Identification of toxic substances in United Kingdom estuaries

The organic load of bulk water samples, collected from five industrially impacted estuaries, was extracted using solid-phase extraction. Where toxicity was demonstrated using a Tisbe battagliai bioassay, a toxicity directed fractionation 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 were identified by GC-MS. All procedures were evaluated with a series of reference compounds of widely differing polarity. The method was successful in identifying a number of compounds, which traditionally have not been selected for inclusion in monitoring programs, as the probable cause of detrimental 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 compounds, as yet unidentified, also contribute to poor water quality. It is suggested that the identified compounds should now be surveyed more widely and considered for inclusion in future monitoring programs.