scholarly journals Health risk of cyanotoxins in Lake Victoria and household drinking water for riparian communities along Nyanza Gulf

2020 ◽  
Author(s):  
Lilian Otoigo
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Health Risk ◽  
Lake Victoria ◽  
Primary Liver Cancer ◽  
Statistical Significance ◽  
Epidemiological Studies ◽  
Assay Method ◽  
Toxic Cyanobacteria ◽  
Riparian Communities

Cyanotoxins are produced by cyanobacteria which are single-celled algae that thrive in warm and nutrient rich water bodies including lakes. There are different kinds of cyanotoxins and microcystin is the most common. Microcystin mostly affects the liver. Epidemiological studies in China and Serbia have shown an association between cyanotoxins and occurrence of Primary Liver Cancer. Cyanobacteria have been reported in Lake Victoria, which is an important source of drinking water for the riparian communities, thus posing a danger to human health. However, the health risk from exposure to toxic cyanobacteria in the Nyanza Gulf water remains unknown. The purpose of this study was to assess the health risk of toxic cyanobacteria to the riparian communities in the Nyanza Gulf. In a longitudinal study adopting survey and experimental design, 127 samples were collected monthly from both households and six beaches over six months. Cyanobacterial levels were determined using an enzyme assay method (PP2A). Different methods of household water treatment were compared. Two-way ANOVA was done to determine statistical significance of microcystins levels. 84% of water samples contained microcystins. Concentration of microcystins was 3.44g/L which is over the WHO limit of 1g/L. There was no variation between beaches and water treatment (ANOVA: F=0.97, p=0.47). Filtration proved to be the most efficient method of water treatment. The health risk factor of cyanotoxins in drinking water is 3.86. There is a health risk posed by cyanotoxins to the residents of the Nyanza Gulf who use the lake water for drinking since is over the WHO limit. This information provides an insight into the quality of Lake Victoria water for drinking. The study recommends development of cyanobacteria removal methods as well as sensitizing the riparian communities on the health risk of cyanotoxins in drinking water.

scholarly journals Identification and quantification of Cyanotoxins in Lake and household water around Lake Victoria, Kenya

2020 ◽  
Author(s):  
Lilian Otoigo
Keyword(s):  
Significant Variation ◽  
High Performance ◽  
Enzyme Assay ◽  
Lake Victoria ◽  
Statistical Significance ◽  
Assay Method ◽  
Household Water ◽  
Insight Into ◽  
Riparian Communities

Cyanobacteria are single-celled algae that thrive in warm and nutrient rich water bodies. They can produce different kinds of toxins called cyanotoxins that can affect the liver. Cyanobacteria have been reported in Lake Victoria, which is an important source of drinking water for the riparian communities. This is as a result of eutrophication in Lake Victoria increasing the levels of cyanobacteria in the Nyanza Gulf. The purpose of this study was to identify and quantify microcystins in household and Lake Victoria water in Nyanza Gulf. In a longitudinal study adopting experimental design, six beaches were studied and 127 samples collected monthly from both households and beaches over six months. Cyanobacterial levels were determined using an enzyme assay method (PP2A) and microcystin strains identified using High Performance Liquid Chromatography (HPLC). Two-way ANOVA was done to determine statistical significance of microcystins. The results showed that all beaches were eutrophic resulting in flourishing of cyanobacteria. 84% of water samples contained microcystins. Concentration of microcystins was 3.44g/L. Microcystin RR (MC-RR) is the most abundant cyanotoxins followed by Microcystin YR (MC-YR) and Microcystin LR (MC-LR) is the least abundant in the Nyanza Gulf. There was significant variation between different beaches and different months (ANOVA: F=12.09, p<0.0005). This information provides an insight into the quality of Lake Victoria water for drinking based on quantities of microcystins in the sampled water. The study recommends regular monitoring of cyanobacterial cells in the lake water.

Microcystin class of toxins: health effects and safety of drinking water supplies

1994 ◽  
Vol 2 (2) ◽  
pp. 167-186 ◽  
Author(s):  
T. W. Lambert ◽  
C. F. B. Holmes ◽  
S. E. Hrudey
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Health Risk ◽  
Health Effects ◽  
Tumor Promoter ◽  
Water Supplies ◽  
Blue Green Algae ◽  
Adverse Health Effects ◽  
Human Illness ◽  
Safety Of Drinking Water

The microcystins are produced by several species of common planktonic cyanobacteria found in surface waters, but their biological function remains unknown. The microcystins have been shown to be extremely potent hepatotoxins in a variety of experimental animals and they are lethal at low doses. Microcystin-LR, one of over 40 microcystin analogues, has also been shown to be a potent tumor promoter. The toxic effects of the microcystins have been attributed to the inhibition of protein phosphatases. This inhibition causes collapse of the cytoskeleton and interferes with a general signal transduction mechanism in cells. The presence of toxic cyanobacteria in surface water has been documented in all parts of the world. The microcystins have been related to a few incidents of human illness and several incidents of animal poisoning in Canada, United States, Australia, Europe, and Africa. Therefore, exposure to the microcystins is a potentially significant health risk and toxin removal from drinking water is becoming a concern worldwide. Conventional water treatment processes (coagulation/sedimentation, chlorination) have generally proven ineffective at removing microcystin toxins from drinking water. Activated carbon, ozone, and free chlorine have been effective in removing microcystins below detectable concentrations in laboratory experiments. Considering these factors, the occurrence of microcystins in drinking water supplies deserves serious attention to insure that adverse health effects are prevented.Key words: microcystins, hepatotoxins, cyanobacteria, blue-green algae, water treatment, health risk.

scholarly journals Cyanotoxins and Cyanobacteria Cell Accumulations in Drinking Water Treatment Plants with a Low Risk of Bloom Formation at the Source

Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 430 ◽  
Author(s):  
Husein Almuhtaram ◽  
Yijing Cui ◽  
Arash Zamyadi ◽  
Ron Hofmann
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Algal Blooms ◽  
Water Concentration ◽  
Drinking Water Treatment ◽  
Enzyme Linked Immunosorbent Assay ◽  
Water Treatment Plants ◽  
Bloom Formation ◽  
Toxic Cyanobacteria ◽  
Cell Accumulation

Toxic cyanobacteria have been shown to accumulate in drinking water treatment plants that are susceptible to algal blooms. However, the risk for plants that do not experience algal blooms, but that receive a low influx of cells, is not well known. This study determined the extent of cell accumulation and presence of cyanotoxins across the treatment trains of four plants in the Great Lakes region. Samples were collected for microscopic enumeration and enzyme-linked immunosorbent assay (ELISA) measurements for microcystins, anatoxin-a, saxitoxin, cylindrospermopsin, and β-methylamino-L-alanine (BMAA). Low cell influxes (under 1000 cells/mL) resulted in significant cell accumulations (over 1 × 105 cells/mL) in clarifier sludge and filter backwash samples. Microcystins peaked at 7.2 µg/L in one clarifier sludge sample, exceeding the raw water concentration by a factor of 12. Anatoxin-a was detected in the finished drinking water of one plant at 0.6 µg/L. BMAA may have been detected in three finished water samples, though inconsistencies among the BMAA ELISAs call these results into question. In summary, the results show that plants receiving a low influx of cells can be at risk of toxic cyanobacterial accumulation, and therefore, the absence of a bloom at the source does not indicate the absence of risk.

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