PERSISTENCE OF ORGANIC CONTAMINANTS
Report No DWI0442

Sept 1991

SUMMARY

The objectives of this programme of work are to determine the abiotic degradation rates of selected priority pollutants via different pathways, under controlled laboratory conditions (mimicking the environment), and to establish predictive procedures to enable environmental persistence to be estimated under different conditions.

In order to provide assessments of the environmental fate and persistence of organic contaminants, information is required about their rates of biotic and abiotic transformation and physicochemical properties. The use of experimental data from aqueous laboratory degradation tests under controlled conditions, and predictive evaluations such as quantitative structure activity relationships (QSARs) should enable better estimations of environmental fate to be made. Also a combined approach should facilitate swifter evaluation of the potential of new and existing chemicals for persistence, toxicity and bioaccumulation.

Investigations into the rate of specific abiotic processes responsible for the degradation of selected Red-list chemicals have been carried out. Work has focused on the hydrolysis and photolysis of an organophosphorus pesticide, and two triazine herbicides. Experiments have been carried out under sterile and unsterile conditions at constant temperature and at variable pH and the influence of suspended inorganic minerals on degradation rates has also been investigated.

Copies of this report may be available as an Acrobat pdf download under the 'Pre 2000 Reports' heading on the DWI website.