Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have been used in industry and consumer products, worldwide, since the early 1950?s. Sought-after for their physical and chemical properties, PFAS have been integrated extensively into consumer products and industrial applications, such as stain resistant textiles and carpeting, food-handling materials, medical devices, fire-fighting foam, and construction materials. Over the past few decades, growing concern over health effects associated with PFAS has led to industry and government actions designed to halt production of long-chain PFAS, most notably perfluorooctanoic acid (PFOA) and perfluorooctane sulfate (PFOS), and precursors known to transform into long-chain PFAS. Fluorinated replacements for these legacy compounds, consisting of shorter-chain formulas, rapidly emerged and have been promoted as safer alternatives due in large part to shorter elimination half-lives (T1/2) observed in animal models. However, in vivo evidence and pharmacokinetic models suggest exposure to these emerging compounds may result in similar adverse health outcomes. With the rapid, ongoing global transition from long- to short- chain compounds and numerous options entering the market, the specific PFAS in production and the extent of potential human exposure are largely unknown. Research is needed to identify current chemicals in use, particularly in occupational settings where the potential for repeat exposure to concentrated chemicals is considerable; characterize the range of exposure in humans; and to evaluate indicators of health effects associated with short-chain compounds in human populations. Studies of occupationally exposed populations are anticipated to provide critical human exposure information and information on the potential upper range of human exposure as well as insight into chemicals currently in production. This information can then be used to inform toxicological assessments and further research into the human health effects of PFAS. In the first year of this project, FY20, NIOSH completed a review of literature pertaining to occupational exposure, health effects in occupational and relevant community populations (including epidemiologic and toxicologic studies), and methodology. The literature review included 1384 documents primarily pulled from peer reviewed literature and government sources. A manuscript summarizing the occupational exposure literature is in progress. NIOSH has selected their approach for the collection and analysis of air samples and methods development is ongoing. NIOSH is exploring additional methods, including semi- and non-targeted analyses and wipe sample collection. NIOSH has acquired 3 samples of aqueous film forming foam (AFFF) to assist with methods development. These products are known to contain PFAS and have been analyzed by other labs. As there are a number of ongoing PFAS projects, NIOSH has initiated coordinated discussions within NIOSH as well as other government and academic researchers investigating PFAS exposure. Communications are ongoing with many of these organizations, most notably ATSDR. A draft of the study protocol will be submitted for internal review and will undergo in peer and tripartite review in the first quarter of FY21.
