ATTEMPTS TO ASSESS THE ENVIRONMENTAL-HAZARD POSED BY COMPLEX-MIXTURES OF ORGANIC-CHEMICALS IN UK ESTUARIES

The potential hazards of a range of industrial organic chemicals (71 in total) found in surface waters from several UK estuaries were assessed by consulting published aquatic toxicity data. Quantitative structure-activity relationships (QSARs) were used in some cases where no data were available. Some of the chemical analytical techniques used were only semi-quantitative, but for most of the chemicals for which an assessment could be made (68%) it is unlikely that they were present at individually harmful concentrations. They may have exerted toxicity as a mixture, but there is insufficient information and understanding to allow joint toxicity to be calculated. Subsequent tests of surface waters from the relevant estuaries, using an oyster embryo bioassay, revealed that two of them (the Tyne and the Tees) were of poor biological quality. The paper concludes that initial assessment of marine water quality should be based on the results of biological effects observations and that routine observations of the chemical quality of marine waters should be focused primarily on areas where biological effects are observed.