From the movie Erin Brockovich to the hexavalent chromium pollution in groundwater and clean-up at

Speaker:
Kai Dunn, Ph.D., P.E.
Water Resource Control Engineer
California Regional Water Quality Control Board
Lahontan Region – Victorville OfficeAbstract
The Pacific Gas and Electric Company (PG&E) Hinkley Compressor Station (near Barstow) compresses natural gas before transporting it through. Between 1952 and 1966, PG&E used hexavalent chromium Cr(VI) as an anti-corrosion agent in the cooling tower water. Since 1952 wastewater containing Cr(VI) discharged to unlined evaporation ponds and percolated to the groundwater aquifer resulted in pollution. Hinkley Cr(VI) pollution came to light in a 1987 water quality survey. Beginning in 1992, PG&E installed a groundwater remediation system which extracted groundwater containing Cr(VI) and used it to irrigate alfalfa fields on land. In 2001, the California Regional Water Quality Control Board Lahontan Region issued a Cleanup and Abatement Order to shut down the remediation system to eliminate the threatening nuisance condition due to the spray irrigation which could be releasing Cr(VI) into the air. The most current project approved by the Lahontan Board to clean Cr(VI) from polluted groundwater includes stopping further migration of the Cr(VI) plume and reducing Cr(VI) to non-toxic trivalent chromium Cr(III) using natural process in the soil through subsurface irrigation. The other project, in-situ remediation, aims to clean the plume's most contaminated part using injection of biological reagents such as emulsified vegetable oil (EVO) and food-grade lactate into groundwater to enhance reduction of Cr(VI) to Cr(III).

Location: Seeley G. Mudd Bldg., Room 101

Audiences: Everyone Is Invited

Contact: Evangeline Reyes