Environmental (per-) halogenated acids: Detection, distribution, sources, and bioaccumulation

Halogenated acetic acids (HAAs) and perfluorinated acids (PFAs) are organic contaminants that are distributed ubiquitously in the environment. A multitude of chlorinated and fluorinated HAAs have already been detected in atmospheric deposition, but a previously unidentified HAA, chlorodifluoroacetic acid (CDFA), was detected in rain samples from Guelph and Toronto, ON, at mean concentrations of 14 and 17 ng L−1, respectively. The source of CDFA was postulated to be photodegradation of CFC-113, and to a lesser extent HCFC-142b. Alkalized annular denuders were used for collection of gaseous and particle phase HAAs in ambient air. Trifluoro- (TFA), monochloro- (MCA), dichloro- (DCA), and trichloroacetic acid (TCA) were the dominant HAAs in air, at mean concentrations of 0.76, 3.4, 1.3, and 0.14 ng m−3, respectively. Lower concentrations of monofluoro- (MFA), difluoro- (DFA), and CDFA were also detected. The particle fractions (&phis;) were 0.17, 0.15, 0.20, and 0.50, for TFA, MCA, DCA, and TCA, respectively. The relationship between meteorological conditions and HAA concentrations allowed for a discussion of potential HAA sources.; In flow-through aqueous exposures of rainbow trout (Oncorhynchus mykiss) to a homologous series of perfluoroalkyl carboxylates and sulfonates, it was demonstrated that PFAs accumulate preferentially in the blood, liver, kidney, and bile. Carboxylates having less than 7, and sulfonates having less than 6 perfluoroalkyl carbons did not bioconcentrate. For longer PFAs, bioconcentration factors (BCFs) increased with increasing length of the perfluoroalkyl chain, ranging from 4.0 to 23,000, and sulfonates accumulated to a greater extent than carboxylates of equivalent perfluoroalkyl chain length. Dietary exposure of rainbow trout to the same PFAs revealed high assimilation efficiencies and a similar trend of increasing biomagnification factors (BMFs) with increasing chain length, however, BMFs were always less than 1.; In high volume air samples we confirmed the presence of three neutral perfluorooctane sulfonate (PFOS) derivatives, and three fluorotelomer alcohols, by gas chromatography/chemical ionization mass spectrometry. It was hypothesized that the source of these compounds is commercially available surface treatment chemicals, which contain the detected compounds as impurities, or which may degrade over time to yield the detected compounds.