Introduction

In this course, there is constant reference to 'toxicity of pollutants' and their impacts. However, many otherwise environmentally informed people do not understand how toxic substances have their effect. The lecture on this topic is intended as an introduction to significant aspects of  toxicology   - it can only be an introduction as Toxicology is a massive subject in its own right. Thus, the principal purpose of this lecture is to give a brief introduction to to the terminology and major relevant aspects of toxicology to students whose main interest is in Ecotoxicology, (on which more information is given if you follow the link) .

Toxicology is the study of the effects of poisonous substances on living organisms including the way in which they gain entry into the organisms

Moriarty has clarified the situation by stating that ‘toxicology is concerned with effects on single organisms; ecotoxicology is concerned with effects on ecosystems.

Exposure to toxins above a critical level causes detrimental effects to the well-being of the organism. It is expected that above the critical level, there is a dose-response relationship

Assessing toxicity of a substance can be achieved using one of two approaches:

1                    Prediction on the basis of its molecular structure using Quantitative Structure Activity  Relationships (QSARs)

2                    Measurement using model test systems

However, prediction of toxicity is too complicated a subject for this course.

Test systems used to measure the toxicity of a substance range from relatively simple laboratory tests to more complex field tests involving natural or semi-natural communities.

Laboratory tests are designed to evaluate both chronic and acute tests. Chronic tests are designed to effects resulting from longer-term (usually several weeks)

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FURTHER READING:

Walker, CH. Hopkin, SP. Sibly, RM. & Peakall, DB (2001) Principles of Ecotoxicology (2^nd Edn) Taylor Francis, Lond.

Connell,D., Lam,P., Richardson, B & Wu, R. (1999). Introduction to Ecotoxicology. Blackwell, Oxford.

Alloway, B.J. & Ayres, D. (1997). Chemical Principles of Environmental Pollution. 2nd Edn. Blackie Academic,London.

(Overheads from the Lecture are available for download as a Word File or as Powerpoint on VITAL

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