The Issaquah city council voted unanimously Monday night to spend $988,000 to study, fix and activate its contaminated No. 4 groundwater well. The well was found to have PFC chemical contamination at levels three times what the EPA advises is safe.
The water in Issaquah has consistently met all EPA standards, but the city took the well — and the deeper one right next to it — out of service last month while studying a way to fix the issue and find the source of the PFC contamination.
The council voted to fund a mechanical carbon filter process to remove the chemicals at the well and study the contamination’s origin. Engineers told the council the No. 4 and No. 5 wells are necessary to meet demand as the weather gets warmer.
“If we take four and five out of the mix now, we don’t have enough water to serve those areas in the summer that are traditionally served by groundwater,” said engineer Jeff Hanson.
The PFC chemical found in Issaquah water is Perfluorooctane Sulfonate (or PFOS). It was found at levels exceeding EPA guidelines, but the parts per million ratio was deemed to be safe when Issaquah blended the water with other wells. Animals tested with PFOS in studies suffered liver, thyroid, developmental and immune system damage.
Although the source of the chemical contamination is still unknown, some believe the contamination happened in 2002 when thousands of gallons of firefighting foam made with PFOS was used to douse a gasoline tanker fire on I-90 at State Route 900.