Continuous monitoring shows that treated water released from the Australian Nuclear Science and Technology Organisation to the outfall at Potter Point does not pose any health risk.
Dr John Ferris of ANSTO’s Environment Division said that ANSTO carries out seawater and biological sampling programs to assess potential doses to members of the public who might swim in the ocean near Potter Point or eat fish from the area.
"The biological monitoring program involves the collection of barnacles, seaweed and blackfish and is designed to maximise the chances of detecting radionuclides in the marine environment," he said.
"Water is also sampled in the sea at various distances from the Potter Point outfall for tritium analysis. The dispersion of this tritiumcontaining effluent from Potter Point has been modelled and, with ANSTO's detailed knowledge of its effluent releases, the modelling can predict the levels of tritium at any given point in space and time in the vicinity of the Potter Point outfall."
"Seaweed growing on the rocks at Potter Point is known to concentrate radionuclides. Nevertheless, despite the fact that Blackfish eat this kind of seaweed, the low levels of radionuclides that could be attributed to ANSTO are not detected in these fish."
ANSTO has always complied with its agreement with Sydney Water Corporation allowing the Organisation to discharge treated effluent. This agreement depends upon ANSTO's compliance with the World Health Organisation's 1993 Guidelines for Drinking Water Quality at the Cronulla Sewage Treatment Plant and concentration limits for non-radiological components of the effluent.
"Calculations of the external radiation exposure rates from ANSTO's effluent have shown that they are less than one part in one million of the internationally recognised dose rate limits for the public. Information about ANSTO's liquid effluent discharges is freely available in the Organisation's Environmental and Effluent Monitoring Reports, published each year," Dr Ferris said.