ABSTRACT
This chapter examines community responses of benthic organisms to heavy metals in streams. Descriptive approaches, such as routine biomonitoring of community structure and measurement of levels of metals in organisms, are the most commonly employed techniques for assessing the biological integrity of streams. Stream biomonitoring approaches for evaluating the impact of contaminants typically involve comparison of upstream reference sites to downstream impacted and recovery sites. Responses of algae and periphyton communities to heavy metals in streams have received considerable attention. In a stream that received several metals, community respiration, gross primary productivity, chlorophyll a content, and ash free dry mass were greater at impacted and recovery sites than at reference stations. Impacted sites were dominated by green and blue-green algae. Concentrations of heavy metals in periphyton are often employed as indicators of the presence of heavy metals in streams. The distribution and abundance of benthic macroinvertebrates have routinely been employed as indicators of water quality in streams.
