Bisphenol A in German watersheds: Part II. FlowEQ model‐based characterization of sources and current and future conditions

Abstract

Increasing scientific and regulatory concern regarding environmental concentrations of bisphenol A (BPA) increases the need to understand the 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 physicochemical 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 decrease. 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. Integr Environ Assess Manag 2023;00:1–13. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Bisphenol A in surface waters in Germany: Part I. Reassessment of sources and emissions pathways for FlowEQ modeling

“…However, the restriction on the use of BPA in thermal paper has entered into force in January 2020, and it is expected that this will have a significant effect on the circulating BPA in the paper recycling system and eventually on the future BPA concentration in surface waters. So, in the companion paper (Bock et al, 2023), attention should be paid to different scenarios for estimating surface water concentrations based on the different extent of future contributions from this important pathway. The current importance of the paper recycling pathway is strikingly indicated by the BPA levels in toilet paper.…”

“…The calculated loadings were 0.017 kg a −1 (Category 1b), 0.38 kg a −1 (Category 2), 0.00012 kg a −1 (Category 3), 0.0077 kg a −1 (Category 4), and 6.3 kg a −1 (Category 5). These values form the basis for calculating loadings per landfill used as input to the FlowEQ model, described in Bock et al (2023). The calculated loadings for Class 1a (49 kg a −1 ) do not enter the surface water or WWTP directly, because they undergo an on-site pretreatment first.…”

“…The measurements provided above are used as the basis for calculating per capita or per facility (paper recycling and landfills) loadings to surface water or wastewater for input to the FlowEQ model described in Bock et al (2023). Briefly, BPA loadings from the consumer use of articles were calculated using concentrations in articles, annual article use, fraction of BPA leached to water, and the population of Germany.…”

“…The model considers emissions (loading to soil, water, and air), advection (transport of surface water in a flow network), degradation, and multimedia exchange (see Figure 1). The model domain includes German watersheds and the upstream drainage areas (Bock et al, 2023). An earlier version of this model was previously used for the assessment of BPA in the environment (Ramboll Environ/ BiPRO, 2015).…”

“…The current article and Bock et al (2023) are intended to address the uncertainties identified above and to determine the sources of BPA in surface waters more precisely. This article serves to provide the data needed for more realistic and precise modeling in Bock et al (2023). Due to the lack of sufficient monitoring of BPA in wastewater and landfill leachate, BPA measurements at 23 wastewater treatment plants (WWTPs; influent/effluent, sewage sludge) and 21 landfills (leachate) in Germany were performed.…”