PUBLIC HEALTH ASSESSMENT
EL DORADO, UNION COUNTY, ARKANSAS
The Popile, Inc. site is located on South West Avenue about 3/4 mile south of El Dorado, Arkansas. A former woodtreatment facility operated on the site from 1947 to 1982. Previous studies and environmental sampling indicate thatchemicals such as creosote and pentachlorophenol that were used in wood treatment operations on the site, and wastematerials, such as sludges and wastewater from the site operations, have contaminated site soils and groundwater witha number of contaminants, including VOCs, PAHs, phenols (primarily pentachlorophenol), furans/dioxins, andmetals. Site contaminants have also been found in the surface water and sediments of Bayou de Loutre adjacent to thesite.
Former employees of the wood treatment facility were likely exposed to on-site contaminants including PAHs,pentachlorophenol, dioxins, arsenic, and lead, through incidental ingestion of contaminated media such as soils,sludges, sediments, and surface water. In addition, there have been reports of individuals using Bayou de Loutre, nearthe site, for recreational purposes. These persons have likely been exposed to contaminants, such as PAHs,pentachlorophenol, dioxins, arsenic, and lead, through the ingestion of contaminated surface water and sediments inthe bayou.
Other persons potentially exposed to site contaminants include 1) past on-site workers and possibly other persons onand around the site who may have inhaled contaminants in ambient air and air-borne dusts; 2) persons accessing thesite, such as site investigative personnel, fisherman, hunters, and trespassers, who may have ingested contaminatedsurface soils; and 3) persons who may have ingested contaminants from eating fish caught in Bayou de Loutre nearthe site. In addition, private well users downgradient of the site may be exposed to site-related groundwatercontaminants in the future if their wells become contaminated. Persons who may work or live on the site in the futurecould also be exposed to groundwater contaminants if on-site wells are used to supply their drinking water.
The Popile, Inc. site poses an indeterminate public health hazard because available information isinsufficient to determine whether past exposures to site contaminants may have occurred at levels that could haveresulted in adverse health conditions. In addition, current exposures to site contaminants, although not expected tocause adverse health conditions, cannot be fully evaluated because contaminant data for some media (such as fish inBayou de Loutre) are unavailable. However, based on the present level of contaminants in on-site groundwater, thesite could pose a public health hazard in the future if the site is developed for residential and/orcommercial/industrial activities and on-site wells are used for drinking water purposes.
A private citizen's concern about possible health effects from proposed remediation activities (i.e. incineration) is nolonger applicable since the EPA has decided to use on-site biological remediation instead.
ATSDR has made recommendations in this public health assessment to 1) reduce the potential for future exposure tosite-related contaminants, and 2) further characterize site-related contamination and potential exposure points for some environmental media.
The Agency for Toxic Substances and Disease Registry (ATSDR) has evaluated the public health significance of thePopile, Inc. site to determine whether health effects are possible and has recommended actions to reduce or preventpossible health effects. ATSDR, located in Atlanta, Georgia, is a federal agency within the U.S. Department of Healthand Human Services and is authorized by the Comprehensive Environmental Response, Compensation, and LiabilityAct (CERCLA), as amended, to conduct public health assessments at hazardous waste sites. The CERCLA legislationis commonly called "Superfund".
The Popile, Inc. site (Figures 1 and 2, Appendix A) is a former wood-treatment facility located approximately 1/4mile south of the intersection of South West Avenue (also known as Southfield Road) and U.S. Highway 82 in ElDorado, Union County, Arkansas. The site is about 3/4 mile south of the El Dorado city limits. The property isbordered by South West Avenue on the west, the Ouachita Railroad on the east and Bayou de Loutre, a perennialcreek, on the north. These three boundaries intersect on the north end of the site. A forested highland area bordersthe site on the south (1).
A small timber and pulpwood operation, which is not related to the former site activities, stores wood adjacent to thenorthwest boundary of the site. A drainage ditch along the northwest site boundary discharges into Bayou de Loutreat the northwest corner of the site. Two large sewage disposal ponds owned by the city of El Dorado are locatedabout 3/4 mile east of the site next to the Bayou (1).
Prior to being used for wood treatment, the site was associated with oil field and refinery operations. A 1936 aerialphotograph of the site showed several large storage tanks and possibly oil refinery pits in the immediate site vicinity. The containment area for one of the tanks was located about 100 feet south of where the wood treatment facility waslater located. Three other areas located across the railroad tracks to the east appeared blackened in the photograph,most likely due to discharges from oil field operations. In addition, records have indicated that several oil wells datingfrom this period were located near the site. However, no evidence of these wells can be found (1).
