PRELIMINARY PUBLIC HEALTH ASSESSMENT
MONROE AUTO EQUIPMENT COMPANY (PARAGOULD PIT)
PARAGOULD, GREENE COUNTY, ARKANSAS
The Monroe Auto Equipment Company site (aliases Paragould Pit and
Finch Road Landfill) is an industrial landfill located near
Paragould, Arkansas. This landfill received wastewater 
treatment
sludge , which contained trichloroethylene and various heavy
metals, from the Monroe Auto Equipment Company's Paragould
manufacturing facility. Groundwater on-site is contaminated with
volatile organic compounds and metals with concentrations of
trans-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 contaminated
with cadmium, chromium, and lead. One residential well has been
shown to be contaminated with trans-1,2-dichloroethene. Three
other residential wells have been shown to be contaminated with
lead; this may not be site-related. Although the Arkansas
Department of Health has notified the residents of the elevated
levels of lead in their water and, in one case, in their blood,
and although they have alerted these residents to the health
risks associated with elevated lead levels, the people have not
been dissociated from exposure to contaminated drinking water.
Approximately 3 dozen households are within a 1-mile radius of the site. The entire area depends on groundwater for drinking water and domestic use. Exposure pathways of potential concern include ingestion and inhalation of and dermal contact with contaminated groundwater. Subsurface soil is contaminated with chromium and lead. Exposure pathways of potential concern related to soil include ingestion and inhalation of and dermal contact with disturbed contaminated soil and volatilized organic compounds. The Monroe Auto Equipment Company Site is an indeterminate public health hazard because there is insufficient information regarding whether people are being or have been exposed to hazardous substances at concentrations that may result in adverse health effects. In addition, one private drinking water well has been found to have elevated levels of lead; the water in that well may pose a public health hazard to those drinking from it. This contamination, however, is not site related.
This document has been made available for public comment. As a result of comments received by ATSDR, the document has been revised to reflect publicly stated concerns regarding the document. Appendix 1 contains further information regarding public comments.
A. Site Description and History
The Monroe Auto Equipment Company Site (Monroe Site) is located about 3 miles west of Paragould, Arkansas. This landfill site is owned and operated by the Monroe Auto Equipment Company (Monroe Auto Company) which is headquartered in Monroe, Michigan, and which also operates an auto parts manufacturing facility in Paragould. The site has functioned as a landfill and has previously been referred to as the Paragould Pit and the Finch Road Landfill.
The 4-acre site includes a 1-acre inactive landfill. The area is completely fenced with a 6-foot-high chain-link fence and three strands of barbed wire on top; access to the area is through a locked gate. Monroe Auto Company purchased this land in 1973 and received temporary approval from the Arkansas Department of Pollution Control and Ecology to use the land as a landfill. From 1973 to 1978, Monroe Auto Company disposed of alum and lime electroplating sludge at the landfill. The landfill reached capacity in 1978 and was closed and covered with 3 feet of dirt in 1979.
The Monroe Site was proposed for the EPA National Priorities List
(NPL) on October 25, 1989. For purposes of the Agency for Toxic
Substances and Disease Registry (ATSDR) preliminary public health
assessment, the site is defined as the 4-acre area enclosed
within the chain-link fence which includes the sludge disposal
area, two springs, and a pond.
During the ATSDR site visit in January 1990, it was noted that Monroe Auto Company had recently purchased private property across the highway from the southeast boundary of the site (1). The property had previously been owned and occupied by citizens whose well had been contaminated (residential well [RW] #1; see Figure 4). This property is presently unoccupied (direct observation).
In July 1988 and April 1989, Arkansas Department of Health (ADH) officials notified nearby residents to the northwest of the site that their well water was contaminated with lead and that they should stop using the well (RW #7) for potable water (2,3). These residents continue to use this water supply for domestic use despite the warnings.
C. Demographics, Land Use, and Natural Resource Use
The area around the site is rural and sparsely populated. An estimated 2,000 persons live within a 3-mile radius of the site. Approximately 3 dozen households are located within a 1-mile radius of the site. The entire population in this area relies on groundwater for drinking and domestic use (4). A residential well survey that EPA conducted in the general vicinity of the site was not comprehensive because the depths of all the residential wells are unknown.
