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Muluye T, Fetahi T, Engdaw F, Mohammed A. Cyanotoxins in African waterbodies: occurrence, adverse effects, and potential risk to animal and human health. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2023; 45:7519-7542. [PMID: 37603139 DOI: 10.1007/s10653-023-01724-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/03/2023] [Indexed: 08/22/2023]
Abstract
Public concerns about cyanotoxins production in water and its detrimental impacts on human and animal health are growing primarily due to the widespread eutrophication observed in aquatic ecosystems. A review of relevant literature was done to determine the degree of cyanotoxin occurrence and its harmful effects in African waterbodies. Data were extracted from 64 published studies from 1990 to 2022 that quantified the concentration of cyanotoxins in African aquatic ecosystems. Cyanotoxins have been reported in 95 waterbodies (29 lakes, 41 reservoirs, 10 ponds, 9 rivers, 5 coastal waters, and 1 irrigation canal) from 15 African countries. Cyanotoxins were documented in all the regions of Africa except the central region. Microcystins have been reported in nearly all waterbodies (98.9%), but anatoxin-a (5.3%), cylindrospermopsin (2.1%), nodularins (2.1%), homoanatoxin-a (1.1%), and β-N-methylamino-L-alanine (1.1%) were encountered in a small number of water ecosystems, homoanatoxin-a and β-N-methylamino-L-alanine each occurred in one waterbody. The largest concentrations of microcystins and nodularins were reported in South African Lakes Nhlanganzwani (49,410 μg L-1) and Zeekoevlei (347,000 μg g-1). Microcystin concentrations exceeding the WHO guideline for lifetime drinking water (1 μg L-1) were reported in 63% of the aquatic ecosystems surveyed. The most frequently reported toxin-producing cyanobacteria genus is Microcystis spp. (73.7%), followed by Oscillatoria spp. (35.8%) and Dolichospermum spp. (33.7%). Cyanotoxin-related animal mortality and human illness were reported in the continent. Consequently, it is necessary to regularly monitor the level of nutrients, cyanobacteria, and cyanotoxins in African waterbodies in an integrated manner to devise a sustainable water resources management.
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Affiliation(s)
- Tesfaye Muluye
- Africa Centre of Excellence for Water Management, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
| | - Tadesse Fetahi
- Department of Zoological Sciences, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
| | - Flipos Engdaw
- Africa Centre of Excellence for Water Management, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
| | - Adem Mohammed
- Africa Centre of Excellence for Water Management, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
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Chia MA, Ameh I, George KC, Balogun EO, Akinyemi SA, Lorenzi AS. Genetic Diversity of Microcystin Producers (Cyanobacteria) and Microcystin Congeners in Aquatic Resources across Africa: A Review Paper. TOXICS 2022; 10:772. [PMID: 36548605 PMCID: PMC9783101 DOI: 10.3390/toxics10120772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/30/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
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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Affiliation(s)
- Mathias Ahii Chia
- Department of Botany, Ahmadu Bello University, Zaria 810107, Nigeria
| | - Ilu Ameh
- Department of Biochemistry, Ahmadu Bello University, Zaria 810107, Nigeria
- African Centre of Excellence for Neglected Tropical Diseases and Forensic Biotechnology, Ahmadu Bello University, Zaria 810107, Nigeria
| | - Korie Chibuike George
- Department of Biochemistry, Ahmadu Bello University, Zaria 810107, Nigeria
- African Centre of Excellence for Neglected Tropical Diseases and Forensic Biotechnology, Ahmadu Bello University, Zaria 810107, Nigeria
| | | | | | - Adriana Sturion Lorenzi
- Department of Cellular Biology, Institute of Biological Sciences, University of Brasília—UnB, Brasília 70910-900, Brazil
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Abdullahi H, Tanimu Y, Akinyemi SA, do Carmo Bittencourt-Oliveira M, Chia MA. Assessment of microcystins in surface water and irrigated vegetables in Kwaru stream, Hayin Danmani, Kaduna-Nigeria. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:78303-78313. [PMID: 35689773 DOI: 10.1007/s11356-022-21381-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
Microcystins (MCs) are hepatotoxic secondary metabolites produced by several genera of cyanobacteria. Human exposure routes include drinking contaminated water and consuming contaminated fish, vegetables, crops, and even food supplements that contain cyanotoxin. This study investigated the presence of MCs in a stream with a long history of use as a source of water for irrigation farming. To establish the risk of a lack of monitoring programs, we studied MCs contamination of irrigated vegetables. Toxin levels in the water were generally <0.05 μg L-1 in all the investigated stations. Total microcystin concentrations in spinach (0.306 μg Kg-1 upstream and 0.217 μg Kg-1 downstream), lettuce (0.085 μg Kg-1 upstream and 0.462 μg Kg-1 downstream), carrot (0.050 μg Kg-1 downstream and 0.116 μg Kg-1 downstream), cabbage (0.014 μg Kg-1 upstream and 0.031 μg Kg-1 downstream), tomatoes (0.233 μg Kg-1 upstream), and bitter leaf (0.460 μg Kg-1 upstream and 0.050 μg Kg-1 downstream) collected in March were higher than the levels detected in samples of the same vegetables collected in April. These results highlight Nigeria's severe public health problem, especially in regions with long dry season spells. The level of MCs contamination of irrigated vegetables implies a potential for chronic exposure and associated health challenges.
