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Thursday, 17 February 2000
Page: 12079

Senator Allison asked the Minister for the Environment and Heritage, upon notice, on 22 December 1999:

(1) Is it a fact that the Ranger wetlands filtration system dried out earlier in 1999.

(2) When the rain did fall on the wetlands filtration system, is it the case that radionuclides and heavy metals were remobilised.

(3) Can any reports and correspondence be tabled from or between the Environmental Research Institute of the Supervising Scientist, Environment Australia and the Minister's office relating to this event.

(4) What action has been taken by the Environmental Research Institute of the Supervising Scientist, Environment Australia and/or the Minister's office regarding this matter.

Senator Hill (Minister for the Environment and Heritage) —The answer to the honourable senator's question is as follows:

(1) No. At the end of the 1999 dry season all pumpable Restricted Release Zone (RRZ) water was removed and the system was refilled with non-RRZ water. At no time did any of the ponds in the wetland filter dry out. The ponds were deliberately dried out in the previous (1998) dry season as part of a controlled experiment.

(2) In the 1998 experiment the levels of uranium in the filter ponds rose because of remobilisation following wetting by rainfall. Uranium levels were monitored and had fallen substantially to historical levels, reflecting the re-activation of the natural adsorption processes in the filter, before any water was allowed to leave the ponds and flow into the RP1 catchment.

(3) The Supervising Scientist reported on the 1998 drying out in his Annual Report for 1998-99 (Page 247-s.3.3.5 Restricted Release Zone-RP2 Water). The matter was also discussed in the Ranger Minesite Technical Committee meetings of 20/1/99, 2/3/99 and 21/5/99 attended by OSS, NT DME, ERA and NLC.

(4) The Environmental Research Institute of the Supervising Scientist monitored results of experiments as made available by ERA and also collected separate samples for analysis. In 1999 there was continuous assessment of the routine monitoring data supplied by ERA. No anomalous results were observed in either case and there has been no detrimental impact to the environment.