May 16, 2006 CCP - Laserfiche WebLink

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Update: Perfluorochemicals and Private Drinking Water Wells in Lake Elmo May 2006 As you are aware, local and state agencies are continuing to investigate the extent and levels of chemicals in the perfluorochemicals (PFCs) group in the groundwater under western Lake Elmo. The purpose of this update is to let you know about several recent developments. Background Beginning in 2004, the Minnesota Department of Health (MDH) and the Minnesota Pollution Control Agency (MPCA) tested drinking water from private wells for two members of the perfluorochemical group: PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate). Because PFCs were used and disposed in Minnesota, the MDH developed Health Based Values for PFOA and PFOS in 2002. A Health Based Value (HBV) is the amount of a chemical in drinking water that we consider to be safe for people to drink daily for up to a lifetime. The HBV for PFOA is currently 7 parts per billion and the HBV for PFOS is 1 part per billion. Initially, the MDH laboratory did not have a laboratory test for detecting PFCs in groundwater. In 2004, the MDH laboratory developed a method for detecting PFOA and PFOS. Since that time, we have tested and reported results for those two chemicals to well owners. Decisions about which wells require water treatment were based on test results for PFOA and PFOS and the HBVs of 7 micrograms per liter (ug/L) and 1 ug/L, respectively. If more than one chemical is detected in the same well, MDH evaluates the toxicity of all the chemicals together. Modifying the HBVs for PFOA and PFOS Around the world, scientists are studying PFCs and the way they act in the environment, and effects on laboratory animals and on workers who were exposed through manufacturing processes. Scientists at MDH are constantly reviewing these studies and evaluating the implications to ensure that the actions we take are protective of people's health. Since 2002, when the original HBVs were developed, MDH scientists have been reviewing toxicological studies as they become available. Preliminary review of new information indicates that the current HBVs for PFOA and PFOS need to be revised to lower values. It will take some time for MDH to evaluate the studies and calculate the specific number. Until that process can be completed, we are using the most protective value that would likely result from the reevaluation to determine which homes should be provided with an alternate water supply. Minnesota Department of Health+Division of Environmental Health+Site Assessment and Consultation Unit 651.201.4897, or 1.800.657.3908, press O+www.health.state.mn.us