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ENVIRONMENTALCONTAMINANTS AND OTHER HAZARDS

To identify other facilities that might contribute to the contamination at the Duell& Gardner Landfill site, the MDPH searched the Toxic Chemical Release Inventory (TRI)data base for 1987, 1988, 1989, and 1990. The U.S. EPA compiles the TRI from reportsprovided by industries. There were no entries for the Duell & Gardner Landfill in theTRI. Searching the TRI for facilities in the same zip code (49445) as the Duell &Gardner Landfill yielded one -- the Nor-Am Chemical Co., located approximately 3 milessouthwest of the landfill. Over the four years, Nor-Am reported releases of sulfuric acid,sodium hydroxide solution, methanol, hydrochloric acid, chlorine, acetone, cumene,toluene, and 1,2,4-trimethylbenzene to the air, and releases of methanol, hydrochloricacid, chlorine, acetone, toluene, and 1,2,4-trimethylbenzene to the waters of Little BearCreek, a tributary that enters Bear Creek approximately 3 miles downstream from thelandfill's vicinity. The releases to Little Bear Creek cannot reach the Duell &Gardner Landfill site area. The air releases are not likely to contribute to theenvironmental contamination in the landfill vicinity, due to the distance involved and thedissimilarity between the contaminants found on the site and the chemicals released fromthe facility.

Contaminants of concern at this site were selected from those chemicals for which theconcentration in at least one environmental medium exceeded a health-based comparisonvalue. Lifetime exposure to chemical concentrations at or below the appropriate comparisonvalues for a chemical should not result in more than 1 case of cancer in 1 million peopleexposed or any increase in non-cancer health effects. Comparison values used in thisassessment include:

ATSDR Environmental Media Exposure Guides (EMEGs)

ATSDR Cancer Risk Evaluation Guides (CREGs)

Concentrations computed from the U.S. EPA Reference Dose (RfD) for chronic exposure of a child, assuming pica behavior for soil ingestion1

U.S. EPA Drinking Water Health Advisories (Lifetime)

U.S. EPA Safe Drinking Water Act Maximum Contaminant Levels

If no comparison values for a chemical in a medium exist, or there is no CREG availablefor a carcinogen, the chemical is retained as a contaminant of concern. In addition, ifthe community has expressed specific concerns about exposure to a chemical, that chemicalwill be retained as a contaminant of concern.

All data in this section, unless cited otherwise, is from the final RI report (1).

A. On-Site Contamination

Groundwater

The two residential wells on the site (PW-19 and PW-20 in Figure 2) were sampled for chemical analysis for volatileorganic chemicals (VOCs) and inorganic chemicals by the MDNR in July 1981. No VOCs weredetected, and the inorganic chemicals found did not exceed available comparison values (Table 2 in Appendix B).Iron was found in one well at 1,900 parts per billion (ppb) which did exceed the U.S.EPA's Secondary Maximum Contaminant Level (SMCL) of 300 ppb, a water quality standardwhich is based on aesthetic considerations such as color, taste, and odor.

Information on the monitoring wells installed on the site is summarized in Table 3 in Appendix B,and the locations are shown in Figure 3. Fourmonitoring wells (MW-1 through MW-4) were installed on the site in 1982, and the MDNRsampled them for chemical analysis in 1983. No "significant" concentrations oforganic or inorganic chemicals were detected, except for 750 parts per billion (ppb) ofzinc in MW-1 (the upgradient well) and 75 ppb zinc in MW-4. The other wells did notcontain zinc above the detection limit of 50 ppb (5). Two moreshallow monitoring wells (MW-10 and MW-11) were installed by the MDNR in January 1986. TheMDNR sampled MW-1, MW-2, MW-3, and the two new wells in January 1986. Methylene chloridewas found in MW-1, along with several other unidentified or tentatively identifiedchemicals. No further data from these samplings were presented in Reference 1.

During Phase I of the RI field work in September and October 1987, the RI contractorsinstalled 24 additional monitoring wells on or close to the site. All monitoring wells onthe site except MW-10 were sampled in October 1987. All the monitoring wells includingMW-10 were sampled again in February 1989. During July and August 1989, the contractorsinstalled 9 more monitoring wells. In September and October 1989, they sampled 35 of themonitoring wells, omitting wells MW-10, MW-11, and MW-20, which were dry, and MW-12, whichwas bent and unusable. Concentrations of contaminants of concern in water samples frommonitoring wells on the site collected during the RI are listed in Table 4 in Appendix B.

