Superfund Information Systems: Site Profile

Superfund Site:

ALCOA (POINT COMFORT)/LAVACA BAY
POINT COMFORT, TX

Cleanup Activities

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Background

Site Background

The Alcoa (Point Comfort)/Lavaca Bay site is located in Calhoun County, Texas, near the City of Point Comfort. The area includes the 3,500-acre Alcoa Point Comfort Operations (PCO) Plant, the 420-acre Dredge Island, portions of Lavaca Bay, Cox Bay, Cox Creek, Cox Cove, Cox Lake and western Matagorda Bay.

The PCO Plant was established as an aluminum smelter in 1948. Smelting operations were shut down in 1980. Bauxite refining, which utilizes bauxite ore to produce alumina, began in 1958. Past operations that have been dismantled and removed include the smelter, a cryolite plant, a chlor-alkali plant, and the Witco coal tar processing plant.

A chlor-alkali production plant operated on site from 1966 until 1979. Between 1966 and 1970, operations transported wastewater from the chlor-alkali production plant to an offshore lagoon on Dredge Island. After a settling period, the overflow from the gypsum lagoon was discharged to Lavaca Bay from two outfalls on Dredge Island.

The Texas Department of Health (TDH), now the Texas Department of State Health Services (TDSHS) has sampled fish, crabs, and oysters since the 1970s. On April 20, 1988, TDH issued an order closing an area of approximately 1 square mile of Lavaca Bay to the taking of finfish and crabs. On January 13, 2000, TDH reopened a portion of the closure area (Cox Bay). The closure for Cox Bay was removed because sampling showed that levels of mercury in finfish and crabs had decreased to a level acceptable for human consumption based on TDH’s risk characterization.

ADDITIONAL RESOURCES:

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What Has Been Done to Clean Up the Site?

 

EPA signed the Record of Decision (ROD) for the Site on December 20, 2001. The ROD set forth the selected remedy for the Site, which included actions to address mercury- and PAH- contaminated sediments in Lavaca Bay, ongoing unpermitted discharges of mercury and PAHs into Lavaca Bay, soil contamination at the former Chlor-alkali Process Area, and soil contamination at the former Witco area.

The remedy presented in the ROD included extraction and treatment of ground water at the CAPA, installation of a collection trench to stop dense non-aqueous phase liquid (DNAPL) from moving into Lavaca Bay from the CAPA, collection and off-site disposal of DNAPL, removal and on-site disposal of contaminated sediment, and placement of a cover over the disposal areas. Other components of the remedy included cleanup of Witco Marsh, natural recovery of sediment left in place, institutional controls to continue to control fish and shellfish consumption, and monitoring of sediment and fish tissue. The long-term remedy also included removal of an on-site building, capping of the area surrounding the on-site building, institutional controls to limit future uses, and soil capping. EPA updated the long-term remedy to remove enhanced natural recovery and cap construction requirements for the open water areas of Lavaca Bay.

Site cleanup also included removal actions, or short-term cleanups, to address immediate threats to human health and the environment. A non-time-critical removal action on Dredge Island disposed of 93,000 cubic yards of mercury-contaminated soil and 523,000 cubic yards of mercury-contaminated dredge spoils in an on-site disposal area.

The Preliminary Close Out Report (PCOR) for the Alcoa/Lavaca Bay site was signed on July 23, 2007. The PCOR documents that all construction activities required by the ROD were completed. Long term monitoring of red drum and blue crab is required to evaluate the recovery of mercury levels in fish and shellfish.

EPA signed the Record of Decision (ROD) for the Site on December 20, 2001. The ROD set forth the selected remedy for the Site, which included actions to address mercury- and PAH- contaminated sediments in Lavaca Bay, ongoing unpermitted discharges of mercury and PAHs into Lavaca Bay, soil contamination at the former Chlor-alkali Process Area, and soil contamination at the former Witco area.

The remedy presented in the ROD included extraction and treatment of ground water at the CAPA, installation of a collection trench to stop dense non-aqueous phase liquid (DNAPL) from moving into Lavaca Bay from the CAPA, collection and off-site disposal of DNAPL, removal and on-site disposal of contaminated sediment, and placement of a cover over the disposal areas. Other components of the remedy included cleanup of Witco Marsh, natural recovery of sediment left in place, institutional controls to continue to control fish and shellfish consumption, and monitoring of sediment and fish tissue. The long-term remedy also included removal of an on-site building, capping of the area surrounding the on-site building, institutional controls to limit future uses, and soil capping. EPA updated the long-term remedy to remove enhanced natural recovery and cap construction requirements for the open water areas of Lavaca Bay.

Site cleanup also included removal actions, or short-term cleanups, to address immediate threats to human health and the environment. A non-time-critical removal action on Dredge Island disposed of 93,000 cubic yards of mercury-contaminated soil and 523,000 cubic yards of mercury-contaminated dredge spoils in an on-site disposal area.

The Preliminary Close Out Report (PCOR) for the Alcoa/Lavaca Bay site was signed on July 23, 2007. The PCOR documents that all construction activities required by the ROD were completed. Long term monitoring of red drum and blue crab is required to evaluate the recovery of mercury levels in fish and shellfish.

The site is being addressed through federal, state and potentially responsible party (PRP) actions.

Cleanup measures should eventually result in TDSHS removing the Fish Closure Order. This would enable people to keep fish and shellfish from all areas of Lavaca Bay.

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What Is the Current Site Status?

Alcoa submitted the 2015 annual remedial action effectiveness report (RAAER) to EPA in March 2016. The 2015 RAERR evaluates the results from performance monitoirng conducted during 2015 and assesses the progress made towards meeting the remediation goals presented in the ROD.

EPA completed the second Five-Year Review (FYR) for the Site in July 2016. The purpose of the Five-Year Review is to determine if the remedial actions conducted at the Site are still protective of human health and the environment and functioning as built.

The results of the FYR concluded that the remedy for the Site is protective of human health and the environment in the short term. However, a determination of the long term protectiveness of the remedy for Site could not be made until further information is obtained. The remedial actions implemented to date have been effective in reducing the level of mercury in sediment for sensitive habitats and open water areas. Operation of the groundwater recovery system at CAPA is effective in reducing the migration of mercury-contaminated groundwater to Lavaca Bay. In addition, results from the annual juvenile blue crab sampling show that recovery is ongoing in the majority of the Closed Area as evidenced by downward trends in mercury levels. However, based on annual finfish sampling conducted, average mercury concentrations in red drum in the Closed Area do not show similar trends of recovery. The FYR identified a number of studies that need to be conducted to better understand the reasons for the continued elevated levels of mercury in red drum. The results of the studies will be incorporated into a remedial action plan that once implemented would reduce mercury levels in red drum. EPA will reassess the long term protectiveness of the remedy in a FYR Addendum which will be completed by September 30, 2019.

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Sampling and Monitoring

Under the terms of the Consent Decree, Alcoa prepares a Remedial Action Annual Effectiveness Report (RAAER). The RAAER evaluates the effectiveness of the remedial action including, but not limited to, an evaluation of the performance of the hydraulic control system at CAPA, natural recovery of sediments in Lavaca Bay, trends in fish/shellfish tissue values, and O&M activities. The RAAER is submitted to EPA and the Texas Commission on Environmental Quality (TCEQ) annually in March. The RAAERs have been submitted annually since March 2006.

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