Impact of Solid Wastes on Groundwater Quality in Dandora, Nairobi County, Kenya
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Date
2016-11
Authors
Musoni, Bruce
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Management of solid waste and related environmental impacts presents a challenge to
both developing and developed countries. Dumpsites facilities are responsible for the
gradual quality degradation of groundwater reservoirs due to leachate generation and
percolation. Dandora dumping site is not considered to be well managed and there is a
potential of such observed impacts which contribute to further damage of groundwater
quality. This research was conducted in Dandora dumpsite, Dandora division, Nairobi.
The general objective of the study was to assess the impact of solid wastes on
groundwater quality in Dandora. The study specific objectives were i) to assess the
levels of pollutants in leachate produced by Dandora dumpsite and groundwater as
compared to National Environment Management Authority guidelines for effluent
discharge and Kenya bureau of standards and World Health Organization guidelines for
drinking water quality; ii) evaluate the effects of dry and wet seasons on pollutants
concentration in groundwater and finally iii) establish the correlation between levels of
pollutants in groundwater with respect to distance from dumpsite. The study employed
purposive sampling whereby during dry season (Sept-October) and wet season (Nov-
December) 36 groundwater samples and 4 leachate composite samples were collected
from nine wells and the dumpsite respectively. Physicochemical and biological
parameters in leachate and groundwater were analyzed in accordance with standard
procedures. Data obtained were analyzed using single-sample t test, dependent t test and
the Pearson correlation. The study found that in groundwater the levels of electrical
conductivity (p= 0.001), Biochemical oxygen demand (p= 0.02), Lead (p= 0.004),
Escherichia coli (p= 0.001) and total coliforms (p= 0.001) were significantly higher than
Kenya bureau of standards and/or World health organization guideline for drinking
water quality, this makes water unsuitable for consumption. Leachate results indicated
that Dandora dumpsite was in anaerobic conditions of waste decomposition
characterized by increase of pH, decline of sulphate and organic compounds in leachate:
The results also showed that during wet season the levels were higher for Conductivity
(p= 0.001), Total dissolved solids (p= 0.002), pH (p= 0.001), Nitrate (p= 0.002),
Cadmium (p= 0.05), Lead (p= 0.002) and Chromium (p= 0.02) as compared to dry
season. This can be attributed to flushing and infiltration effect of rain water that washed
out chemicals contained in refuse. The study further revealed that the levels of pH (r= -
0.70, p= 0.03), Biochemical oxygen demand (r= - 0.95, p= 0.001), Chemical oxygen
demand (r= - 0.95, p= 0.001), Phosphate (r= - 0.77, p= 0.01), Chloride (r= - 0.88, p=
0.001), Cadmium (r= - 0.81,p= 0.008), Lead (r= - 0.86,p= 0.003) and Chromium (r=-
0.80, p= 0.009) significantly correlated with distance between wells and dumpsite.
Groundwater in Dandora is polluted by solid wastes; therefore it is recommended that
groundwater should not be used for human consumption.
Description
A Thesis Submitted in Partial Fulfillment of the requirement for the Award of Degree of Master of Environmental Science in the School of Environmental Studies, Kenyatta University, November, 2016