The groundwater contamination with organic chemicals is found in two plumes, as shownin Figure 3, one predominantly aniline andN,N-dimethylaniline, the other primarily chloroform and carbon tetrachloride. As of 1989,the plumes had apparently not migrated far off the site, though the exact extent has onlybeen inferred due to lack of further downgradient sampling locations. Chloroform andcarbon tetrachloride were found in two shallow wells, MW-13 and MW-25S, but not in thedeeper wells of the MW-25 cluster, MW-25I and MW-25D. Aniline and N,N-dimethylaniline werefound in deeper wells, MW-14I, MW-14D, MW-14E, MW-18I, and MW-23D, but not in nearbyshallow wells, MW-14S, MW-18, and MW-23S. Low levels of aniline, N,N-dimethylaniline, andcrystal violet were found in the shallow wells MW-11 and MW-11R, though not in MW-8, lessthan 100 feet upgradient of the MW-11 cluster. The data indicate that there is a sourcearea for aniline and related chemicals between MW-8 and MW-11, from which a plume ofcontaminants enters the groundwater and the contaminants sink as they migrate to thesoutheast with the groundwater flow.

Other organic contaminants of concern were found sporadically, in a few wells andusually not repeated from sampling round to sampling round. Beta-BHC was only detected inone sample, that from MW-21S in Round 3, to cite one example.

Analysis for inorganic chemicals was only done on the first and third rounds ofsampling. All samples were field-filtered (through a 0.45 ┬Ám filter), therefore, theanalysis measured the concentrations of dissolved metals. Concentrations in individualwells often varied greatly over the interval between samplings of nearly two years.Arsenic, beryllium, cadmium, and thallium were only detected once. Chromium, lead, andvanadium were detected several times but the comparison levels were exceeded only once foreach metal. Antimony was detected once in each of four wells (MW-3, MW-13, MW-14E, andMW-14I) during round 3, all at concentrations above the comparison value. Wells locatedbetween the four, including the other wells in the MW-14 cluster, did not containdetectable antimony. MW-14D is screened between MW-14E and MW-14I in depth, and containedno detectable antimony. All the reported antimony concentrations were footnoted in thedata tables in Reference 1 as, "Value is greater than or equal to the instrumentdetection limit, but less than the contract required detection limit." Neither ofthese detection limits is specified in Reference 1. Since the values reported are allabove 30 ppb, when the comparison value is 4 ppb (derived from the RfD), it is possiblethat some of the samples reported as containing no detectable antimony may contain aconcentration of the metal above the comparison value.

The zinc concentration exceeded the comparison value in round 1 sampling from MW-6S,MW-8, MW-11, MW-11R, MW-13, MW-16, MW-17, MW-18, and MW-23S. The zinc concentration inMW-13 exceeded the comparison value in round 3. The round 1 sample from MW-6S, anupgradient well used to establish background levels, contained the highest zincconcentration of any sample, 8,270 ppb, cited in Table 4.The round 3 sample from the same well contained 1,710 ppb zinc. The second highest zincconcentration was in MW-8, 4,210 ppb in round 1, 910 ppb in round 3. The locations ofthese wells seem to indicate that the high zinc concentrations may not have a commonenvironmental source. The wells are generally not directly up- or downgradient from oneanother, except for MW-8, MW-11, MW-11R, and MW-23S, and in these cases, wells betweenMW-11 and MW-23S did not contain high levels of zinc. All the wells that had high zincconcentrations were made of galvanized steel, and, except for MW-11, had been recentlyinstalled at the time of the first round of sampling in the RI. Except for MW-11, whichhad gone dry and could not be sampled, and MW-13, these wells contained lower zincconcentrations in the third round of sampling. It appears that the high zincconcentrations found in the first round of sampling may be largely due to zinc beingleached out of the new galvanized pipe in the monitoring wells. The round 1 results fromMW-11, 2,640 ppb, and MW-11R, 2,660-2,900 ppb in duplicate samples, were marked asestimates due to an interference. The MW-13 result from round 3, 2,550 ppb, was marked asan estimate due to "Spike sample recovery not within control limits."

The RI contractors also sampled the two residential wells on the site during samplingrounds 1 and 3. No contaminants of concern were found at concentrations above availablecomparison values (Table 2 in Appendix B). Iron was again detected at concentrationsabove the SMCL.

