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Valley Water Monitors Wells for Carcinogenic Chemicals

Last month the non-profit organization, Environmental Working Group (EWG), released a report indicating that PFAS, a group of highly toxic fluorinated chemicals, were detected at varying levels in 74 community water systems throughout California, potentially affecting 7.5 million residents who rely on those systems. PFAS stands for per-and polyfluorinated substances and were previously referred to as perfluorochemicals (PFCs).

These chemicals, which are used in firefighting foams and also found in everyday consumer products, can cause cancer and a host of other health problems, even from very low dose exposure.

PFAS represents more than 4,500 chemicals including two common types, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). PFAS chemicals are found in products used to resist heat, oil, stains and water such as carpets, clothing, food packaging and cookware. The main sources of PFAS water contamination are from firefighting, industrial sites, landfills and wastewater treatment plants and biosolids.


“All of the detections in California water systems’ sources exceeded 1 part per trillion, or ppt, the safe level recommended by the best independent studies and endorsed by EWG,” the report stated.

The EWG report is based upon testing conducted by the state, which began in 2013, when the Environmental Protection Agency ordered nationwide sampling for PFAS, and 2019, as California’s State Water Board’s Division of Drinking Water has begun developing a protocol for dealing with the PFAS contamination.

The levels of PFAS chemicals documented in the report show the maximum extent of the contamination at each source since 2013, and so doesn’t reflect what’s currently in the water systems. However, what’s especially concerning about PFAS is that they’re “forever chemicals” that don’t break down naturally in the environment, and can accumulate inside people’s blood and organs.

The Centers for Disease Control has conducted tests of the U. S. population for the toxins and found that nearly all people tested had levels of PFAS in their bodies. Furthermore, EWG estimates based on unreleased EPA data that more than 100 million Americans may have PFAS chemicals in their drinking water.

The EWG report shows PFAS detections in widely varying concentrations in many water systems in both Northern and Southern California including the Santa Clara Valley Water District.

While more than 40 percent of the systems had at least one sample with over 70 parts per trillion total PFAS, the amount detected in the Valley Water sampling was 11.9 ppt, taken in 2018 at W. Campbell Avenue – Well B. The highest detection was at Camp Pendleton, a Marine Corps Base in San Diego where the total measurement was 820 ppt. Another high reading was at the California Water Service Company system in Oroville, with detections over 450 ppt.

According to Matt Keller, Public & Media Relations Supervisor for Valley Water, the agency has been testing for PFAS in shallow monitoring wells in a limited area for 10 years, and that during EPA-mandated testing between 2013 and 2015, there were no detections of PFAS in surface water, groundwater or retailer wells in Santa Clara County.

“No significant contamination sources of PFAS in Santa Clara County have been identified,” stated Keller. “Testing continues to improve and has given us the ability to detect these chemicals at even lower levels. Based on a sampling in August 2018, PFOA and PFOS were not detected in Valley Water’s imported or treated water supplies. Valley Water has detected PFOA and PFOS in two of three water supply wells that we have in place for emergency backup. No water from these wells has ever been delivered to water retailers or consumers. Also, the levels detected in these wells are below the notification levels set by the California State Water Resources Control Board.

“Although PFOA and PFOS have been detected in some groundwater monitoring wells in Santa Clara County, these shallow wells are not used for the drinking water supply. We continue to monitor these wells and are looking at the potential impacts PFAS could have on the groundwater basin,” Keller continued.

In terms of continued testing for PFAS, Valley Water follows the protocols and standards set by the State Water Board and EPA. “State and federal lawmakers and regulators are moving toward stricter standards and guidelines for the detection, public notification, and treatment of PFOA and PFOS in drinking water,” Keller offered.

The EPA has set a lifetime drinking water health advisory at 70 ppt for combined PFOA and PFOS exposure, a threshold that the EWG says is “inadequate.” The California State Water Resources Control Board has a drinking water notification level set at 5.1 ppt for PFOA and 6.5 ppt for PFOS, and if reached water providers must notify government authorities. If levels exceed 70 ppt combined PFOA and PFOS, the State Board recommends taking the drinking water source offline.

“If Valley Water received drinking water test results exceeding the drinking water notification level for PFOA and PFOS, we would follow state and federal recommendations and would notify impacted water retailers,” explained Keller. “If levels exceed 70 ppt for PFOA and PFOS combined, we would follow the State Board recommendation to remove the drinking water source from service.”

The EPA is currently seeking public comments on a draft set of recommendations for cleaning up groundwater with PFOA and PFOS. This is intended to provide guidance for federal cleanup programs. The State Water Board is collecting data on PFAS to determine the prevalence of PFAS and developing a web portal for the public to view sample location data. The EPA has also suggested treatment technologies for members of the public concerned about PFAS in drinking water.

Because of PG&E’s recent Public Safety Power Shutoff due to increased wildfire risk and aging infrastructure, there were several outages at Valley Water facilities. Power to those facilities was restored by Oct. 10 and no issues were reported.


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