In 1947, El Dorado Creosote Company began treating wood at this site using pentachlorophenol (PCP) and creosote. The first surface impoundment for storage of process wastewater and sludge was constructed east of the facility areabetween 1951 and 1956. In 1958, El Dorado Pole and Piling company purchased the property and continued thewood treatment operations. By 1969, three surface impoundments east of the facility area had been constructed, andby early 1976 wastewater treatment had begun. Wood treatment operations at the site ceased on July 1, 1982 andhave not resumed. Figure 2 shows the site as it existed during the former wood treatment operations (1).
On July 7, 1982, approximately 34 acres of the property were sold to El Ark Industries, Inc. The seven remainingacres, which included the three surface impoundments containing wood treatment wastes, were sold to Popile, Inc. This company (Popile) was apparently created to conduct Resource Conservation and Recovery Act (RCRA) closureactivities for the impoundments. Closure of the three impoundments, which was completed by Popile, Inc., inOctober 1984, consisted of removal of sludges from the impoundments and disposal in an on-site RCRA unit (1).
Following closure, site inspections by the Arkansas Department of Pollution Control and Ecology (ADPCE) revealedsurface contamination and possible groundwater contamination due to leakage from the RCRA unit. In September1989, ADPCE requested assistance from the U.S. Environmental Protection Agency (EPA) to abate the threat posedby site contamination (1,2).
In response to ADPCE's request, an EPA Technical Assistance Team (TAT) conducted a Site Assessment (SA) inOctober 1989. The SA focused on the El Ark Industries property which included the wood treatment facility area andthe site drainage area. In their May 1990 SA report (3), the TAT indicated that the wood treatment facility area hadnot been included in the 1984 RCRA closure. According to the report, the treatment facility consisted of a run-downbuilding and associated features which covered about one acre southwest of the closed impoundments. In thebuilding, one pressure cooker, two steam boilers, one stack, one separator, a complex grid of flow lines and anengineering laboratory were found. Other features associated with the plant operations included a railroad dryingtrack and treated wood storage area, two suspected sumps and/or underground storage tanks, one horizontal tank, onelarge upright tank, and one unlined containment area. The site drainage area, on the north side of the site, coveredapproximately 5 acres and had been used in dewatering the impoundments prior to their closure. A drainage ditchwas reported between the treatment facility area and the closed impoundments. This drainage ditch migrated throughan area characterized by a tar mat within a sandy soil matrix that was devoid of any vegetation and spotted with deadtree trunks. Heavy contamination was reported to be visible in drainage areas throughout the site. The TAT reportalso noted the presence of a waste pile stretching east to west along the northern part of the site property. Except forthe information presented above, little is known about the actual operations which occurred at the site.
During the October 1989 SA, the TAT collected samples of various environmental media at the site. Analysis of thesesamples revealed the presence of polycyclic aromatic hydrocarbons (PAHs), pentachlorophenol (PCP), and dioxins/furans.
Following the SA report, various site inspections were conducted to further evaluate the site. A July 13, 1990inspection revealed that a major flood event had occurred at the site subsequent to the 1989 SA. This flood inundatedthe site drainage area, and the resulting drainage to the Bayou eroded a channel along the northern boundary of thesite. The channel that was formed allowed heavily contaminated materials to drain off the site and directly enter theBayou. After additional site inspections by the EPA Environmental Response Team (ERT), EPA approved anEmergency Removal Action (2).
In September 1990, the EPA Emergency Response Branch (ERB), TAT, and Emergency Response Cleanup Services(ERCS) began removal actions at the site. From September 1990 through August 1991, the removal personnel (1)constructed a drainage diversion system to collect and treat surface runoff during the removal action; (2) constructedtwo clay-lined holding cells; (3) dismantled the old wood treatment facility; (4) excavated contaminated soil from theoriginal RCRA closure impoundments; (5) stabilized contaminated materials with rice hulls and fly ash; (6) placed thestabilized materials, facility debris, and excavated soil into the two holding cells; (7) backfilled the excavated areas;(8) capped all contaminated materials with compacted clay; (9) spread topsoil and seeded the entire site; (10)constructed drainage ditches and took other erosion control measures; and (11) installed a security fence with warningsigns around the site (1,2). The Popile Inc. site was proposed for the EPA National Priorities List (NPL) in February1992. The site was subsequently listed as final on the NPL in October 1992.
During February and March 1992, an EPA contractor conducted a Remedial Investigation (RI) of the Popile siteunder the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) and the SuperfundAmendments and Reauthorization Act (SARA). The primary purpose of the RI was to evaluate findings of previoussite investigations, to collect additional information that would assist in characterizing current and future risks posedby site contamination, and to develop and evaluate long-term and permanent remedial alternatives (1).