Soil

In June 1979, the MDNR collected one soil sample and two samples from on-site drums foranalysis. The soil sample contained 7.7 parts per million (ppm) of polychlorinatedbiphenyls (PCBs). The drum samples did not contain detectable levels of PCBs or otherchlorinated hydrocarbons. Maximum concentrations of other on-site soil contaminantsdetected during sampling before 1986 include arsenic, 96 ppm; cobalt, 301 ppm; chromium,21 ppm; and cyanide, 30 ppm (6). The presence of soil colorsmay indicate high concentrations of organic chemicals with 4 on-site purple stained areasbelieved to be due to gentian (or crystal) violet contamination.

Soil sampling during the RI included samples from borings and from test pits in theformer landfill. The samples from the soil borings were collected from the surface levelto 10 feet below ground level, and were composites of 1.5 to 2 feet of soil. Theshallowest of these do not correspond with the ATSDR preference for surface soil samples.ATSDR recommends that surface soil samples be taken no more than 3 inches deep, but areusable, for evaluation of health effects from contact with and incidental ingestion ofsoils, if they are as much as 6 inches deep.

Concentrations of contaminants of concern found in the shallow soil samples (no morethan 2 feet deep) are listed in Table 5 in Appendix B.Concentrations of contaminants of concern found in deeper soil samples, including samplesfrom borings and test pits, are listed in Table 6 inAppendix B. As seen in Table 5, the concentrations ofcrystal violet, 4,4'-DDD, 4,4'-DDT, PCBs, arsenic, and chromium in shallow soil samplesexceeded available comparison values. 1,1-Dichloroethane, aluminum, calcium, copper, iron,lead, magnesium, mercury, potassium, tin, vanadium, and zinc were also detected in theshallow soil samples, but no comparison values for these substances are available.

Air

Air monitoring for total hydrocarbon concentrations did not detect airbornecontaminants during drum removal in 1986. However, high levels of organic vapors, anOrganic Vapor Analysis (OVA) meter reading over 1,000 ppm, were reportedly detected duringa test pitting operation in September, 1987. The lowest reading reported was 0.2-0.5 ppm.The RI contractors monitored ambient air for worker health and safety purposes during thePhase II test pitting operation in December 1989. No results of this monitoring arepresented in the RI report (1).

Soil Gas

There was no report of sampling of soil gas on the landfill. This is a significant datagap in the RI, since landfills often generate methane through anaerobic decomposition oforganic matter. Methane could pose a fire or explosion hazard.

B. Off-Site Contamination

Groundwater

Figure 2 shows the locations of 24 private wells onand near the Duell & Gardner Landfill site that were sampled during the RI and in theFebruary 1993 MDNR sampling, including the two that are on the site itself (PW-19 andPW-20).(2) The sampled off-site wells arelocated mainly to the south of the site, with a few to the east.

The MDNR sampled PW-9 in July 1981, along with the on-site wells. No contaminants ofconcern were found at levels above available comparison values.

The RI contractors collected water samples from private residential wells in the sitevicinity in three rounds, in October 1987, February 1989, and September 1989. The specificwells sampled in each round are listed in Table 7 inAppendix B. Concentrations of contaminants of concern found in water from these privatewells are listed in Table 8 in Appendix B. None of theorganic contaminants of concern were detected in more than one sample from any singlewell, either from different rounds or duplicate samples in the same round. The onlyinstance in which any organic chemical was detected in multiple samples from the same wellwas when one well contained 15 parts per billion (ppb) of acetone in Round 1, 6 ppb in onesample in Round 2 but none detected in a duplicate sample, and none detected in Round 3.Acetone is not a contaminant of concern for this assessment, because the comparison valuefor drinking water (1,000 ppb, based on the RfD) was never exceeded.

None of the inorganic contaminants of concern that have established comparison valueswere found in the private wells at concentrations that exceeded the comparison values (Table 8). Only copper and potassium were found in theprivate wells at concentrations above those found in upgradient monitoring wells (MW-5S,MW-6S, and MW-7 in Figure 3).

The MDNR collected water samples from 10 residential wells south of the site inFebruary 1993. The wells sampled were PW-5, -6, -7, -8, -10, -11, -12, -16, -17, and -24.PW-24, located a short distance outside the southwest corner of the site, had not beensampled before. No site-related contaminants were detected. Samples from five of the wellsdid contain carbon disulfide (maximum concentration 19 ppb) at levels well below theappropriate comparison value (1,000 ppb, based on the RfD) (7).