The family that had used RW #1 was comprised of two adults in their mid thirties, one adult over 50, and three children between 12 and 17 years old. The family resided in two mobile homes (1).
The site is surrounded by wooded areas, irrigated agricultural areas, pastures, and residences. Limited hunting of squirrel and rabbit occurs in the area near the site.
ATSDR searched the EPA Chemical Toxic Release Inventory for 1987 and 1988 to identify other possible facilities that could contribute to the groundwater contamination within the area of concern. The Toxic Release Inventory did not contain any information on site-related toxic chemical releases in Greene County.
ATSDR has identified the following state and local health data sources as potentially pertinent to this site:
These documents are generated through the Arkansas State Department of Health. The vital statistics are analyzed down to the county level. Although a cancer registry was begun in the early 1970's, the information gathered was incomplete and unreliable. Efforts to continue the registry ceased in the early 1980's; it has not been functioning for the past ten years. No independent studies related to health effects of the population around the Monroe Site have been identified.
In January 1991, the EPA conducted interviews of citizens residing near the Monroe Site (5). Citizens expressed general concerns about the safety of their well water. One citizen mentioned a concern about cancer and another noted that her hair was falling out. In February 1987, residents living by and using RW #1 reported to state health officials an oily film surface on their water. They also complained of skin irritation, skin rashes, stinging sensations during showering, and of their hair falling out (1). There have been no further complaints since the household moved in April 1987.
ENVIRONMENTAL CONTAMINATION AND OTHER HAZARDS
Table 1 lists the contaminants of concern found at the Monroe Site and the concentration ranges found in each environmental medium. In this report, contaminants were selected for further evaluation by comparing the environmental sampling analytical results to the following comparison values:
EMEGs are media-specific estimates of exposure levels which pose a minimal risk of non-cancer health effects to humans. They are based on ATSDR's minimal risk levels (MRLs) or EPA's reference doses (RfDs) which are derived from results obtained from human and animal studies. CREGs are estimated contaminant concentrations based on a one-excess cancer in a million persons exposed over a lifetime. CREGs are calculated from EPA's cancer slope factors. MCLs represent contaminant concentrations that EPA deems protective of public health (considering the availability and economics of water treatment technology) over a lifetime (70 years) at an exposure rate of 2 liters water per day. MCLs are typically first proposed as PMCLs and remain as PMCLs until the review process is over and a final value has been determined.
Data in Table 1 is taken from references 6, 7, 8 and 9.
Table 1. Table of Contaminants of Concern On-Site
Monroe Auto Equipment Company National Priorities List Site
Paragould, Greene County, Arkansas
| Contaminant |
Media
|
In Parts per Billion
|
|
|
Range of Contamination
|
Comparison Value
|
||
|
|
|||
|
Subsurface Soil/Buried Sludge
|
|||
| 1,2-Dichloroethene |
<5-38,000
|
14,000,000a
|
|
| 1,2-Dichloroethane |
25
|
7,700b
|
|
| Chromium (Total) |
<3,000-5,000,000
|
None
|
|
| Lead |
<1,000-3,000,000
|
None
|
|
|
Perched Aquifer
|
|||
| Trans-1,2-Dichloroethene |
<5
|
100c
|
|
| 1,2-Dichloroethane |
<5
|
5c
|
|
| Chromium (Total) |
<10-300
|
50c
|
|
| Lead |
<10-180
|
5d
|
|
|
Water Table Aquifer
|
|||
| Trans-1,2-Dichloroethene |
<5-750
|
100c
|
|
| 1,2 Dichloroethane |
<5
|
5c
|
|
| Chromium (Total) |
<5-180
|
50c
|
|
| Lead |
<5-590
|
5d
|
|
|
Surface Water
|
|||
| Trans-1,2-Dichloroethene |
<5
|
100c
|
|
| 1,2-Dichloroethane |
<5
|
5c
|
|
| Chromium (Total) |
<10-40
|
50c
|
|
| Lead |
<5-10
|
5d
|
|
Notes:
a-EMEG
b-CREG
c-MCL
d-PMCL
Sludge wastes disposed of at the landfill were analyzed in November 1972 by Barrow-Agee Laboratories, Inc., for four metals and for oil and grease content only. The results indicated some chromium contamination (238,000 parts per billion (ppb)). More extensive analyses for heavy metals were performed on sludge samples produced under similar circumstances but not disposed of at the Monroe Site. The results of these analyses indicated the presence of lead.
