BIOAVAILABILITY AND UPTAKE OF HYDROPHOBIC ORGANIC CONTAMINANTS IN BIVALVE FILTER-FEEDERS

The degree to which aquatic organisms accumulate organic contaminants depends upon rate processes involved in the uptake, distribution and e limination of the contaminant. These processes may be influenced by bo th abiotic and biotic factors, and may thus differ between locations a nd organisms. In this paper, environmental and physiological aspects o f bioavailability and uptake of hydrophobic organic contaminants in bi valve filter-feeders are reviewed. This includes environmental distrib ution of contaminants; the relative importance of freely dissolved ver sus particle-associated contaminant uptake; and the role of physiologi cal regulation of processes involved in contaminant uptake. It appears that more emphasis on considering food as a source of uptake together with particle concentration dependent physiological processes such as water-pumping, filtration and ingestion is important. Thus, contamina nt accumulation in filter-feeding bivalves may be better predicted by bioenergetic rather than thermodynamic models.