Mid-Atlantic Superfund

EPA Region 3 (Mid-Atlantic)

Delaware
Kent County
Cheswold

EPA ID# DED980714141

1st Congressional District

Last Update: January 2009

Other Names

None

Current Site Status

The U.S. Environmental Protection Agency is overseeing groundwater monitoring and cleanup activities. Groundwater pumping and treatment began in 1997 and was stopped in October 1999 when it was found that groundwater quality had substantially improved. Subsequently, EPA identified increasing levels of trichloroethene (TCE) in two site monitoring wells. As a result, the potentially responsible parties (PRPs) resumed groundwater pumping in November 2003 after implementing minor modifications to improve the efficiency of the groundwater collection system. Groundwater pumping and monitoring is continuing. Groundwater use will remain restricted until cleanup levels are attained. EPA concluded the second five year review in September 2008.

The 2008 Five Year Review found that the remedy was constructed in accordance with the requirements of the Record of Decision (ROD). One Explanation of Significant Differences (ESD) was issued in order to eliminate the requirement specified in the ROD that a notice be placed in the property records of properties located within the GWMZ at the Site. The remedy is functioning as designed. The immediate threats have been addressed and the remedy is expected to be protective when the groundwater cleanup standards have been achieved.

The remedy currently protects human health and the environment because exposure pathways that could result in unacceptable risks are being controlled. Institutional controls are preventing exposure to contaminated groundwater. To view the 2003 and 2008 Five-Year Review Report as well as other related Site information, go to Superfunds Documents website.

Site Description

The 1 ½-acre Chem-Solv, Inc. site, located in Cheswold, Delaware, served as a small solvent distillation facility beginning in 1982. The facility recycled waste solvents by heating the drummed wastes on an electric coil heater and collecting the distilled solvents into a separate drum. In 1984, an explosion and fire at the site destroyed the distillation facility. Witnesses observed fluids flowing off a concrete pad and into the soil. After the fire, the State and the PRPs evaluated the Columbia aquifer beneath the site. High concentrations of volatile organic compounds (VOCs), primarily TCE, were found in the aquifer. In 1995, TCE was found in a private water supply well located immediately downgradient of the former solvent recycling facility at levels 200 times greater than the Maximum Contaminant Level (MCL) allowable for public drinking water supplies. In 1997, TCE was found in a downgradient domestic well at a level slightly above the MCL. The total population of Cheswold is approximately 300 people.

Site Responsibility

Cleanup of this site is the responsibility of federal and state governments and parties potentially responsible for site contamination.

NPL Listing History

This site was proposed to the National Priorities List of the most serious uncontrolled or abandoned hazardous waste sites requiring long term remedial action on January 22, 1987. The site was formally added to the list August 30, 1990, making it eligible for federal cleanup funds.

Threats and Contaminants

The groundwater and soil are contaminated with VOCs as a result of past waste handling practices. Site investigations have shown that the concentrations of contaminants in the soils do not pose an unacceptable risk to human health or the environment. Groundwater in the Columbia aquifer remains contaminated with VOCs, primarily TCE, and the inorganic contaminant manganese at levels which pose an unacceptable risk to human health.

Contaminant descriptions and risk factors are available from the Agency for Toxic Substances and Disease Registry, an arm of the CDC.

Cleanup Progress

In 1985, the state excavated and treated 1,300 cubic yards of contaminated soil using a process that passes air through the soil to remove VOCs. This process reduced the contaminant concentrations to levels that permitted the soil to be returned to the excavated area. The state also installed a groundwater recovery system which it operated from 1985 to 1988. The extraction of contaminated groundwater reduced TCE concentrations in the Columbia aquifer beneath the site from the 200-300 parts per million (ppm) range to the 1 ppm range.

In March of 1992, EPA issued a Record of Decision (ROD) which requires: additional recovery of contaminated groundwater in order to reduce contaminant concentrations in the Columbia aquifer to MCLs; restriction of groundwater use in the contaminated aquifer until cleanup levels are achieved; and provision of an alternate water supply to area residents and businesses, if necessary. In December of 1992, EPA issued a Unilateral Administrative Order to 33 PRPs, including The BOC Group, Crown Cork & Seal Company, ILC Dover, and Texaco Refining and Marketing, requiring them to implement the ROD.

Groundwater recovery and treatment operations began in 1997. Following the treatment of 48 million gallons of contaminated ground water, pumping was conditionally terminated based on substantial improvement in groundwater quality and the improbability of exposure to site contaminants. EPA identified increasing levels of TCE in two site monitoring wells and notified the PRPs of the need to resume groundwater pumping and treatment. In addition to the pump and treat operations taking place, the PRPs will continue to perform the required ground water monitoring at domestic, recovery and monitoring wells until the cleanup levels are achieved. A ground water management zone has been established which restricts ground water use until cleanup levels are achieved.

As required by the ROD, the PRPs immediately provided bottled water to the owners of the contaminated private water supply wells. In October of 1996 and January of 1998, the PRPs replaced two contaminated private wells with wells that tap a deeper, uncontaminated aquifer. The PRPs also replaced six uncontaminated private wells located downgradient of the site with deeper wells in January of 1998.

Contacts

Site Contacts

Administrative Record Locations