Soil samples collected from the drilling of observation wells and borings were analyzed by Southwestern Laboratories for Monroe Auto Company in July 1979. Chromium was present (78,000 ppb); background chromium concentration levels for this site ranged from 4 to 118 ppb. In September 1989, Engineering-Science conducted soil borings within the landfill, including borings into the buried sludge. Analyses of these samples indicated contamination by total 1,2-dichloroethene (maximum 38,000 ppb), chromium (maximum 5,000,000 ppb, total), and lead (maximum 3,000,000 ppb). Concentrations of the heavy metals at levels of potential health concern were found 4 or more feet below the surface. No samples were collected from the top 3 inches of surface soil.
In April 1986, Engineering-Science collected groundwater samples for Monroe Auto Company from observation wells. Analyses of these samples indicated contamination with 1,1-dichloroethene, trans-1,2-dichloroethene, 1,1,1-trichloroethane, trichloroethylene, and methylene chloride. However, these wells were not drilled in accordance with EPA specifications and results may not adequately represent the groundwater quality at the site. Furthermore, because trichloroethylene and methylene chloride were observed in controls, Engineering-Science consultants noted that reported levels were likely the result of laboratory contamination (7).
In March 1988, Engineering-Science collected groundwater samples for Monroe Auto Company from wells drilled to EPA specifications. The primary contaminant detected in the aquifer was trans-1,2-dichloroethene (<5-750 ppb). Only one other volatile organic compound (VOC) (1,1-dichloroethane, <5-97 ppb) was detected in groundwater. Inorganic compounds, including chromium (<10-300 ppb total chromium) and lead (<5-180 ppb), were found in the perched water table.
Also in March 1988, the company collected surface water samples (on-site pond and springs) for Monroe Auto Company. Analyses indicated 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 surface water samples.
Table 2 lists the contaminants of concern found off-site at the Monroe Site. Contaminants were selected for further evaluation by comparing the environmental sampling analytical results to comparison values described in the On-Site Contamination section above. Data in Table 2 is taken from references 6, 7, 8 and 9.
Table 2. Table of Contaminants of Concern Off-Site
Monroe Auto Equipment Company National Priorities List Site
Paragould, Greene County, Arkansas
| Contaminant |
Media
|
In Parts per Billion
|
|
|
Range of Contamination
|
Comparison Value
|
||
|
|
|||
|
Residential Well # 1
|
|||
| Trans-1,2-Dichloroethene | <46-110 (122*) | 100a | |
| 1,2-Dichloroethane | <0.2 (247*) | 5a | |
| Cadmium | <0.3 | 10a | |
| Chromium (Total) | 5.6** | 100a | |
| Lead | 3.4** | 5b | |
|
Monitoring Well ESW-8
|
|||
| Trans-1,2-Dichloroethene | <5 | 100a | |
| 1,2-Dichloroethane | <5 | 5a | |
| Cadmium | <5-17 | 10a | |
| Chromium (Total) | 42-810 | 100a | |
| Lead | 8.3-590 | 5b | |
Notes:
* - 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 by ADH in July 1987, by Engineering-Science for Monroe Auto Company in August 1987, and by ICF Technology Incorporated for EPA in November 1987. A total of 13 private wells were sampled (see Figure 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. In addition, small amounts of 1,1-dichloroethane, 1,1,1-trichlor-oethane, and trichloroethylene were detected in RW #1. The use of this well has been discontinued for drinking purposes since April 1987. The well was capped October 1989.
The 1,2-dichloroethane contamination level of 247 ppb was reported once at RW #1 with no accompanying quality assurance/quality control (QA/QC) information; subsequent sampling of this well by Engineering-Science with appropriate QA indicated 1,2-dichloroethane levels below the detection limit of 0.2 ppb. Therefore, it is unknown if 1,2-dichloroethane was actually present in the water sample or if this was a result of field or laboratory contamination.
