Occurrence, fate and environmental risk of anionic surfactants, bisphenol A, perfluorinated compounds and personal care products in sludge stabilization treatments

Abstract

In this work, twenty-three endocrine disrupting compounds have been monitored in sludge from different stages of four sludge stabilization treatments (anaerobic digestion, aerobic digestion, composting and anaerobic stabilization ponds). Their occurrence and fate in sludge stabilization plants and their potential environmental risk in treated sludge and in treated sludge-amended soils have been evaluated. Monitored compounds were six perfluoroalkyl compounds (PFC), four anionic surfactants (sodium alkylsulfates), a plasticiser (bisphenol A (BPA)), four preservatives (parabens), six UV-filters (benzophenones) and two biocides (triclosan and triclocarban). Only two of the UV-filters were not detected in any of the 141 analysed samples. Anionic surfactants (mean concentrations up to 1673 ng/g dry matter (dm) for the sum of surfactants) were the compounds at the highest concentration levels followed by biocides (up to 512 ng/g dm) and UV-filters (up to 662 ng/g dm). The concentrations of anionic surfactants, preservatives and UV-filters decreased 78, 25 and 80%, respectively, after anaerobic digestion. The concentration of perfluorinated carboxylic acids only decreased after composting (80% reduction) whereas biocides and BPA were not affected by any of the studied treatments. Environmental risks (risk quotients > 1) were obtained for all compounds, except for triclocarban and sodium octadecylsulfate, in treated sludge. In treated sludge-amended soils, risk quotients were lower than 1 for all compounds except for triclosan.