Per and polyfluoroalkyl substances (PFAS)1 are a group of manmade fluorinated compounds which are used for a variety of applications by both industry and residential households. These chemicals are widely used because they are resistant to heat, water, and oil. PFAS are commonly found in every American household, and in products as diverse as non-stick cookware, furniture, clothing, cosmetics, lubricants, paint, carpets, pizza boxes, popcorn bags, and many others. Although there is some evidence that exposure to PFAS at certain levels can lead to adverse health outcomes in humans, health outcomes are still largely unknown. Several recent legislative and regulatory efforts across the US to address PFAS have focused on limiting levels in drinking water as policy makers act to minimize human interaction with these chemicals. Unfortunately, many of these actions have not followed the usual scientific and public review process for addressing chemicals of concern.
Please note that Pima County (Tucson) Arizona has lifted their moratorium on the land application of biosolids. The return to land application is because of the comprehensive study done by the University of Arizona, Jacobs Engineering, and the National Science Foundation, and which I previously shared with you and is at the link below. For context, Pima County had successfully land applied Class B biosolids since 1984 but a concern was brought to the Board of Supervisors in late 2019 for the potential contamination of groundwater with PFAS from the biosolids. Pima County began landfilling their biosolids on January 1, 2020 at at least twice the monetary expense and to the detriment of soil health. They commissioned the subject study which began in March 2020 on sites which had received the biosolids and concluded there is minimal transport through the topsoil and negligible concern for groundwater. Though Pima County is an arid climate and depth to groundwater is more than 150 feet, the sites received between 30 and 54 inches of irrigation water which equates to rainfall in heavy precipitation areas of the US and even if groundwater were shallower, minimal transport was found. Many thanks to all involved in this study and especially project lead, Dr. Ian Pepper (U of AZ), and to Houssam el Jerdi with the Pima County RWRD. – Greg
- bd-Per- and Polyfluoroalkyl Substances and Agricultural Land Application October 29 2020
- Fate of PFAS at Long Term Biosolids Application Sites, Pima County AZ
- CASA Summary of GSI Environmental Evaluation of OEHHA Recommendations
- GSI Environmental Evaluation of Science Used by OEHHA in setting Notification Levels for PFOA and PFOS
- California State Water Resources Control Board adopts new Notification Levels for PFOA and PFOS