A recent report published in the San Francisco Chronicle, has found that for the past 30 years California state regulators have allowed oil companies to dispose of billions of gallons wastewater into clean groundwater resources. While early tests of drinking wells don’t show any contamination, the Environmental Protection Agency is “threatening to seize control of regulating the waste-injection wells”[i] that the oil companies use to dispose of “produced water” into the aquifers.
California oil producers use and capture a lot water to collect oil. Other than Texas and North Dakota, California produces more oil than any other state. The oil fields are saturated with salty water, and for every barrel of oil that is extracted from oil wells, nine to 10 barrels of water are brought to the surface. California companies are also actively using the process of hydraulic fracturing, which involves pumping water and chemicals into crack rocks. Additional acid and water is used to clear away debris that would clog the wells.
According to the Center for Biological Diversity, “Wastewater from oil and gas drilling can contain chemicals like arsenic and benzene, heavy metals, and radioactive material. The average presence of benzene, a human carcinogen, in drilling wastewater is at levels 700 times higher than federal standards allow.”[ii]
The water pumped to the surface and captured from the fracking and cleaning processes needs to be disposed of, and beginning in 1983, the companies started to inject them back underground. In the 80s, a bureaucratic error that resulted in two different copies of a signed agreement between the EPA and oil field regulators followed by poor record keeping, found that the state’s Division of Oil, Gas and Geothermal Resources had “authorized oil companies to pump wastewater into some high-quality aquifers that were supposed to be off-limits.”
The EPA found that 464 wells were responsible for injecting wastewater into the aquifers that should have been protected. Among the aquifers, 181 of them were clean aquifers, and 253 were salty but usable with treatment. While it is unknown how much water is in the aquifers that were used for wastewater injection, some of the aquifers are already being used for drinking water and irrigation, which led to the closure of 11 of the injection wells in July 2014.
Samples tested at nine drinking wells in the Central Valley have found high levels of arsenic and nitrates, which isn’t unusual for the area where arsenic from the native rocks leaches into the water. Experts, however, are still concerned about the potential that pollutants from the injection wells could migrate closer to drinking wells.
One of the biggest concerns about the injection wells and the threat to groundwater is the fact that California is in a drought. In these dry times, farmers are relying more on the aquifers, and there are already stories about water from the tainted aquifers destroying crops.
California has promised to stop the wastewater injection process by October 15, 2015.
Read more about the story at SFGate.com.
Teledyne Tekmar has published several blogs relating to Hydraulic Fracturing. In those blogs we reference how Teledyne Tekmar has been at the forefront of analyzing drinking water samples for methane. There is a potential concern for methane migrating into driving water supplies from Hydraulic Fracturing. The most common method used for analyzing methane in drinking water is EPA SOP RSK175. Click to read our previous blog post on Hydraulic Fracking. Tekmar has also published a couple application notes on RSK175.