Occurrence and prevalence of antibiotics in wastewater treatment plants and effluent receiving rivers in South Africa using UHPLC-MS determination

Omuferen-Oke Loveth Oharisi; Somandla Ncube; Hlengilizwe Nyoni; Mzukisi Lawrence Madikizela; Oluwole Joshua Olowoyo; Bethusile Rejoice Maseko

doi:10.1016/j.jenvman.2023.118621

Occurrence and prevalence of antibiotics in wastewater treatment plants and effluent receiving rivers in South Africa using UHPLC-MS determination

J Environ Manage. 2023 Nov 1:345:118621. doi: 10.1016/j.jenvman.2023.118621. Epub 2023 Jul 20.

Authors

Omuferen-Oke Loveth Oharisi¹, Somandla Ncube², Hlengilizwe Nyoni³, Mzukisi Lawrence Madikizela³, Oluwole Joshua Olowoyo⁴, Bethusile Rejoice Maseko⁵

Affiliations

¹ Department of Chemistry, Sefako Makgatho Health Sciences University, P.O Box 60, Medunsa, 0204, South Africa.
² Department of Chemistry, Durban University of Technology, P O Box 1334, Durban, 4000, South Africa.
³ Institute for Nanotechnology and Water Sustainability, College of Science, Engineering and Technology, University of South Africa, Florida Science Campus, 1710, South Africa.
⁴ Department of Health Science and the Water School, Florida Gulf Coast University, Fort Myers, FL, USA.
⁵ Department of Chemistry, Sefako Makgatho Health Sciences University, P.O Box 60, Medunsa, 0204, South Africa. Electronic address: bethusile.maseko@smu.ac.za.

PMID: 37480667
DOI: 10.1016/j.jenvman.2023.118621

Abstract

The increased usage of antibiotics over the recent years has led to an increased interest in monitoring their presence in wastewater all over the world. In this study the occurrence of sixteen (16) selected antibiotics (amoxicillin, ampicillin, azithromycin, ciprofloxacin, doxycycline, erythromycin, gentamicin, metronidazole, norfloxacin, ofloxacin, penicillin, sulfamethoxazole, sulfapyridine, sulfamethizole, tetracycline and trimethoprim) were determined in two wastewater treatment plants and two effluent receiving rivers in Northern part of Pretoria, South Africa. Targeted screening and identification of antibiotics was done using ultra high-performance liquid chromatography coupled with mass spectrometry after sample clean-up and pre-concentration using solid phase extraction. The concentrations of the targeted antibiotics detected in influent samples ranged between 0.78 and 96.8 ng mL^-1 and those in effluent were between 0.12 and 9.89 ng mL^-1. The highest recorded concentrations in all samples were those of doxycycline (30.9-120 ng mL^-1) and sulfamethoxazole (2.52-96.8 ng mL^-1) in effluent and influent samples, respectively. The concentrations of antibiotics in the rivers receiving effluents were between 0.03 and 72.8 ng mL^-1 in upstream samples and 0.008-76.8 ng mL^-1 in downstream samples, indicating that there is other source of contaminate to these rivers other than the treatment plants. Risk assessment using the hazard quotients ranged between 0.24 and 889 indicating that the presence of these antibiotics and antibiotic mixtures posed higher ecological risks to aquatic organisms. From the study, it could be concluded that wastewater treatment plants were releasing antibiotics to the environment and posing a risk to the aquatic ecosystem and public health. Therefore, there is a need to research into developing more efficient conventional wastewater treatment technologies that can completely remove antibiotics from wastewater.

Keywords: Antibiotic resistance; Antibiotics; Ecotoxicity; Removal efficiency; Wastewater treatment plant.

MeSH terms

Anti-Bacterial Agents*
Chromatography, High Pressure Liquid
Doxycycline*
Ecosystem
Prevalence
South Africa
Sulfamethoxazole
Wastewater

Substances

Anti-Bacterial Agents
Doxycycline
Wastewater
Sulfamethoxazole