It seems that the California drought has spawned the use of untested, chemical-laden water to irrigate some crops in California. Here are a few of the many articles on this issue, here, and here, and here.
Water testing has been limited to naturally occurring toxins, like salt and arsenic, but no testing is done for the chemicals used in oil production. Farmers don’t test crops for chemicals that may have absorbed through the roots from water.
Samples were collected from the canals that provide water to the farms, and they contained acetone and methylene chloride (a potential carcinogen) solvents used to degrease equipment or soften thick crude oil. The water also contained C20 and C34, hydrocarbons found in oil, according to the lab that analyzed the samples.