PRELIMINARY PUBLIC HEALTH ASSESSMENT
MONROE AUTO EQUIPMENT COMPANY (PARAGOULD PIT)
PARAGOULD, GREENE COUNTY, ARKANSAS
The Monroe Auto Equipment Company site (aliases Paragould Pit andFinch Road Landfill) is an industrial landfill located nearParagould, Arkansas. This landfill received wastewater treatmentsludge , which contained trichloroethylene and various heavymetals, from the Monroe Auto Equipment Company's Paragouldmanufacturing facility. Groundwater on-site is contaminated withvolatile organic compounds and metals with concentrations oftrans-1,2-dichloroethene, chromium and lead exceeding U.S.Environmental Protection Agency (EPA) drinking water standards. One off-site monitoring well has been shown to be contaminatedwith cadmium, chromium, and lead. One residential well has beenshown to be contaminated with trans-1,2-dichloroethene. Threeother residential wells have been shown to be contaminated withlead; this may not be site-related. Although the ArkansasDepartment of Health has notified the residents of the elevatedlevels of lead in their water and, in one case, in their blood,and although they have alerted these residents to the healthrisks associated with elevated lead levels, the people have notbeen dissociated from exposure to contaminated drinking water.
Approximately 3 dozen households are within a 1-mile radius ofthe site. The entire area depends on groundwater for drinkingwater and domestic use. Exposure pathways of potential concerninclude ingestion and inhalation of and dermal contact withcontaminated groundwater. Subsurface soil is contaminated withchromium and lead. Exposure pathways of potential concernrelated to soil include ingestion and inhalation of and dermalcontact with disturbed contaminated soil and volatilized organiccompounds. The Monroe Auto Equipment Company Site is anindeterminate public health hazard because there is insufficientinformation regarding whether people are being or have beenexposed to hazardous substances at concentrations that may resultin adverse health effects. In addition, one private drinkingwater well has been found to have elevated levels of lead; thewater in that well may pose a public health hazard to thosedrinking from it. This contamination, however, is not siterelated.
This document has been made available for public comment. As aresult of comments received by ATSDR, the document has beenrevised to reflect publicly stated concerns regarding thedocument. Appendix 1 contains further information regardingpublic comments.
The Monroe Auto Equipment Company Site (Monroe Site) is locatedabout 3 miles west of Paragould, Arkansas. This landfill site isowned and operated by the Monroe Auto Equipment Company (MonroeAuto Company) which is headquartered in Monroe, Michigan, andwhich also operates an auto parts manufacturing facility inParagould. The site has functioned as a landfill and haspreviously been referred to as the Paragould Pit and the FinchRoad Landfill.
The 4-acre site includes a 1-acre inactive landfill. The area iscompletely fenced with a 6-foot-high chain-link fence and threestrands of barbed wire on top; access to the area is through alocked gate. Monroe Auto Company purchased this land in 1973 andreceived temporary approval from the Arkansas Department ofPollution Control and Ecology to use the land as a landfill. From 1973 to 1978, Monroe Auto Company disposed of alum and limeelectroplating sludge at the landfill. The landfill reachedcapacity in 1978 and was closed and covered with 3 feet of dirtin 1979.
The Monroe Site was proposed for the EPANational Priorities List(NPL) on October 25, 1989. For purposes of the Agency for ToxicSubstances and Disease Registry (ATSDR) preliminary public healthassessment, the site is defined as the 4-acre area enclosedwithin the chain-link fence which includes the sludge disposalarea, two springs, and a pond.
During the ATSDR site visit in January 1990, it was noted thatMonroe Auto Company had recently purchased private propertyacross the highway from the southeast boundary of the site (1). The property had previously been owned and occupied by citizenswhose well had been contaminated (residential well [RW] #1; seeFigure 4). This property is presently unoccupied (directobservation).
In July 1988 and April 1989, Arkansas Department of Health (ADH)officials notified nearby residents to the northwest of the sitethat their well water was contaminated with lead and that theyshould stop using the well (RW #7) for potable water (2,3). These residents continue to use this water supply for domesticuse despite the warnings.
The area around the site is rural and sparsely populated. Anestimated 2,000 persons live within a 3-mile radius of the site. Approximately 3 dozen households are located within a 1-mileradius of the site. The entire population in this area relies ongroundwater for drinking and domestic use (4). A residentialwell survey that EPA conducted in the general vicinity of thesite was not comprehensive because the depths of all theresidential wells are unknown.
The family that had used RW #1 was comprised of two adults intheir mid thirties, one adult over 50, and three children between12 and 17 years old. The family resided in two mobile homes (1).
The site is surrounded by wooded areas, irrigated agriculturalareas, pastures, and residences. Limited hunting of squirrel andrabbit occurs in the area near the site.
ATSDR searched the EPA Chemical Toxic Release Inventory for 1987and 1988 to identify other possible facilities that couldcontribute to the groundwater contamination within the area ofconcern. The Toxic Release Inventory did not contain anyinformation on site-related toxic chemical releases in GreeneCounty.
ATSDR has identified the following state and local health datasources as potentially pertinent to this site:
- Arkansas Vital Statistics.
- Cancer Incidence and Mortality in Arkansas.
