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State of the Science for Risk Assessment of PFAS at Contaminated Sites
Published in David M. Kempisty, LeeAnn Racz, Forever Chemicals, 2021
Jeanmarie Zodrow, Jennifer Arblaster, Jason Conder
Environmentally relevant PFAS exhibit a wide range of physical and chemical properties that greatly influence their human health and ecological hazard profiles (Hekster et al. 2003; Conder et al. 2008; Ahrens 2011; Buck et al. 2011; Guelfo and Higgins 2013; ITRC 2020). The fate of the perfluoroalkyl acids (PFAAs), particularly the perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) like perfluorooctanoate (PFOA) and perfluorooctane sulfonic acid (PFOS), have received the most study, as PFCAs and PFSAs are often the most prevalent transformation products for many PFAS precursors in the environment (Houtz et al. 2013). Under normal environmental conditions, PFCAs and PFSAs cannot transform any further and thus are persistent in the environment (Buck et al. 2011; ITRC 2020). PFCAs and PFSAs are organic anions at common environmental pH values (Buck et al. 2011) and are relatively water-soluble and mobile in the environment compared to other persistent organic chemicals of concern at contaminated sites. PFCAs and PFSAs are not volatile (i.e., they do not evaporate to the atmosphere readily [Field et al. 2017]). PFCAs and PFSAs can sorb to the organic carbon present in soil or sediment such that organic carbon-normalized distribution coefficients (i.e., KOC values) can be useful parameters for evaluating transport potential in soil, sediment, and water (Higgins and Luthy 2006; Guelfo and Higgins, 2013). Given their sorptive properties, PFCAs and PFSAs, in addition to other neutral, cationic, and zwitterionic PFAS (ITRC 2020), can accumulate in soils and sediments. Some PFAS have a proclivity to bioaccumulate in animals and plants, and persistent PFAS such as PFCAs and PFSAs do not undergo significant biodegradation or biotransformation once present in a biological system (Conder et al. 2008). Given the wide range of solubility, sorption, and bioaccumulation properties, PFCAs and PFSAs (and other PFAS) can be prevalent in a wide variety of environmental media, including groundwater, surface water, soil, sediment, biosolids, landfill leachate, plants, fish, invertebrates, and wildlife, both at contaminated sites where PFAS are initial released to the environment, and in off-site areas to which PFAS has been transported by natural physical processes (Lau 2012).
Uptake, accumulation and metabolism of PFASs in plants and health perspectives: A critical review
Published in Critical Reviews in Environmental Science and Technology, 2021
Xingchun Jiao, Qingyang Shi, Jay Gan
The objective of this review is to summarize recent findings on the uptake, accumulation, distribution and metabolism of PFASs in plants, with a specific focus on plant metabolism of some representative polyfluoroalkyl chemicals. The potential risk of PFASs in plant-origin food for human exposure is also discussed. The perfluoroalkyl compounds considered in the current review consist mainly of perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonic acids (PFSAs), and polyfluoroalkyl substances that may be transformed to environmentally significant perfluorinated substances such as PFOA or PFOS.
Prenatal and postnatal transfer of perfluoroalkyl substances from mothers to their offspring
Published in Critical Reviews in Environmental Science and Technology, 2022
Yingxue Liu, An Li, Qi An, Kai Liu, Ping Zheng, Shanshan Yin, Weiping Liu
Since the first production of polyfluoroalkyl and perfluoroalkyl substances (PFASs) by Minnesota Mining and Manufacturing Corporation (3 M Corporation) in the United States in 1947, the number of PFASs with defined chemical structures have exceeded 5000 (USEPA, 2020). They are widely used in various industrial and civilian fields and universally detected in biological tissues and human bodies (Giesy & Kannan, 2002). Growing evidence proved that PFASs could have toxic effects on animals (UNEP, 2006) and adversely affected human health (USDHHS, 2018). Among these pollutants, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and their related compounds have been included in the list of Persistent Organic Pollutants (POPs) in Stockholm Convention to restrict their production and use because of their environmental persistence, long-distance migration ability, bioaccumulation potential, and biological toxicity (UNEP, 2009, 2020). Although less-investigated than PFOS and PFOA, some other perfluoroalkanesulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) have also been found to have increasing environmental levels with time (Bjerregaard-Olesen et al., 2016; Nyberg et al., 2018), potential toxic effects (Chen et al., 2019), and health risks (Workman et al., 2019). Additionally, both PFOA and PFOS have isomers with the same molecular formula but different structures. Some of these isomers, such as 1 m-, 2 m-, 3 m-, 4 m-, 5 m-, and 4,5 m2-PFOS where “m-” is the carbon position of the branched -CF3 group, are chiral with enantiomers. Isomers and enantiomers of PFASs may elicit diverse biological behaviors and toxicological effects (Fang et al., 2014; Liu et al., 2015; O'Brien et al., 2011). The chemical properties and structural diversity make the impact and threat of PFASs on human health complicated and severe.
Sub-ppm determination of perfluorinated carboxylic acids in solution by UV–vis high-performance liquid chromatography through solid phase extraction
Published in Journal of Environmental Science and Health, Part A, 2023
Hongjiao Pang, Mayumi Allinson, Peter J. Scales
Perfluoroalkyl carboxylic acids (PFCAs) are a class of man-made fluorinated organic chemicals with all the hydrogen atoms on the carbon backbone replaced by fluorine atoms. PFCAs are compounds with -COOH structure as the head group moieties to provide a hydrophilic function and short to long carbon chains with fluorine atoms to provide a hydrophobic function.[1,2] The short carbon chain PFCA compounds include Perfluorobutanoic acid (PFBA, C4), Perfluoropentanoic acid (PFPeA, C5), Perfluorohexanoic acid (PFHxA, C6) and Perfluoroheptanoic acid (PFHpA, C7), and long carbon chain PFCA compounds consist of perfluorooctanoate (PFOA, C8) and Perfluorononanoic acid (PFNA, C9), among which PFOA is the most common. PFCA compounds have extreme chemical and thermal stability under environmental conditions due to the presence of very strong C–F covalent bonds and the hydrophobic carbon chain and hydrophilic functional groups provide water and oil repellency and surfactancy.[3,4] Hence, since the 1950s, PFCA chemicals have been widely used in industrial and commercial applications, including firefighting foams, water repellency, food packing, the manufacture of nonstick cookware and stain resistant products. The result is that they are now detected globally in different environmental matrices, including surface water,[5–7] soil,[6,8,9] ground water,[9–11] and even wildlife and humans.[12,13] Literature indicates that PFCA compounds, associated with a high bioaccumulation potential, have acute and chronic toxicity on plants, bacteria, animals and even humans with damage to the liver, kidney and lungs.[14–16] Therefore, more and more countries report PFCAs as a series of emerging contaminants for the environment.[17–21]