Seminar: Evaluating the fate of benzophenone-UV filters and transformation products during managed aquifer recharge: the role of reactive barriers and the biofilm as an environmental compartment
Next Seminar: Thursday 18 nov at 12:15h
Room: UPC, Building D2 2º Floor, Room 212
Presenter: Sonia Jou, PhD Student
Title: Evaluating the fate of benzophenone-UV filters and transformation products during managed aquifer recharge: the role of reactive barriers and the biofilm as an environmental compartment
The fate of selected UV filters (UVFs) in two Managed Aquifer Recharge (MAR) systems was investigated by determining their concentration in the water source, along the flow paths, and in the aquifer material and biofilm. Overall, our recharge systems improved the degradation of UV filters with higher rates in the recharge system implemented with a reactive barrier made up of compost. Three transformation products (TPs) of benzophenone-3 (oxybenzone, BP-3) were also detected and quantified (benzophenone-1 (BP-1), 4,4’-dihydroxybenzophenone (4-DHB), and 2,2’-dihydroxy-4-methoxybenzophenone (DHMB)). Similar to BP-3, their degradation was higher in the compost system, which could be associated to a higher variability of the redox conditions produced by the reactive barrier. Indeed, in the system operated with the reactive barrier, another metabolite of BP-3, 4-hydroxybenzophenone (4-HB), was detected. Interestingly, only this compound was found in both the biofilm and the soil. Its accumulation in the biofilm can be explained by its lipophilicity (logKow= 3.02). The other UVFs, benzophenone-4 (BP-4) and avobenzone (AVO) were found at low concentration in waters, however, AVO was also detected in the biofilm, probably due to its high lipophilicity (logKow= 4.51) . BP-4 concentration in water was quite high, which could be associated with a low degradability in the WWTP, low lipophilicity (logKow= 0.88) and weak acidic character (pKa 2.4). Despite that, this compound was also adsorbed onto the sediment and biofilm. Overall, this work demonstrates that the implementation of a reactive barrier in MAR systems improves substantially the degradation extent of UVFs, specially of BP-3 and its TPs, and that biofilm can be considered as a key environmental compartment favoring the retention and further degradation of the UVFs in porous media.