These documents are generated through the Arkansas StateDepartment of Health. The vital statistics are analyzed down tothe county level. Although a cancer registry was begun in theearly 1970's, the information gathered was incomplete andunreliable. Efforts to continue the registry ceased in the early1980's; it has not been functioning for the past ten years. Noindependent studies related to health effects of the populationaround the Monroe Site have been identified.
In January 1991, the EPA conducted interviews of citizensresiding near the Monroe Site (5). Citizens expressed generalconcerns about the safety of their well water. One citizenmentioned a concern about cancer and another noted that her hairwas falling out. In February 1987, residents living by and usingRW #1 reported to state health officials an oily film surface ontheir water. They also complained of skin irritation, skinrashes, stinging sensations during showering, and of their hairfalling out (1). There have been no further complaints since thehousehold moved in April 1987.
Table 1 lists the contaminants of concern found at the MonroeSite and the concentration ranges found in each environmentalmedium. In this report, contaminants were selected for furtherevaluation by comparing the environmental sampling analyticalresults to the following comparison values:
- CREG = Cancer Risk Evaluation Guide
- EMEG = Environmental Media Evaluation Guide
- MCL = Maximum Contaminant Level
- PMCL = Proposed Maximum Contaminant Level
EMEGs are media-specific estimates of exposure levels which posea minimal risk of non-cancer health effects to humans. They arebased on ATSDR's minimal risk levels (MRLs) or EPA's referencedoses (RfDs) which are derived from results obtained from humanand animal studies. CREGs are estimated contaminantconcentrations based on a one-excess cancer in a million personsexposed over a lifetime. CREGs are calculated from EPA's cancerslope factors. MCLs represent contaminant concentrations thatEPA deems protective of public health (considering theavailability and economics of water treatment technology) over alifetime (70 years) at an exposure rate of 2 liters water perday. MCLs are typically first proposed as PMCLs and remain asPMCLs until the review process is over and a final value has beendetermined.
Data in Table 1 is taken from references 6, 7, 8 and 9.
|Contaminant||Media||In Parts per Billion|
|Range of Contamination||Comparison Value|
|Subsurface Soil/Buried Sludge|
|Chromium (Total)|| |
|Chromium (Total)|| |
|Water Table Aquifer|
|1,2 Dichloroethane|| |
|Chromium (Total)|| |
|Chromium (Total)|| |
Sludge wastes disposed of at the landfill were analyzed inNovember 1972 by Barrow-Agee Laboratories, Inc., for four metalsand for oil and grease content only. The results indicated somechromium contamination (238,000 parts per billion (ppb)). Moreextensive analyses for heavy metals were performed on sludgesamples produced under similar circumstances but not disposed ofat the Monroe Site. The results of these analyses indicated thepresence of lead.
Soil samples collected from the drilling of observation wells andborings were analyzed by Southwestern Laboratories for MonroeAuto Company in July 1979. Chromium was present (78,000 ppb);background chromium concentration levels for this site rangedfrom 4 to 118 ppb. In September 1989, Engineering-Scienceconducted soil borings within the landfill, including boringsinto the buried sludge. Analyses of these samples indicatedcontamination by total 1,2-dichloroethene (maximum 38,000 ppb),chromium (maximum 5,000,000 ppb, total), and lead (maximum3,000,000 ppb). Concentrations of the heavy metals at levels ofpotential health concern were found 4 or more feet below thesurface. No samples were collected from the top 3 inches ofsurface soil.
In April 1986, Engineering-Science collected groundwater samplesfor Monroe Auto Company from observation wells. Analyses ofthese samples indicated contamination with 1,1-dichloroethene,trans-1,2-dichloroethene, 1,1,1-trichloroethane,trichloroethylene, and methylene chloride. However, thesewells were not drilled in accordance with EPA specificationsand results may not adequately represent the groundwater qualityat the site. Furthermore, because trichloroethylene andmethylene chloride were observed in controls, Engineering-Scienceconsultants noted that reported levels were likely the resultof laboratory contamination (7).
In March 1988, Engineering-Science collected groundwatersamples for Monroe Auto Company from wells drilled to EPAspecifications. The primary contaminant detected in the aquiferwas trans-1,2-dichloroethene (<5-750 ppb). Only one othervolatile organic compound (VOC) (1,1-dichloroethane, <5-97 ppb)was detected in groundwater. Inorganic compounds, includingchromium (<10-300 ppb total chromium) and lead (<5-180 ppb), werefound in the perched water table.
Also in March 1988, the company collected surface water samples(on-site pond and springs) for Monroe Auto Company. Analysesindicated total chromium (<10-40 ppb) and lead (<5-10 ppb)contamination in the pond. Trans-1,2-dichloroethene and 1,2-dichloroethane were below detection level (5 ppb) in all surfacewater samples.
