DETERMINATION OF BACTERIAL COMPOSITION, HEAVY METAL CONTAMINATION AND PHYSICO-CHEMICAL PARAMETERS OF FISH POND WATER IN ABOTHUGUCHI CENTRAL, MERU COUNTY, KENYA

Abstract

Abstract. Laibu PK, Maingi J, Kebira A. 2018. Determination of bacterial composition, heavy metal contamination and physicochemical parameters of fish pond water in Abothuguchi Central, Meru County, Kenya. Bioteknologi 15: 66-79. Humans have consumed fish as a supplementary source of proteins and as a source of income. Because fish performs all their body functions in water, the quality of water is essential to their livelihood. Fish farmers have encountered losses due to the death and stunted growth of fish due to bacterial infections and diseases among other causes. Bacteria found in fish pond water and their pathogenic effects differ with the quality of the pond water along with the variation in the frequency with which water is changed in the ponds. Physico-chemical parameters of pond water and heavy metals influence the growth and productivity of fish. This study aimed at determining the contamination levels of both fecal and pathogenic bacteria namely Salmonella spp., fecal Streptococcus, fecal coliforms Pseudomonas spp., Vibrio cholerae and E. coli in fish ponds water, the concentration of heavy metal contamination and variability of physicochemical parameters and their effects on fish. Isolation of fecal indicators and pathogens was carried out using standard laboratory methods. Some physicochemical parameters were measured in situ using a portable Universal multiline P4 WTW meter while others were analyzed in the laboratory. The determination of the heavy metal presence and concentration in the water samples was carried out by employing of Flame Atomic Absorption Spectrometer. The results indicated that the pond water was heavily contaminated with fecal streptococci and fecal coliforms and they varied significantly in the sites. Pearson correlation analysis showed a positive correlation between the prevalence of fecal streptococci and fecal coliforms. Potential pathogens such as Vibrio spp., Salmonella spp., P. aeruginosa, and E.coli were taken from the water samples with high population. Physico-chemical parameters namely pH and dissolved oxygen deviated from the permissible limits according to international standard. The study has shown that the fish ponds water was highly contaminated with both fecal and pathogenic bacteria with physicochemical parameters varying significantly. Heavy metals except for iron were within the recommended limits hence no significant contamination of the fish pond water. The study suggests the use of treated tap water, routine monitoring of fish pond water and sensitization of farmers on bacterial contamination of pond water. More studies with the aid of molecular techniques should be employed to characterize the bacteria. The finding of this study can, thereby, serve as an impetus to improve fish farming in Meru County, as a way of meeting the growing nutritional demands in the country.