Relationships between microbial water quality and environmental conditionsin coastal recreational waters: The Fylde coast, UK

This paper explores ways in which the analysis of microbial data from routi ne compliance monitoring, in combination with basic environmental data, can provide insight into the factors affecting faecal-indicator organism conce ntrations in coastal waters. In the case study presented, eight designated bathing waters on the Fylde coast are continuing to exhibit unreliable comp liance with the Imperative standards for total coliform (TC) and faecal col iform (FC) concentrations specified in the EU Bathing Water Directive (76/1 60/EEC), despite significant reductions in geometric mean concentrations fo llowing recent major investment in the sewerage infrastructure. Faecal stre ptococci (FS) concentrations have remained high and have not been improved by the new sewerage schemes. The results suggest that, prior to the schemes , higher bacterial concentrations were strongly associated with rainfall: a nd sewage sources were important for TC and FC, but less important for FS, which may have been more strongly affected by diffuse catchment sources. In the post-schemes period, catchment sources appear to be of greater signifi cance rainfall remains as a significant, though less important, predictors and tide height at time of sampling, together with variables such as sunshi ne and the proportion of onshore winds (which affect the survival and movem ent of bacteria that have already entered the coastal waters), assume great er significance. The approach used here provides a cost-effective managemen t tool for the exploratory investigation of any monitoring point that is fa iling to meet recreational water quality standards. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.