Table 2 lists the contaminants of concern found off-site at theMonroe Site. Contaminants were selected for further evaluationby comparing the environmental sampling analytical results tocomparison values described in the On-Site Contamination sectionabove. Data in Table 2 is taken from references 6, 7, 8 and 9.
|In Parts per Billion|
Range of Contamination
|Residential Well # 1|
Monitoring Well ESW-8
* - Numbers in parentheses have no QA/QC information
** - Below contract-required detection limits (CRDL)
a - MCL
b - PMCL
Groundwater samples were collected off-site in private wells byADH in July 1987, by Engineering-Science for Monroe Auto Companyin August 1987, and by ICF Technology Incorporated for EPA inNovember 1987. A total of 13 private wells were sampled (seeFigure 1). Analyses indicated contamination by VOCs and lead;only residence wells #1 and #7 were found to be contaminated. Trans-1,2-dichloroethene (122 ppb), 1,2-dichloroethane (247 ppb),and total chromium (5.6 ppb) were found by ADH in RW #1. Inaddition, small amounts of 1,1-dichloroethane, 1,1,1-trichlor-oethane, and trichloroethylene were detected in RW #1. The useof this well has been discontinued for drinking purposes sinceApril 1987. The well was capped October 1989.
The 1,2-dichloroethane contamination level of 247 ppb wasreported once at RW #1 with no accompanying qualityassurance/quality control (QA/QC) information; subsequentsampling of this well by Engineering-Science with appropriate QAindicated 1,2-dichloroethane levels below the detection limit of0.2 ppb. Therefore, it is unknown if 1,2-dichloroethane wasactually present in the water sample or if this was a result offield or laboratory contamination.
Results of subsequent groundwater sampling in August and November1987 indicated trans-1,2-dichloroethene at 110 ppb and 57 ppb inRW #1.
Groundwater monitoring conducted by Engineering-Science in 1989did not confirm VOC contamination off-site in RW #1 and ESW #8. however, this round of monitoring indicated that lead (maximum590 ppb), total chromium (maximum 810 ppb), and cadmium (maximum17 ppb) have migrated off-site.
Elevated levels of lead (312 ppb) were found in RW #7 by ICF. ICF stated that this high lead concentration was possiblyrelated to the residents' plumbing system (10). In May 1988 andFebruary 1989, ADH sampled two private wells in the vicinity ofRW #7 and found lead contamination (15 and 10 ppb respectively)(11). No QA/QC information accompanied these latter twoanalyses.
In preparing this preliminary public health assessment, ATSDRrelies on the information provided in the reference documents andassumes that adequate data quality assurance and QA/QC measureswere followed with regard to chain-of-custody, laboratoryprocedures, and data reporting. The validity of the analysis andthe conclusions drawn in this preliminary public healthassessment are determined by the availability and reliability ofthe referenced information.
When the detection limits for a compound is reported to be higherthan the contract laboratory program requirements, it may not bepossible to conclude with certainty whether contaminants arepresent at levels that may be of public health concern. Forexample, the detection limit for the lead water analyses reportedby Engineering-Science was sometimes higher than the ContractLaboratory Program requirements of 5 parts per billion (ppb). Nevertheless, the data for lead in this case may still beevaluated.
Some groundwater samples were filtered before metal chemicalanalysis. The EPA drinking water standards are based on total(unfiltered) metal analyses rather than the (filtered) dissolvedfraction. Valid site comparisons between site samples and thehealth standards can only be made with unfiltered samples.
No physical or other hazards associated with the site were noted.
From 1973 to 1978, approximately 15,400 cubic yards of sludgewere buried at 1 acre of the 4-acre Monroe Auto Site. The sludgewas produced by Monroe Auto Company as the result of electro-plating operations at the Paragould Plant. Results ofpreliminary investigations indicate the sludge contains heavymetals (chromium and lead) and VOCs (trichloroethylene and1,1,1-trichloroethane). The electroplating operations produce asludge in which, under some circumstances, heavy metals and VOCsmay be mobile and may not be easily retarded upon filtration andpercolation (leaching) into the groundwater.
The soil at the Monroe Site is composed primarily of overlayinglayers of sand and gravel separated by lenses of clay. Thisgeology tends to permit rapid percolation and movement of waterand contaminants.
Groundwater is found at and around the NPL site in three zones. A perched water table exists directly under the disposal area, isnot continuous across the site, and does not appear to existbeyond the site boundaries. The direction of flow within theperched water table is toward the southwest and appears todischarge to the surface as localized springs (on- and off-site). Two groundwater aquifer zones were encountered. The uppermostzone, a water table aquifer, is probably in the upper portion ofthe Wilcox group. Groundwater flow in this zone is generallyeast-southeast from the southern edge of the site. A secondaquifer zone in the Wilcox Aquifer has been identified beneaththe clay layer that underlies the water table aquifer. Groundwater flow patterns in this zone have not been preciselydetermined, but the gradient has a southerly component. Thesetwo zones are the primary source of potable water for individualssurrounding the site.
Investigations indicate that contaminants from the sludge havemigrated into the perched water zone and the upper groundwaterzone. The results of the groundwater sample analyses indicateheavy metal contamination has moved off-site toward the southeast(monitoring well ESW-8). VOC contamination has migrated thefarthest and entered a local residential well (RW #1).
In addition to allowing the extent of VOC contamination tobe determined, the analytical results indicate the original VOCsdisposed of at the site (trichloroethylene and1,1,1-trichloroethane) have been biodegraded (transformedby microorganisms normally found in soil) totrans-1,2-dichloroethene and 1,2-dichloroethane.
