10 research outputs found
Source attribution of poly- and perfluoroalkyl substances (PFASs) in surface waters from Rhode Island and the New York Metropolitan Area
Exposure to poly- and perfluoroalkyl substances (PFASs) has been associated with adverse health effects in humans and wildlife. Understanding pollution sources is essential for environmental regulation, but source attribution for PFASs has been confounded by limited information about industrial releases and rapid changes in chemical production. Here we use principal component analysis (PCA), hierarchical clustering, and geospatial analysis to understand source contributions to 14 PFASs measured across 37 sites in the northeastern United States in 2014. PFASs are significantly elevated in urban areas compared to rural sites except for perfluorobutanesulfonate, N-methyl perfluorooctanesulfonamidoacetic acid, perfluoroundecanate, and perfluorododecanate. The highest PFAS concentrations across sites were those of perfluorooctanate (PFOA, 56 ng L−1) and perfluorohexanesulfonate (PFHxS, 43 ng L−1), and perfluorooctanesulfonate (PFOS) levels are lower than earlier measurements of U.S. surface waters. PCA and cluster analysis indicate three main statistical groupings of PFASs. Geospatial analysis of watersheds reveals the first component/cluster originates from a mixture of contemporary point sources such as airports and textile mills. Atmospheric sources from the waste sector are consistent with the second component, and the metal smelting industry plausibly explains the third component. We find this source-attribution technique is effective for better understanding PFAS sources in urban areas
Haynaldia villosa NAM-V1 is linked with the powdery mildew resistance gene Pm21 and contributes to increasing grain protein content in wheat
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Can profiles of poly- and Perfluoroalkyl substances (PFASs) in human serum provide information on major exposure sources?
Background: Humans are exposed to poly- and perfluoroalkyl substances (PFASs) from diverse sources and this has been associated with negative health impacts. Advances in analytical methods have enabled routine detection of more than 15 PFASs in human sera, allowing better profiling of PFAS exposures. The composition of PFASs in human sera reflects the complexity of exposure sources but source identification can be confounded by differences in toxicokinetics affecting uptake, distribution, and elimination. Common PFASs, such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS) and their precursors are ubiquitous in multiple exposure sources. However, their composition varies among sources, which may impact associated adverse health effects. Methods: We use available PFAS concentrations from several demographic groups in a North Atlantic seafood consuming population (Faroe Islands) to explore whether chemical fingerprints in human sera provide insights into predominant exposure sources. We compare serum PFAS profiles from Faroese individuals to other North American populations to investigate commonalities in potential exposure sources. We compare individuals with similar demographic and physiological characteristics and samples from the same years to reduce confounding by toxicokinetic differences and changing environmental releases. Results: Using principal components analysis (PCA) confirmed by hierarchical clustering, we assess variability in serum PFAS concentrations across three Faroese groups. The first principal component (PC)/cluster consists of C9-C12 perfluoroalkyl carboxylates (PFCAs) and is consistent with measured PFAS profiles in consumed seafood. The second PC/cluster includes perfluorohexanesulfonic acid (PFHxS) and the PFOS precursor N-ethyl perfluorooctane sulfonamidoacetate (N-EtFOSAA), which are directly used or metabolized from fluorochemicals in consumer products such as carpet and food packaging. We find that the same compounds are associated with the same exposure sources in two North American populations, suggesting generalizability of results from the Faroese population. Conclusions: We conclude that PFAS homologue profiles in serum provide valuable information on major exposure sources. It is essential to compare samples collected at similar time periods and to correct for demographic groups that are highly affected by differences in physiological processes (e.g., pregnancy). Information on PFAS homologue profiles is crucial for attributing adverse health effects to the proper mixtures or individual PFASs. Electronic supplementary material The online version of this article (10.1186/s12940-018-0355-4) contains supplementary material, which is available to authorized users
Shifting Global Exposures to Poly- and Perfluoroalkyl Substances (PFASs) Evident in Longitudinal Birth Cohorts from a Seafood-Consuming Population
Rapid
declines in legacy poly- and perfluoroalkyl substances (PFASs) have
been reported in human populations globally following changes in production
since 2000. However, changes in exposure sources are not well understood.
