title: Effects of salinity and organic matter on the partitioning of perfluoroalkyl acid (PFAs) to clay particles.
abstract: The influence of salinity and organic matter on the distribution coefficient (K(d)) for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in a brackish water-clay system was studied. The distribution coefficients (K(d)) for PFAs onto inorganic clay surfaces increased with salinity, providing evidence for electrostatic interaction for the sorption of PFAs, whereas the relationship between K(d) and organic carbon content (f(oc)) suggested that hydrophobic interaction is the primary driving force for the sorption of PFAs onto organic matter. The organic carbon normalized adsorption coefficient (K(oc)) of PFAs can be slightly overestimated due to the electrostatic interaction within uncoated inorganic surfaces. In addition, the dissolved organic matter released from coated clay particles seemed to solvate PFA molecules in solution, which contributed to a decrease in K(d). A positive relationship between K(d) and salinity was apparent, but an empirical relationship for the 'salting-out' effect was not evident. The K(d) values of PFAs are relatively small compared with those reported for persistent organic pollutants. Thus, sorption may not be a significant route of mass transfer of PFAs from water columns in estuarine environments. However, enhancement of sorption of PFAs to particulate matter at high salinity values could evoke potential risks to benthic organisms in estuarine areas.
authors.affiliation: Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, Korea.
authors.forename: Junho
authors.initials: J
authors.lastname: Jeon
authors.forename: Kurunthachalam
authors.initials: K
authors.lastname: Kannan
authors.forename: Byung J
authors.initials: BJ
authors.lastname: Lim
authors.forename: Kwang Guk
authors.initials: KG
authors.lastname: An
authors.forename: Sang Don
authors.initials: SD
authors.lastname: Kim
mesh_terms: D017738:Alkanesulfonic Acids / Q000032:analysis* / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry*; D002210:Caprylates / Q000032:analysis* / Q000737:chemistry; D000077215:Clay; D005466:Fluorocarbons / Q000032:analysis* / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry; D007700:Kinetics; D054712:Salinity; D012623:Seawater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D017738:Alkanesulfonic Acids; D000538:Aluminum Silicates; D002210:Caprylates; D005466:Fluorocarbons; D014874:Water Pollutants, Chemical; C023036:perfluorooctanoic acid; C076994:perfluorooctane sulfonic acid; D000077215:Clay