Ecotoxicological risk assessments have their roots in the social activism of the 1960s (inspired by such things as Rachel Carson's Silent Spring, 1962). Governments in many countries created protocols that matured over the period from the mid 1960s to the mid 1990s and that continue to evolve. These methods have a particular focus: the assessment, approval and auditing of pollutants and toxicants in a regulatory system.

Circumstances demanded the rapid development of conventions, experimental techniques and standards for interpretation of evidence. These things coalesced into the ecotoxicological paradigm (Chapter 3). The system rests on the foundations summarized by Suter (1993): management and policy goals, assessment endpoints as well as indicators and measures of effect. This chapter examines the system's relationships with epidemiology and toxicology, and with broader concepts of environmental risk assessment.

To reiterate the ecological hierarchy outlined in Chapter 3, management goals encapsulate the spirit of a management or monitoring programme. As such, these goals have a social mandate and are ecologically relevant. Assessment endpoints are formal expressions of the environmental values to be protected. They provide a means by which management goals may be measured and audited.

Measures of effect (measurement and test endpoints, US EPA 1998) are quantitative biological responses, such as toxic effects on survival and fecundity. Indices are created from field measurements or laboratory tests. They represent sensitivities of ecosystem components to toxic substances and act as surrogates for other elements of the ecosystem.