Cyanobacteria and microcystin contamination in untreated and treated drinking water in Ghana

© 2017, Page Press Publications. All rights reserved. Although cyanobacterial blooms and cyanotoxins represent a worldwide-occurring phenomenon, there are large differences among different countries in cyanotoxin-related human health risk assessment, management practices and policies. While national standards, guideline values and detailed regulatory frameworks for effective management of cyanotoxin risks have been implemented in many in­dustrialized countries, the extent of cyanobacteria occurrence and cyanotoxin contamination in certain geographical regions is underreported and not very well understood. Such regions include major parts of tropical West and Central Africa, a region constisting of more than 25 countries occupying an area of 12 million km2, with a total population of 500 milion people. Only few studies focusing on cyanotoxin occurrence in this region have been published so far, and reports dealing specifically with cyanotoxin contamination in drinking water are extremely scarce. In this study, we report seasonal data on cyanobactcria and microcystin (MC) contamination in drinking water reservoirs and adjacent treatment plants located in Ghana, West Africa. During January-June 2005, concentrations of MCs were monitored in four treatment plants supplying drinking water to major metropolitan areas in Ghana: the treatment plants Barekese and Owabi, which serve Kumasi Metropolitan Area, and the plants Kpong and Weija, providing water for Accra-Tema Metropolitan Area. HPLC analyses showed that 65% samples of raw water at the intake of the treatment plants contained intracellular MCs (maximal detected concentration was 8.73 fig L-1), whereas dissolved toxins were detected in 33% of the samples. Significant reduction of cyanobacterial cell counts and MC concentrations was achieved during the entire monitoring period by the applied conventional water treatment methods (alum flocculation, sedimentation, rapid sand filtration and chlorination), and MC concentration in the final treated water never exceeded 1 fig L-1 (WHO guideline limit for MC-LR in drinking water). However, cyanobacterial cells (93-3,055 cell mL-1) were frequently found in the final treated water and intracellular MCs were detected in 17% of the samples (maximal concentration 0.61 (μg L-1), while dissolved MCs were present in 14% of the final treated water samples (maximal concentration 0.81 μg L-1). It indicates a borderline efficiency of the water treatment, thus MC concentrations in drinking water might exceed the WHO guideline limit if the treatment efficiency gets compromised. In addition, MC concentrations found in the raw water might represent significant human health risks for people living in areas with only a limited access to the treated or underground drinking water

Toxic cyanobacteria, cyanotoxins and drinking water production in Ghana: implications to human health

The management and control of cyanobacteria and their toxins in drinking water reservoirs and water supplies have engaged the attention of many scientists worldwide due to their negative effects on population health. The cyanotoxin, microcystin, the main focus of this research has been responsible for much documented illness in humans and is the most wildly studied cyanotoxin. The World Health Organization has set a guideline limit of 1 µg/l in drinking water. A number of methodologies have been used in this research. These include the use of an inverted microscope for the identification and quantification of cyanobacteria species after sedimentation in counting chambers. The biomass of picocyanobacteria was determined by epifluorescence microscopy after staining with DAPI. Extraction, purification and concentration of dissolved microcystins were done using the Solid Phase Extraction method. Identification of microcystins was done through comparison with commercial standards and their characteristic UV- spectra, and quantified by extrapolations of HPLC peak areas at 238 nin to a linear calibration curve for microcystin-LR standard. Nutrients (N0₂-N, N0₃-N and P0₃-P) in reservoirs in Ghana were analysed using the American Public Health Association standard methods. The results which are the first of their kind from Ghana, and for most part in West Africa, highlight that the water treatment processing currently in place is not effective in removing cyanobacteria cells from the final drinking water. Positive correlations were obtained between cyanobacteria biomass and nutrients concentrations in the reservoirs. Fifteen new cyanobacteria species were identified for the first time in Ghana of which Cyanogranisferrugineais reported for the first time in tropical waters. Four known microcystin variants -1R, -RR, - LF and -YR in both dissolved and intracellular samples were identified in four drinking water reservoirs. The study concludes that, the presence and dominance of potentially toxic small sized cyanobacteria such as Aphanocapsa nubilum, Cyanogranis ferruginea, Geitlerinema unigranulatum and other toxic cyanobacteria species like Cylindrospermopsis raciborskii, Planktothrix agardhii and Microcystis spp in the Weija, Kpong, Barekese and the Owabi reservoirs all with basic conventional drinking water treatment facilities, shown to be ineffective in removing cyanobacteria and their toxins, present a potential risk to human health through exposure to cyanotoxins such as microcystins and cylindrospermopsin. Even though the concentrations of dissolved microcystins obtained in the reservoirs and drinking water supplies were lower than the WHO limit, there is potentially a risk to public health and ongoing monitoring would be a good idea

Toxic cyanobacteria, cyanotoxins and drinking water production in Ghana: implications to human health

