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

全氟和多氟烷基物质（PFAS）是一组自1950年代初以来在世界范围内用于工业和消费品的合成化学品。PFAS因其物理和化学特性而广受欢迎，已广泛集成到消费品和工业应用中，如耐污纺织品和地毯、食品处理材料、医疗设备、消防泡沫和建筑材料。在过去几十年里，人们对与全氟辛烷磺酸相关的健康影响的日益关注，促使工业界和政府采取行动，旨在停止生产长链全氟辛烷磺酸，尤其是全氟辛酸（PFOA）和全氟辛烷硫酸盐（PFOS），以及已知可转化为长链全氟辛烷磺酸的前体。由短链配方组成的这些遗留化合物的氟化替代品迅速出现，并作为更安全的替代品得到推广，这在很大程度上是因为在动物模型中观察到的消除半衰期（T1/2）更短。然而，体内证据和药代动力学模型表明，暴露于这些新出现的化合物可能导致类似的不良健康结果。随着全球范围内从长链化合物向短链化合物的快速过渡以及众多选择进入市场，生产中的具体PFAS和潜在的人类暴露程度在很大程度上是未知的。需要进行研究以查明目前正在使用的化学品，特别是在重复接触浓缩化学品的可能性很大的职业环境中；描述人类接触的范围；并评估短链化合物对人类健康影响的指标。预计对职业接触人群的研究将提供关键的人类接触信息和关于人类接触可能上限的信息，并深入了解目前正在生产的化学品。然后，这些信息可用于对PFAS对人类健康影响的毒理学评估和进一步研究。在该项目的第一年，即2020财年，NIOSH完成了一项关于职业暴露、职业和相关社区人群健康影响（包括流行病学和毒理学研究）以及方法的文献审查。文献综述包括1384份文献，主要来自同行评审文献和政府来源。一份总结职业暴露文献的手稿正在撰写中。NIOSH已经选择了收集和分析空气样本的方法，方法的开发正在进行中。NIOSH正在探索其他方法，包括半目标分析和非目标分析以及擦拭样本收集。NIOSH获得了3个水成膜泡沫（AFFF）样品，以协助方法开发。这些产品已知含有PFAS，并已由其他实验室进行了分析。由于有许多正在进行的PFAS项目，NIOSH已经发起了NIOSH内部以及其他政府和学术研究人员对PFAS暴露的协调讨论。正在与这些组织中的许多组织进行沟通，其中最值得注意的是ATSDR。研究方案草案将提交内部审查，并将在21财年第一季度进行同行和三方审查。

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.