Effects of Metals on Freshwater Macroinvertebrates: A Review and Case Study of the Correspondence of Multimetric Index, Toxicity Testing, and Copper Concentrations in Sediment and Water
The use of multimetric indices (MMIS) as interpretive tools in biological surveys is widespread, particularly in the United States. However, two considerations related to their use are whether pollutant-specific indexes are needed and the need for independent validations of index responses. In this chapter, the performance of the benthic macroinvertebrate index of biotic integrity (B-IBI) is tested with a known, specific pollutant (copper). The B-IBI is a nonspecific index that is promoted as a broadly effective tool (Karr and Chu, 1999). Patterns of effects of elevated metals on macroinvertebrate assemblages are described, and a case study relating multimetric assemblage indexes to sediment toxicity and concentrations of copper in water and sediment are described. The chaper concludes with recommendations on the use of multimetric indexes in relation to other assessment tools.