Perfluorooctane sulfonate (PFOS)
Seattle Public Utilities
Perfluorooctane sulfonate (PFOS) is a member of a group of perfluorinated chemicals used in many consumer products. PFOS and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | N/A | 0 | 0 | N/A |
| 2015 | ND | 8 | 0 | ND |
| 2016 | N/A | 0 | 0 | N/A |
| 2017 | N/A | 0 | 0 | N/A |
| 2018 | N/A | 0 | 0 | N/A |
| 2019 | N/A | 0 | 0 | N/A |
ppt = parts per trillion
State and national drinking water standards and health guidelines
EWG Health Guideline 1 ppt
The EWG Health Guideline of 1 ppt for PFOS was defined by EWG based on studies by Phillipe Grandjean of Harvard University and many other independent researchers who found reduced effectiveness of vaccines and adverse impacts on mammary gland development from exposure to PFOA and PFOS, the two PFAS most widely detected in drinking water. This health guideline applies to the entire class of PFAS detected in water.
EPA Maximum Contaminant
Level (MCL) 4 ppt
ppt = parts per trillion
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2015-01-13 | 201501140525AM | ND |
| 2015-01-13 | 201501140778AM | ND |
| 2015-04-06 | 201504070229AM | ND |
| 2015-04-06 | 201504070359AM | ND |
| 2015-07-22 | 201507230482AM | ND |
| 2015-07-22 | 201507230496AM | ND |
| 2015-10-13 | 201509280091AM | ND |
| 2015-10-13 | 201509280090AM | ND |