The analytical results of surface water samples, taken from anon-site pond and two springs, indicate heavy metal contamination. As previously discussed, the springs are thought to be fed by theperched water table. Therefore, it is not surprising to findheavy metal contamination at these locations. The pond foundon-site is thought to be the result of local rain runoff. AnyVOCs that may migrate into the surface waters will tend tovolatilize. Surface water associated with the pond is believedto percolate into the ground on-site. The springs appear to flowoff-site, toward the southwest.
Animals and plants can bioaccumulate (concentrate) heavy metalsbut generally not VOCs. Therefore, any animals or plants on ornear the Monroe Site could have elevated levels of heavy metals. This may be particularly true for biota using the surface waterassociated with spring #2.
In addition to migrating from the sludge into the groundwater andsurface water, the VOCs in the sludge could volatilize directlyinto the atmosphere. To date, no air monitoring has beenconducted at the Monroe Site. The heavy metals in the sludge arenot anticipated to migrate into the atmosphere unless the sludgeis disturbed--for example, during activities such asremediation--because heavy metals do not easily volatilize andbecause the soil cap on top of the sludge should prevent thegeneration of dust from the sludge.
To date, no sediment samples have been taken in the springs andoff-site creeks. Because heavy metal contamination was found inthe surface water samples, sediment sampling should be conductedto evaluate this potential environmental pathway.
Several contaminated wells have been identified that are screenedin the Crowley's Ridge aquifer: One observation well and threemonitoring wells located on-site, one off-site monitoring well,and one private residential well located off-site. Threeadditional contaminated off-site residential wells have beenidentified for which the contamination source may not besite-related. The observation wells have been capped, themonitoring wells are used exclusively for sampling, and use ofone residential well (RW #1) has been discontinued. However, thecontaminated residential well was in use for some time. Residents using RW #1 may have been exposed to trans-1,2-dichlor-oethene via ingestion of drinking water, dermal contact, andinhalation of aerosols and vapors during showering or otherhousehold activities.
As contaminants migrate through the aquifer, they may contaminateadditional private wells at some future time, thereby exposingpeople to contaminants in groundwater via ingestion of drinkingwater, dermal contact, and inhalation of aerosols and vaporsduring showering or other household activities. Water used forirrigation purposes may become contaminated as a result ofcontaminant migration. At this time, ingestion of irrigatedcrops is not likely to be a source of exposure; however, becauseplants may accumulate lead (11), ingestion of food products grownusing potentially contaminated water may constitute an exposureroute of concern in the future.
Available groundwater sampling data indicate total chromium(maximum 300 ppb) and lead (maximum 180 ppb) contamination in theperched water table. People are not likely to be exposed to thiscontaminant because this water is not used for any purpose, it isnot directly accessible for contact, and it migrates to thesurface rather than into the aquifer. Available surface watersampling data indicate chromium (maximum 40 ppb) and lead(maximum 10 ppb) contamination in the pond. Because access tothe pond is restricted, there is little potential for any directexposure at this time. Since animals have access to surfacewater, and because heavy metals bioaccumulate, there is apotential for human exposure via ingestion of contaminated food-chain entities. Given the low frequency of hunting, humanexposure via this pathway may not be significant.
Groundwater originating from RW #7 may present a source ofexposure to lead upon its ingestion. The plumbing may be theoriginal source of the lead. In April and October 1989, ADHsampled the blood of persons using the well. Analyses indicatedelevated levels of protoporphyrin and blood lead (12). Theelevated blood levels of these persons indicate exposure. Theuse of this well continues despite warnings from state officials. Efforts have been made by representatives of ATSDR to dissociatepeople from exposure to water contaminated with lead. The statehealth department has been contacted by ATSDR staff regarding theprovision of drinking water to residences in the vicinity of theMonroe Site, but the state is unable to provide an alternatewater supply at this time. RW #7 is north of the site. Becausethe groundwater is thought to flow toward the south-southeast,the lead contamination in this well is apparently notsite-related.
Available data indicate chromium (maximum 5,000,000 ppb totalchromium) and lead (maximum 3,000,000 ppb) contamination insubsurface soil on-site. Elevated concentrations of thesecontaminants have been found at 4 or more feet below the surface. If subsurface soil is disturbed during work or other activities,workers may be exposed via dermal contact with the soil andingestion or inhalation of released airborne particulates. Additionally, work activities may cause the release of volatileorganic vapors and heavy metals which could result in humanexposure via inhalation. There are no data regarding air qualityat this site, therefore, human exposure via inhalation cannot beevaluated. The inaccessibility of the site precludes these typesof exposures to the general population.
Ingestion and inhalation of off-site drinking water suppliescontaminated by trans-1,2-dichloroethene may pose a potentialpublic health concern. The maximum level of trans-1,2-dichloroethene in groundwater detected to date (750 ppb in an on-site monitoring well) exceeds the EPA Proposed MaximumContaminant Level (PMCL) (100 ppb) promulgated under the SafeDrinking Water Act (SDWA). No known exposures have occurred atthe maximum concentration of 750 ppb because no one drinks on-site water. Although no known exposures have occurred, it ispossible for the contaminated water to migrate to a drinkingwater well where exposure may occur. Trans-1,2-dichloroetheneconcentrations found at RW #1 (46-110 ppb) approximate the PMCLlevel.