Results of subsequent groundwater sampling in August and November 1987 indicated trans-1,2-dichloroethene at 110 ppb and 57 ppb in RW #1.
Groundwater monitoring conducted by Engineering-Science in 1989 did not confirm VOC contamination off-site in RW #1 and ESW #8. however, this round of monitoring indicated that lead (maximum 590 ppb), total chromium (maximum 810 ppb), and cadmium (maximum 17 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 possibly related to the residents' plumbing system (10). In May 1988 and February 1989, ADH sampled two private wells in the vicinity of RW #7 and found lead contamination (15 and 10 ppb respectively) (11). No QA/QC information accompanied these latter two analyses.
C. Quality Assurance and Quality Control
In preparing this preliminary public health assessment, ATSDR relies on the information provided in the reference documents and assumes that adequate data quality assurance and QA/QC measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting. The validity of the analysis and the conclusions drawn in this preliminary public health assessment are determined by the availability and reliability of the referenced information.
When the detection limits for a compound is reported to be higher than the contract laboratory program requirements, it may not be possible to conclude with certainty whether contaminants are present at levels that may be of public health concern. For example, the detection limit for the lead water analyses reported by Engineering-Science was sometimes higher than the Contract Laboratory Program requirements of 5 parts per billion (ppb). Nevertheless, the data for lead in this case may still be evaluated.
Some groundwater samples were filtered before metal chemical analysis. The EPA drinking water standards are based on total (unfiltered) metal analyses rather than the (filtered) dissolved fraction. Valid site comparisons between site samples and the health standards can only be made with unfiltered samples.
No physical or other hazards associated with the site were noted.
A. Environmental Pathways (Fate and Transport)
From 1973 to 1978, approximately 15,400 cubic yards of sludge were buried at 1 acre of the 4-acre Monroe Auto Site. The sludge was produced by Monroe Auto Company as the result of electro-plating operations at the Paragould Plant. Results of preliminary investigations indicate the sludge contains heavy metals (chromium and lead) and VOCs (trichloroethylene and 1,1,1-trichloroethane). The electroplating operations produce a sludge in which, under some circumstances, heavy metals and VOCs may be mobile and may not be easily retarded upon filtration and percolation (leaching) into the groundwater.
The soil at the Monroe Site is composed primarily of overlaying layers of sand and gravel separated by lenses of clay. This geology tends to permit rapid percolation and movement of water and contaminants.
Groundwater is found at and around the NPL site in three zones. A perched water table exists directly under the disposal area, is not continuous across the site, and does not appear to exist beyond the site boundaries. The direction of flow within the perched water table is toward the southwest and appears to discharge to the surface as localized springs (on- and off-site). Two groundwater aquifer zones were encountered. The uppermost zone, a water table aquifer, is probably in the upper portion of the Wilcox group. Groundwater flow in this zone is generally east-southeast from the southern edge of the site. A second aquifer zone in the Wilcox Aquifer has been identified beneath the clay layer that underlies the water table aquifer. Groundwater flow patterns in this zone have not been precisely determined, but the gradient has a southerly component. These two zones are the primary source of potable water for individuals surrounding the site.
Investigations indicate that contaminants from the sludge have migrated into the perched water zone and the upper groundwater zone. The results of the groundwater sample analyses indicate heavy metal contamination has moved off-site toward the southeast (monitoring well ESW-8). VOC contamination has migrated the farthest and entered a local residential well (RW #1).
In addition to allowing the extent of VOC contamination to be determined, the analytical results indicate the original VOCs disposed of at the site (trichloroethylene and 1,1,1-trichloroethane) have been biodegraded (transformed by microorganisms normally found in soil) to trans-1,2-dichloroethene and 1,2-dichloroethane.
The analytical results of surface water samples, taken from an on-site pond and two springs, indicate heavy metal contamination. As previously discussed, the springs are thought to be fed by the perched water table. Therefore, it is not surprising to find heavy metal contamination at these locations. The pond found on-site is thought to be the result of local rain runoff. Any VOCs that may migrate into the surface waters will tend to volatilize. Surface water associated with the pond is believed to percolate into the ground on-site. The springs appear to flow off-site, toward the southwest.
