Background:Perfluoroalkyl phosphinic acids (PFPiAs) have been detected in humans, wildlife, and various environmental matrices. These compounds have been used with perfluoroalkyl phosphonic acids (PFPAs) as surfactants in consumer products and as nonfoaming additives in pesticide formulations. Unlike the structurally related perfluoroalkyl sulfonic and carboxylic acids, little is known about the biological fate of PFPiAs.Objectives:We determined the biotransformation products of PFPiAs and some pharmacokinetic parameters in a rat model.Methods:Male Sprague-Dawley rats received an oral gavage dose of either normalC6/C8PFPiA, normalC8/C8PFPiA, or normalC8PFPA. Blood was sampled over time, and livers were harvested upon sacrifice. Analytes were quantified using ultra-high-performance liquid chromatography–tandem mass spectrometry or gas chromatography–mass spectrometry.Results:PFPiAs were metabolized to the corresponding PFPAs and 1H-perfluoroalkanes (1H-PFAs), with 70% and 75% biotransformation 2 wk after a single bolus dose for normalC6/C8PFPiA and normalC8/C8PFPiA, respectively. This is the first reported cleavage of a C-P bond in mammals, and the first attempt, with a single-dose exposure, to characterize the degradation of any perfluoroalkyl acid. Elimination half-lives were 1.9±0.5 and 2.8±0.8 days for normalC6/C8PFPiA and normalC8/C8PFPiA, respectively, and 0.95±0.17 days for normalC8PFPA. Although elimination half-lives were not determined for 1H-PFAs, concentrations were higher than the corresponding PFPAs 48 h after rats were dosed with PFPiAs, suggestive of slower elimination.Conclusions:PFPiAs were metabolized in Sprague-Dawley rats to form persistent PFPAs as well as 1H-PFAs, which contain a labile hydrogen that may undergo further metabolism. These results in rats produced preliminary findings of the pharmacokinetics and metabolism of PFPiAs, which should be further investigated in humans. If there is a parallel between the disposition of these chemicals in humans and rats, then humans with detectable amounts of PFPiAs in their blood may be undergoing continuous exposure. https://doi.org/10.1289/EHP1841
Trifluoroacetic acid (TFA) is a persistent and mobile pollutant that is present ubiquitously in the environment. As a result of a few studies reporting its presence in pre-industrial samples and...
This work presents evidence for the formation of αacyloxyalkyl-1-hydroperoxides (AAHPs) from the reaction of carboxylic acids with Criegee intermediates formed by gas-phase ozone reacting heterogeneously with a condensed-phase alkene, squalene. With liquid chromatography-electrospray-tandem mass spectrometry, it is shown that a long-chain fatty acid, palmitic acid, is lost when squalene is exposed to ozone in the presence of palmitic acid. This is consistent with the formation of higher molecular weight products via Criegee intermediate reactions observed by direct analysis in real-time mass spectrometry. Confirmation of AAHP formation comes from application of a new atmospheric pressure chemical ionization-tandem mass spectrometry method that is specific to organic hydroperoxides. Experiments with perfluorotetradecanoic acid confirm that the perfluoroalkyl carboxylic acids, a class of compounds that was heretofore thought to be unreactive in the condensed phase, can also be lost via reactions with Criegee intermediates in this manner. Condensedphase water competes with this reaction, likely leading to α-hydroxyhydroperoxides via the direct reaction of water with the Criegee intermediates. The potential environmental importance of this chemistry is discussed in terms of the fate of perfluoroalkyl carboxylic acids, secondary organic aerosol formation, and oxidation of organic films in indoor settings.
The Red River originates in the U.S., drains into Lake Winnipeg, and is a significant pathway for nutrients. We investigate its role as a source for pesticides, pharmaceuticals, per- and polyfluoroalkyl substances (PFASs), and microbes bearing antibiotic resistance genes (ARGs). We delineate agricultural, urban, and rural land-use for organic contaminants to determine the extent of chemical transboundary riverine fluxes, and characterize levels and trends of organic contaminants and ARGs between spring and fall 2014 and 2015. The herbicide atrazine peaked at over 500 ng/L (14-day time-weighted average) near the border, indicating that the U.S. represents the major source into Canada from the Red River. Neonicotinoid insecticides had relatively constant concentrations, suggesting more widespread agricultural use in both countries. Pesticide concentrations were greatest post-application in June and July. Mass loadings of pesticides over the sampling periods, from the river to Lake Winnipeg, ranged from approximately 800 kg of atrazine, to 120 kg of thiamethoxam and clothianidin, to 40 kg of imidacloprid. Exposure distributions for atrazine exceeded benchmark water quality guidelines for protection of aquatic life (0.2% probability of exceeding chronic benchmark) with no exceedances for neonicotinoids. Seven pharmaceuticals were detected, mostly at low ng/L levels downstream of the City of Winnipeg wastewater treatment plant. Carbamazepine, the only pharmaceutical detected consistently at all sites, contributed on average 20 kg each year into Lake Winnipeg. While minor inputs were observed all along the river, city inputs represented the greatest source of pharmaceuticals to the river. Both PFASs and ARGs were observed consistently and ubiquitously, indicative of an anthropogenically-influenced system with no indications of any single point-source signature. While transboundary flux from the U.S. was an important source of pesticides to the Red River, especially for atrazine, observed concentrations of all measured contaminants suggest that known aquatic toxicological risk is minimal.
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