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Investigating the role of desorption on the bioavailability of sediment‐associated 3,4,3′,4′‐tetrachlorobiphenyl in benthic invertebrates
Author(s) -
Leppänen Matti T.,
Landrum Peter F.,
Kukkonen Jussi V. K.,
Greenberg Marc S.,
Burton G. Allen,
Robinson Sander D.,
Gossiaux Duane C.
Publication year - 2003
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 - 10.1897/02-541
Subject(s) - tenax , bioavailability , bioaccumulation , environmental chemistry , sediment , hyalella azteca , chemistry , extraction (chemistry) , biota , desorption , benthic zone , chromatography , ecology , adsorption , biology , amphipoda , gas chromatography , paleontology , bioinformatics , organic chemistry , crustacean
Only a fraction of all sediment‐associated hydrophobic organic contaminants are bioavailable, and a simple Tenax® extraction procedure may estimate this fraction. Bioavailability is assumed to coincide with the rapidly and, possibly, slowly desorbing sediment‐associated contaminant. River sediment was spiked with radiolabeled ( 14 C) and nonradiolabeled ( 12 C) 3,4,3,4′‐tetrachlorobiphenyl (TCBP), and desorption kinetics using Tenax extraction were obtained at 10°C and 22°C. Bioaccumulation was measured in Lumbriculus variegatus, Chironomus tentans , and Hyalella azteca . Desorption of TCBP was triphasic at 22°C and slowed at 10°C to show only biphasic kinetics. The rapidly desorbing fractions decreased with increasing TCBP sediment concentration. The biota sediment accumulation factors, biota accumulation factors, and sediment clearance coefficients ( k s ) also decreased with increasing sediment TCBP concentration. The rapidly plus slowly desorbing fractions and the total TCBP desorbed when 99.9% of the rapidly desorbing fraction had desorbed were used to estimate bioavailable TCBP. These Tenax‐based fractions did not explain the decreasing bioavailability with increasing TCBP load. Several factors, such as animal behavior and TCBP water solubility limitations, were evaluated to explain the concentration effect, but the most likely cause was severe diffusion limitations in whole sediment that were not predicted by the fully mixed Tenax extraction. Therefore, desorbing fractions determined by Tenax extraction overestimated the bioavailable fractions in sediments.