Health Risk Assessment of Nitrate Contamination in Groundwater in Urban Informal Settlements in Kisumu, Kenya
Abstract
Background
Groundwater is increasingly being used as a primary source of water for domestic use in low- and
middle-income countries worldwide. This water is vulnerable to nitrate contamination due to a
variety of factors, the most significant of which are excessive nitrogen-based fertilizer use and
widespread onsite sanitation (use of pit latrines). Increase of nitrate concentration in groundwater
has become a global concern in recent years. Prolonged nitrate exposure can cause a number of
non-communicable diseases.
Objective
The objective of this study was to determine the nitrate concentration in various groundwater
sources (wells and springs) and to calculate the health risk of exposure among residents as an
indicator of public health impact.
Methods
This was a cross sectional study on informal settlements in urban and peri urban areas of Kisumu
County. The study was conducted in urban and peri urban informal settlements within Kisumu
County. Groundwater sources were identified using the snowball method while households were
selected using simple random sampling. A structured questionnaire was used to collect data among
heads of households. Water samples were analysed to determine their nitrate levels. The chronic
daily intake (CDI) and hazard quotient (HQ) were used to assess human health risk.
Results
Nitrate levels in 26.6% (n=45) of the groundwater sources were above the WHO recommended
cut-off. Prevalence of diabetes and hypertension was 4% (n=299) and 19% (n=299) within this
community. The chronic daily index was 0.189 mg/kg/day while the hazard index was 0.118.
Conclusion
The presence of nitrate in groundwater was contributed by pit latrines and use of fertilizers in the
urban and peri-urban settlements respectively. Since the hazard index is less than one, the
population is currently at low risk of disease.
Recommendation
The management of groundwater in the area and the implementation of preventive measures to
stop further pollution will benefit from the study’s findings because doing so is essential for longterm
sustainability.
Publisher
University of Nairobi
Rights
Attribution-NonCommercial-NoDerivs 3.0 United StatesUsage Rights
http://creativecommons.org/licenses/by-nc-nd/3.0/us/Collections
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