Issaquah

Perfluorooctanesulfonic acid (PFOS) was detected in a water supply production well owned by the City of Issaquah as part of sampling required under the federal Unregulated Contaminant Monitoring Rule (UCMR). PFOS is one of a group of thousands of similar man-made polyfluorinated compounds that are rapidly emerging as potential hazards to human health and the environment. PFOS was found at levels in excess of the US EPA advisory level of 0.07 parts per billion (ppb), the source of which was not known among multiple possibilities. Geosyntec was retained to help the impacted city respond to the detection of PFOS in their system, identify and characterize the extent of PFOS contamination in their shallow and deep aquifers, help them evaluate long-term water supply and treatment options, and present technical information and respond to the City Council and the general public.