Use of Oilfield Wastewater to Irrigate Crops.

California Water Board to investigate Use of Oilfield Wastewater to Irrigate Crops.

By Brett Walton, Circle of Blue, Monday, 11 January 2016

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 Expert panel will assess safety of eating food grown with treated wastewather.

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 centimetres (10 inches) of rain per year.


Dibujo 69 .Industria Petrolera CaliforniaPhoto © J. Carl Ganter / Circle of Blue. Kern County is the center of California’s oil industry. The practice of treating and reusing oilfield wastewater for irrigation is coming under greater scrutiny.

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 Defence, 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.

0 0 votes
Article Rating
Notify of

Inline Feedbacks
View all comments