Toxicity Characterization of Organic Contaminants in Industrialized UK Estuaries and Coastal Waters

This report describes the isolation and identification of organic toxicants present in marine surface waters collected from industrially impacted areas around the UK in 1997. The characterization process utilized Toxicity Identification Evaluation (TIE) procedures that have been adapted for marine samples and a small volume bioassay using the marine copepod Tisbe battagliai. The dissolved organic content of bulk water samples was isolated using a layered solid phase extraction system to provide sample concentrates which were tested for acute toxicity. Where acute toxicity was demonstrated, the extracts were fractionated using reverse phase HPLC and tested further. Each fraction showing toxicity was then analysed by gas chromatography-mass spectrometry. The results of this investigation demonstrate that surface water concentrates collected from several impacted estuaries show acute toxicity. Organic extracts from surface waters may be concentrated using simple chromatographic techniques to induce toxicity in test species. Fractionation showed that the majority of this toxicity is associated with low to medium polarity contaminants. Compounds that were identified by gas chromatography–mass spectrometry as the possible cause of toxic effect include alkylphenols, alkyl substituted naphthalenes, alkyl-substituted fluorenes and dimethyl benzoquinone, however, the identity of certain toxic compounds remains unknown. It is concluded that the technique is a valuable tool in identifying compounds that may be potentially harmful to the aquatic environment.