G. Ewald et al., EFFECT OF OLIGOCHAETE BIOTURBATION ON SEDIMENT ACCUMULATION OF 2,2',4,4'-TETRACHLOROBIPHENYL, Ecotoxicology and environmental safety, 36(1), 1997, pp. 66-71
The influence of clay content, organic carbon, and bioturbation on sed
iment accumulation of 2,2',4,4'-tetrachlorobiphenyl (TCB) was investig
ated in microcosms. Four types of sediments differing in porosity, den
sity, organic carbon, and clay content were used in the study. The sed
iments, with or without oligochaete bioturbation, mere exposed for 100
days to water with a constant concentration of C-14-labeled TCB, in a
continuous-flow system. The hypothesis for the experiment was that bi
oturbation would enhance the accumulation rate of TCB by redistributin
g the sediment particles and/or by changing the physical properties, e
.g., porosity of the sediment, in a way that would increase the diffus
ion rate. The highest accumulation was found in sediments of low organ
ic carbon content. No effect of clay content was found. Contrary to th
e hypothesis, bioturbation did not increase sediment accumulation of T
CB. Instead, the sediment accumulation could be explained by retarded
diffusion, a combined effect of the processes of adsorption and diffus
ion. (C) 1997 Academic Press.