Salmonella: relations with indicators in recreational waters affected by sewage discharges

Densities of bacterial indicators of marine faecal pollution were compared, in coastal areas affected by sewage and river discharges, with Salmonella spp. t-tests comparing numbers of TC, FC and FS in samples positive and negative for Salmonella showed a good association between TC and FC (p significant at 0.006 and 0.034 respectively) and the pathogen. The levels of all three indicators in the guide standards of the EU Bathing Water Quality Directive predict absence of Salmonella. The Imperative standards of the directive do not. The conclusion is reached that if sewage works discharges into the watercourse effluent with low indicator counts the risk of Salmonella in the water will be minimal.