Mass loading and removal of benzotriazoles, benzothiazoles, benzophenones, and bisphenols in Indian sewage treatment plants

Abstract

Little is known about the occurrence of emerging environmental contaminants, such as benzotriazoles (BTRs), benzothiazoles (BTHs), benzophenones (BzPs), and bisphenol analogues (BPs) in India. In this study, we determined the occurrence and removal of BTRs, BTHs, BzPs, and BPs in five Indian sewage treatment plants (STPs). The respective measured mean concentrations (N = 5) in influents and effluents were 370 and 57.4 ng L−1 for BTRs, 50800 and 20200 ng L−1 for BTHs, 351 and 163 ng L−1 for BzPs, and 98.0 and 9.6 ng L−1 for BPs. Among the target chemicals analyzed, BTHs were found at elevated levels, and the measured levels were some of the highest ever reported in the literature. The mean concentrations (N = 5) of BTRs, BTHs, BzPs, and BPs in sludge were 44.2, 51200, 124, and 200 ng g−1 dry wt, respectively. The removal efficiencies for BTRs, BTHs, BzPs, and BPs ranged as follows: 54.2–85.6%, 23.4–85.0%, 51.8–71%, and 76.0–97.0%, respectively, and were comparable to those reported for other countries. Elevated concentrations of BTHs in Indian STPs can be related to consumption of these chemicals in a wide range of products including paper, textile and rubber materials.