August 29, 2018 - The Michigan Department of Environmental Quality (DEQ) has released data from its latest round of finished drinking water PFAS testing. Those results show that Ann Arbor drinking water remains significantly below the Health Advisory Level established by Environmental Protection Agency (EPA) and adopted by the State of Michigan. The city continues to monitor for PFAS compounds and remains committed to providing safe drinking water that complies or is better than all regulatory guidelines.
PFAS, or per- and polyfluoroalkyl substances, have been found in drinking water supplies around the country due to their ubiquitous use in everyday products and their long decay time. The EPA has established a health advisory level of 70 parts per trillion (ppt) for two specific PFAS, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).
Test results received from DEQ indicate that PFOS/PFOA levels in the city's drinking water are 4 ppt, well below the current health advisory level of 70 ppt. PFOS/PFOA represent the two PFAS with the most health data available. Because analytical techniques are now available to test other PFAS compounds, the State of Michigan also tested for an additional 22 PFAS chemicals. Researchers are studying potential health impacts of several PFAS, but limited health-impact data is available for these additional chemicals. However, the state is taking a conservative approach and totalizing the concentration for all 24 PFAS chemicals. The city's total concentration for all 24 chemicals reported by the state is 39 ppt. Since there is no health advisory for these additional PFAS chemicals, it is currently not possible to compare the total concentrations of the 24 chemicals measured to an acceptable health level.
Currently, granular activated carbon (GAC) filtration is the best available technology for removing PFAS in drinking water. The city has GAC filters, and has been proactive in piloting a new type of carbon in several of its filters since November 2017. This new carbon has demonstrated enhanced removal of PFAS. Due to this success, city staff will present a plan to City Council in September to propose replacing all of the older carbon in the city's filters with the new type of carbon. It is estimated that the additional cost to replace the GAC in the filters will be $850,000 in fiscal year 2019.
For more information on PFAS and Ann Arbor drinking water, residents are encouraged to visit a2gov.org/pfas.
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