Published: August 01, 2008 10:19 am      

Remedy decision delayed at Chemplex Superfund site

CLINTON — The U.S. Environmental Protection Agency has delayed a decision on a new remedy for the ongoing remediation project at the seven-acre Chemplex Superfund site until performance testing of the recommended remedy has been completed.

The Chemplex facility was constructed in 1967 and is located five miles west of Clinton, south of U.S. 30 and west of U.S. 67. The facility currently is operated by Lyondell, formerly Equistar, and manufactures high- and low-density polyethylene plastics. According to EPA fact sheets, groundwater and soil at the site were contaminated due to past waste disposal practices. The site was identified as a potentially uncontrolled hazardous waste site and proposed for the National Priorities List in 1984. The site was removed from the list in 1991 under the Resource Conservation and Recovery Act.

The contaminants of concern at the site are volatile organic compounds and polynuclear aromatic hydrocarbons in the form of Perchloroethylene, Dichloroethylene and Trichloroethylene.

The EPA has been working with the Iowa Department of Natural Resources and Citigroup and ChevronTexaco, known as ACC/GCC or the American Chemical Company and Getty Chemical Co., to clean up the site.

The initial clean-up plan was approved in 1989. The site was managed in two units, one addressing groundwater contamination through an extraction and treatment remedy that has been in operation since May 1994. The second unit addressed contaminated soil and waste at the site by capping and soil vapor extraction. That remedy began in 1998 and ceased operation in 2003 because it met the shutoff criteria established. Through 2003, over 23,000 pounds of VOCs had been recovered from the site via groundwater extraction and treatment.

In the last two Five Year Review reports in 1999 and 2004, experts reported that the remedy at the site was protective of human health and the environment.

But in the 2004 report, the EPA concluded that a plan was needed to address the inability of the current pump and treat system to contain contaminated groundwater in the designated area. The EPA requested that ACC/GCC prepare a Focused Feasibility Study to evaluate potential alternatives to the existing extraction and treatment system.

ACC/GCC recommended replacing the pump and treat system with a combination of monitored natural attenuation and hot-spot treatment, as well as extending the Camanche municipal water system into the area down gradient of the contamination. The EPA has concluded that data showing the revised remedy can effectively control contaminant migration would be valuable in making a final decision to revise the remedy.

The EPA and ACC/GCC have agreed on plans to conduct a performance test. The test will include placing the pump and treat system in temporary standby condition to allow the ground water system to return to natural flow conditions. Shutdown of the system is anticipated this fall. Then, increased monitoring would be done to verify that contaminant reduction is occurring. A final monitoring plan is anticipated to be complete later this year. A plan to treat in place the areas with high contaminant concentrations is anticipated to developed by spring 2009.

Then the municipal water line would be extended westward to residents down gradient of the site. Currently, ACC/GCC and the city of Camanche are working on the necessary agreements to construct the water line. While the city of Camanche would be responsible for pipeline design, construction and operation, ACC/GCC would pay for the reasonable costs of water line hookups if they are completed during the construction of the pipeline. The company would not offer compensation for new residences built or to residents electing to connect to the pipeline after construction is complete. Any continued use and maintenance of existing wells following the availability of the extended water line would be the responsibility of the residents.

Once arrangements are in place for design and construction of the water pipeline, the existing pump and treat system would be shut down, but remain in a state of readiness for five years. After a “mothball” period, the system would be permanently shut down and demolished or abandoned.

Following the permanent shutdown, selected extraction wells would be converted to monitoring wells while others would be abandoned in accordance with state well abandonment procedures. Groundwater extraction and treatment equipment would be removed from service and buried piping and conduits would be abandoned in place.

The existing treatment building, blower building and lift stations would be demolished or left in place as storage buildings.

In addition to the exposure controls, institutional controls would be implemented including environmental covenants that would restrict the use of groundwater underlying the site and adjoining properties. Land use controls to prevent activities that might interfere with the actions are to be developed, with a Land Use Control Plan anticipated in spring 2009.

Upon approval of the plans, ACC/GCC will complete the performance test. According to a July 2008 Fact Sheet Update of New Response Action, the EPA anticipates using the information obtained during the performance test to decide whether the changes in the remedy are appropriate.

If the EPA believes a remedy change is called for, the EPA will publish a proposed plan with a public comment period, issue an amended record of decision and make changes as necessary in the Consent Decree.

Information relating to the performance test will be included in the Administrative Record as it becomes available. The Administrative Record File previously maintained at the Clinton Public Library will be closed, Making the Administrative Record File located at the Camanche Public Library, 102 12th Ave. in Camanche, the only file near the site.

For more information on the site or the proposed performance test, contact Beckie Himes, EPA Region 7 community involvement coordinator, at the Office of Public Affairs by calling 1-800-223-0425 or at himes.beckie@epa.gov.

The next five year review of the Chemplex Superfund site is slated to be completed in 2009.