Benzosulfonamides in wastewater: Method development, occurrence and removal efficiencies

Abstract

Benzosulfonamides (BeSAs) are a family of compounds with a broad application as industrial chemicals: plasticizers, intermediates for pesticides and drugs or used in the production of artificial sweeteners, among others. BeSAs constitute a class of organic compounds of emerging environmental concern. However, analytical methodologies for their determination in the environment are scarce as well as there is a lack of environmental occurrence data for these substances. An analytical methodology based on pseudo-SRM liquid chromatography–tandem mass spectrometry (LC–(ESI–)MS/MS) was developed and optimized for the determination of three BeSAs (benzenesulfonamide (BSA), o-toluenesulfonamide (o-TSA) and p-toluenesulfonamide (p-TSA)) in wastewater. The solid phase extraction protocol was also carefully optimized. The method provided recoveries in the range 83–118% (three different fortification levels). Good precision (<10.2% (intra-day) and <13.6% (inter-day)) and limits of detection achieved (11–89ngL−1) allow a reliable quantification of these compounds in both effluent and influent wastewaters. The presence of BeSAs has been evaluated during seven consecutive days in influent and effluent samples from the wastewater treatment plant of Athens, Greece. o-TSA and p-TSA were detected in 100% of the samples, while BSA was detected in all the influents and in 43% of the effluents. All three compounds were determined in relevant concentrations (up to 1.4μgL−1 in the case of p-TSA), constituting the first evidence of the presence of these compounds in Greece, and contributing to the scarce occurrence data. Removal efficiencies of BeSAs during wastewater treatment was also assessed and discussed. In this regard, different behaviors were observed: while BSA and p-TSA were removed in different rates, o-TSA was formed during wastewater treatment. A daily load of 0.48kg of o-TSA and 0.47kg of p-TSA was discarded in the receiving Saronikos Gulf.