ANSTO has just released its environmental compliance report for 1996, showing that it complied with all effluent discharge authorisations and relevant environmental regulations.
The publicly available report, "Environmental and Effluent Monitoring at Lucas Heights Science and Technology Centre, 1996", presents results from environmental, effluent and meteorological monitoring of samples taken around the Lucas Heights Science and Technology Centre and at the sewage outfall at Potter Point.
Potential maximum radiation doses to members of the public resulting from the discharges are also presented.
The 1996 results were audited by the Australian Radiation Laboratory, an independent body which is part of the Commonwealth Department of Health and Family Services. As points of reference, the international unit of radiation dose is the sievert.
All Australians receive an annual average radiation dose of 2 millisieverts from natural sources such as the sun, the earth itself, building materials and the food and drink we consume. The National Health and Medical Research Council (NH&MRC) recommends that members of the public should not receive an additional annual dose of more than one millisievert from other sources, excluding doses from medical exposures.
The results of the 1996 ANSTO environmental monitoring program were: Air:
Total radioactive airborne emissions from the Lucas Heights site in 1996 resulted in a potential effective dose of less than 1% of the annual dose of 1 millisievert for members of the public recommended by the NH&MRC.
Liquid:
In 1996 releases from ANSTO to the sewer averaged 20% of the limit for radionuclides specified in the Trade Wastewater Agreement with Sydney Water Corporation. In 1995, releases averaged 22% of the limit.
Analyses of stormwater drainage from ANSTO showed that the stormwater complied with the NSW Clean Waters Regulations (1972) at the agreed sampling points on the three creeks receiving most of the run-off from site. Samples collected from the Woronora River and Forbes Creek showed no evidence of radionuclides produced by ANSTO.
Seawater samples were taken from the vicinity of Potter Point, near Cronulla, where treated sewage from Sutherland Shire, including that from ANSTO, is released into the ocean. Other samples included fish, algae and barnacles.
No levels of radioactivity which could be attributed to ANSTO were found in any biological samples taken from Potter Point in 1996.
Analysis of the seawater samples showed that tritium, or radioactive hydrogen, levels are usually below the limit of detection. On November 14, 1996, low levels of tritium were detected due to calm conditions causing the sewage effluent plume to rise to the surface near the cliff outfall. The maximum tritium level detected was 3.2% of the World Health Organisation (WHO) permitted value for tritium in drinking water.
Other locations:
Sensitive thermoluminescent dosimeters, which measure ambient external gamma radiation, were placed at various locations around ANSTOs perimeter and at three private residences in the nearby suburbs of Barden Ridge, Engadine and Woronora. Each dosimeter was supplied by the Australian Radiation Laboratory.
The dosimeters at each of the three private residences registered an average absorbed radiation dose of 0.7 millisieverts per year. This is consistent with the dose level reported by the ARL for Australian capital cities as a result of naturally occurring radiation sources.