Document Detail


Comparative assessment of the global fate and transport pathways of long-chain perfluorocarboxylic acids (PFCAs) and perfluorocarboxylates (PFCs) emitted from direct sources.
MedLine Citation:
PMID:  19731684     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A global-scale multispecies mass balance model was used to simulate the long-term fate and transport of perfluorocarboxylic acids (PFCAs) with eight to thirteen carbons (C8-C13) and their conjugate bases, the perfluorocarboxylates (PFCs). The main purpose of this study was to assess the relative long-range transport (LRT) potential of each conjugate pair, collectively termed PFC(A)s, considering emissions from direct sources (i.e., manufacturing and use) only. Overall LRT potential (atmospheric + oceanic) varied as a function of chain length and depended on assumptions regarding pKa and mode of entry. Atmospheric transport makes a relatively higher contribution to overall LRT potential for PFC(A)s with longer chain length, which reflects the increasing trend in the air-water partition coefficient (K(AW)) of the neutral PFCA species with chain length. Model scenarios using estimated direct emissions of the C8, C9, and C11 PFC(A)s indicate that the mass fluxes to the Arctic marine environment associated with oceanic transport are in excess of mass fluxes from indirect sources (i.e., atmospheric transport of precursor substances such as fluorotelomer alcohols and subsequent degradation to PFCAs). Modeled concentrations of C8 and C9 in the abiotic environment are broadly consistent with available monitoring data in surface ocean waters. Furthermore, the modeled concentration ratios of C8 to C9 are reconcilable with the homologue pattern frequently observed in biota, assuming a positive correlation between bioaccumulation potential and chain length. Modeled concentration ratios of C11 to C10 are more difficult to reconcile with monitoring data in both source and remote regions. Our model results for C11 and C10 therefore imply that either (i) indirect sources are dominant or (ii) estimates of direct emission are not accurate for these homologues.
Authors:
James M Armitage; Matthew Macleod; Ian T Cousins
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Environmental science & technology     Volume:  43     ISSN:  0013-936X     ISO Abbreviation:  Environ. Sci. Technol.     Publication Date:  2009 Aug 
Date Detail:
Created Date:  2009-09-07     Completed Date:  2009-10-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0213155     Medline TA:  Environ Sci Technol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  5830-6     Citation Subset:  IM    
Affiliation:
Department of Applied Environmental Science (ITM), Stockholm University, SE-10691 Stockholm, Sweden.
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MeSH Terms
Descriptor/Qualifier:
Air
Air Pollutants / analysis*
Biological Transport
Carbon / analysis,  pharmacokinetics*
Carboxylic Acids / analysis,  pharmacokinetics*
Computer Simulation
Environmental Monitoring / methods*
Environmental Pollutants / chemistry
Fluorocarbons / analysis,  pharmacokinetics*
Geography
Hydrogen-Ion Concentration
Seawater
Water / chemistry
Water Pollutants, Chemical / analysis
Chemical
Reg. No./Substance:
0/Air Pollutants; 0/Carboxylic Acids; 0/Environmental Pollutants; 0/Fluorocarbons; 0/Water Pollutants, Chemical; 7440-44-0/Carbon; 7732-18-5/Water
Comments/Corrections
Comment In:
Environ Sci Technol. 2009 Sep 15;43(18):7155-6; author reply 7153-4   [PMID:  19806757 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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