Animals and plants can bioaccumulate (concentrate) heavy metals but generally not VOCs. Therefore, any animals or plants on or near the Monroe Site could have elevated levels of heavy metals. This may be particularly true for biota using the surface water associated with spring #2.
In addition to migrating from the sludge into the groundwater and surface water, the VOCs in the sludge could volatilize directly into the atmosphere. To date, no air monitoring has been conducted at the Monroe Site. The heavy metals in the sludge are not anticipated to migrate into the atmosphere unless the sludge is disturbed--for example, during activities such as remediation--because heavy metals do not easily volatilize and because the soil cap on top of the sludge should prevent the generation of dust from the sludge.
To date, no sediment samples have been taken in the springs and off-site creeks. Because heavy metal contamination was found in the surface water samples, sediment sampling should be conducted to evaluate this potential environmental pathway.
Several contaminated wells have been identified that are screened in the Crowley's Ridge aquifer: One observation well and three monitoring wells located on-site, one off-site monitoring well, and one private residential well located off-site. Three additional contaminated off-site residential wells have been identified for which the contamination source may not be site-related. The observation wells have been capped, the monitoring wells are used exclusively for sampling, and use of one residential well (RW #1) has been discontinued. However, the contaminated 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, and inhalation of aerosols and vapors during showering or other household activities.
As contaminants migrate through the aquifer, they may contaminate additional private wells at some future time, thereby exposing people to contaminants in groundwater via ingestion of drinking water, dermal contact, and inhalation of aerosols and vapors during showering or other household activities. Water used for irrigation purposes may become contaminated as a result of contaminant migration. At this time, ingestion of irrigated crops is not likely to be a source of exposure; however, because plants may accumulate lead (11), ingestion of food products grown using potentially contaminated water may constitute an exposure route of concern in the future.
Available groundwater sampling data indicate total chromium (maximum 300 ppb) and lead (maximum 180 ppb) contamination in the perched water table. People are not likely to be exposed to this contaminant because this water is not used for any purpose, it is not directly accessible for contact, and it migrates to the surface rather than into the aquifer. Available surface water sampling data indicate chromium (maximum 40 ppb) and lead (maximum 10 ppb) contamination in the pond. Because access to the pond is restricted, there is little potential for any direct exposure at this time. Since animals have access to surface water, and because heavy metals bioaccumulate, there is a potential for human exposure via ingestion of contaminated food-chain entities. Given the low frequency of hunting, human exposure via this pathway may not be significant.
Groundwater originating from RW #7 may present a source of exposure to lead upon its ingestion. The plumbing may be the original source of the lead. In April and October 1989, ADH sampled the blood of persons using the well. Analyses indicated elevated levels of protoporphyrin and blood lead (12). The elevated blood levels of these persons indicate exposure. The use of this well continues despite warnings from state officials. Efforts have been made by representatives of ATSDR to dissociate people from exposure to water contaminated with lead. The state health department has been contacted by ATSDR staff regarding the provision of drinking water to residences in the vicinity of the Monroe Site, but the state is unable to provide an alternate water supply at this time. RW #7 is north of the site. Because the groundwater is thought to flow toward the south-southeast, the lead contamination in this well is apparently not site-related.
Available data indicate chromium (maximum 5,000,000 ppb total chromium) and lead (maximum 3,000,000 ppb) contamination in subsurface soil on-site. Elevated concentrations of these contaminants 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 and ingestion or inhalation of released airborne particulates. Additionally, work activities may cause the release of volatile organic vapors and heavy metals which could result in human exposure via inhalation. There are no data regarding air quality at this site, therefore, human exposure via inhalation cannot be evaluated. The inaccessibility of the site precludes these types of exposures to the general population.
