Detection of Pharmaceutical Residues in Surface Waters of the Eastern Cape Province

Abstract

Pharmaceuticals are emerging contaminants in the aquatic environments. Their presence poses toxicological effects in humans and animals even at trace concentrations. This study investigated the presence of antibiotics, anti-epilepsy and anti-inflammatory drugs in river water of selected rivers in the Eastern Cape Province in South Africa. Enzyme-linked immunosorbent assay was used for screening of sulfamethoxazole and fluoroquinolones antibiotics. The samples were collected in upper-stream, middle-stream and lower-stream regions of the rivers and effluent of selected wastewater treatment plants. Pre-concentration of the samples was conducted using lyophilisation and extraction was conducted using solid phase extraction (SPE) on Waters Oasis hydrophilic-lipophilic-balanced cartridge. The percentage recovery after sample clean-up on SPE was 103% ± 6.9%. This was followed by ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry. The detected analytes were sulfamethoxazole, erythromycin, clarithromycin and carbamazepine. Carbamazepine and erythromycin were detected in high concentrations ranging from 81.8 to 36,576.2 ng/L and 11.2 to 11,800 ng/L respectively, while clarithromycin and sulfamethoxazole were detected at moderate concentrations ranging from 4.8 to 3280.4 ng/L and 6.6 to 6968 ng/L, respectively. High concentrations of pharmaceuticals were detected on the lower-stream sites as compared to upper-stream sites.

Trace Detection and Quantitation of Antibiotics in a South African Stream Receiving Wastewater Effluents and Municipal Dumpsite Leachates

“…The general observation from these reviews is that the number and classes of pharmaceuticals targeted in each study remains limited. In South African alone, the number of antibiotics monitored recently in various studies is low, with 13 antibiotics monitored in Durban water bodies (Faleye et al, 2019), 4 in the surface waters of the Eastern Cape Province (Vumazonke et al, 2020) and 3 in water samples from the Gauteng Province (Mashile et al, 2021).…”

Development of a GIS-based knowledge hub for contaminants of emerging concern in South African water resources using open-source software: Lessons learnt

“…Archer et al [ 40 ] detected 40 pharmaceuticals and PPCPs in a surface water source in Gauteng including antibiotics, NSAIDs, antihistamines, stimulants, anti-epileptics, anti-depressants, analgesics, medication for diabetics and hypertension, drug precursors, plasticizers, UV filters, parabens, x-ray contrast media and beta blockers. Targeted analysis in samples collected at rivers in the Eastern Cape (Buffalo, Bloukrans, Swartkops and Tyhume) revealed high levels of antibiotics (erythromycin −11.2 to 11 800 ng/L, clarithromycin −4.8 to 3280.4 ng/L, sulfamethoxazole −6.6 to 6968 ng/L), anti-epileptics (81.8–36 576.2 ng/L), and anti-inflammatory drug residues [ 41 ]. The presence of these compounds in South Africa surface waters is an indication of the fact that the WWTPs are not effective in removing these compounds during the sewage treatment process [ 39 , 42 ].…”

Minimizing the environmental impact of unused pharmaceuticals: Review focused on prevention

“…The concentrations of drugs found in the environment are under therapeutic levels. In water surfaces that receive treated wastewater, pharmaceuticals are detected in concentrations less than 100 ng/L (Vumazonke et al, 2020;Björklund and Svahn, 2021;Li et al, 2021). These low concentrations are the reason for the difficult assessment of their toxic effects on the ecosystem and human health.…”