ABSTRACT
Nonbenthic aquatic species, that is, species that do not reside in the sediment for an extended portion of their life cycle, have been useful in assessments of sediment contamination, since testing began in the late 1970s. Nonbenthic organisms that have been successfully used in sediment evaluations include bacteria, protozoa, phytoplankton, macrophytes, cladocera, fish, and amphibians. An aquatic ecosystem is a complex milieu comprised of interacting physicochemical and biological components whose dynamics are often integrated, and their respective spatial and temporal scales may vary by several orders of magnitude. Test conditions in sediment toxicity studies have varied widely, making data comparisons infeasible. A wide variety of single and multispecies assays using bacteria and protozoan systems have been used in benthic and water column studies of sediment toxicity. Toxicity testing with fish in sediment systems has been limited primarily to the fathead minnow; however, other species have been used, such as the rainbow trout, goldfish, largemouth bass, and bluegill bream.