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Affiliation(s)
| | - Yahuza Tanimu
- Department of Botany, Ahmadu Bello University, Zaria, Nigeria
| | | | - Maria do Carmo Bittencourt-Oliveira
- Department of Biological Sciences, Luiz de Queiroz College of Agriculture, University of São Paulo, Av. Pádua Dias, 11, São Dimas, Zip Code 13, Piracicaba, SP, 418-900, Brazil
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Zhang J, Wei J, Massey IY, Peng T, Yang F. Immobilization of Microbes for Biodegradation of Microcystins: A Mini Review. Toxins (Basel) 2022; 14:toxins14080573. [PMID: 36006234 PMCID: PMC9416196 DOI: 10.3390/toxins14080573] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/13/2022] [Accepted: 07/19/2022] [Indexed: 12/02/2022] Open
Abstract
Harmful cyanobacterial blooms (HCBs) frequently occur in eutrophic freshwater ecosystems worldwide. Microcystins (MCs) are considered to be the most prominent and toxic metabolites during HCBs. MCs may be harmful to human and animal health through drinking water and recreational water. Biodegradation is eco-friendly, cost-effective and one of the most effective methods to remove MCs. Many novel MC-degrading bacteria and their potential for MCs degradation have been documented. However, it is a challenge to apply the free MC-degrading bacterial cells in natural environments due to the long-term operational instability and difficult recycling. Immobilization is the process of restricting the mobility of bacteria using carriers, which has several advantages as biocatalysts compared to free bacterial cells. Biological water treatment systems with microbial immobilization technology can potentially be utilized to treat MC-polluted wastewater. In this review article, various types of supporting materials and methods for microbial immobilization and the application of bacterial immobilization technology for the treatment of MCs-contaminated water are discussed. This article may further broaden the application of microbial immobilization technology to the bioremediation of MC-polluted environments.
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Affiliation(s)
- Jiajia Zhang
- Hunan Provincial Key Laboratory of Clinical Epidemiology, Xiangya School of Public Health, Central South University, Changsha 410078, China
| | - Jia Wei
- Hunan Provincial Key Laboratory of Clinical Epidemiology, Xiangya School of Public Health, Central South University, Changsha 410078, China
| | - Isaac Yaw Massey
- Hunan Provincial Key Laboratory of Clinical Epidemiology, Xiangya School of Public Health, Central South University, Changsha 410078, China
| | - Tangjian Peng
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, China
- Correspondence: (T.P.); (F.Y.); Tel./Fax: +86-731-8480-5460 (F.Y.)
| | - Fei Yang
- Hunan Provincial Key Laboratory of Clinical Epidemiology, Xiangya School of Public Health, Central South University, Changsha 410078, China
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, China
- The Key Laboratory of Ecological Environment and Critical Human Diseases Prevention of Hunan Province, Department of Education, School of Basic Medical Sciences, Hengyang Medical School, University of South China, Hengyang 421001, China
- Correspondence: (T.P.); (F.Y.); Tel./Fax: +86-731-8480-5460 (F.Y.)
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