Surface Water and Sediments

The RI contractors collected samples of surface water and sediments from the tributaryto Bear Creek and from the drainage ditch east of the site. Concentrations of contaminantsof concern found in the surface water samples are listed in Table9 in Appendix B, and the concentrations found in sediment samples are listed in Table 10.

An agricultural drainage ditch located south of the site was not investigated duringthe RI. At the MDNR public meeting mentioned above under "Community HealthConcerns," area residents asked why it had not been investigated. The MDNR and U.S.EPA representatives present suggested that the ditch might be sampled during furtherremedial design investigation at the site. The MDNR collected 5 sediment samples from 4locations along the ditch in February 1993. Concentrations of contaminants of concernfound in these samples are listed in Table 11 inAppendix B. Neither crystal violet, aniline, or N,N-dimethylaniline were found in thesamples. None of the contaminants of concern were detected at concentrations abovecomparison values. There is no indication of site-related contamination in the ditch (7). Only one of the five samples collected contained anydetectable beta-BHC. That sample was a duplicate of one that contained no detectablebeta-BHC.

C. Quality Assurance andQuality Control

In preparing this Health Assessment, the MDPH relied on the information provided in thereferenced documents and assumed that adequate quality assurance and quality controlmeasures were followed with regards to chain-of-custody, laboratory procedures, and datareporting. The validity of the analysis and conclusions drawn for this Health Assessmentis determined by the reliability of the referenced information.

All the positive detections for antimony in groundwater from the RI were flagged inReference 1 as being above the instrument detection limit but below the contract requireddetection limit. Several of the concentrations of zinc in the groundwater from the RI werereported in Reference 1 as estimates due to interferences or to spike sample recoverybeing outside control limits. Any qualifications on the data cited in the above sectionsof this assessment are discussed with the data.

The presence of 4,4'-DDT and 4,4'-DDD in the surface soils on the site but not 4,4'-DDEseems puzzling, since 4,4'-DDT degrades aerobically to 4,4'-DDE and anaerobically to4,4'-DDD. It seems unlikely that anaerobic conditions would persist in the surface soil.The presence of heptachlor and aldrin in the environment usually represent a recent spillor application, since they are readily converted in the environment to their epoxides(heptachlor epoxide and dieldrin). It also seems unusual to find chlorinated pesticides inthe groundwater and not at high levels in the soil.

D. Physical and Other Hazards

Anaerobic degradation of organic materials such as household wastes can generatemethane gas. Methane and other organic vapors can collect in confined areas toconcentrations that exceed the limits of flammability, at which point a spark could causefire or explosion. There is no record of analysis of soil gas from the landfill, so thedanger from this source is not known. The landfill is covered with native, sandy soil, soanaerobic generation of methane is not likely under such a porous cover. Any vapors thatmight migrate elsewhere are more likely to migrate upwards through the surface sand anddiffuse into the ambient air. The cap that is being considered for the landfill willinclude vents for any gas that might be generated under it.

PATHWAYS ANALYSES

To determine whether nearby residents are exposed to contaminants associated with acontamination site, ATSDR evaluates the environmental and human components that lead tohuman exposure. An exposure pathway contains five major elements: a source ofcontamination, transport through an environmental medium, a point of exposure, a route ofhuman exposure, and an exposed population.

An exposure pathway is considered a completed pathway if there is evidence that allfive of these elements are or have in the past been present at the same time. A pathway isconsidered a potential pathway if one or more of these elements is not known to be or havebeen present, but could be or have been present. An exposure pathway can be eliminatedfrom consideration if one of the elements is not present and could never be present. Thefollowing sections discuss the most important exposure pathways at this site.

A. Completed Exposure Pathways

Surface Soil

There are elevated concentrations of various chemicals in the surface soil at variouson-site locations. A worker or trespasser on the site could come into skin contact withthe contaminated soil. The chemicals could then enter the body by absorption through theskin or by incidental ingestion. Exposures to contaminated soil have been learned of byMDPH through conversations with a resident who operated earth moving equipment on the sitemany years ago and came into direct contact with discolored soil. Additionally, signs ofoccasional trespass on the site have been noted by MDPH, MDNR, and U.S. EPA personnel.Remediation of the site that disturbs the waste may liberate volatile contaminants andcontaminated dust. Transport of particulates and volatilization of VOCs should becarefully monitored during any remediation process. Of particular concern are the presenceof aniline-based dyes (i.e. gentian violet) that could result in adverse human healtheffects if inhaled in large quantities.

