Effects of Human Activities on Water Quality of Rupingazi River, Embu County, Kenya
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Date
2017-06
Authors
Bonareri, Somoni Prisca
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Quality of water in rivers and lakes depends on physical, chemical and biological properties. Inland water resources in Kenya are under pressure of pollution from agrochemicals, municipal and other domestic wastes variably affecting water quality. The aim of this study was to assess the effects of human activities on water quality of river Rupingazi and its major tributaries that transverse parts of Embu County in Kenya. The parameters selected as indicators of water quality were temperature, pH, Electrical conductivity (EC), Dissolved Oxygen (DO), Total Suspended Solids (TSS), Total Dissolved Solids (TDS), turbidity, phosphates, nitrates and nitrites. The study objectives were to determine whether there was variation in the selected physicochemical parameters of water; find out the major human activities carried out by the community adjacent to the river and their effects on the quality of water of river Rupingazi and its tributaries. Standard laboratory methods and in-situ measurements were used to obtain data for water sampled from 12 purposely chosen points along the Rupingazi River. Laboratory and field data were statistically analyzed (p<0.05) by primarily applying Analysis of Variance (ANOVA), t-test and regression analysis. Results are displayed in tables and graphs. The results obtained showed significant seasonal variation between some parameters for wet and dry seasons. Temperature and pH were significantly higher in dry season recording 22.97±0.20C and 8.16±0.04 respectively (n=36, p<0.05). Turbidity, DO, TSS and nitrates were all significantly higher in wet season. Recorded results were Turbidity 98.59±13.34NTU; DO 6.64±0.31mg/L; TSS 103.33±12.43mg/L; Nitrates 12.16±1.88mg/L (n=36, p< 0.05). There was no noted significant variation in EC and TDS for both seasons (n=36, p>0.05).A semi-structured questionnaire was administered to 144 randomly selected household heads (HHH) of whom 52.77% were men and 47.23% were women to obtain data on human activities in the study area. Primary level of education was identified as the highest level attained by 50.5%, with subsistence farming as the main source of income. On average farm size owned per house hold (HH) was 1.08 acres. Agriculture was the main human activity practiced in the study area with 98.8% of respondents using Di-Ammonium Phosphate (DAP), Calcium Ammonium Nitrate (CAN) and 23-23fertilizersto improve crop yields. The results obtained were compared with known standards for drinking water such as World Health Organization (WHO), National Environment Management Authority (NEMA) and Kenya Bureau of Standards (KEBS).All the physicochemical parameters analyzed were within the limits set by above standards except turbidity. There was variation noted in the selected physicochemical parameters of water from river Rupingazi and its tributaries. The variation was per site and per season. Agriculture contributed to pollution of the river through reliance on fertilizer application and through methods of weeds and pests control on the farms. The findings in this study show that all the measured water quality parameters were within recommended WHO, KEBS and NEMA guideline values except turbidity. The water of river Rupingazi and its tributaries is suitable for drinking.
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However there is need for adequate treatment since turbidity values were noted to be significantly high.
Description
A thesis submitted in partial fulfillment of the requirements for the award of the degree of Master of Environmental Science in the School of Environmental Studies of Kenyatta University