Monitoring the toxicity of complex materials such as industrial effluents is vital, particularly when implementing the requirements of the EU water framework directive. But the toxicity of the material as a whole cannot be predicted from those of the substances it contains.

Andrew Knight and colleagues at Gentronix, Manchester, together with co-workers at AstraZeneca Global Safety, Vickers Laboratories, Euroclone and the University of Luton, have examined seven alternative direct toxicity assessment (DTA) tests, comparing them with tests using regulatory organisms. The DTA approach monitors the effect of a whole sample on living organisms, therefore detecting the combined effect of all the chemicals present.

The results, which highlight the tests' strengths and weaknesses, are extremely useful for industrial monitoring and water quality testing.

Rowena Milan