DETECTION OF VIRUSES IN COASTAL AND RIVER WATER-SYSTEMS IN SYDNEY, AUSTRALIA

Two prospective studies on the occurrence of human viruses in samples of coastal & river origin have been undertaken since September 1989. V iruses were detected using concentration methods & cell culture techni ques. Water samples (100L) were reduced to 1L using hollow fibre ultra filtration and then treated with PEG. Sewage and sediment samples were treated with PEG only. Over a two year period, viruses were detected in 24/202 (12%) of water samples and 29/60 effluents from the river sy stem. Coastal waters have been contaminated by cliff edge discharge of sewage for at least the 1 ast 70 years. Recently, deepwater ocean out falls have been installed to discharge effluent some 3 km away from th e coast. Prior to the installation of deepwater ocean outfalls viruses were detected in 28% of water samples compared to 9% post installatio n. In sediment samples viruses were isolated in 87/260 (34%) samples, the discharge via the new outfalls having no effect on the isolation r ate. The data points to long term survival of viruses in sediments and /or contamination from other sources such as storm water discharge: 10 -25% of storm water drains were also found to be positive for viruses. The viruses isolated were enteroviruses, adenoviruses & reoviruses. A lthough viruses were consistently isolated with some seasonal trends, comparisons between the detection of viruses in clinical and environme ntal samples over this two year period were inconclusive.