Ingestion and inhalation of off-site drinking water supplies contaminated by trans-1,2-dichloroethene may pose a potential public 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 Maximum Contaminant Level (PMCL) (100 ppb) promulgated under the Safe Drinking Water Act (SDWA). No known exposures have occurred at the maximum concentration of 750 ppb because no one drinks on-site water. Although no known exposures have occurred, it is possible for the contaminated water to migrate to a drinking water well where exposure may occur. Trans-1,2-dichloroethene concentrations found at RW #1 (46-110 ppb) approximate the PMCL level.
Toxicological data regarding chronic exposure to low concentrations of trans-1,2-dichloroethene are limited, and minimum exposure levels that cause adverse health effects in humans have not been reported. Data from limited animal studies indicate that ingestion at lethal (1,000 mg trans-1,2-dichloroethene per kg body weight) and near-lethal levels causes damage to the lung, liver, and central nervous system. Inhalation at low levels (6,800-8,800 ppb for 5 minutes or 4,800 ppb for 10 minutes) has caused nausea, drowsiness, fatigue, vertigo, and intracranial pressure in humans. Results of animal studies indicate that inhalation of trans-1,2-dichlor-oethene at 200,000 ppb for 16 weeks may cause severe lung and liver damage; inhalation at 3,000,000 ppb for 8 hours may cause heart pathology (all studies from reference 13). These levels are significantly higher than those associated with this site.
Human ingestion of lead-contaminated drinking water from the off-site RW #7 (312 ppb) is of public health concern. This concentration exceeds the EPA PMCL (5 ppb) promulgated under the SDWA. Exposure to lead in contemporary American society may result from contact with multiple sources. Further, lead is a cumulative human toxicant. Multiple sources and accumulation of lead in human body compartments necessitates attention to toxicity risks even if only low levels of lead are being absorbed at a given time from a given source.
Lead toxicological studies only show health effects in humans at contamination levels higher than the highest level found around the Monroe Site. Most studies discuss information in terms of blood lead level rather than external exposure level. The Centers for Disease Control has recently revaluated its guidelines on acceptable blood lead levels based on recent scientific information and studies (14). New data indicate that significant adverse health effects of lead exposure can occur in children at blood lead levels previously believed to be safe. Some health effects have been documented at blood lead levels as low 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 been explored. Headaches were not reported in the literature. No data on the association between human oral exposure to lead and cancer have been reported. Animal oral exposure studies suggest a qualitative relationship between exposure to lead in food and renal tumors. Human occupational inhalation data are inconclusive but suggest an increase in malignant neoplasms. The EPA 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 of potential public health concern. Cadmium is a naturally occurring element in the soil. There are no known benefits of exposure to cadmium; both acute, high-level exposures and long-term, low-level exposures can lead to adverse health effects in humans. The concentration found in the off-site monitoring well (17 ppb) exceeds the EPA's Maximum Contaminant Level (MCL) of 10 ppb promulgated under SDWA. This MCL is based primarily on health effects, but also considers cost and feasibility; EPA has set an advisory Maximum Contaminant Level Goal (MCLG), based solely on health considerations, of 5 ppb.
Animal and human studies indicate that long-term, low-level oral exposure to cadmium may cause kidney damage. Studies indicate that doses of 30,000 ppb for 6 weeks may lead to proteinuria, or a dysfunction in renal absorption of certain proteins, in animals. Additional studies indicate kidney damage in humans, however, dose-response data are not available. Kidney damage may not be life-threatening, but can lead to kidney stones and skeletal effects, which can be painful and debilitating (all studies from reference 16).
Human ingestion of chromium-contaminated drinking water may be of potential public health concern. Although the chromium at the Monroe Site is measured as total chromium, chromium exists in three major states: Chromium (0), chromium (III), and chromium (VI). Studies of oral exposure to chromium in humans and animals indicate that chromium (VI) is toxic to the kidneys and the liver at doses very much higher that those which could be associated with this site. Studies with rats of chronic (over a year long) exposure to chromium, even at levels 10 to 100,000 times higher than those associated with this site, have shown no observable adverse health effects (17). Exposure to chromium (III) has not been shown to result in adverse health effects and is the form thought to be an essential food nutrient when ingested in small amounts. Chromium (0) is not well characterized in terms of levels 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 health effects data generated from inhalation studies which indicate that chromium is carcinogenic. Other studies indicate that oral exposure to chromium is not associated with cancer (17).