The RI included the following tasks:
- compiling and evaluating existing data regarding the nature and extent of contamination at the site;
- collecting and evaluating data to determine 1) the types, concentrations, extent, and movement of contaminants present in surface and subsurface soils, surface water, sediment, and groundwater at the site, and 2) the extent of surface contamination remaining following the previous removal actions; and
- collecting and evaluating data to characterize the subsurface geology and hydrogeologic conditions.
Sampling results from the RI are discussed in the "Environmental Contamination and Other Hazards" section of this document.
In February 1993, EPA issued a Record of Decision (ROD) which selected a remedial action to address contaminatedgroundwater and soils at the Popile site. The selected remedy included excavation and biological treatment ofcontaminated soils and sludges in an on-site land treatment unit; extraction and physical and/or biological treatment ofcontaminated groundwater; and in-situ bioremediation of vadose zone soils and groundwater contaminated by non-aqueous phase liquids. In addition, environmental monitoring will be conducted during implementation of theremedy to evaluate its effectiveness. The time required for completion of the remedial action is estimated to be 15 to20 years (4).
In February 1994, the EPA ERB inspected the Popile site and found that six sections of the perimeter fencing hadbeen cut. The ERB also observed that site was draining as intended and the clay cap was intact. The ERB thenrepaired the damaged fence sections and installed warning signs (5).
Mr. Stephen Richardson and Ms. Déborah Boling with ATSDR, Atlanta, Georgia, and Ms. Jennifer Lyke, ATSDRRegional Representative, Dallas, Texas, visited the site area on September 24-25, 1992. The following was observedand learned during the site visit:
- the site was surrounded by a barbed-wire fence; however, the fence was not continuous (along the eastern site perimeter next to the railroad tracks), and would not prevent access to the site;
- an active timber shipping operation was located immediately outside the entrance to the site, and a commercial trucking operation was in business west of the site across South West Avenue;
- virtually the entire site appeared to be covered with a layer of compacted clay and was well vegetated;
- there was little evidence of past site operations;
- there was little evidence of surface contamination except for a few small areas of creosote-tainted soil and treated wood where past investigative trenching occurred;
- no evidence of trespassing or use of the site was found; and no children were observed on or near the site; and
- several private residences were located along South West Avenue southwest of the site.
Union County, Arkansas, encompasses an area of 1,053 square miles with a 1986 population of 49,000. Thepopulation density (1986) was 46.5 individuals per square mile.
The area surrounding the Popile site is rural and residential/commercial. Although no homes are located along the siteperimeter, several residences are located about 1/5 mile southwest of the site along South West Avenue. Acommercial trucking company operates just west of the site across South West Avenue. A large oil refinery and tankfarm are approximately one mile northwest of the site, and a chemical plant is about two miles west of the site (1).
Natural Resource Use
Groundwater is the principal source of water for most communities and businesses in the site region and is suppliedby several aquifers.
The Quaternary Alluvium is a shallow formation, generally less than 25 feet thick, and is present in most streambottoms in Union County. The lower part of the Alluvium, composed mostly of sands and gravels, is generallyinterconnected with the underlying Cockfield Formation. The Alluvium is not used a major source of potable waterin the region, but has sufficient production capacity to support drinking water or other uses (1,6).
The Cockfield Formation, which is composed of lignite sand and clay, is approximately 200 feet thick. In the past, theCockfield was the principal aquifer for rural domestic supply in the area. However, in recent years, the use of theCockfield has decreased considerably, and currently most rural water is supplied by the deeper El Dorado Aquifer. Water levels in the Cockfield are shallow, ranging from near land surface in bottomlands to about 50 feet below landsurface on hills and ridges (1).
In some areas, the overlying Cockfield is absent, and outcrops of the Cook Mountain Formation are exposed. Thisformation, which is 100 to 150 feet thick, is composed mainly of clays and silty clays with some minor sands. Because of its very low permeability, the Cook Mountain formation is not considered as a viable aquifer but, rather,generally serves as a confining layer between the Cockfield above and the Sparta Sand below (1).
The Sparta Sand, approximately 600 feet in thickness, is divided roughly in the middle by a continuous, clay layerinto two distinct aquifers - the upper Greensand Aquifer and the lower El Dorado Aquifer. Although the Greensand isused for water supply (about 0.5 million gallons per day (MGD) in 1982), the El Dorado is the principal water sourcefor most residences and businesses in Union County. In 1982, pumpage from the El Dorado aquifer, which wascentered in El Dorado, averaged 16 MGD. All municipal drinking wells operated by the City of El Dorado and theParkers Chapel Rural Water Associations are screened in this aquifer. Wells drawing from this aquifer in the area aretypically 750 feet deep. Beneath the Popile site, the depth to the El Dorado Aquifer is approximately 500 feet belowthe ground surface (1,6).