Toxicological data regarding chronic exposure to lowconcentrations of trans-1,2-dichloroethene are limited, andminimum exposure levels that cause adverse health effects inhumans have not been reported. Data from limited animalstudies indicate that ingestion at lethal (1,000 mgtrans-1,2-dichloroethene per kg body weight) and near-lethallevels causes damage to the lung, liver, and central nervoussystem. Inhalation at low levels (6,800-8,800 ppb for 5 minutesor 4,800 ppb for 10 minutes) has caused nausea, drowsiness,fatigue, vertigo, and intracranial pressure in humans. Resultsof animal studies indicate that inhalation of trans-1,2-dichlor-oethene at 200,000 ppb for 16 weeks may cause severe lung andliver damage; inhalation at 3,000,000 ppb for 8 hours may causeheart pathology (all studies from reference 13). These levelsare significantly higher than those associated with this site.
Human ingestion of lead-contaminated drinking water from theoff-site RW #7 (312 ppb) is of public health concern. Thisconcentration exceeds the EPA PMCL (5 ppb) promulgated underthe SDWA. Exposure to lead in contemporary American society mayresult from contact with multiple sources. Further, lead is acumulative human toxicant. Multiple sources and accumulation oflead in human body compartments necessitates attention totoxicity risks even if only low levels of lead are being absorbedat a given time from a given source.
Lead toxicological studies only show health effects in humans atcontamination levels higher than the highest level found aroundthe Monroe Site. Most studies discuss information in terms ofblood lead level rather than external exposure level. TheCenters for Disease Control has recently revaluated itsguidelines on acceptable blood lead levels based on recentscientific information and studies (14). New data indicate thatsignificant adverse health effects of lead exposure can occur inchildren at blood lead levels previously believed to be safe. Some health effects have been documented at blood lead levels aslow as 10 µg/dl (14).
Blood lead concentrations of 10 µg/dl are associated with neurobehavioral deficits, hearing impairments, and inhibition of hemoglobin synthesis in children (14). Blood lead levels between 10-20 µg/dl in children have been shown to result in a four- to five-point decrease in the Intelligence Quotient (I.Q.) and in electrophysiological changes in brain activity. Blood lead concentrations greater than 33 µg/dl in children produce neurotoxic effects as well as a depression in plasma levels of Vitamin D. Neurotoxic effects of lead in children are of primary concern since those effects can be irreversible, even after blood lead levels return to a normal range (11).
Gastrointestinal symptoms are characteristic of lead poisoning(11); however, a dose-response relationship has not beenexplored. Headaches were not reported in the literature. Nodata on the association between human oral exposure to lead andcancer have been reported. Animal oral exposure studies suggesta qualitative relationship between exposure to lead in food andrenal tumors. Human occupational inhalation data areinconclusive but suggest an increase in malignant neoplasms. TheEPA has classified lead as a probable human carcinogen. Therefore, exposure to lead should be avoided at any level.
Studies indicate that lead can affect bodily functions at blood levels as low as 10 micrograms per deciliter (µg/dl). Lead primarily affects the development and maintenance of the brain and the central nervous system, especially during prenatal and early childhood development. In addition, studies indicate that blood levels of lead as low as 10 µg/dl can disturb the synthesis of hemoglobin, the substance that delivers oxygen in the blood. Studies indicate that blood lead levels as low as 10-15 µg/dl may affect the growth and mental development of the human fetus. Long-term, low-level exposure may lead to delayed cognitive development (corresponding to blood levels as low as 6 µg/dl), decreased I.Q. scores (<25 µg/dl), and hearing deficits (as low as 4 µg/dl). Exposure to lead may result in hypertension in middle-aged men (30 µg/dl). Higher concentrations of lead can lead to encephalopathy (100 µg/dl in adults, 80 µg/dl in children) and anemia (80 µg/dl) (all studies from references 11 and 15).
Human ingestion of cadmium-contaminated drinking water may be ofpotential public health concern. Cadmium is a naturallyoccurring element in the soil. There are no known benefits ofexposure to cadmium; both acute, high-level exposures andlong-term, low-level exposures can lead to adverse health effectsin humans. The concentration found in the off-site monitoringwell (17 ppb) exceeds the EPA's Maximum Contaminant Level (MCL)of 10 ppb promulgated under SDWA. This MCL is based primarily onhealth effects, but also considers cost and feasibility; EPA hasset an advisory Maximum Contaminant Level Goal (MCLG), basedsolely on health considerations, of 5 ppb.
Animal and human studies indicate that long-term, low-level oralexposure to cadmium may cause kidney damage. Studies indicatethat doses of 30,000 ppb for 6 weeks may lead to proteinuria, ora dysfunction in renal absorption of certain proteins, inanimals. Additional studies indicate kidney damage in humans,however, dose-response data are not available. Kidney damage maynot be life-threatening, but can lead to kidney stones andskeletal effects, which can be painful and debilitating (allstudies from reference 16).
