Bisphenol A in German Watersheds: Part II: FlowEQ Model Based Characterization of Sources and Current/Future Conditions
Increasing scientific and regulatory concern regarding environmental concentrations of bisphenol A (BPA) increases the need to understand sources and sinks of this chemical. We developed a coupled flow network/fugacity-based fate and transport model to assess the contribution of different emissions sources to the concentration of BPA in surface water in Germany. The model utilizes BPA loadings and sinks, BPA physico/chemical properties, a water flow network, environmental characteristics, and fugacity equations. The model considers industrial emissions, leaching from BPA containing articles, wastewater treatment and bypass events, and emissions from landfills. The model also considers different scenarios that account for changes in the usage profile of BPA. Model predictions compare favorably to measured surface water concentrations, with the modeled concentrations generally falling within the range of measured values. Model scenarios that consider reductions in BPA usage due to government mandated restrictions and voluntary reductions in usage predict falling BPA concentrations that are consistent with the most recent monitoring data. Model predictions of the contributions from different usage scenarios and wastewater treatment methods can be used to assess the efficacy of different restrictions and waste handling strategies to support efforts to evaluate the costs and benefits associated with actions aimed at reducing BPA levels in the environment. This feature of the model is of particular importance given current efforts to update the regulations regarding BPA usage in the EU. The model indicates that as the current restriction on BPA in thermal paper works through the paper recycling process, BPA concentrations will continue to drop. Other actions, such as upgrades to the stormwater and wastewater infrastructure to minimize the frequency of storm related bypasses, are predicted to provide more meaningful reductions than additional restrictions on usage.