Current Effects of Cyanobacteria Toxin in Water Sources and Containers in the Hartbeespoort Dam Area, South Africa

Mokoena, Matodzi Michael; Mukhola, Murembiwa Stanley

doi:10.3390/ijerph16224468

Cited by 10 publications

(3 citation statements)

References 11 publications

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“…In South Africa, most poisonings have been associated with M. aeruginosa, and the first case of cattle intoxication by Microcystis was reported as far back as 1927 [38]. In the following years, South African cyanobacteria have been characterized by several studies on ecology, toxicology, and water management implications [24,26,38,103,109,120].…”

Section: South Africamentioning

confidence: 99%

Genetic Diversity of Microcystin Producers (Cyanobacteria) and Microcystin Congeners in Aquatic Resources across Africa: A Review Paper

Chia

Ameh

George

et al. 2022

Toxics

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Microcystins are produced by multifaceted organisms called cyanobacteria, which are integral to Africa’s freshwater environments. The excessive proliferation of cyanobacteria caused by rising temperature and eutrophication leads to the production and release of copious amounts of microcystins, requiring critical management and control approaches to prevent the adverse environmental and public health problems associated with these bioactive metabolites. Despite hypotheses reported to explain the phylogeography and mechanisms responsible for cyanobacterial blooms in aquatic water bodies, many aspects are scarcely understood in Africa due to the paucity of investigations and lack of uniformity of experimental methods. Due to a lack of information and large-scale studies, cyanobacteria occurrence and genetic diversity are seldom reported in African aquatic ecosystems. This review covers the diversity and geographical distribution of potential microcystin-producing and non-microcystin-producing cyanobacterial taxa in Africa. Molecular analyses using housekeeping genes (e.g., 16S rRNA, ITS, rpoC1, etc.) revealed significant sequence divergence across several cyanobacterial strains from East, North, West, and South Africa, but the lack of uniformity in molecular markers employed made continent-wise phylogenetic comparisons impossible. Planktothrix agardhii, Microcystis aeruginosa, and Cylindrospermopsis raciborskii (presently known as Raphidiopsis raciborskii) were the most commonly reported genera. Potential microcystin (MCs)-producing cyanobacteria were detected using mcy genes, and several microcystin congeners were recorded. Studying cyanobacteria species from the African continent is urgent to effectively safeguard public and environmental health because more than 80% of the continent has no data on these important microorganisms and their bioactive secondary metabolites.

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Section: South Africamentioning

confidence: 99%

Genetic Diversity of Microcystin Producers (Cyanobacteria) and Microcystin Congeners in Aquatic Resources across Africa: A Review Paper

Chia

Ameh

George

et al. 2022

Toxics

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“…The quality of water in the Hartbeespoort Dam has gradually deteriorated with time; the dam is characterised by eutrophic conditions, an overabundance of Hyacinth [9,[21][22][23][24][25][26][27], as well as persistent cyanobacterial blooms [13,[28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Multivariate Analysis of the Dynamics in Water Quality and Trophic Status of the Crocodile River and Hartbeespoort Dam

Matlala¹

2023

eer

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Economic expansion coupled with population growth and associated anthropogenic activities are a threat to water resources globally. This study assessed the dynamics in water quality and trophic status of one of South Africa's hyper-eutrophic reservoirs, the Hartbeespoort Dam. Spatio-temporal variability in water quality parameters was determined on historical data spanning a period of forty years , with the aim of determining decadal changes in the Water Quality Index (WQI), the Water Pollution Index (WPI), the Canadian Council of Ministers of the Environment-Water Quality Index (CCME-WQI) as well as the Nutrient Pollution Index (NPI) and TN:TP ratios in the Hartbeespoort Dam as well as the Crocodile River. The calculated indices provide a single aggregated standardized score of water quality. The efficiency of a bioremediation programme (2007)(2008)(2009)(2010)(2011)(2012) implemented as a mitigation measure to combat eutrophication in the dam was assessed. The study also investigated the impact of rainfall on the variability of the concentration and level of selected physico-chemical parameters. The results of the study revealed that apart from turbidity, rainfall has no significant impact on the variability of other water quality parameters studied. Furthermore, the WQI, CCME-WQI, WPI, as well as the NPI classified the general water quality of the dam as extremely poor and highly polluted. Moreover, TN:TP showed an increase in TP over time, further exacerbating hypereutrophic conditions in the catchment. The study also showed that the bioremediation programme was effective in reducing external P loading, however, bioturbation resulted in the resuspension of historical internal P loads, thus maintaining high phosphate concentrations at the site downstream from the Hartbeespoort Dam.

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“…A cyanobacterial bloom occurrence may result in metabolite (cyanotoxins and taste and odor agents) production and release, which is considered a widespread problem in drinking water resources around the world [1][2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Evidence-Based Framework to Manage Cyanobacteria and Cyanotoxins in Water and Sludge from Drinking Water Treatment Plants

Jalili

Moradinejad

Zamyadi

et al. 2022

Toxins

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Freshwater bodies and, consequently, drinking water treatment plants (DWTPs) sources are increasingly facing toxic cyanobacterial blooms. Even though conventional treatment processes including coagulation, flocculation, sedimentation, and filtration can control cyanobacteria and cell-bound cyanotoxins, these processes may encounter challenges such as inefficient removal of dissolved metabolites and cyanobacterial cell breakthrough. Furthermore, conventional treatment processes may lead to the accumulation of cyanobacteria cells and cyanotoxins in sludge. Pre-oxidation can enhance coagulation efficiency as it provides the first barrier against cyanobacteria and cyanotoxins and it decreases cell accumulation in DWTP sludge. This critical review aims to: (i) evaluate the state of the science of cyanobacteria and cyanotoxin management throughout DWTPs, as well as their associated sludge, and (ii) develop a decision framework to manage cyanobacteria and cyanotoxins in DWTPs and sludge. The review identified that lab-cultured-based pre-oxidation studies may not represent the real bloom pre-oxidation efficacy. Moreover, the application of a common exposure unit CT (residual concentration × contact time) provides a proper understanding of cyanobacteria pre-oxidation efficiency. Recently, reported challenges on cyanobacterial survival and growth in sludge alongside the cell lysis and cyanotoxin release raised health and technical concerns with regards to sludge storage and sludge supernatant recycling to the head of DWTPs. According to the review, oxidation has not been identified as a feasible option to handle cyanobacterial-laden sludge due to low cell and cyanotoxin removal efficacy. Based on the reviewed literature, a decision framework is proposed to manage cyanobacteria and cyanotoxins and their associated sludge in DWTPs.

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Current Effects of Cyanobacteria Toxin in Water Sources and Containers in the Hartbeespoort Dam Area, South Africa

Cited by 10 publications

References 11 publications

Genetic Diversity of Microcystin Producers (Cyanobacteria) and Microcystin Congeners in Aquatic Resources across Africa: A Review Paper

Genetic Diversity of Microcystin Producers (Cyanobacteria) and Microcystin Congeners in Aquatic Resources across Africa: A Review Paper

Multivariate Analysis of the Dynamics in Water Quality and Trophic Status of the Crocodile River and Hartbeespoort Dam

Evidence-Based Framework to Manage Cyanobacteria and Cyanotoxins in Water and Sludge from Drinking Water Treatment Plants

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