Human ingestion of chromium-contaminated drinking water may be ofpotential public health concern. Although the chromium at theMonroe Site is measured as total chromium, chromium exists inthree major states: Chromium (0), chromium (III), and chromium(VI). Studies of oral exposure to chromium in humans and animalsindicate that chromium (VI) is toxic to the kidneys and the liverat doses very much higher that those which could be associatedwith this site. Studies with rats of chronic (over a year long)exposure to chromium, even at levels 10 to 100,000 times higherthan those associated with this site, have shown no observableadverse health effects (17). Exposure to chromium (III) has notbeen shown to result in adverse health effects and is the formthought to be an essential food nutrient when ingested in smallamounts. Chromium (0) is not well characterized in terms oflevels of exposure or potential health effects (17).
The total chromium level found in the off-site monitoring well(810 ppb) exceeds the EPA's MCL of 50 ppb promulgated under SDWA. The EPA drinking water standard is based primarily on healtheffects data generated from inhalation studies which indicatethat chromium is carcinogenic. Other studies indicate that oralexposure to chromium is not associated with cancer (17).
Disturbance of soil contaminated with chromium (maximum 5,000,000ppb) and lead (maximum 3,000,000 ppb) may cause these metals tobe released into the air as particulates. Human exposure tothese airborne particulates via inhalation and dermal contact isof potential public health concern to remedial/removal workers. Long-term exposure of workers to airborne levels of totalchromium higher than those in the natural environment has beenassociated with lung cancer. In addition, short-term, high-levelexposure to chromium (VI) can result in adverse effects at thesite of contact such as ulcers of the skin, irritation of thenasal mucosa and perforation of the nasal septum, and irritationof the gastrointestinal tract (17).
There was no health outcome data evaluated for this site. ATSDRdetermined that there exists only one known past completedexposure pathway from the Monroe Auto site and one presentcompleted exposure pathway which may not be site related. Therewere only two families, one from each pathway, who had beenexposed. ATSDR staff believe that analysis of existing healthoutcome information would not be helpful for such a smallpopulation. In addition, ATSDR is unaware of any recent healthconcerns within the community related to site-associatedcontamination. If new information becomes available which showsthat other people have been or are being exposed, or that nearbyresidents have health concerns about contaminants associated withthe site, ATSDR will reconsider evaluating health outcome data.
A community member expressed concern about cancer. No exposureshave occurred with any possible, probable, or known humancarcinogens. Two contaminants at the site are associated withcancer (1,2 dichloroethane and chromium). 1,2 dichloroethane hasbeen found only on-site in the waste material, where people arenot likely to come into contact with it. Chromium, associatedwith cancer only through the inhalation route, is not likely tobe inhaled. People have not been, are not being, and are notlikely to be exposed to any site-related contaminants associatedwith cancer.
Residents who used RW #1 have expressed concerns about skinirritation, rashes, a stinging sensation during showering, and their hair falling out. One other community member alsoexpressed concern about hair loss. In the general population, itwould not be expected to see any of these symptoms as a result ofexposure to contaminants at levels found in RW #1. Althoughsolvents can cause skin irritation, dichloroethane concentrationsfound at the residential well are too low to have reasonablycaused any dermal effects. There are numerous causes for skinirritation, rashes, stinging sensations while showering, and hairloss; these symptoms may be unrelated to the site.
Based on available information, ATSDR has concluded that theMonroe Site is an indeterminate public health hazard because ofinsufficient information regarding whether people are being orhave been exposed to hazardous substances at concentrations thatmay result in adverse health effects. As noted in the HumanExposure Pathways Section of this preliminary public healthassessment, exposure to elevated levels oftrans-1,2-dichloroethene has occurred and may be occurring, andpossible migration of trans-1,2-dichloroethene into drinkingwater supplies might result in future exposure. This would be ofpotential public health concern because of human exposure totrans-1,2-dichloroethene at concentrations that may result inadverse health effects.
The concentrations of cadmium, chromium, and lead found in awater sample from an off-site monitoring well (ESW-8) are also ofpotential public health concern because possible migration ofthese contaminants into drinking water supplies might result infuture exposure. Ingestion of these contaminants at the reportedconcentrations (maximum 17 ppb, 810 ppb, and 310 ppbrespectively) may result in adverse human health effects.
Additionally, human exposure to elevated levels of lead may beoccurring and may have occurred in the past via ingestion ofcontaminated water in RW #7 and neighboring wells. This is apublic health hazard, although it is apparently not site-related.
Remediation efforts may create conditions where human exposure tochromium and lead may occur. This would be of potential publichealth concern because humans may be exposed to these heavymetals at concentrations that may result in adverse healtheffects.
The ATSDR recommends the following:
- Determine the extent of groundwater, soil, sediment, andsurface water contamination on-site and off-site.
- Monitor air to determine whether emissions are occurringon-site.
- Monitor, on a semi-annual basis, for site-relatedcontaminants at residential wells down-gradient of the site.
- Determine the source and extent of lead contamination nearRW #7.
- Ensure that workers conducting remedial activities useadequate personal protective equipment that meetsOccupational Safety and Health Administration standards andNational Institute for Occupational Safety and Healthrecommendations.
- Ensure that careful dust control methods accompany anydisturbance of the contaminated sludge and subsurface soilto minimize airborne contaminants.
