Surveys monitoring the sea and beaches in the vicinity of Durban, South Africa: a case study

A microbiological surveillance programme was initiated in Durban, South Africa, to provide an objective assessment of changes in the local seawater quality before and after the commissioning of two submarine outfalls in 1969 and has been ongoing until the present day. A classification system including Escherichia coli I, helminthic parasite ova, pathogenic staphylococci, salmonellae, shigellae, and salinity was used. This system, functioning as an audit, has proved useful in detecting problem areas which may have passed unnoticed in the routine E coli I assessments performed by the Durban Municipality. The salient features that have manifested themselves are (a) alterations in the seawater quality have been shown to be invariably a consequence of changes effected upon the shore or meteorological events and (b) that measuring more than one indicator of water quality, plus the use of salinity as a physical parameter for assessing the dilution or impairment of pristine seawater, has proved valuable.