Identification of toxic substances in United Kingdom estuaries

The organic load of bulk water samples, collected from five industrially im pacted estuaries, was extracted using solid-phase extraction. Where toxicit y was demonstrated using a Tisbe battagliai bioassay, a toxicity directed f ractionation scheme was applied to isolate causal compounds. To reduce the complexity of the extracts toxicity profiles were obtained following solid- phase fractionation and reverse-phase HPLC. Candidate toxic contaminants we re identified by GC-MS. All procedures were evaluated with a series of refe rence compounds of widely differing polarity. The method was successful in identifying a number of compounds, which traditionally have not been select ed for inclusion in monitoring programs, as the probable cause of detriment al environmental effect. The results suggest that chlorinated phenols are a major contributor to poor water quality in the lower reaches of the river Tyne and alkylphenol surfactant metabolites in the river Tees. Other compou nds, as yet unidentified, also contribute to poor water quality. It is sugg ested that the identified compounds should now be surveyed more widely and considered for inclusion in future monitoring programs.