Disturbance of soil contaminated with chromium (maximum 5,000,000 ppb) and lead (maximum 3,000,000 ppb) may cause these metals to be released into the air as particulates. Human exposure to these airborne particulates via inhalation and dermal contact is of potential public health concern to remedial/removal workers. Long-term exposure of workers to airborne levels of total chromium higher than those in the natural environment has been associated with lung cancer. In addition, short-term, high-level exposure to chromium (VI) can result in adverse effects at the site of contact such as ulcers of the skin, irritation of the nasal mucosa and perforation of the nasal septum, and irritation of the gastrointestinal tract (17).
B. Health Outcome Data Evaluation
There was no health outcome data evaluated for this site. ATSDR determined that there exists only one known past completed exposure pathway from the Monroe Auto site and one present completed exposure pathway which may not be site related. There were only two families, one from each pathway, who had been exposed. ATSDR staff believe that analysis of existing health outcome information would not be helpful for such a small population. In addition, ATSDR is unaware of any recent health concerns within the community related to site-associated contamination. If new information becomes available which shows that other people have been or are being exposed, or that nearby residents have health concerns about contaminants associated with the site, ATSDR will reconsider evaluating health outcome data.
C. Community Health Concerns Evaluation
A community member expressed concern about cancer. No exposures have occurred with any possible, probable, or known human carcinogens. Two contaminants at the site are associated with cancer (1,2 dichloroethane and chromium). 1,2 dichloroethane has been found only on-site in the waste material, where people are not likely to come into contact with it. Chromium, associated with cancer only through the inhalation route, is not likely to be inhaled. People have not been, are not being, and are not likely to be exposed to any site-related contaminants associated with cancer.
Residents who used RW #1 have expressed concerns about skin irritation, rashes, a stinging sensation during showering, and their hair falling out. One other community member also expressed concern about hair loss. In the general population, it would not be expected to see any of these symptoms as a result of exposure to contaminants at levels found in RW #1. Although solvents can cause skin irritation, dichloroethane concentrations found at the residential well are too low to have reasonably caused any dermal effects. There are numerous causes for skin irritation, rashes, stinging sensations while showering, and hair loss; these symptoms may be unrelated to the site.
Based on available information, ATSDR has concluded that the Monroe Site is an indeterminate public health hazard because of insufficient information regarding whether people are being or have been exposed to hazardous substances at concentrations that may result in adverse health effects. As noted in the Human Exposure Pathways Section of this preliminary public health assessment, exposure to elevated levels of trans-1,2-dichloroethene has occurred and may be occurring, and possible migration of trans-1,2-dichloroethene into drinking water supplies might result in future exposure. This would be of potential public health concern because of human exposure to trans-1,2-dichloroethene at concentrations that may result in adverse health effects.
The concentrations of cadmium, chromium, and lead found in a water sample from an off-site monitoring well (ESW-8) are also of potential public health concern because possible migration of these contaminants into drinking water supplies might result in future exposure. Ingestion of these contaminants at the reported concentrations (maximum 17 ppb, 810 ppb, and 310 ppb respectively) may result in adverse human health effects.
Additionally, human exposure to elevated levels of lead may be occurring and may have occurred in the past via ingestion of contaminated water in RW #7 and neighboring wells. This is a public health hazard, although it is apparently not site-related.
Remediation efforts may create conditions where human exposure to chromium and lead may occur. This would be of potential public health concern because humans may be exposed to these heavy metals at concentrations that may result in adverse health effects.
The ATSDR recommends the following:
ATSDR will coordinate with the appropriate environmental agencies to develop plans to implement the site characterization recommendations.
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 the State of Arkansas, will provide environmental health education for the community to assist the community in assessing possible adverse health effects associated with exposure to hazardous substances.
ATSDR concurs with the past public health action taken by the Arkansas Department of Health of testing blood lead levels of users of a well contaminated with lead and of alerting them to the health risks associated with elevated lead levels.
Environmental Reviewer:
Sven E. Rodenbeck, P.E.
