Seasonal assessment of groundwater quality in Ruiru Kiambu County, Kenya
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Date
2016-11
Authors
Otieno, Rachel Olonga
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Water is essential for life and the bloodstream of the green economy. Lack of access to
wholesome drinking water adversely affects the public health of many developing
countries and Kenya is not an exception. Ruiru, a small but fast growing town in the
outskirts of Nairobi, is one area where limited resources and services are facing
relentless pressure due to rapid population growth. The residents experience unreliable
water supply and are therefore highly dependent on groundwater sources such as
boreholes and shallow wells as the main source of water for domestic use. The present
study is an attempt to assess the groundwater quality and the seasonal variation with a
view of ascertaining its suitability for domestic use. A total of 109 drinking water
samples from groundwater source from Ruiru were randomly sampled and assessed to
determine their physico-chemical and bacteriological characteristics together with their
seasonal variations. Water samples were collected during the dry (January- February,
2015) and Wet season (March- April, 2015) and analyzed for temperature, pH, colour,
turbidity, conductivity, total dissolved solids, total alkalinity, total hardness, iron,
manganese, fluoride and major cations (calcium, magnesium, sodium and potassium)
and major anions (chloride, sulfate, Nitrate) using Standard Methods for the
Examination of Water and waste water. The results obtained were compared to
guideline values of the World Health Organization (WHO) and Kenya Bureau of
Standards (KEBS) to establish the suitability of groundwater for domestic purposes.
Generally, seasonal variations showed that there was a decrease in most of the
parameters in boreholes with a shift of the season from dry to wet and vice versa for
shallow wells. The concentration of fluoride, nitrates, turbidity and Iron in some of the
samples exceeded the prescribed KEBS and WHO standards of ISm/I, 10 mg/l, NTU
and 0.3 mg/l respectively. The student's Hest performed showed a significant
difference (p :s 0.01) between the means of the sampled boreholes and shallow wells
water for the following parameters; pH, Electrical conductivity, total Dissolved solids,
calcium, total alkalinity, chlorides, fluorides, nitrates, Iron, manganese, total coliforms
and E.coli. The difference was also significant (p :s 0.05) for colour,turbidity, total
hardness and magnesium. The sampled boreho!es and shallow wells had faecal coliform
contamination and did not conform to the WHO and KEBS guideline value of 0
MPNIl 00 ml. The study revealed poor bacteriological quality of drinking water
sources. Therefore the need for the provision of reliable potable water to the local
dwellers by government is highly recommended to avert waterborne related diseases.
Description
A thesis submitted in partial fulfillment of the requirement for the award of the Degree of Master of Science in Environmental Science in the School of Environmental Studies of Kenyatta University, November, 2016