California is suffering a record-setting drought. It is forcing the state to take drastic measures to ensure water is conserved for priority uses. To help deal with the shortage some farmers are using wastewater from oil production to water their crops.
The practice is seeing wider adoption now, facing the brunt of the drought, but it has been occurring in some capacity for over 20 years. Using the wastewater for crop irrigation allows both sides of the equation to benefit. Oil companies have an effective means of disposing of their wastewater and farmers have a new source of water.
Yet, it isn’t a perfect solution as their are major concerns regarding the effect the wastewater will have on the crops themselves. Concerns include increased levels of carcinogens occurring in the crops, something the crops currently aren’t checked for.
California doesn’t have statewide regulations for recycling wastewater for agriculture. Instead, nine regional water boards issue permits to local water districts. Once a year, the Cawelo Water District is required to send data about the salt and boron content to the Central Valley Water Board, according to Clay Rodgers, the board’s assistant executive officer. But the district isn’t obligated to test for other components, like heavy metals, arsenic, radioactive materials and chemicals that might be used in the drilling process. Ansolabehere says Cawelo has tested for radioactive elements “a couple of times” over the past 20 years, since “it’s very expensive” to test for, and isn’t required by the board. Those tests have not turned up any positive results.
Avner Vengosh, a Duke University geochemist, is serving on an expert panel for the U.S. Geological Survey while it begins to look into the quality of produced oil-field water from Kern County. His data are “only preliminary,” but he has found “high levels of vanadium, chromium, and selenium” in the samples of wastewater he has tested (although he was unable to say if the water was produced from Chevron’s operations or another of the many operators in the area). Those levels are consistent with data from oil-and-gas-produced water from other basins in the U.S., according to Vengosh.
People exposed to crops irrigated with this wastewater may have no way of knowing, as of yet, exactly what they are putting in their bodies.