Beneath the Sparta Sand lies the Cane River Formation, a confining stratum of low permeability. Below the CaneRiver are several other groundwater formations. However, due to high salinity, the water in these formations is notused for human consumption (1).
At the Popile site, the Alluvium and the Cockfield formations are of particular interest since they are the aquifers mostsusceptible to site contamination. In the site area, the transition between these two aquifers is difficult to distinguishand widespread communication between them is likely. As a result, the two formations are sometimes treated as asingle hydrogeologic unit (1).
Groundwater at the site is generally deeper beneath the higher surface elevations on the west side of the site, andshallower approaching Bayou de Loutre. Depths to groundwater range from near ground surface at the northerncorner of the site to 10 feet below ground surface near the west-central edge of the site. The general direction ofgroundwater movement is downslope toward the bayou, with a horizontal gradient ranging from 0.08 ft/ft to 0.03 ft/ft. Hydraulic conductivities are estimated to be on the order of 10-4 cm/sec for wells completed in sands and 10-7 cm/secfor wells completed in clays and silty clays (1,2).
A number of private wells have been reported in the general area of the Popile site. The nearest usable drinking waterwell is located on South West Avenue, approximately 3/4 mile south/southwest of the site. This deep well, which isscreened in the Greensand Aquifer may serve one of the several residences located on South West Avenue near thesite. However, these residences are considered to be upgradient of the site and, reportedly, receive drinking waterfrom a public water supply (Parkers Chapel Rural Water System). A second private well of unknown depth has beenreported to exist within one mile of the site and a third (58 feet in depth) within 2 miles; however, the exact location ofthese wells is unknown. Additional private wells have been reported at distances exceeding 2 miles. Shallow, privatewells in the area are mostly used for livestock watering and irrigation (6).
No public water supply wells are known to exist within one mile of the site. The City of El Dorado has 10 drinkingwater wells, 3 of which are located within 2 miles of the site. Four of the remaining wells are within 4 miles. All 10wells are screened in the El Dorado Aquifer 700 to 800 feet below ground surface. The city water system, which hasmore than 11,000 connections, serves users within the El Dorado city limits. Parkers Chapel Rural Water Systemoperates two wells within 2 to 3 miles of the site. These wells, which are about 700 feet deep, are screened in the ElDorado Aquifer. The Parkers Chapel system has 710 connections and serves areas south of the southern city limits,including the general site area (6).
The principal surface water features in the vicinity of the site are Bayou de Loutre, a perennial stream, which bordersthe site to the north and east and the City of El Dorado sewage disposal ponds located about 1,000 feet east of the site. Surface drainage at the northern end of the site occurs as overland flow or drains into a small intermittent stream alongthe northwest edge of the site that flows into Bayou de Loutre. Along the eastern edge of the site, surface runoffenters drainage ditches along the railroad track which also empty into the Bayou. Drainage of other site areas is byoverland flow following site topography. Areas of standing water are intermittently present on low-lying areas of thesite (1).
The average annual flow in Bayou de Loutre is estimated to be about 1 cubic foot per second (CFS). However, it isestimated that flow could exceed 100 CFS following extended, heavy rainfall. The Bayou flows southeast for about15 miles before crossing the Louisiana state line and then entering the Ouachita River about 10 miles north ofMonroe, Louisiana (1).
Surface water from Bayou de Loutre is not used as a municipal drinking water source by the City of El Dorado. It hasbeen reported that the Bayou is used for various recreational activities, including wading, fishing, and possiblywaterfowl hunting, on a seasonal basis. During the fishing season (March to September), up to 100 people a weekmay fish in the Bayou (6).
Health outcome data were not evaluated for this site because the population of concern is very small (probably lessthan 200 individuals). Details of why the data were not analyzed are presented in the Public Health Implications --Health Outcome Data Evaluation subsection.
As part of the development of this public health assessment, ATSDR staff held an informal, one-on-one publicavailability session to learn about the community's site-related concerns. The availability session was held onSeptember 24, 1992 at the Barton Public Library in El Dorado. About 13 individuals, including a local news reporter,attended the session.
At the availability meeting, a resident raised the following site-related health concern:
- What are the possible respiratory effects should harmful air emissions escape from the site during incineration?
This health concern will be addressed in the Public Health Implications section.