Occurrence of selected pharmaceuticals in wastewater and sludge samples from wastewater treatment plants in Eastern Cape province of South Africa

Abstract

ABSTRACT The occurrence of pharmaceuticals in various wastewater treatment plants (WWTPs) and their discharge into the surface water are existing global challenges. However, such challenges are more detrimental in developing countries due to the aging infrastructure and its vandalism influenced by poverty, resulting in the illegal breakdown of the WWTPs. This study investigated the presence of efavirenz, ibuprofen, naproxen, sulfamethoxazole, and trimethoprim in WWTPs. Ultrasound-assisted extraction (UAE) followed by solid-phase extraction (SPE) was used to extract these pharmaceuticals in sludge samples, with wastewater extracted with only the latter. This was followed with analysis using a high-performance liquid chromatography-photo-diode array detection system. Recoveries found after spiking the samples with analytes at different concentrations ranged from 56 to 117%. An antibiotic, sulfamethoxazole, was among the prominent drugs in untreated wastewater with its concentration reaching 77 ug L-1. All the analytes were detected in sludge samples, with naproxen having the highest concentration of 13.35 ng g-1. The pharmaceutical with the lowest removal efficiency (2-12%) in WWTPs was efavirenz, while other drugs were fairly removed from wastewater. Overall, the findings of this study indicate the dysfunctionality of selected WWTPs in the Eastern Cape province of South Africa due to the release of high amounts of pharmaceuticals into the surface water which can be detrimental to humans, animals, and aquatic life.