AN INVESTIGATION INTO PARAMETRIC RELATIONSHIPS BETWEEN ENTEROVIRUS AND FECAL INDICATOR ORGANISMS IN THE COASTAL WATERS OF ENGLAND AND WALES

Previous research has resulted in conflicting conclusions concerning p ossible statistical relationships between bacterial indicator and ente rovirus concentrations in marine waters. Results have suggested either highly significant relationships or no significant correlation. To ex amine these relationships further, large compliance assessment data se ts for identified bathing waters on the English and Welsh coast, betwe en 1988 and 1992, were extended to include enterovirus and faecal stre ptococci counts in addition to total and faecal coliform data. The sui tability of these data for parametric correlation analysis was assesse d by examining the nature of the statistical distributions of raw data and residual values from regression analyses. The data were acceptabl e for parametric analysis when (i) zero enterovirus samples were exclu ded and (ii) enterovirus counts were logarithmically transformed. The analysis of over 690 data pairs produced positive Pearson correlation coefficients between coliforms, faecal coliforms, faecal streptococci and enterovirus concentrations. Though the correlations were significa nt (P < 0.001, i.e. > 99.9% confidence) they were low (r < 0.5). The a mount of variance in enterovirus concentration explained by bacterial concentration was only 15-16%. Relationships were similar for each bac terial determinand. Correlations above successive quartile values of b acterial concentration revealed no threshold effect in these relations hips. These results suggest poor statistical relationships between con centrations of bacterial indicators of sewage pollution and enteroviru s in marine waters resulting in a low predictive capability.