Here, we report serum concentrations of 19 PFASs (∑<sub>19</sub>PFAS) measured in children between 1993 and 2012 from a North Atlantic
fishing community (Faroe Islands). Median ∑<sub>19</sub>PFAS
concentrations in children (ages 5–13 years) peaked in 2000
(47.7 ng mL<sup>–1</sup>) and declined significantly by 14.4%
year<sup>–1</sup> until 2012. Principal component analysis
(PCA) identified two groups of PFASs that likely reflect exposures
from diverse consumer products and a third group that consisted of
perfluorocarboxylic acids (PFCAs) with nine or more carbons (C ≥
9). These C ≥ 9 PFASs are strongly associated with mercury
in children’s hair, a well-established proxy for seafood consumption,
especially perfluoroundecanoic acid (PFUnDA, <i>r</i> =
0.72). Toxicokinetic modeling shows PFAS exposures from seafood have
become increasingly important (53% of perfluorooctanesulfonate, PFOS,
in 2012), despite a decline in whale consumption in recent years.
We infer that even in a major seafood-consuming population, declines
in legacy PFAS exposure after 2000 were achieved by the rapid phase
out of PFOS and its precursors in consumer products. These results
emphasize the importance of better understanding exposures to replacement
PFASs in these sources
Temporal Shifts in Poly- and Perfluoroalkyl Substances (PFASs) in North Atlantic Pilot Whales Indicate Large Contribution of Atmospheric Precursors
Poly-
and perfluoroalkyl substances (PFASs) are persistent, bioaccumulative
anthropogenic compounds associated with adverse health impacts on
humans and wildlife. PFAS production changed in North America and
Europe around the year 2000, but impacts on wildlife appear to vary
across species and location. Unlike other mammal species, cetaceans
lack the enzyme for transforming an important intermediate precursor
(perfluorooctane sulfonamide: FOSA), into a prevalent compound in
most wildlife (perfluorooctanesulfonate: PFOS). Thus, their tissue
burden differentiates these two compounds while other mammals contain
PFOS from both direct exposure and precursor degradation. Here we
report temporal trends in 15 PFASs measured in muscle from juvenile
male North Atlantic pilot whales (<i>Globicephala melas</i>) harvested between 1986 and 2013. FOSA accounted for a peak of 84%
of the 15 PFASs around 2000 but declined to 34% in recent years. PFOS
and long-chained PFCAs (C9–C13) increased significantly over
the whole period (2.8% yr<sup>–1</sup> to 8.3% yr<sup>–1</sup>), but FOSA declined by 13% yr<sup>–1</sup> after 2006. Results
from FOSA partitioning and bioaccumulation modeling forced by changes
in atmospheric inputs reasonably capture magnitudes and temporal patterns
in FOSA concentrations measured in pilot whales. Rapid changes in
atmospheric FOSA in polar and subpolar regions around 2000 helps to
explain large declines in PFOS exposure for species that metabolize
FOSA, including seafood consuming human populations. This work reinforces
the importance of accounting for biological exposures to PFAS precursors
Detection of Poly- and Perfluoroalkyl Substances (PFASs) in U.S. Drinking Water Linked to Industrial Sites, Military Fire Training Areas, and Wastewater Treatment Plants
Drinking water contamination with poly- and perfluoroalkyl substances (PFASs) poses risks to the developmental, immune, metabolic, and endocrine health of consumers. We present a spatial analysis of 2013–2015 national drinking water PFAS concentrations from the U.S. Environmental Protection Agency’s (US EPA) third Unregulated Contaminant Monitoring Rule (UCMR3) program. The number of industrial sites that manufacture or use these compounds, the number of military fire training areas, and the number of wastewater treatment plants are all significant predictors of PFAS detection frequencies and concentrations in public water supplies. Among samples with detectable PFAS levels, each additional military site within a watershed’s eight-digit hydrologic unit is associated with a 20% increase in PFHxS, a 10% increase in both PFHpA and PFOA, and a 35% increase in PFOS. The number of civilian airports with personnel trained in the use of aqueous film-forming foams is significantly associated with the detection of PFASs above the minimal reporting level. We find drinking water supplies for 6 million U.S. residents exceed US EPA’s lifetime health advisory (70 ng/L) for PFOS and PFOA. Lower analytical reporting limits and additional sampling of smaller utilities serving <10000 individuals and private wells would greatly assist in further identifying PFAS contamination sources