Alice Springs town basin, review 2003
Read, R. E.
E-Publications; E-Books; PublicationNT; Report ; no. 42/2003
Made available via the Publications (Legal Deposit) Act 2004 (NT).
Department of Infrastructure, Planning and Environment
Report ; no. 42/2003
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C- 1 1 Hydrocarbon pollution 1.1 Power Station Drain outfall This was the earliest investigation of hydrocarbon pollution in the Town Basin. Berry (1992) records that sampling of existing was undertaken to find the extent of contamination. By chance a folder was found with dissolved organic carbon values in it. Results are in Appendix C. A level of 30 mg/L was found in RN 13916 in 1990, but subsequently dissipated. High levels of dissolves organic carbon were found in 1990, but appeared to have dissipated by 1992. In more recent sampling of Town Basin production bores Total Petroleum Hydrocarbons have been below detection limits. G. Ride (pers. com.) states that on occasions oil had been collected in pits in the creek downstream of the power station. 1.2 BP Depot Losses of petroleum products in around 1998 led to a drilling investigation that identified up to 0.5 m of phase separated hydrocarbon and a plume of dissolved hydrocarbon that extended some 200 m to the SSE (OTEK 2002). Hydrocarbons were removed by sparging. Testing of groundwater samples showed that anaerobic biological attenuation of the plume is occurring. 1.3 Railway Yards Drilling identified two free phase hydrocarbon plumes of diesel fuel. The first of these appeared to have reached a steady state. Modelling predicted that dissolved phase hydrocarbons will decline to below the guideline level of 100 g/L by 2085. The second is predicted to continue to expand to 2010, and still to be present at above guideline levels in 2085. 1.4 Shell Todd Small plume of dissolved hydrocarbons, no free phase 1.5 Shell Depot In May 1997 petrol vapour was noticed in a stormwater drain near the site (Golder Associates 2001). Subsequent investigations showed that a large plume extended south from the site, originating in part from the petrol leak of 1997, but also from earlier leaks, including diesel fuel. Monitoring over a three year period suggested that the plume has been stabilised by bio-degradation.