422 research outputs found
The universe of fluorinated polymers and polymeric substances and potential environmental impacts and concerns
Per- and polyfluoroalkyl substances (PFAS) are a diverse group of surface treatment chemicals falling under non-polymeric and polymeric categories. Polymeric PFAS are comprised of fluoropolymers, perfluoropolyethers, and side-chain fluorinated polymers (SCFPs). Fluorinated polymers and polymeric substances have gained a significant market due to their chemical stability. To date, research and regulatory concern has primarily focused on the environmental occurrence and health effects of non-polymeric PFAS, particularly perfluoroalkyl acids and precursors. Industries consider most fluoropolymers as being “polymers of low concern”, although there is already a considerable environmental burden and widespread contamination resulting from their production, manufacturing, and use. For example, SCFPs are widely used, and known to release their perfluorinated side chains. Concerted action is needed to address the dearth of environment-associated information and understanding on polymeric PFAS
A reassessment of the nomenclature of polychlorinated biphenyl (PCB) metabolites.
Polychlorinated biphenyls (PCBs) are a widespread class of persistent organic chemicals that accumulate in the environment and humans and are associated with a broad spectrum of health effects. PCB biotransformation has been shown to lead to two classes of PCB metabolites that are present as contaminant residues in the tissues of selected biota: hydroxylated (HO) and methyl sulfone (MeSO2) PCBs. Although these two types of metabolites are related structures, different rules for abbreviation of both classes have emerged. It is important that a standardized nomenclature for the notation of PCB metabolites be universally agreed upon. We suggest that the full chemical name of the PCB metabolite and a shorthand notation should be adopted using the International Union of Pure and Applied Chemistry's chemical name/original Ballschmiter and Zell number of the parent congener, followed by the assignment of the phenyl ring position number of the MeSO2- or HO-substituent. This nomenclature provides a clear, unequivocal set of rules in naming and abbreviating the PCB metabolite structure. Furthermore, this unified PCB metabolite nomenclature approach can be extended to the naming and abbreviation of potential metabolites of structurally analogous contaminants such as HO-polybrominated biphenyls and HO-polybrominated diphenyl ethers
Contemporary 14C radiocarbon levels of oxygenated polybrominated diphenyl ethers (O-PBDEs) isolated in sponge–cyanobacteria associations
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Marine Pollution Bulletin 62 (2011): 631-636, doi:10.1016/j.marpolbul.2010.12.022.Considerable debate surrounds the sources of oxygenated polybrominated diphenyl
ethers (O-PBDEs) in wildlife as to whether they are naturally produced or result from
anthropogenic industrial activities. Natural radiocarbon (14C) abundance has proven to
be a powerful tool to address this problem as recently biosynthesized compounds contain contemporary (i.e. modern) amounts of atmospheric radiocarbon; whereas
industrial chemicals, mostly produced from fossil fuels, contain no detectable 14C.
However, few compounds isolated from organisms have been analyzed for their
radiocarbon content. To provide a baseline, we analyzed the 14C content of four OPBDEs.
These compounds, 6-OH-BDE47, 2’-OH-BDE68, 2’,6-diOH-BDE159, and a
recently identified compound, 2’-MeO-6-OH-BDE120, were isolated from the
tropical marine sponges Dysidea granulosa and Lendenfeldia dendyi. The modern
radiocarbon content of their chemical structures (i.e. diphenyl ethers, C12H22O)
indicates that they are naturally produced. This adds to a growing baseline on, at least,
the sources of these unusual compounds.The project described was supported in part by Grant Numbers NA16RU1496 and
NA06OAR4300227 from the National Oceanic and Atmospheric Administration, and
Grant Number 5P20RR021929 from the National Center for Research Resources
Organohalogen contaminants and metabolites in cerebrospinal fluid and cerebellum gray matter in short-beaked common dolphins and Atlantic white-sided dolphins from the western North Atlantic
Author Posting. © The Authors, 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Environmental Pollution 157 (2009):2345-2358, doi:10.1016/j.envpol.2009.03.024.Concentrations of several congeners and classes of organohalogen contaminants (OHCs) and/or their metabolites, namely organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), hydroxylated-PCBs (OH-PCBs), methylsulfonyl-PCBs (MeSO2-PCBs), polybrominated diphenyl ether (PBDE) flame retardants, and OH-PBDEs, were measured in cerebrospinal fluid (CSF) of short-beaked common dolphins (n = 2), Atlantic white-sided dolphins (n = 8), and gray seal (n = 1) from the western North Atlantic. In three Atlantic white-sided dolphins, cerebellum gray matter (GM) was also analyzed. The levels of OCs, PCBs, MeSO2-PCBs, PBDEs, and OH-PBDEs in cerebellum GM were higher than the concentrations in CSF. 4-OH-2,3,3’,4’,5-pentachlorobiphenyl (4-OH-CB107) was the only detectable OH-PCB congener present in CSF. The sum (Σ) OH-PCBs/ Σ PCB concentration ratio in CSF was approximately two to three orders of magnitude greater than the ratio in cerebellum GM for dolphins.This study was supported through an Environmental Protection Agency STAR fellowship (U-91616101-2) and a National Woman’s Farm and Garden Association Scholarship awarded to Dr. Eric Montie, and by the WHOI Ocean Life Institute, the Quebec Labrador Fund/Atlantic Center for the Environment, the WHOI Academic Programs Office, the Sawyer Endowment, Walter A. and Hope Noyes Smith, and Dr. David Mann at the University of South Florida
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