2012•WSUD 2012: Water sensitive urban design; Building the water sensiitve community; 7th international conference on water sensitive urban designRequires access
A holistic assessment of stormwater quality from urban catchments
Meng Nan Chong, Jatinder Sidhu, Rupak Aryal, Janet Tang, Wolfgang Gernjak, Beate I. Escher, S. Toze
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Abstract
Stormwater is one of the last major untapped urban water resources that could be exploited as an alternative water source in Australia. The information in the current Australian Guidelines for Water Recycling relating to stormwater harvesting and use only emphasize a limited number of stormwater quality parameters. In order to supply stormwater as a source for higher value end-uses, a more comprehensive assessment on the potential public health risks has to be undertaken. Owing to the stochastic variations in rainfall and catchment hydrology and the types of non-point pollution sources that can provide contaminants relating to different anthropogenic activities and catchment land uses, the characterisation of public health risks in stormwater is complex, tedious and not always possible to assess through conventional detection and analytical methods. In this study, a holistic approach was undertaken to assess potential public health risks in urban stormwater samples from a medium-density residential catchment. A combined chemical-toxicological assessment was used to characterise the possible health risks from chemical pollutants, while a combination of culture methods quantitative polymerase chain reaction (qPCR) detection methods were used for detection and quantification of faecal indicator bacteria (FIB) and pathogens in urban stormwater. Preliminary results showed that the concentration of chemical pollutants and the associated toxicity was relatively low. However, the concentrations of heavy metals particularly Cadmium (Cd) and Lead (Pb) have exceeded the Australian guideline values, indicating potential public health risks. Also, high numbers of FIB were detected in stormwater samples obtained from wet weather events. In addition, qPCR detection of human-related pathogens suggested frequent sewage ingression into the urban stormwater runoff during wet weather events. Further stormwater quality monitoring study will be conducted at different contrasting urban catchments, in order to undertake a more comprehensive public health risk assessment.