by Christin Ayers and Abigail SterlingBy Christin Ayers

SAN FRANCISCO (KPIX 5) — Is it safe to use oilfield wastewater to irrigate crops? A consultant hired by the water district that’s selling the water to farmers has just finished a third round of tests on produce.

California’s Kern River oilfield is one of the biggest in the country, pumping up 70,000 barrels of oil a day.

Along with the oil, ten times as much water is also pumped, something increasingly valuable in drought-stricken California.

KPIX SPECIAL REPORT: Oilfield Wastewater Irrigation Series

Every day, much of it flows into a steaming reservoir, then down a canal and into neighboring orchards, irrigating well-known brands of fruits and nuts.

The discharge goes through various filters and booms to become what’s known as “produced” water, but it still smells like crude. No one questioned whether the practice is really safe until last year. Since then a new panel of experts appointed by the water board has made progress on safety related research.

Three rounds of tests have been completed this year, first on almonds, pistachios and grapes, then on a variety of citrus, and most recently on carrots and potatoes. “There is really no problem with any of the water usage at this point in time,” said David Ansolabehere, General Manager of the Cawelo water district, one of three districts currently using oilfield water.

In water tests for 70 petroleum related chemicals, only nine showed up, at or below drinking water standards. Food tests for those nine chemicals also came back clear. “Now the water is being tested for over 160 different chemicals,” said Ansolabehere. “[With] the next group of crop testing, anything that had been identified in the water from those 160 chemical tests, those will also be put in to test the fruit.”

It’s all music to the ears of growers in the area. “It doesn’t appear to be a food safety risk,” said Christopher Valadez with the California Fresh Fruit Association. “And so, for us and our growers, that is encouraging for them to continue to use this water.”

But environmental groups caution the work is far from over. “The tests that were conducted were very limited,” said Tasha Stoiber, a senior scientist with the research firm Environmental Working Group.

Stoiber has also been reviewing the new data. “The chemicals that were selected to be tested in the fruit were based on water tests that were collected in the spring of 2015, and they only collected five water samples over two days,” she said.

Stoiber maintains the crop samples, about two dozen in all, are too few. “We can’t make any conclusions about the long-term safety of this study based on such a small amount of samples that were collected,” she said. More research is needed, Stoiber said.

Ansolabehere agreed. “We need to continue testing, because we don’t know everything yet. And our goal is to ensure that this is a safe water source to use,” he said.

The two major oil companies selling produced water for irrigation are now required to test it more often .. and for a much greater number of chemicals.

Chevron, one of the biggest producers of oilfield wastewater sent us this statement:

Chevron has provided to the Water Board information on chemicals or additives used in the Kern River Field, including the volume used of these products. Chevron also provided to the Water Board the Material Safety Data Sheets (or Safety Data Sheets as applicable) for each of the products used. Information provided by Chevron is available on the Water Board’s website (part way down the page under “Available Data”).

Chevron provided updated information regarding chemical usage in its reporting program submittal for the second quarter 2016 and this information also is available through the Water Board’s website.

Chevron has tested for all chemicals and additives used in the Kern River Field for which an EPA-approved testing method exists. Chevron has provided all of these testing results to the Water Board. The results from this testing are included in Chevron’s submittal to the Water Board for the second and third quarter 2016 and are available through the Water Board’s website.

All test results from tests performed by Chevron and the Cawelo Water District have shown that water supplied by Chevron to the Cawelo Water District is in compliance with its existing permit issued by the Regional Water Quality Control Board (Water Board). In no instance was any regulatory requirement not met. Chevron’s provision of produced water to the Cawelo Water District for irrigation purposes has been run appropriately for the benefit of California agriculture and in accordance with all regulatory requirements.