Occupational Exposure Assessment of Emerging Per- and Polyfluoroalkyl Substances (PFAS)

National Institute Of Environmental Health Sciences

Investigators

Abstract

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. In FY23 the study team published a literature review, actively worked to recruit companies to participate in the study and established three contracts necessary for analyses of exposure and indicators of health. Company recruitment began in Q1 of FY23 using multiple sources, to identify potential study sites including publicly available EPA Toxic Release Inventory data, union representatives, trade organizations, an industrial hygiene consultant, web searches, and other resources. NIOSH is contracting with external partners for analyses of biomarkers of health in blood and PFAS in urine. NIOSH is working to develop analytical capabilities for personal monitoring of PFAS in a variety of media, including urine and blood and for total fluorine and targeted panels of semi-volatile and volatile PFAS. NIOSH has developed methods for PFAS in personal and area workplace air samples, and these methods will be tested in the field. NIOSH chemists are currently working on developing an entry for the NIOSH Manual of Analytical Methods (NMAM) so the methodology will be available for use by other entities.