The management and control of cyanobacteria and their toxins in drinking water reservoirs and water supplies have engaged the attention of many scientists worldwide due to their negative effects on population health. The cyanotoxin, microcystin, the main focus of this research has been responsible for much documented illness in humans and is the most wildly studied cyanotoxin. The World Health Organization has set a guideline limit of 1 µg/l in drinking water. A number of methodologies have been used in this research. These include the use of an inverted microscope for the identification and quantification of cyanobacteria species after sedimentation in counting chambers. The biomass of picocyanobacteria was determined by epifluorescence microscopy after staining with DAPI. Extraction, purification and concentration of dissolved microcystins were done using the Solid Phase Extraction method. Identification of microcystins was done through comparison with commercial standards and their characteristic UV- spectra, and quantified by extrapolations of HPLC peak areas at 238 nin to a linear calibration curve for microcystin-LR standard. Nutrients (N0₂-N, N0₃-N and P0₃-P) in reservoirs in Ghana were analysed using the American Public Health Association standard methods. The results which are the first of their kind from Ghana, and for most part in West Africa, highlight that the water treatment processing currently in place is not effective in removing cyanobacteria cells from the final drinking water. Positive correlations were obtained between cyanobacteria biomass and nutrients concentrations in the reservoirs. Fifteen new cyanobacteria species were identified for the first time in Ghana of which Cyanogranisferrugineais reported for the first time in tropical waters. Four known microcystin variants -1R, -RR, - LF and -YR in both dissolved and intracellular samples were identified in four drinking water reservoirs. The study concludes that, the presence and dominance of potentially toxic small sized cyanobacteria such as Aphanocapsa nubilum, Cyanogranis ferruginea, Geitlerinema unigranulatum and other toxic cyanobacteria species like Cylindrospermopsis raciborskii, Planktothrix agardhii and Microcystis spp in the Weija, Kpong, Barekese and the Owabi reservoirs all with basic conventional drinking water treatment facilities, shown to be ineffective in removing cyanobacteria and their toxins, present a potential risk to human health through exposure to cyanotoxins such as microcystins and cylindrospermopsin. Even though the concentrations of dissolved microcystins obtained in the reservoirs and drinking water supplies were lower than the WHO limit, there is potentially a risk to public health and ongoing monitoring would be a good idea.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Hepatotoxic-microcystins in two drinking water reservoirs in the central region of Ghana.

Background: Microcystins are cyclic peptides containing seven amino acids with the condensation of two terminal amino acids of the linear peptide to form a cyclic compound. The cyclic nature of microcystins suggests that they are highly stable in water across a wide range of pH and temperatures. Microcystins are produced by several blue-green algae (cyanobacteria) including Microcystis, Anabaena, Planktothrix, Oscillatoria and Radiocystis commonly found in freshwater reservoirs in Ghana. Microcystins have very serious health implications on both humans and animals. Known symptoms associated with microcystin poisoning include skin irritation, allergic responses, mucosa blistering, muscular and joint pains, gastroenteritis, pulmonary consolidation, liver and kidney damage and other neurological effects. Methods: In this study, we present results of toxicological analysis conducted on water samples from the Brimsu and Kwanyarko Reservoirs used as sources of drinking water by some parts of the Central Region of Ghana in 2011. HPLC was used to measure microcystin and phytoplankton was identified using an inverted microscope. Results: HPLC analyses of samples gave four variants of microcystin, MC-LR, MC-YR, MC-RR and MC-LA with microcystins ranging from 0.79 μg/L during the intake of water at the Brimsu treatment plant to 0.1 μg/L in the final drinking water products of both reservoirs. Microcystin-LA is a microcystin variant identified in Ghana for the first time. Cyanobacteria diversity was low in both reservoirs. However, biomass was very high and constituted about 84% and 93% of the total algal counts of the water intake for Kwanyarko and Brimsu Reservoirs respectively. Dominant cyanobacteria species found in these reservoirs are Microcystis aeroginosa and Planktothrix agardhii. Conclusions: Due to the chronic effect of these toxins it is recommended that drinking reservoirs with low levels of microcystins must be regularly monitored to keep it free from microcystin to ensure safeguarding human health

Preliminary investigation into the chemical composition of the invasive brown seaweed Sargassum along the West Coast of Ghana

The arrival of the invasive brown seaweed Sargassum in the Western Region of Ghana was first reported in 2009. This impacted negatively on biodiversity, tourism and the livelihoods of the coastal communities. The objectives of the study among others were to identify and determine the nutritional and toxicological contents of the seaweed. Twenty four samples collected from 6 zones along the Western Region were analysed. Nutritional and toxicological analyses were carried out using an Atomic Absorption Spectrophotometer (AAS) 900T. Results of the study indicated that the Sargassum samples analyzed contained low concentrations of nitrogen. However, nitrogen utilized by plants, namely, nitrate and ammonia were very high, together with phosphates. This makes the Sargassum a good source organic fertilizer. However, the high concentrations of toxic heavy metals in the Sargassum defeat this assertion. Heavy metals have implications in both the growth and metabolic activities of plants. Most heavy metals, especially arsenic and lead are carcinogenic and are capable of causing skin, lung, liver and bladder cancers and miscarriages. Indiscriminate domestic and industrial wastes disposal, oil and gas activities, mining and high shipping traffic may have contributed to the heavy metal concentrations in the seaweeds.Key words: Seaweed, Sargassum, nutrients, toxins, health