California Water Board to Investigate Use of Oilfield Wastewater to Irrigate Crops
Expert panel will assess safety of eating food grown with treated wastewater
By Brett Walton
Circle of Blue
On January 12, in an office building east of Sacramento, an expert panel on food safety will gather for its first public meeting. The panel’s task: determine what safeguards are required for the reuse of oilfield wastewater for irrigation in California’s Central Valley so that the food that is grown does not cause illness and disease.
The panel is a project of the Central Valley Water Board, the state agency charged with preventing water pollution in the 720-kilometer (400-mile) long valley that is the heart of America’s fruit, vegetable, and nut industries.
Oilfield wastewater, produced water in technical terms, has been used for more than two decades to grow oranges, grapes, and other crops in Kern County, which accounts for more than 70 percent of California’s oil production. At the southern end of the Central Valley, Kern County is a desert, receiving less than 25 centimeters (10 inches) of rain per year.
Produced water flows out of a well along with the oil. California’s oilfield geology is particularly water-rich, with roughly 15 barrels of water for each barrel of oil. More than 3.3 billion barrels (140 billion gallons) of produced water came to the surface in 2014. Most of the salty, chemical-laden water is reinjected underground to increase oil production. But water districts, keen to secure additional supplies as water availability wanes, are eyeing it as a new source.
The convening of the food safety panel follows many months of serious questions about California’s handling of its oilfield waste. A U.S. Environmental Protection Agency investigation that concluded in 2014 determined that oil companies, with permits from state regulators, injected wastewater into aquifers that were meant to be protected. Fifty-six injection wells have since been shuttered in an attempt to regain compliance. The Central Valley Water Board is also reviewing the integrity of above-ground ponds, another disposal method, and will issue rulings by December on whether the 619 active ponds can continue operating.
Environmental groups, including Water Defense, founded by the actor Mark Ruffalo, also brought to the board’s attention potential problems with the treated produced water used for irrigation in Kern County.
For that reason, the Central Valley Water Board decided to enlist the expert panel.
“The effort is primarily to make sure that crops that are irrigated with produced water are OK for human consumption,” Clay Rodgers, manager of the Fresno office of the Central Valley Water Board and the organizer of the panel, told Circle of Blue. “There is no specific timeline. We would like the report as soon as possible, but this is a complex topic and there is not much research. We want to know: Where are the data gaps? What more information do we need?”
The food safety panel is a departure for the Central Valley Water Board, whose main purpose is to ensure the quality of rivers, streams, and aquifers.
Rodgers said that he wants to take a conservative approach and would consider amending water quality permits, if the panel found that crops grown with produced water were a disease risk.
“If it came to light that there is an issue with certain crops and compounds, we would place stricter standards on the water permit to protect human health,” Rodgers said.
Environmental health experts are urging greater caution when using produced water because districts do not know exactly what chemicals are in the product.
“What they are monitoring for are naturally occurring substances that come from these geologic formations — hydrocarbons, heavy metals,” said Seth B.C. Shonkoff, a member of the expert panel and the executive director of PSE Healthy Energy, a science policy institute in Oakland. They are not testing for any chemical additives that oil companies use to clean and operate their wells, he said. California has no state requirement to disclose all of the chemicals that go down a well.
Shonkoff added that, in general, reusing water is a smart idea, especially as California grapples with increasing water insecurity and the worst drought in state history. But the use of produced water, he argued, needs to be examined with more rigor. What are these chemicals? In what quantity are they used? How toxic are they? Are there spikes in concentrations that infrequent testing would miss?
“There are a number of data gaps,” Shonkoff said. “But the most flagrant is the lack of disclosure of chemical additives.” Senate Bill 248, introduced last year in the California Legislature, would require oil companies to disclose all chemicals injected into a well. It would also require monthly reports on the chemical composition of produced water.
Scientific reports also point out gaps in monitoring for chemicals used in hydraulic fracturing, or fracking. Though fracking is rare in California, a California Council of Science and Technology report published in July 2015 concluded that more research is needed on the use of produced water for irrigation. In only two oilfields that supply produced water for irrigation — Mount Poso and Kern River — has fracking taken place, and only three times since 2012, all in Kern River. However, water districts are not required to monitor produced water for the fluids used in fracking.
Water Districts Welcome the Panel
Those districts that already use produced water welcome the investigation.
“We have no problem with the panel,” said David Ansolabehere, general manager of the Cawelo Water District, which has used produced water for irrigation since 1995. “It will be good to prove that this is good quality water and that the program should be expanded.”
Ansolabehere, who will testify at the January 12 meeting, told Circle of Blue that the produced water it acquires from Chevron and Valley Water Management accounts for 30 percent of the district’s supply, roughly 30,000 acre-feet (9.7 billion gallons) per year. The produced water is treated and then blended with fresh water to dilute the salts, which can kill crops.
As canal deliveries from northern California to the Central Valley become less certain, more districts are looking to follow Cawelo’s lead. Last September, North Kern Water District, a nearby jurisdiction, began taking what could amount to 21,000 acre-feet (6.8 billion gallons) of produced water per year from California Resources Corporation.
There are several pathways that people could be exposed to chemicals in produced water used for irrigation: food consumption; sprinkler irrigation systems that could spray field workers; and groundwater that might have been contaminated by irrigation runoff. The expert panel, however, will look only at the first pathway, Rodgers said: the food.
The eight-person panel includes officials from the California Department of Food and Agriculture, California Department of Public Health, and California Department of Fish and Wildlife. It includes representatives of the Almond Board of California, and environmental health and food safety researchers from Lawrence Berkeley National Laboratory, Exponent, and Environmental Resources Management.
Brett writes about agriculture, energy, infrastructure, and the politics and economics of water in the United States. He also writes the Federal Water Tap, Circle of Blue’s weekly digest of U.S. government water news. He is the winner of two Society of Environmental Journalists reporting awards, one of the top honors in American environmental journalism: first place for explanatory reporting for a series on septic system pollution in the United States(2016) and third place for beat reporting in a small market (2014). He received the Sierra Club’s Distinguished Service Award in 2018. Brett lives in Seattle, where he hikes the mountains and bakes pies. Contact Brett Walton
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