Modeling pentachlorophenol bioavailability and bioaccumulation by the freshwater fingernail clam Sphaerium corneum using artificial particles and humic acids

The uptake of anthropogenic chemicals by benthic bivalves may occur through the water phase and also by the ingestion of particles from both the suspe nded matter and bottom sediments. Many chemicals sorb to sediments and, sub sequently, are released in the digestive tract of animals. The assessment o f sediment-bound chemicals has been difficult because of the complexity of the association between these chemicals and natural particles. To simplify this complexity, we previously devised a test system using artificial parti cles with known chemical structures. In the present work, we improved this experimental design by adding humic materials as a source of organic matter . Bioassays were conducted by exposing the fingernail clam Sphaerium corneu m to sublethal levels of pentachlorophenol (PCP) in the presence or absence of the artificial particles, treated with or without a commercial preparat ion of humic acids. The results showed that the bioavailability and bioaccu mulation could be explained on the basis of the interactions of PCP with th e active groups and/or the backbone of the resins, both in systems with or without humic acids. This model may constitute a useful approach to modelin g and predicting the uptake and accumulation of chemicals bound to natural sediments.