19E - WATER QUALITY REPORT - Laserfiche WebLink

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DRINKING WATER SAMPLE COLLECTION FOR PER AND POLYFLUORINATED ALKYL SUBSTANCES (PFAS) SAMPLING GUIDANCE I. INTRODUCTION Obtaining representative samples and maintaining their integrity are critical elements of any monitoring program. Analytical methods may be standardized but the results of analyses are only as good as the sampling and the sample preservation methods. Sampling is the first key element in a monitoring program that must be performed properly to assure valid data. The goal of this sampling guidance is to present the steps for drinking water sampling on per and poly - fluorinated alkyl substances. Per- and polyfluorinated alkyl substances (PFAS) are a large group of synthetic fluorinated chemicals widely used in industrial processes and consumer products. These synthetic compounds are very persistent in the environment. People are exposed to these compounds through food, food packaging, textiles, electronics, personal hygiene products, consumer products, air, soils, and drinking water. Studies indicate that continued exposure to low levels of PFAS may result in adverse health effects. California water utilities tested drinking water supplies for perfluorooctanic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) between 2013 and 2015, as required by United States Environmental Protection Agency (USEPA) under the third Unregulated Contaminant Monitoring Rule (UCMR3). In May 2016, the USEPA issued a lifetime health advisory for PFOS and PFOA in drinking water, advising municipalities that they should notify their customers of the presence of levels over 70 parts per trillion (ppt) of total combined PFOS and PFOA in community water supplies. USEPA recommended that the notification of customers include information on the increased risk to health, especially for susceptible populations. On July 13, 2018, the State Water Resources Control Board's Division of Drinking Water issued a drinking water notification level (NL) of 14 ppt for PFOA and a NL of 13 ppt for PFOS due to liver toxicity and cancer risks (for PFOA) and immunotoxicity risks (for PFOS). The collection of PFAS drinking water data can support future regulatory determinations and other actions to protect public health. The analytical methodologies used to assess the PFAS in drinking water are EPA Method 537.1 (released in November 2018), and EPA Method 537 Revision 1.1 (2009). These are the only methods validated by the USEPA and acceptable to the Division of Drinking Water for drinking water analyses. II. PURPOSE OF SAMPLING GUIDANCE Due to the prevalent nature of PFAS in commonly used sampling materials and personal protective equipment, as well as in clothing, food packaging and personal care products, careful procedures must be implemented to prevent contamination of a field sample. The detection of 19E-21