- The information and data developed in the Monroe AutoEquipment Preliminary Public Health Assessment have beenevaluated by the ATSDR Health Activities RecommendationPanel (HARP) for appropriate follow-up with respect tohealth activities. The Panel concurred with ADH's previousactions of monitoring residents' blood lead levels andproviding community health education due to human exposureto off-site contamination. Furthermore, the Paneldetermined that additional community health education is anappropriate follow-up health action because of humanexposure to off-site contamination.
ATSDR will coordinate with the appropriate environmental agenciesto develop plans to implement the site characterizationrecommendations.
Based on data evaluated and the recommendations made by HARP,ATSDR is planning the following Public Health Action:
ATSDR, in cooperation with the appropriate agency in theState of Arkansas, will provide environmental healtheducation for the community to assist the community inassessing possible adverse health effects associated withexposure to hazardous substances.
ATSDR concurs with the past public health action taken by theArkansas Department of Health of testing blood lead levels ofusers of a well contaminated with lead and of alerting them tothe health risks associated with elevated lead levels.
Sven E. Rodenbeck, P.E.
Environmental Engineer Consultant
Remedial Programs Branch
Environmental Health Scientist
Remedial Programs Branch
George L. Pettigrew
Field Operations Branch
- Gray. Dump site questions are raised. Jonesboro Sun 1989,Sep 24:1.
- McChesney TC. Arkansas Department of Health. Letter.April 28, 1989.
- Neill R. Arkansas Department of Health. Letter. July 1, 1988.
- Personal communication, Lee Presley, County Sanitarian.
- U.S. Environmental Protection Agency. Notes from CommunityInterview Questions on the Monroe Auto Equipment Site. January 1991.
- U.S. Environmental Protection Agency. Hazard Ranking SystemPackage, Monroe Pit, March 28, 1989.
- Engineering-Science, Atlanta, Georgia. Preliminary SiteInvestigation: Finch Road Landfill, Monroe Auto Equipment,Paragould, Arkansas. August 1989.
- Monroe Auto Equipment. Comments to the EnvironmentalProtection Agency regarding the proposed inclusion onNational Priorities List (NPL) of Finch Road Landfill Site("Monroe Auto Pit"). December 22, 1989.
- Engineering-Science, Atlanta, Georgia. SupplementalFindings: Finch Road Landfill Site Investigation, Volumes Iand II, Monroe Auto Equipment, Paragould, Arkansas.
- Debra R. Pandak, Environmental Scientist, ICF Technology. Memorandum to David Wineman, Remedial Project Officer, EPA Region 6; January 27, 1988.
- Agency for Toxic Substances and Disease Registry (ATSDR).Toxicological profile for lead. Atlanta, Georgia: ATSDR,1989.
- Unpublished data from Greene County Sanitarian (Lee Presley)files.
- Agency for Toxic Substances and Disease Registry (ATSDR).Toxicological profile for 1,2-dichloroethene. Atlanta,Georgia: ATSDR, 1989 (in draft).
- Preventing Lead Poisoning in Young Children. Centers forDisease Control, U.S. Public Health Service, October 1991.
- Agency for Toxic Substances and Disease Registry (ATSDR).The nature and extent of lead poisoning in children in theUnited States: A report to Congress. Atlanta, Georgia:ATSDR, 1988.
- Agency for Toxic Substances and Disease Registry (ATSDR).Toxicological profile for cadmium. Atlanta, Georgia: ATSDR,1989.
- Agency for Toxic Substances and Disease Registry (ATSDR).Toxicological profile for chromium. Atlanta, Georgia: ATSDR, 1989.
The Monroe Auto Equipment Company Preliminary Public HealthAssessment (PHA) was available for public review and comment fromJuly 1 through July 31, 1991. ATSDR received five writtenresponses pertaining to the Monroe Auto Equipment Public CommentPeriod. The comments and the corresponding responses aresummarized below.
Comments Received During Public Comment Period and Responses
- Why weren't all residential wells sampled?
- Our property value has decreased.
- The residential well survey was comprehensive and allresidential wells that may be impacted by the site have beensampled.
- Community concerns have not been adequately discussed in thePHA. Information from community members' interviews (whichwere attached to responder's comment) has not been included.
- Trans-1,2-dichloroethene was not the only volatile organiccompound detected in the March 1988 sampling event.
- Data collected to date does not show that the lower Wilcoxaquifer has been contaminated.
- Water from Spring 1 commingles with Spring 2 and flows off-site.
- The perched water discharges into springs which migrate off-site, so perched water is accessible to humans.
- Off-site wells need be monitored semi-annually rather thanquarterly.
- The Preliminary Public Health Assessment was preparedwithout benefit of the most current and comprehensive siteinvestigation report available.
- Monroe Auto is not an "industrial landfill", did not"receive sludge", and is not located 3 miles west ofParagould.
- The residential well shown to be contaminated with t-1,2-dichloroethene is no longer active and, at the time it wasactive, the well owners reportedly did not use the water asa drinking water supply.
- Discussions of the lead-contaminated upgradient well #7 aremisleading as they imply contamination due to site-relatedsources.
- Reference to Figure 1 on page 2 is incorrect.
- Trans-1,2-Dichloroethene was not sampled for in soil buttotal 1,2-Dichloroethene was. 1,2-Dichloroethane was neverdetected in RW#1 but 1,1-Dichloroethane was.
