Recovery of viruses and bacteria in waters off Bondi beach: a pilot study

A pilot study was conducted between February and April, 1989, on the occurrence of sewage-derived viruses and bacteria in the beach and nearshore waters off Bondi, Sydney. Enteroviruses were isolated from 41% of a total of 66 sewage, sea-water, grease and sediment samples. Poliovirus vaccine strains accounted for 78% of the isolates. Adenoviruses were isolated four times and coxsackievirus B was isolated twice in samples that were collected away from the bathing area. Rotavirus and hepatitis A virus were not detected. The number of faecal coliforms, faecal streptococci, Aeromonas hydrophila and Clostridium perfringens in the sewage ranged from 10(4) to 10(7) cfu/100 mL. An initial reduction of 10(2)-10(3) in bacterial counts was observed in the plume (the effluent's initial dilution zone) and a further reduction of 10(2)-10(4) in counts in samples that were collected away from the plume. Salmonella spp. were detected in one-third of the samples and low numbers of Campylobacter jejuni were found in the sewage and plume. Salmonella serotypes that were associated with the sewage and plume were distinct from those in the stormwater and beachwater, indicating that stormwater may be an important source of pollution on Bondi beach.