More than half the country’s vegetables, fruits, and nuts are grown in California’s Central Valley, often called “America’s salad bowl.” The valley is also oil country, a strange mix that has some worried.
Wastewater from oil production (called “produced water”) is used to irrigate crops across some 95,000 acres in the valley. That’s not a lot compared to the 9.6 million acres of farmland California irrigates every year, but the drought-stressed state is looking to expand the practice. Some hail it as an innovative way to recycle the massive amounts of oil industry wastewater, while others have decried the practice, saying the human health effects have not yet been studied enough in depth.
Out of the 173 chemicals used in oil and gas fields that provide water for agriculture, as many as 66 remain undisclosed by oil companies, which classify them as “trade secrets,” according to a report released in September by PSE Healthy Energy research institute.
That means dozens of chemicals with unknown health impacts have not been tested in the water itself or in the crops grown with it. Even some of the chemicals that have been disclosed have insufficient toxicology data to determine safe levels for human consumption, according to the report.
One of the report’s authors, Dr. William Stringfellow of the Lawrence Berkeley National Laboratory, is also part of an expert panel convened by the Central Valley Regional Water Quality Control Board to assess the safety of this practice.
At the most recent meeting of this panel in October, board members were mostly positive about the use of the water, noting that studies done by toxicology firm Enviro-Tox (including one released earlier this month) have shown only nine chemicals were absorbed by crops and only at low levels.
