Modelling of endocrine disrupting chemicals (EDCs) in recycling schemes with multimedia fugacity model in South East Queensland
Global climate change, fast population growth, and the worst drought conditions have placed great pressure on water supplies in South East Queensland. To address this issue, the West Corridor Recycled Water Project (WCRWP) was commenced in 2006 with a capacity of 232 ML/d of purified recycled wastewater. About half of the recycled water will be pumped to power stations and the remaining 115 ML/d will be recharged into Wivenhoe reservoir for drinking water supply. The major challenge for recycling systems is the removal of harmful substances to meet drinking water supply guidelines and industrial requirements. A variety of methods can remove these harmful substances to very low level, which minimises health risks to humans and wild life species. However, recent research shows that some contaminants can impose adverse effects even at extreme low concentration levels (e.g. ng/L). Endocrine disrupting chemicals (EDCs) such as steroidal compounds are one group of these contaminants with particular importance. Exposure to EDCs has led to increased level of vitellogenin (VTG), altered sexual ratio, and reproductive abnormalities in aquatic species. Male testicular and prostate cancers, female breast cancers and other adverse human health effects have also been linked to EDCs. The major point source of EDCs is effluent from wastewater treatment plants. Although the effluent from six wastewater treatment plants in the WCRWP will be treated by high efficient reverse osmosis (RO) and advanced oxidation process (AOP), the final distribution of EDCs in different phases such as water, sediment, soil, biota in the Wivenhoe reservoir is unknown. Therefore, the aim of this paper is to use a multimedia fugacity model to predict the distribution of three most important steroidal estrogens (estrone (E1), 17߭estradiol (E2) and 17a-ethinylestradiol (EE2)) in Wivenhoe reservoir. With physiochemical properties, environmental parameters, removal efficiencies and degradation half-lives as model input, the final results indicated that over 99% of the estrogens were removed through reaction (94% to 99%) and advection (0.23% to 6.0%) in the water phase, followed by sediment with less than 0.50%. The removal through air and soil was negligible. At typical conditions, the predicted distribution concentrations in water, sediment, soil, biota and suspended sediments will not imposes threat to human health and aquatic species.
AWA Qld Regional Conference