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Vol. 38 No. 8 (2026): Vol 38, Issue 8 (2026)

Copyright (c) 2026 Landry Sendango Omalanga

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Influence of Physico-Chemical and Microbiological Water-Quality Variables on Aquaculture Species: A Vaal River Case Study (Gauteng, South Africa)

https://doi.org/10.14233/ajchem.2026.35827
Landry S. Omalanga
Department of Civil and Environmental Engineering and Building Science, School of Engineering and Built Environment, University of South Africa, Pretoria 0003, South Africa
https://orcid.org/0000-0002-1536-3475
Ednah K. Onyari
Department of Civil and Environmental Engineering and Building Science, School of Engineering and Built Environment, University of South Africa, Pretoria 0003, South Africa
https://orcid.org/0000-0001-6606-2675

Corresponding Author(s) : Landry S. Omalanga

omalals@unisa.ac.za

Asian Journal of Chemistry, Vol. 38 No. 8 (2026): Vol 38, Issue 8 (2026)

Abstract

This review examines the influence of physico-chemical and microbiological water‑quality variables on freshwater aquaculture in the Vaal river (Gauteng, South Africa). Available literature was examined to characterise key water‑quality parameters, including total dissolved solids (TDS), electrical conductivity (EC), turbidity, nutrients, heavy metals, microplastics, dissolved oxygen (DO), pH and microbial indicators such as Escherichia coli. In particular, this study discusses the interactive effects and aquaculture response in the Vaal river, links microbial dynamics to aquaculture health outcomes, gives the mechanistic interpretation of physico-chemical-biological linkages. The results showed the high TDS concentration (~177 mg/L) in the main stream of the Vaal river system is a potential threat to the agricultural sector, as it could be impacting on crop and aquacultural production and indications on DO concentrations are usually relatively high (>60%). The concentrations of metals in the Vaal river are generally high, leading to frequent fish kills. Furthermore, the high TDS concentrations in the Vaal river evidently influence the turbidity of the water and the higher pH values (6.3-8.7) in the Vaal river can be ascribed to higher algal concentrations. The high concentrations in E. coli (240 counts/100 mL) and algal pigments (69 mg/L) constitute a high risk the aquaculture production in the Vaal river system. To address these challenges, the water quality problem must be evaluated and resolved by reconsidering new management strategies and implementing treatment technologies. The findings of this work will assist relevant authorities in choosing appropriate water quality monitoring parameters for aquaculture areas.

Keywords

Vaal river Water quality Physico-chemical parameters Microbiological parameters Aquaculture South Africa
(1)
Omalanga, L. S.; Onyari, E. K. Influence of Physico-Chemical and Microbiological Water-Quality Variables on Aquaculture Species: A Vaal River Case Study (Gauteng, South Africa). ajc 2026, 38, 1987-1994.
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