Oil wastewater used to irrigate food crops in California’s Central Valley was found to contain carcinogens and other toxins in a preliminary report by scientists from the University of California, Berkeley, the Lawrence Berkeley National Laboratory, the University of the Pacific, and the nonprofit PSE Healthy Energy.
The Central Valley Regional Water Quality Control Board demanded that Chevron, Valley Water Management, and five other oil and gas companies release the data used in the report. “Out of 107 chemicals identified by the researchers from this information request, at least ten have been identified as carcinogens, eight are listed under California law as chemicals known to cause cancer or reproductive health problems, and eight are listed by the U.S. EPA’s National Primary Drinking Water Standards (NPDWS) and Advisory Chemicals list,” said the Center for Environmental Health in an email alert. CEH has called on Gov. Jerry Brown to halt the use of wastewater on state farms. “Thirty-nine of the chemicals are classified as substances that pose a significant hazard to aquatic environments. Fifteen chemicals were found to be resistant to biodegradation or not biodegradable.”
A second data set, based on a list of 72 chemicals permitted by Chevron and California Resources Corporation (CRC) for use in their oil-and-gas operations that provide irrigation water, included eight chemicals that are considered by California to cause cancer or major reproductive health issues. Eight more are “on the U.S. EPA’s National Primary Drinking Water Standards (NPDWS) and Advisory Chemicals list, and three are non-biodegradable,” said CEH.
According to the report, water from oil fields “has been used to irrigate food crops in the Cawelo Water District since the mid-1990s,” and is now starting to be used in North Kern Water Storage District. Other counties are considering it for agriculture and livestock watering, as well as drinking water and other uses.
While the report noted the potential toxicity of oil field wastewater, it added that the true threat to human and environmental health depends on the amount of chemicals used and the physical properties of those chemicals, among other factors. Researchers were reluctant to quantify the actual danger posed in this preliminary investigation.