By: JIM STEINBERG | California Water News Daily
HINKLEY >> Some residential wells in the unincorporated community of Hinkley have levels of arsenic many times greater than the state safe drinking water standard, U.S Geological Survey study has found.
One residenital well was shown to have an arsenic reading of 510 parts per billion, more than 50 times the state drinking water limit of 10 parts per billion, said John Izbicki, a USGS scientist in charge of a comprehensive study of Hinkley’s groundwater.
The survey of wells for arsenic and uranium was incidential to the main focus of the $5.6 million, five-year study to determine how much of the world’s largest chromium-6 plume formed naturally and how much is how much is the result of Pacific Gas & Electric Co. operations in the area.
Hinkley’s plume of cancer-causing chromium-6 was made famous in the 2000 movie “Erin Brockovich”.
The arsenic and uranium research was tacked onto the study because Hinkley residents were concerned about these elements in their water, Izbicki said.
All residents whose wells showed contaminate levels exceeding the safe drinking water standard were notified, Izbicki said.
The findings were published late last month in a report describing progress of the study from January 2015 and May 2017.
Hinkley is located about 10 miles west of Barstow.
No conclusions about PG&E’s role in Hinkley’s groundwater were included in this interim report which primarily described what will be the methodology for the completed study.
The final report is expected to be ready for review, in March 2019, by scientists within the USGS, scientists outside the USGS, a working group of PG&E and its consultants, members of the Hinkley community and the community’ s scientific advisor, Project Navigator, Izbicki said.
I could be well over a year before that review is complete and the full report becomes public, Izbicki said, in a recent interview.
One sampling well showed the arsenic level to be 910 parts per billion. “That’s a personal best for me,” said Izbicki, who has studied groundwater in California’s Mojave desert for decades.
The sampling well was one drilled for the study, and has never been used to provide drinking water.
Several residential wells had levels of uranium exceeding the safe drinking water standard, but not to the magniturde of arsenic, Izbicki said.
In the 1950s, PG&E used chromium-6 to kill microbes and provide corrosion protection for its massive cooling towers at a natural gas pumping station in Hinkley. Those towers were drained into unlined ponds, allowing chromium-6 to percolate into the groundwater during a time when the cancer-causing properties of the chemical were not fully known.
Arsenic and uranium can be found in wells throughout the state. The presence of both aresenic and uranium in the groundwater of the Hinkley Valley is not related to PG&E’s operations, Izbicki said.