Environmental Engineer Consultant
Remedial Programs Branch
Health Reviewer:
Stephanie Prausnitz
Environmental Health Scientist
Remedial Programs Branch
Regional Representative:
George L. Pettigrew
Field Operations Branch
Dallas, Texas
APPENDIX 1: RESPONSE TO PUBLIC COMMENTS
The Monroe Auto Equipment Company Preliminary Public Health Assessment (PHA) was available for public review and comment from July 1 through July 31, 1991. ATSDR received five written responses pertaining to the Monroe Auto Equipment Public Comment Period. The comments and the corresponding responses are summarized below.
Comments Received During Public Comment Period and Responses
ATSDR has recommended that the extent of groundwater contamination off-site be determined. ATSDR does not conduct well sampling itself, but can only recommend that it be done. Other federal and state agencies have conducted some sampling. In a recent sampling round, one residential well was not sampled because it was considered to be inaccessible on the day sampling took place. Other wells have not been sampled because they were believed to be outside the range of possible contamination migration. Please check with the local health department for further information regarding the sampling of individual wells.
While this is a real concern to property owners, it is beyond this public health agency's mission. The mission of ATSDR is to prevent or mitigate adverse human health effects and diminished quality of life resulting from exposure to hazardous substances in the environment.
ATSDR has reviewed available information and concurs that the well survey was comprehensive and that all residential wells which may be impacted by the site have been sampled. The PHA has been corrected.
ATSDR has reviewed the attached interviews. Health concerns stated included general concerns about drinking water safety, cancer, and hair loss. Many people reported no health concerns. The PHA has incorporated a discussion of the concerns contained in the interviews.
ATSDR concurs. The PHA has been corrected.
ATSDR concurs that the lower Wilcox aquifer zone has not been shown to be contaminated by the site. The PHA has been revised.
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 sufficiently protect public health. The PHA has been revised to reflect this issue.
At the time this PHA was being drafted for public comment, the most current and comprehensive site investigation report had not been made available to ATSDR staff. ATSDR has since received the May 1990 reference, has read the information, and has incorporated all new information which substantially changes the report. These changes are discussed under other comments in this appendix. This, and any other new information ATSDR receives in a timely fashion, will be used in the drafting of subsequent documents.
The PHA has been revised to clarify that Monroe Auto is a company and that the landfill which Monroe Auto owned and operated 3 miles west of Paragould received sludge.
The PHA has been revised to clarify well usage.
Discussions regarding the lead contamination in residential wells are all qualified by a statement to the effect that the lead contamination may not be site related. The exclusion of data from well #7 on the Table of Contaminants of Concern Off-Site further dissociates this contamination from the site. Nevertheless, distinct from the EPA, ATSDR is concerned with issues of public health hazard regardless of their source. It is imperative that these discussions remain in this document.
The PHA has been corrected.
The PHA has been corrected.
ATSDR was unable to identify the inaccuracy in the concentration range for trans-1,2-dichloroethene in surface water. The PHA has been corrected with respect to the other contaminants identified above.
The ATSDR does not use the MCL to select contaminants for further evaluation when other more protective numbers are available. The PMCL at the source is a number which is more protective of public health in the case of lead. This PMCL at the source is 5 ppb. Because a contaminant is selected for further evaluation does not necessarily mean it represents a public health problem. That decision and discussion have been incorporated into the Pathways Analyses and Public Health Implications sections of the PHA.
The PHA has been revised to clarify the issue.
The ATSDR believes that a valid comparison between ground water samples and health standards can only be made with unfiltered 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 the statement in question. The PHA has been modified to reflect the lesser potential for migration than as stated in the original text.
ATSDR concurs that the upper groundwater aquifer can be described to be within the Wilcox formation. The PHA has been revised.
The PHA has been corrected.
Evidence exists that people are being exposed to lead from well #7 at a level of public health concern, however, there is no evidence associating the lead with the landfill.
Figure 1. Finch Road Landfill Location Map
Figure 2. Monitoring Well Locations Finch Road Landfill
Figure 3. Wilcox Aquifer Monitoring Well Locations
Figure 4. Approximate Private Well Locations Relative to the Finch Road Landfill