Air

Volatile chemicals could evaporate from contaminated surface soil and be inhaled byanyone on or downwind of the site. Air monitoring on the site reported high concentrationsof organic chemicals during one test-pitting operation. Dust from the contaminated areascould be inhaled, or be transported by the wind to spread the contamination off the site.

B. Potential Exposure Pathways

Groundwater

The wastes deposited on the site contain various organic chemicals. Rainwaterpercolating through the waste areas has washed the contaminants into the groundwaterbeneath the site, as indicated by analysis of groundwater samples collected during the RI.Private wells in the affected aquifer are used by residents in the vicinity of the site.Persons using water from contaminated wells would be exposed to contaminants by ingestion,by dermal exposure, or by inhalation of volatile chemicals secondary to household use.There is no indication to date that any of the nearby private wells contain site-relatedcontaminants. The areal extent of the contamination plumes in the groundwater has not yetbeen completely determined by monitoring well sampling, though the available data indicatethe plumes probably do not extend far beyond the southern site boundary. This groundwaterexposure pathway is not completed. The pathway could become completed in the future,absent any remediation of the site, should the plumes extend to reach private wells or anew well for potable use be drilled into one of the plumes.

PUBLICHEALTH IMPLICATIONS

A. Toxicological Evaluation

The only completed exposure pathways that have been documented at the site are for aworker or trespasser coming into contact with contaminated surface soil or breathing aircontaining chemicals. As mentioned above, there is only partial restriction of access tothe site and all-terrain vehicle tracks have been seen on the site. Some area residentshave worked and played on the site in the past and come in contact with discoloredcontaminated soil. Trespass has occurred in the past and is likely to occur in the future.Such trespass would probably be occasional, and only for short times. Nothing on the sitewould be especially attractive to trespassers. The contaminated areas are also secludedfrom public roadways by distance, wooded terrain, and fenced-off private property. Forthis evaluation, a trespasser will be assumed to be an adult, weighing 70 kilograms (154pounds) and incidentally ingesting 100 mg of soil per day, spending an average of 2 hoursper week in the contaminated areas of the site.

Exposures through the air will not be calculated because the available data does notidentify the chemicals detected. In addition, air contamination has only been documentedduring excavation of the waste, which is not likely to occur except under the moststrictly controlled circumstances. Only remedial workers on the site, who would beexpected to take appropriate precautions against exposure, are likely to be exposed tohighly contaminated air from the site.

Based on the shallow subsurface soil concentrations listed in Table 5 in Appendix B,and under the above assumptions, a trespasser's exposure to contaminants of concern in thesoil at the site would probably not exceed Minimal Risk Levels (MRLs) or Reference Doses(RfDs) or incur a significantly increased cancer risk, for those chemicals for which MRLs,RfDs, or cancer potency factors are available. MRLs, developed by the ATSDR, and RfDs,developed by the U.S. EPA, are exposure levels below which it is commonly considered thatnon-cancer adverse health effects are not likely to occur. Extremely sensitivepopulations, such as the very young, the very old, those people whose immune systems havebeen impaired by other circumstances, and those with a special sensitivity to a specificchemical, may not be protected by the MRLs or RfDs. Cancer risks, as computed fromexposure doses and potency factors, are considered significant if 1 additional case, abovethe number normally expected to occur, would occur in a population of 1,000,000experiencing the exposure over their lifetimes.

Carbon tetrachloride, chloroform, 1,2-dichloroethane, methylene chloride, andtetrachloroethylene have all been classified as probable human carcinogens (U.S. EPA ClassB2) by the U.S. EPA, though the classification for tetrachloroethylene is currently underreview. A person consuming water containing the maximum concentration of any of thesechemicals found in the groundwater at the site for a lifetime might incur a significantlyincreased cancer risk. These chemicals could result in other adverse health effects athigh exposure levels, though it is very unlikely that exposure to the soil or water atthis site would result in sufficient exposure to the chemicals to produce such non-canceradverse health effects (8-12).

