No further comments were received on the public health assessment.


1. E.C. Jordan designations. Well depth below grade in feet: MW-17S - 71, MW-17D - 116.5, MW-17I - 150.
2. Studies of the induction of cancer in animals by 1,1-DCEA have produced equivocal results.
3. State drinking water guidelines range from 1 to 850 ppb.
4. Soil from leachate seeps.


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