Faecal indicators and sanitary water quality of shellfish-harvesting environment: influences of seasonal monsoon and river-runoff

Incidence of faecal coliforms in shellfish harvesting areas of the southern coastal district of Karnataka was examined for evaluating the sanitary quality in relation to the seasonal monsoon and river-runoff. Faecal coliforms (FC) counts in seawater, mussel tissue and sediments were highest in monsoon. Geometric mean for FC in sea water was below 14 MPN/100 ml, standard set for “approved area” under NSSP classification during fishing season, but the 90 percentile were higher. The tissue E. coli levels complied with the EC Directive standard under the “category A”, during mussel fishing season commencing in October in the two mussel beds. MPN FC levels were strongly influenced by the seasonal variations in precipitation and river runoff. During the fishing seasons in pre-monsoon and post-monsoon months, the levels were below the limits.