CA Officials: 260 Oil Waste Wells Shallow/Close Enough To Contaminate Valley Aquifers
All of the wells inject water left over from oil field operations into aquifers that were supposed to be protected by law. While most of those aquifers contain salty water that would need treatment before use, state and federal officials want them preserved as a potential supply for cities and farms in the future.
So far, no wells used for drinking or irrigation have been found to be tainted by the injections. But in a letter to the U.S. Environmental Protection Agency on Friday, the California office that oversees oil drilling said it would seek water-sampling data from each of the wells. The office — the Division of Oil, Gas and Geothermal Resources — has ordered 23 wells shut down so far.
More than 200 of the injection wells are less than 1,500 feet deep. Residents of the state’s parched Central Valley have been sinking new drinking water wells that deep, or deeper, as the water depletes.
“Continued vigilance and testing will be needed, but so far we haven’t found a significant risk to water supplies,” said Steven Bohlen, the division’s supervisor. Oil company documents released by an environmental group Monday, however, showed that one Kern County well closed by the state last year was injecting water tainted with the carcinogen benzene, in levels thousands of times higher than federal standards for safe drinking water. The documents, obtained from the division through a public records request, included a water sample test from 2010 showing 13,000 parts per billion of benzene. The federal limit safety limit is 5 parts per billion. The test was commissioned by the well’s operator, Macpherson Oil Co.
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http://www.sfgate.com/business/article/Oil-wastewater-dumped-into-shallow-Central-Valley-6272051.php