Premium
Equilibrium modeling: A pathway to understanding observed perfluorocarboxylic and perfluorosulfonic acid behavior
Author(s) -
Webster Eva M.,
Ellis David A.
Publication year - 2011
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.637
Subject(s) - bioconcentration , chemistry , partition coefficient , abiotic component , equilibrium constant , octanol , biological system , environmental chemistry , thermodynamics , computational chemistry , organic chemistry , ecology , bioaccumulation , physics , biology
Equilibrium distribution models of hydrophobic neutral partitioning of the perfluorinated carboxylic and sulfonic acids were shown, without the need for any physical chemical properties, to successfully predict the sediment–water distribution ( D SW ) directly from independently measured equilibrium tissue distributions known as the bioconcentration factor (BCF). The constant of proportionality required by the models successfully predicted the correlation between the biotic and abiotic distributions of both sets of chemicals, thus demonstrating the applicability of the assumptions inherent in the models, that is, hydrophobically driven partitioning of the neutral species, and thus the applicability of the models themselves. Colloquially speaking, the models are thus validated as applicable to these chemicals. Subsequent application of the standard equilibrium models showed order of magnitude agreement for 83% of measured BCF values and 88% of measured D SW for the perfluorinated carboxylic acids, confirming the physical chemical properties used. The applicability of the models to perfluorooctane sulfonic acid (PFOSA) was shown by the successful prediction of D SW from BCF. Therefore, the measured D SW and BCF could be used to calculate the octanol–water distribution, D OW , and hence the corresponding p K a : K OW solution set, thus providing independent experimentally based estimates of these properties. For both the perfluorinated carboxylic and sulfonic acids, the existing standard equilibrium models are shown to be applicable. Environ. Toxicol. Chem. 2011;30:2229–2236. © 2011 SETAC