- Concentration ranges for lead and chromium in the watertable and trans-1,2-Dichloroethene and lead in surface waterare incorrect based on data contained in the May 1990report.
- State the basis for using a 5 ppb health comparison valuefor lead when the current MCL is 50 ppb.
- "Subsurface soil" in Table 1 is a misleading label forsludge samples.
- Filtered samples should be used as an indicator of drinkingwater quality.
- 1989 sampling in RW#1 and ESW#8 did not confirm VOCcontamination.
- The issue of detection limits compared to the EPA ContractLaboratory Program (CLP) requirements is questionable.
- The chemical constituents of the sludge is known.
- There is no technical basis for the statement "(t)heelectroplating operations tend to produce a sludge in whichheavy metals and VOCs are very mobile and not easilyretarded upon filtration and percolation (leaching) into thegroundwater." Electroplating operations did not directlyproduce sludge; the sludge produced by electroplatingoperations is treated before disposal. The hexavalentchromium in the sludge is converted to the more insolubletrivalent chromium via a chemical reduction process; infact, all the metals are in their insoluble forms in thesludge. The VOCs typically have a higher affinity for oilthan for water; and the oily nature of the sludge inhibitsinfiltration and percolation.
- The water table aquifer within the Crowley's Ridge formationhas been assessed to be part of the Wilcox formation.
- Surface water lead sampling data is incorrect: The maximumconcentration of lead found in surface water on the site is10 ppb, not 100 ppb.
- No evidence has been noted that would indicate a currentexposure exists due to the landfill.
ATSDR has recommended that the extent of groundwatercontamination off-site be determined. ATSDR does notconduct well sampling itself, but can only recommend that itbe done. Other federal and state agencies have conductedsome sampling. In a recent sampling round, one residentialwell was not sampled because it was considered to beinaccessible on the day sampling took place. Other wellshave not been sampled because they were believed to beoutside the range of possible contamination migration. Please check with the local health department for furtherinformation regarding the sampling of individual wells.
While this is a real concern to property owners, it isbeyond this public health agency's mission. The mission ofATSDR is to prevent or mitigate adverse human health effectsand diminished quality of life resulting from exposure tohazardous substances in the environment.
ATSDR has reviewed available information and concurs thatthe well survey was comprehensive and that all residentialwells which may be impacted by the site have been sampled. The PHA has been corrected.
ATSDR has reviewed the attached interviews. Health concernsstated included general concerns about drinking watersafety, cancer, and hair loss. Many people reported nohealth concerns. The PHA has incorporated a discussion ofthe concerns contained in the interviews.
ATSDR concurs. The PHA has been corrected.
ATSDR concurs that the lower Wilcox aquifer zone has notbeen shown to be contaminated by the site. The PHA has beenrevised.
The PHA has been revised to reflect this issue.
The PHA has been revised to reflect this issue.
ATSDR concurs that semi-annual monitoring would sufficientlyprotect public health. The PHA has been revised to reflectthis issue.
At the time this PHA was being drafted for public comment,the most current and comprehensive site investigation reporthad not been made available to ATSDR staff. ATSDR has sincereceived the May 1990 reference, has read the information,and has incorporated all new information which substantiallychanges the report. These changes are discussed under othercomments in this appendix. This, and any other newinformation ATSDR receives in a timely fashion, will be usedin the drafting of subsequent documents.
The PHA has been revised to clarify that Monroe Auto is acompany and that the landfill which Monroe Auto owned andoperated 3 miles west of Paragould received sludge.
The PHA has been revised to clarify well usage.
Discussions regarding the lead contamination in residentialwells are all qualified by a statement to the effect thatthe lead contamination may not be site related. Theexclusion of data from well #7 on the Table of Contaminantsof Concern Off-Site further dissociates this contaminationfrom the site. Nevertheless, distinct from the EPA, ATSDRis concerned with issues of public health hazard regardlessof their source. It is imperative that these discussionsremain in this document.
The PHA has been corrected.
The PHA has been corrected.
ATSDR was unable to identify the inaccuracy in theconcentration range for trans-1,2-dichloroethene in surfacewater. The PHA has been corrected with respect to the othercontaminants identified above.
The ATSDR does not use the MCL to select contaminants forfurther evaluation when other more protective numbers areavailable. The PMCL at the source is a number which is moreprotective of public health in the case of lead. This PMCLat the source is 5 ppb. Because a contaminant is selectedfor further evaluation does not necessarily mean itrepresents a public health problem. That decision anddiscussion have been incorporated into the Pathways Analysesand Public Health Implications sections of the PHA.
The PHA has been revised to clarify the issue.
The ATSDR believes that a valid comparison between groundwater samples and health standards can only be made withunfiltered samples. EPA concurs.
The PHA has been corrected.
The PHA has been revised to reflect this issue.
The PHA has been revised to reflect this issue.
Based on available information, ATSDR has reassessed thestatement in question. The PHA has been modified to reflectthe lesser potential for migration than as stated in theoriginal text.
ATSDR concurs that the upper groundwater aquifer can bedescribed to be within the Wilcox formation. The PHA hasbeen revised.
The PHA has been corrected.
Evidence exists that people are being exposed to lead fromwell #7 at a level of public health concern, however, thereis no evidence associating the lead with the landfill.