ABSTRACT
Detection and quantification of the effects of chemicals on an ecosystem is a complex undertaking. This chapter focuses on the science of “ecosystem health” which parallels the sciences of human and veterinary medicine. It addresses the identification and use of diagnostic tools, termed “test systems”, which provide both toxicological and ecological information. Assessment must be based on the results of field tests and of tests on samples returned to the laboratory for chemical or physical analysis and bioassay. When spatial and temporal scales of analysis are used to define units of analysis and classify the context of tests, it is possible to address other issues associated with developing ecological realism. Ecosystem health assessments usually proceed either along a hazard assessment or a bioassessment path. Bioassessment uses enclosures and other types of microcosms and mesocosms to carry out controlled exposure studies in an ecosystem.