There is no MRL, RfD, or cancer slope factor available for 1,1-dichloroethane. Atrespasser on the site is not likely to incidentally ingest sufficient soil to obtain thedose of 1,1-dichloroethane at which adverse health effects have been observed inlaboratory animals. Health effects observed in laboratory animals who ingested1,1-dichloroethane over long periods of time include decreased survival, decreased weight,and breast and uterine cancer (13). The U.S. EPA hasclassified 1,1-dichloroethane as a possible human carcinogen (U.S. EPA Class C). Theavailable data does not permit evaluation of a potency factor for the chemical, and henceof the risk from exposure at the site.

Crystal violet (an aniline-based dye) and the related chemicals aniline andN,N-dimethylaniline can produce methemoglobinemia, cardiovascular collapse and respiratoryfailure (anoxia) when inhaled or ingested in large amounts. The U.S. EPA has classifiedaniline as a probable human carcinogen (U.S. EPA Class B2). Long-term exposure to soil orwater containing the maximum levels of aniline found on the site could result in anincreased cancer risk.

Polynuclear aromatic hydrocarbons, such as benzo(a)anthracene, benzo(a)pyrene,benzo(b)fluoranthene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene,dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene, 2-methylnaphthalene, naphthalene, andphenanthrene, were found in the subsurface soil at the site and sediments from theagricultural ditch near the site in concentrations generally comparable to those found inbackground soils (see Table 5-5 in Reference 14). Only thebenzo(a)pyrene concentration in one sediment sample exceeded a comparison value, andoccasional exposure for short periods of time to the sediments in the ditch near the siteis not likely to pose a significant increased cancer risk.

Trace levels of several persistent chlorinated hydrocarbon pesticides (beta- andgamma-BHC, chlordane, aldrin, and heptachlor) were detected in the groundwater at and nearthe site. DDT, DDE, and PCBs were found in soil on the site. These compounds are allconsidered probable (U.S. EPA Class B2) or possible (U.S. EPA Class C) human carcinogensby the U.S. EPA. They are also resistant to environmental degradation (15-20). Long-term exposure to thechemicals at the maximum concentrations found poses some increased cancer risk. Asmentioned above in the QualityAssurance and Quality Control section, the detection of some of thesechemicals in the groundwater but not in the soil casts some doubt on the accuracy of thegroundwater findings.

Several inorganic chemicals were found on the site at concentrations above backgroundlevels, but only arsenic and chromium exceeded comparison values. The comparison value forchromium that was exceeded was for the metal in the hexavalent oxidation state, orchromium(VI), and chromium(VI) tends to be converted in the environment to the trivalentoxidation state, or chromium(III), which is much less toxic. Chromium(VI) compounds can beirritants to the skin and digestive system, can cause liver and kidney damage, and havebeen linked to cancer of the lung, particularly when inhaled. The U.S. EPA has classifiedchromium(VI), when inhaled, as a human carcinogen (U.S. EPA Class A) (21). Long-term exposure to arsenic may result in dermatitis,weight loss, peripheral neuritis, and upsets to the gastrointestinal system. Ingestion ofarsenic is linked to cancer of the skin, liver, bladder, kidney, and lung. The U.S. EPAhas classified arsenic as a human carcinogen (U.S. EPA Class A) (22).At the concentrations found on the site, the most likely adverse health effect fromexposure to arsenic, chromium(VI), and other metals, is a low increased risk ofcontracting cancer on life-long exposure.

B. Health Outcome Data Evaluation

Based on the evaluations performed as part of this public health assessment, there areindications that humans that have worked and played on this site have been exposed tosite-related contaminants. Based on the concentrations identified at the site, theexposures are not expected to be sufficient to cause long term adverse health effects.However, if higher concentrations of contaminants were present in the past, and if peoplewere exposed for a long time, they may have incurred a low increased risk of contractingcancer.

The MDPH reviewed age-adjusted cancer mortality rates available from the Michigan DeathRegistry for Dalton, Muskegon, and Fruitland Townships, Muskegon County for the period of1983-1987. The Duell & Gardner site is located in the south central part of DaltonTownship. Fruitland Township is immediately west of Dalton Township. Muskegon Township isimmediately south of Dalton Township. The number of deaths observed for each of thetownships during this time period were compared to the number of deaths that would beexpected based on the 1985 statewide age-specific mortality rates and the 1983-1987estimated populations by age in the two townships. Population estimates could not becalculated by sex due to the unavailability of census data by sex for this area. Astandard mortality ratio (SMR) was calculated by dividing the number of observed deaths bythe number of expected deaths. An SMR of 1 would mean that the number of observed cancerdeaths during the time interval was exactly equal to the number expected based upon thestatewide rate; an SMR significantly lower than 1 would mean that the number of casesobserved in the townships was less than expected, and; an SMR significantly greater than 1would mean than the number of deaths were more than would be expected based upon thestatewide rate. The number of deaths observed and expected, and the corresponding SMRs arepresented in Table 12 for Dalton, Fruitland, andMuskegon Townships.

