Distribution, removal efficiencies and environmental risk assessment of benzophenone and salicylate UV filters in WWTPs and surface waters from Romania

Abstract

This paper is aimed at assessing the occurrence, fate, transport and ecological risk of ten organic UV filters in the aquatic environment of Romania. In influents, the highest concentration levels were determined for benzophenone-1 and 2,3,4-trihydroxybenzophenone with values of thousands of ng L⁻¹ (up to 2787 and 1108 ng L⁻¹, respectively). In the sewage sludge samples, the predominant contaminants were those with high hydrophobicity, namely benzyl salicylate, homosalate and ethylhexyl salicylate (up to 1395, 1035 and 688 ng g⁻¹ dw, respectively). Although the removal efficiency of these organic micropollutants in the WWTPs proved to be quite high, over 60% of the UV filters monitored, some of them were also detected in effluents, in relatively high concentrations. Thus, the effluents were dominated by ethylhexyl salicylate and benzophenone-1 with concentrations up to 219 and 181 ng L⁻¹, respectively. In surface waters, the most abundant compounds were found to be benzophenone-1, benzophenone-8 and 4-hydroxybenzophenone, with values up to 206, 108 and 159 ng L⁻¹ respectively. On calculating the risk coefficient of the organic UV filters investigated on various aquatic species, it was observed that for fish, benzophenone-2 presents a medium risk both in effluents and in samples taken downstream of the WWTPs, while benzophenone-1 presents a high risk also in effluents as well as in surface waters taken upstream and downstream of the WWTPs. Among the salicylate derivatives, homosalate was found to present a medium risk for Daphnia magna in both effluents and samples taken downstream of the WWTPs, while ethylhexyl salicylate posed a high risk for freshwater algae in all three types of analyzed samples.