US EPA

3061503 

Journal Article 

Isotopic exchange on SPME fiber in sediment under stagnant conditions: Implications for field application of PRC calibration 

Bao, LJ; Wu, X; Jia, F; Zeng, EY; Gan, J 

2015 

Yes 

Environmental Toxicology and Chemistry
ISSN: 0730-7268
EISSN: 1552-8618 

35 

8 

1978-1985 

English 

26678218 

10.1002/etc.3345 

WOS:000380057100012 

An overlooked issue for field application of in situ performance reference compound (PRC) calibration methods is the validity of the assumption that both the sorption of a target compound and desorption of its corresponding PRC follow the first-order kinetics with the same rate constants under stagnant conditions. In the present study, disposable polydimethylsiloxane fibers of two sizes (7- and 35-µm) impregnated with eight (13) C-labeled or deuterated PRCs were statically deployed into different marine sediments, from which the kinetics for sorption of the target compounds and desorption of the PRCs were characterized. Non-symmetrical profiles were observed for exchange of the target analytes and their corresponding PRCs in sediment under stagnant conditions. The hysteretic desorption of PRCs in the kinetic regime may be ascribed to the low chemical potential between the fiber and sediment porewater, which reflects the inability of water molecules to rapidly diffuse through sediment to solvate the PRCs in the aqueous layer around the fiber surface. A moderate correlation (r = 0.77 and r = 0.57, p < 0.05 for both regressions) between the PRC-calibrated equilibrium concentrations of p,p'-DDE and PCB-153 and the lipid normalized levels in worms (Neanthes arenaceodentata) was obtained in co-exposure tests under simulating field conditions, probably resulted from slightly overestimated bioavailability because of the hysteretic desorption of PRCs and toxic effects.