ABSTRACT
It is frequently forgotten that ecotoxicology is the study of the fate as well as the effect of toxic agents in ecosystems. The fate component has been dealt with in other chapters and is mentioned here only to reiterate the importance of its assessment in any ecological or environmental risk assessment, whilst degradation of materials in the environment usually results in a reduction in toxicity there may be the potential for more toxic agents to be found. The effect caused by any agent will be dependant on both its inherent toxicity, and also on the degree of exposure. In turn his will be dependant how much of the material enters the environment, how it partitions in the environment, and how it persists. From this it can be seen that ecotoxicology is an integrative discipline, combining a number of factors to give, hopefully, an end result. It is this integrative capacity, combining the factors within a temporal framework which lies at the heart of the potential of ecotoxicology as a field monitor for the assessment of environmental exposure. Field deployments of sentinel organisms or collection of animals from the environment creates the possibility for the scientist to obtain a time integrated view of what an organism has been exposed to, how long for, and whether the exposure has resulted in an effect. Whether this potential can be realised will be dependant on whether the organisms can accumulate the materials of concern, whether it persists, whether it has an identifiable and quantifiable effect and whether the scientists know what to look for.
