The Pleasanton City Council is set Tuesday to discuss a report from city staff about the response plan to address levels of human-made chemicals in the so-called "per- and polyfluoroalkyl substances (PFAS) family" found in the local water supply.
Generally used for surface coating as an oil and water repellent as well as in firefighting foams, PFAS materials have been phased out by U.S. manufacturers to a major degree but concerns remain about the chemicals contaminating water sources, according to Kathleen Yurchak, director of operations and water utilities.
The State Water Resource Control Board's Division of Drinking Water issued orders this year for local water agencies to test their sources for PFAS contaminants, including perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), Yurchak said in her in staff report to the council.
"Exposure to unsafe levels of PFOA and PFOS over a period of time may result in adverse health effects including developmental effects to fetuses during pregnancy, cancer, liver effects, immune effects, thyroid effects and cholesterol changes," Yurchak stated.
The results of groundwater well testing for the city and the Zone 7 Water Agency raised some red flags.
Initial Zone 7 tests found some groundwater wells to be above the notification levels for PFOS or PFOA, with one well -- Mocho-1 -- testing above the response level for both, according to city officials.
For the city's three active groundwater wells, Well 5 and Well 6 tested above the notification level for PFOS only while Well 8 tested above the level for combined PFOS and PFOA, according to city officials.
As a result, Mocho-1 and Well 8 have been designated as last priority, for use only when absolutely needed for meeting the water demand. City officials noted that its Well 8 has not been in operation since the initial testing and would only be used "under abnormal conditions such as extreme peak demand periods or if there are failures of other supply facilities."
"The city will continue to monitor and test all the wells and collaborate with Zone 7 toward identifying the source of PFOA and PFOS, and has begun investigating infrastructure solutions such as treatment technologies at groundwater wells and the feasibility of increasing imported surface water supplies that meet recommended PFAS levels," officials wrote on the city's PFAS webpage.
PFAS have been extensively used commercially as protectant agents for items such as paper or cardboard packaging, carpets, leather products, textiles, nonstick coatings on cookware and firefighting foams, according to Yurchak.
While PFOA and PFOS have been phased out by American manufacturers, replacement substances in the PFAS family were developed and "appear to behave in a similar toxicological manner," she said.
The major sources of PFAS are fire training or fire response sites (such as airports), industrial sites, landfills and wastewater treatment plants, according to Yurchak.
"Groundwater contamination with PFAS has typically been associated with these sources. PFAS are very stable in the environment and are resistant to breaking down. Once in groundwater they can easily be transported large distances and can contaminate drinking water wells," she said.
City staff have created short- and long-term recommendations to address the contamination concerns based on the initial testing results for Pleasanton's water supply.
Near-term plans include "implementation of operational strategies and public notification" while long-term concepts include "treatment evaluations, alternative water supply evaluations, financial impact evaluations, increased legislative tracking, and regional planning," Yurchak said.
The council is set to talk about those recommendations after hearing a full report on the city's PFAS situation on Tuesday night.
The report is the council's main discussion item listed on the regular meeting agenda, scheduled to kick off at 7 p.m. inside the council chamber at the Pleasanton Civic Center, 200 Old Bernal Ave.
In other business, council members will discuss the final operating budget report -- reflecting the unaudited actual financial results -- for the 2018-19 fiscal year, including how to designate general fund reserves. They will also be presented with a 15-item consent calendar.