Although the actual numbers of deaths observed were fewer than expected based upon astatewide cancer death rate, the differences were not statistically significant (p =0.05). Since the SMRs did not differ significantly from 1, there is no evidence in thisstatistical analysis that any of these townships had a higher or lower than expectednumber of deaths. In considering these calculations, one must keep in mind that they arebased upon records for the entire townships involved. A more localized impact could bepresent but not be obvious when averaged within the larger population of the fulltownship.

C. Community Health ConcernsEvaluation

Concerns regarding this site, as expressed by area residents at and outside of publicmeetings, are addressed in this section of the Public Health Assessment. The following areresponses addressed to the specific health concern topics listed earlier:

1. Whether the residential wells near the site are endangered by site-relatedcontamination.

The private wells in the site area that are potentially endangered by contaminantsmigrating off the site through contaminated groundwater have been sampled on severaloccasions starting in 1981. The most recent sampling round prior to this availabilitysession, in October 1989, was conducted as part of the Remedial Investigation. None of thesampling performed to date has detected contamination from the site in any of the privatewells downgradient (in the direction of groundwater flow) from the site. The MDNR sampledresidential wells downgradient of the site in February 1993. No contamination was found (7).

2. The need exists for better site restriction and more posting of warningsigns along routes used by trespassers entering the site area.

A representative of the MDNR present at the December 10, 1992, meeting, on hearing ofthe need for better posting of warning signs, agreed to pursue installing additional signsat several locations where people are said to be entering the site. Additional signs wereposted on December 30, 1992 (23). MDPH does not believe thatthose who occasionally trespass on the site would receive significant exposure by walkingon contaminated soil, but recommends against any unnecessary exposure to contamination.

3. The possibility that people who played or worked on the site years ago mighthave health effects from this exposure occurring now or which may develop later.

There are latency periods (or time delays) between exposure to toxic substances and theonset of the illnesses they can cause. For some health effects such as cancer, theselatency periods can be very long, sometimes decades. It is very difficult to assess thepossibility of health effects related to this type of on-site exposure since we do nothave good information about the actual level of exposure and the frequency with whichpeople on the site may have been exposed. Breathing air contaminated with high levels ofsolvents such as those that were detected in some of the "hot spot" surface andsubsurface soil can cause acute symptoms like headaches. These symptoms typically willdiminish when the exposure stops. Exposure to carcinogenic contaminants will increase aperson's overall lifetime risk of developing cancer.

4. The relationship of the drainage ditch south of the site boundary and theplume of contaminated water from sources on the site.

The drainage ditch in question runs east, south of the site, and joins another drainthat empties into a tributary of Bear Creek. It is an intermittent drain, one that is dryfor most of the year. When the ditches are draining the land adjacent to them, the wateris most likely from surface runoff and rain infiltrating the surface soil and not likelyto be from the aquifer that contains contaminants from the site. The MDNR collectedsediment samples from the ditch in February 1993. There was no indication from the samplescollected and analyzed that there had been any effect on the ditch attributable to thesite (7).

5. Whether deer and other game hunted on site are contaminated and unsafe toeat.

MDPH does not consider the game that is present on site a health hazard for those whohunt and consume the meat. The contaminants that are present on site do not readily gettaken up into (or bio-accumulate in) the plants on which deer and other game animals feed.Tests conducted on animal tissue by the MDNR at other hazardous waste sites have not shownthis to be a significant exposure pathway.

6. One person mentioned that relatives of his who lived near the site had hadhealth problems.

The attendee said he did not know whether the relatives considered the illnesses to beassociated with the site, but he would check with them and contact the MDPH afterward. Therelatives, the current site owners who live on the northern portion of the site, latercontacted MDPH to describe the headaches they'd developed while working on the site. MDPHrepresentatives answered their health questions and gave them information regarding sitecontamination.

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