Ecotoxicology is the description and understanding of impacts of industrial and agricultural chemicals on ecological systems. It is to be distinguished from toxicology because it focuses on the impacts of chemicals on ecological groupings of organisms rather than on individuals; i.e. on populations, communities and ecosystems. Ecotoxicity tests that focus on the responses of individual organisms to toxic chemicals may not translate straightforwardly to relevant effects on ecological systems. Mathematical models can assist in making these extrapolations from organisms to ecological systems. Ecotoxicology plays a key part in informing ecological risk assessment and hence in the management of the production, use and disposal of industrial and agricultural chemicals.

Key Concepts:

  • Ecotoxicology is a science that is concerned with the effects of industrial and agricultural chemicals on ecological systems.

  • Though derived from toxicology, ecotoxicology is concerned less with the responses of individuals to chemicals and more with their effects on populations, communities and ecosystems.

  • Contaminating chemicals have their first impacts on the molecular and cellular systems within organisms but some of these may be nullified by homeostatic processes and ecological compensation. Others may be magnified by cascading processes. So the relationship between effects observed in tests that focus on individuals and ecologicalā€level responses is not straightforward.

  • It is important to distinguish between contamination (presence of chemicals in the environment) and pollution (presence of chemicals with adverse effects).

  • It is important to distinguish between hazard (the potential of chemicals to cause harm) and risk (the likelihood of that potential being realised).

  • Ecotoxicology plays a key part in informing the assessment of risks from chemicals to ecological systems and hence in managing their impacts.

  • Sensible risk management of chemicals is important because despite their potential to cause harm to ecosystems, chemicals make many contributions to human welfare, for example, in medicine and agricultural production.

Keywords: hazard assessment; pollutant; stressors; risk assessment


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Walker CH, Hopkin SP, Sibly RM and Peakall DB (2012) Principles of Ecotoxicology, 4th edn. Boca Raton, FL: CRC Press.

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Calow, Peter, and Forbes, Valery E(Jul 2014) Ecotoxicology. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0003245.pub2]