Preliminary ecotoxicological assessment of water before and after treatment in a reed-bed and aquifer at Salisbury stormwater ASTR project

[摘要] The Aquifer Storage Transfer and Recovery (ASTR) project aims to determine whether reedbed-treated stormwater that has been stored in an initially brackish aquifer can be recovered at drinking water quality. This stormwater is treated in a reed-bed for a period of around ten days and the product water is then recharged into an aquifer at a depth of 160-180m. The water travels 50 m through the aquifer over a period of about six months before it is recovered from a separate well. Chronic toxicity of stormwater from a drain, inlet and out let channels of the wetland system, two aquifer wells was evaluated using a bacteriium (Vibrio fishceri), a duckweed (Lemna sp), awaterflea (Daphnia carinata), amidge (Chironomus tepperi) and a Pacific blue-eye rainbowfish (Pseudomugil signifier). Two river water samples represented reference water samples in this study. In-situ assessment was also carried out using midges, shrimp and yabbies translocated in cages in the wetland channels for 2-6 weeks. The wetland system was efficient in reducing the contaminant load and improving the water quality. Untreated stormwater drain samples exhibited low toxicity, in comparison, no measurable toxicity was observed in the stormwater samples from inlet and outlet channels of the reed-bed system.Water samples from wells and two rivers did not exhibit toxicity to fish, Daphnia, midges and duckweed. During in-situ assessment, toxicity was observed in shrimp and midges. Analyses of heavy metals in yabby and fish tissue samples exposed to stormwater in both inlet and outlet channels of the wetland indicated that particulate bound contaminants in stormwater could be mobilised within the food chain. This study has demonstrated that in-situ toxicity testing in combination with the laboratory toxicity testing and physicochemical characterisation provides a more realistic ecotoxicological assessment of the water from the Aquifer storage Transfer and Recovery project.

[发布日期] 2011-03-01 [发布机构] CSIRO

[学科分类] 地球科学(综合)