WILLIAM DICK LAGOONS
WEST CALN TOWNSHIP, CHESTER COUNTY, PENNSYLVANIA
The Pennsylvania Department of Health (PADOH) prepared this health consultation to updatethe status of the William Dick Lagoons site in West Caln Township, Chester County,Pennsylvania and determine whether the site poses a public health hazard to communityresidents. A 1992 Interim Health Assessment published by the Agency for Toxic Substances andDisease Registry (ATSDR) and PADOH concluded that the site posed a health hazard from pastexposures to trichloroethlyene (TCE) in private well water. Those exposures were interrupted in1987 with the installation of filters on affected wells, and in 1999 all homes in the area wereconnected to the recently extended public water line.
The William Dick Lagoons site no longer poses a public health threat to the community. Inaddition to the water line, the Environmental Protection Agency (EPA) will implement two moreremedial designs involving groundwater treatment and soil incineration. Both are scheduled tobe on line by early 2003.
The William Dick Lagoon site is 1,000 feet south of Telegraph Road in West Caln Township,Chester County, Pennsylvania (Figures 1 and 2). The former lagoons and associatedgroundwater plume occupy a topographic ridge and hill slope locally known as the Baron Hills(Figures 3 and 4). About 50 years ago, the property owner began disposing of liquid industrialwaste (tank trailer rinse water) in the three unlined earthen impoundments . Resins,chlorinated solvents, and petroleum products were characteristic of the wastes disposed. Wastedisposal ended in 1970 when PADOH ordered closure of the facility. In that same year, two ofthe three lagoons (Figure 4) were breached, allowing 300,000 gallons of waste to flow overlandto a nearby stream, killing fish and causing the temporary closure of the (downstream) publicwater supply for Wilmington, Delaware [2, 3]. In 1970, PADOH approved a clean-up plan forthe site, which was implemented in 1971 and included treatment and spray irrigation ofwastewater , burying contaminated soil in the empty lagoons, and revegetating the site . Apparently, no other significant remedial action was taken until July 1987 when EPA placed thesite on the National Priorities List (NPL), effectively beginning the current remediation. In1992, PADOH and ATSDR published an Interim Health Assessment (IHA) which containsadditional historical information and concludes that the site is a public health hazard from pastexposures to volatile organic compounds (VOCs) through private well water . The IHArecommends continued monitoring of nearby private wells, institutional controls to preventfuture drilling into the plume, and dust suppression measures during soil remediation. The firsttwo recommendations have been followed by EPA and Chester County. Pennsylvania law andEPA require (via the work plan) that no fugitive dust leaves the property boundary duringremediation (oral communication with EPA representative).
Trichloroethylene (TCE), the principal contaminant of concern, migrated off site and contaminated approximately 26 wells and springs . The highest concentration was 280 micrograms per liter (µg/L) in a downgradient spring. There are no reliable records that document how long residents might have been exposed to contaminated groundwater. Shortly after the 1987 listing on the NPL, Chemical Leaman Tank Lines, the potentially responsible party (PRP), agreed to furnish carbon filters to 16 affected water supplies with TCE concentrations at or above 5 parts per billion (ppb), the EPA's maximum concentration level (MCL) for public water supplies .
On October 8, 1995, the PRP and EPA entered into a consent decree which addressed sitecleanup in three distinct operable units (OUs) :
- A water line extension to serve approximately 115 homes near the site (completed in May 1999).
- Hydrogeologic study and interim groundwater treatment. After 5 years, the effectiveness ofthe treatment system will be evaluated and a final long-term plan will be specified. Thepreliminary design is expected to be completed during the current calendar year (2002).
- On-site treatment of contaminated soil. That plan will use thermal desorption (incineration)and soil vapor extraction/biodegradation technologies. The design for soil cleanup is scheduledfor completion in the fall of 2002, followed by implementation in the spring of 2003.
On March 7, 2002, J.E. Godfrey and Christine Brussock of PADOH visited the site andsurrounding area with an EPA representative. A 5-foot high chain link fence surrounded theformer lagoons (Figure 4), but deep, well-grooved off-road vehicle tracks around the fence andthe locked chain across the access road attested to vigorous recreational use by trespassers. There appeared to be no trespassing on the buried lagoon soil. At least one (background)monitoring well had been vandalized by punching a hole through the cap, and that well andanother one nearby had no locked cap at all. The EPA representative promised to contact thePRP regarding the vandalized wells. He also pointed out the other monitoring wells and recovery wells that will be used when the pump and treat process is finally implemented. Therest of the site is much like it was during the last site visit by PADOH in May 1990 .
Implementation of the groundwater treatment phase of remediation has been delayed becausePADEP withdrew a previously issued discharge permit that would have allowed the discharge oftreated water to a nearby stream . As soon as that issue is resolved, the design for the interimgroundwater extraction and treatment will be completed, and actual groundwater treatment willbegin. There are no longer any exposures to contaminated well water from the contaminantplume, and about 115 homes have already been connected to public water. Future homes orbusinesses constructed in the affected areas will be required by county ordinance to connect tothe existing public water supply.
Trespassers who ride vehicles on the site do not drive over contaminated soil because it is fencedoff. Therefore, exposure through direct contact, inhalation, or ingestion is not a public healthconcern.
Geologic cross sections through the site report that the water table is about 40 feet below thesurface of the ground . Considering that information and the relatively low VOCconcentrations in domestic wells, exposure through inhalation of gases over the plume is not athreat, even in homes with basements.
ATSDR and PADOH recognize that when encountering contaminated soil, air, or water, infantsand children can be more sensitive than adults. Children are smaller than adults, resulting inhigher doses of chemical per unit of body weight. They are shorter, and therefore closer to theground, where they can breathe more dust and heavy vapors. Also, the developing body systemsof children can sustain permanent damage if toxic exposures occur during critical growth stages. Therefore, ATSDR and PADOH have evaluated children's special interests at the William DickLagoon site, and have determined that no completed exposure pathways exist that could posespecial risks for children.
The William Dick Lagoons site poses no public health hazard to nearby residents. Homes andbusinesses in the area have been connected to the public water supply installed as OU1. Otheroperable units are in process of completion at the writing of this document, with initialimplementation of the soil remediation phase scheduled for spring 2003.
No public health recommendations are needed for the William Dick Lagoons site.
No further public health action is required for the William Dick Lagoons Site.
- US Environmental Protection Agency Region 3. 1990. The William Dick Lagoons Sitepreliminary final remedial investigation report, West Caln Township, Chester County,Pennsylvania. Washington, DC: US Environmental Protection Agency.
- Agency for Toxic Substances and Disease Registry. 1992. Interim health assessment forWilliam Dick Lagoons, West Caln Township, Chester County, Pennsylvania. Atlanta:US Department of Health and Human Services.
- US Environmental Protection Agency Region 3. 2002. William Dick Lagoons update. Washington, DC: US Environmental Protection Agency.
J.E. Godfrey, PG
Pennsylvania Department of Health
This Health Consultation for the William Dick Lagoons Site was prepared by the PennsylvaniaDepartment of Health (PADOH) under a cooperative agreement with the federal Agency forToxic Substances and Disease Registry (ATSDR). It is in accordance with approvedmethodology and procedures existing at the time the health consultation was initiated.
Technical Project Officer, SPS, SSAB, DHAC
The Division of Health Assessment and Consultation (DHAC), ATSDR, has reviewed this healthconsultation and concurs with its findings.
Richard E. Gillig
SectionChief, SPS, SSAB, DHAC, ATSDR