Trace Metals in Freshwater Sediments: A Review of the Literature and an Assessment of Research Needs

This chapter focuses on the biological availability of sediment-associated trace metals; laboratory approaches used to assess sediment toxicity; and field investigations of trace metal contaminated freshwater sediments. While the physicochemical aspects of trace metal distribution in sediments have received considerable attention, generally less effort has gone into assessing the role of biological variables in the uptake process, particularly among freshwater organisms. When evaluating various organisms for use in freshwater sediment toxicity tests, one must consider the substantial differences that exist in routes of exposure. Trace metals associated with sediments can pose a long-term threat to aquatic ecosystems. Two types of approaches have been used to investigate the effects of sediment associated trace metals on biota under field conditions: empirical studies of sites known to be contaminated by a trace metal or metals; and sampling programs designed to validate laboratory experiments.