Determination of Bacterial Composition, Heavy Metal Contamination and Physico-Chemical Parameters of Fish Pond Water in Abothuguchi Central, Meru County, Kenya
Laibu, P. K.
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Fish farming has been practised all over the world for centuries. Throughout history, humans have used fish as a supplementary source of proteins and as a source of income. Fish performs all their body functions in water and therefore the quality of water is very important to their livelihood. Farmers have suffered losses due to the death and stunted growth of fish as a result of bacterial infections and diseases among other causes. The presence of these bacteria in fish pond water and their pathogenic effects varies with the quality of the pond water together with the variation in the frequency with which water is changed in the ponds. Physico-chemical parameters of pond water and heavy metals affect growth and productivity of fish. This research aimed at determining the contamination levels of both faecal and pathogenic bacteria namely Salmonella spp., faecal Streptococcus, faecal coliforms Pseudomonas spp.,Vibrio cholerae and E. coli in fish ponds water, levels of heavy metal contamination and variability of physico-chemical parameters and their effects on fish. Isolation of faecal indicators and pathogens was carried out using standard laboratory methods. Some physico-chemical parameters were measured in situ using a portable Universal multiline P4 WTW (Wilheim Germany) meter while others were analysed in the laboratory. The determination of heavy metal presence and concentration in the water samples was carried out by the use of Flame Atomic Absorption Spectrometer (FAAS). The results indicated that the pond water was highly contaminated with faecal streptococci and faecal coliforms and they varied significantly in the sites at p=0.0001. Pearson correlation analysis showed positive correlation between prevalence of faecal streptococci and faecal coliforms (r=0.732 at P< 0.01). Potential pathogens namely Vibrio spp., Salmonella spp., P. aeruginosa and E.coli were isolated from the water samples with high population. Physico-chemical parameters namel pH and dissolved oxygen deviated from the permissible limits. The study has indicated that the fish ponds water was highly contaminated with both faecal and pathogenic bacteria with physico-chemical parameters varying significantly at p=0.0001. Heavy metals with the exception of iron were within the recommended limits hence no significant contamination of the fish pond water. The study recommends use of treated tap water, regular monitoring of fish pond water and sensitization of farmers on bacterial contamination of pond water. Further studies with the aid of molecular techniques should be used to characterize the bacteria. The finding of this study can, therefore, serve as an impetus to improve fish farming in Meru County, as a way of meeting the growing nutritional demands in the country.