VENTURA, Calif. – A management review has found no evidence showing that the carcinogen benzene is present in county drinking water at levels exceeding federal standards.
The report comes five months after the Ventura County Board of Supervisors ordered a study of benzene in wastewater generated by oil drilling. The board’s directive was spurred by a story in the Los Angeles Times that found benzene in waste liquid generated by hydraulic fracturing in the state at an average of 700 times the federal standard.
County officials said in their report that they could find no local cases in which benzene levels in drinking water exceeded the federal standard believed to be protective of human health. The U.S. Environmental Protection Agency has a goal of zero based on exposure over a lifetime but allows up to 5 parts per billion.
Those findings suggest that state construction standards for oil wells have proved effective in keeping wastewater from moving into aquifers where drinking water is stored, the report said.
Benzene is a naturally occurring element of crude oil and always has been present in the wastewater produced from oil drilling, the report said. The wastewater is deposited back into the ground through hundreds of injection wells in the county, almost all of them at the drilling sites.
Officials also examined the disposal of wastewater into the ocean from oil platforms off the Ventura County coast, based on records from federal agencies. More than 171,000 barrels per day were discharged overboard last year, a permitted practice as long as the wastewater meets environmental standards. County officials did not report on the impact but said the EPA is monitoring the discharges more often and wants to upgrade its testing protocol.
Officials also looked into whether high concentrations of methylene chloride and acetone had been found in oil field wastewater. The report was mixed. An independent laboratory found acetone in samples of wastewater recently but no methylene chloride. County staff found neither chemical in hydraulic fracturing operations completed last year.
Acetone occurs naturally in the body and the environment but high levels may affect health, according to the U.S. Centers for Disease Control and Prevention. High levels of methylene chloride may be hazardous as well.
The board is scheduled to discuss the report at 1:30 p.m. Tuesday in the board hearing room at the Hall of Administration at the County Government Center, 800 S. Victoria Ave., Ventura.
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This article was written by Kathleen Wilson from Ventura County Star and was legally licensed through the NewsCred publisher network.