Microbial And Physicochemical Parameters Of River Kuywa Water In Bungoma County, Kenya

ABSTRACT

Water contamination is one of the major causes of water borne diseases worldwide. In Kenya, approximately 43% of people lack access to potable water due to human contamination. Physicochemical and biological factors influence microbial community and quality of water. Residents in Bungoma County depend on river Kuywa water for domestic and agricultural use. The river water is currently experiencing contamination due to human activities such as farming and disposal of industrial and domestic wastes. The human and physical factors may affect the microbial, physicochemical parameters and quality of the water. Information on the current status of pollution of river Kuywa water is required. The purpose of this study was to investigate microbial and physicochemical parameters of river Kuywa water. The specific objectives were to determine: - the types of bacteria and fungi, physicochemical parameters influencing water quality, microbial counts in river Kuywa and the relationship between microbiological and physicochemical parameters of river Kuywa. Water samples were randomly collected from one meter along the shoreline from four sites of the river in triplicates: site A (Matisi), site B (Ngwelo), site C (Nzoia water pump) and site D (Chalicha), during the dry season (January-March 2018) and wet season (April-July 2018) and were transported to Maseno University botany laboratory for analysis. Sites were selected based on accessibility, human activities and health problems reported in the region. Bacteria were cultured using Nutrient agar, MacConkey agar, Salmonella Shigella agar while fungi using Potato dextrose agar. The identification of bacteria and fungi were then carried out using the standard microbiological techniques. Physicochemical parameters such as Temperature, pH, Turbidity and dissolved oxygen were measured in-situ using portable meters. Biological oxygen demand was calculated from DO values. Chemical oxygen demand, phosphates and nitrates were determined using dichromate reflex and spectrophotometric method respectively. Data on physicochemical parameters and microbial count were subjected to analysis of variance. Means were separated and compared using Fisher‟s Least Significance Difference at P = 0.05. In this study nine bacterial genera and three fungi were identified from Kuywa river water. Clostridium spp., Staphylococcus spp., Enterobacter spp., Streptococcus spp., E. coli, Klebsiella spp., Shigella spp., Proteus spp. and Salmonella spp. Fungi were Fusarium oxysporum, Aspergillus flavus complex and Penicillium species. Physicochemical parameters levels such as pH 7.68-11.47, turbidity 10.03-13.42 NTU, COD 0.31-0.48 mg/l, NO-3 1.09-1.47 mg/l and PO-4 0.48-0.81 mg/l exceeded WHO permissible limits while temperature 23.83-25.88OC and DO 7.73-12.52 mg/l were within WHO permissible limits. Microbial and physicochemical parameters varied between seasons. Wet season recorded highest bacterial and fungal counts (6.61-7.66 and 3.83-6.75 cfu/ml) respectively. The pH ranged between 8.68-9.02, turbidity 10.88-11.62, COD 0.36-0.42, NO-3 0.69-1.94 and PO-4, DO 8.98-10.23 and temperature between 23.32-27.04oC. Spearman rank correlation showed a positive relationship between some physicochemical parameters and microbial counts. Bacterial counts were positively correlated with temperature (r=0.85) and nitrates (r = 0.95) and negatively correlated with pH (r = - 0.04), Turbidity (r = - 0.89), DO (r = - 0.85), and BOD (r = - 0.89). Fungal count showed negative correlation with temperature and nitrates (r= -0.50), (r=-1.00). Bacterial and fungal counts were not within WHO permissible limits. Presence of Salmonella, Shigella and E. coli and Penicilium spp. indicate the poor quality of river Kuywa water and may pose serious health problems. The results provide baseline information that can be used by researchers and government authorities such as National Environmental Management Authority and Kenya Bureau standards to improve on the quality of river Kuywa water.