Assessment of Water Quality From Selected Boreholes in Naivasha Subcounty, Nakuru Countynya

Abstract

This study was undertaken to assess the quality of borehole water from Naivasha area in Nakuru County. High fluoride levels and the economic activities surrounding the area have raised a major concern over the quality of borehole water within the area. This study was conducted during the months of June 2017 to September 2018. Water samples were taken from 7 different boreholes namely: Matangi NNE (Karagita Area), Koinange Car Wash (Police Line Area), Ushirika Water Project (Kayole Area), Shamba House (Kabati Area), Keroche Borehole (Karate Area), Joywel School and a private borehole belonging to Geoffrey Kinyanjui. Each water sample was tested for pH and electrical conductivity using the pH/conductivity meter (Model: Jenway 3540), turbidity using the bench top turbidimeter (Model: HACH TU 5200) , total suspended and dissolved solids (gravimetrically using dry filter papers and beakers), water color using the color analyzer (Model: LUTRON RGB-1002), fluoride using the EXTECH ® fluoride meter , chloride using the MOHR’s method with AgNO3 standardized with M NaCl, chlorine using the EXTECH ® chlorine meter, total hardness by complexometric titration with EDTA standardized with CaCO3, alkalinity - acid-base titration with H2SO4 standardized with Na2CO3 , manganese, cadmium, lead, copper, iron, chromium, sodium, potassium, zinc – using the AAS (Model: Shimadzu AA-6300), with respective standards and hollow cathode lamps, nitrates, sulfates were determined using the UV/Vis spectrophotometer (Model: Shimadzu UV-1800 ), and E-coli – using the multiple tube fermentation technique (MTF). A comparison was made with the East African Standard and the WHO drinking water guidelines. The results obtained were: pH (7.03-8.45); electrical conductivity (412-1218 μS/cm); turbidity (0.095-0.355 NTU); total suspended solids (1.93-48.00 mg/L); total dissolved solids (43-421 mg/L); water color (2-10 TCU); fluoride (1.20-5.00 mg/L); chloride (27.5-79.9 mg/L); chlorine (0.01-0.08 mg/L); sulfates (154.88-263.88 mg/L); nitrates (6.04-9.94 mg/L); sodium (8.74-17.81 mg/L); potassium (11.80-17.48 mg/L); alkalinity (168.62-511.35 mg/L); total hardness (28.6-85.78 mg/L as CaCO3); manganese <0.01 mg/L; lead (0.0469-0.1962 mg/L); copper (0.1419-0.2139 mg/L); zinc (0.0236-0.0374 mg/L); iron (0.0210-0.1369 mg/L); chromium and cadmium were not detected and E-coli was found to be absent. The results were then compared with the East African Standard and the WHO guidelines for drinking water. The study showed that the total suspended solids, chlorine, fluoride and lead levels were higher than the WHO guideline values while the rest of the parameters met the guideline values. Based on the East African Standard and the WHO guideline for drinking water, none of the sampled borehole water was suitable for drinking purposes and therefore, there was need for some remediation before the water would be safe for drinking.