Effects of Produced Water on Physicochemical Properties of Groundwater in Lokichar Basin, Turkana County, Kenya
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Date
2023-07
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Kenyatta University
Abstract
Globally, there has been an increase in wastewater generation from oil mining activities
that pollutes freshwater resources. Inadequate handling of oil mining wastes in Africa has
caused water bodies to become contaminated. The advent of oil exploration and mining
activities in south Lokichar basin in Turkana County, Kenya (Ngamia 1 oil well pad) has
led to the generation of wastes such as drilling muds, drilling cuttings, and Produced
Water. In Kenya, there are relatively few studies that have been done on the effects of the
oil mining wastes on the environmental resources since oil exploration is a new
phenomenon in the country. This study's goal was to determine if Produced Water from
oil mining operations at Ngamia 1 oil well pad leads to contamination of the groundwater
resources in the study area. The specific objectives were to: 1) determine the
physicochemical properties of Produced Water; 2) determine the physicochemical
properties of boreholes water; and 3) determine the effects of Produced Water on
groundwater quality. To achieve these objectives water samples were collected from ten
boreholes within the catchment divide, and one sample collected from outside the divide
as the control of the study in the month of August 2020. Data on the selected
physicochemical water quality parameters for both the Produced Water and groundwater
was obtained from the field measurements and using standard laboratory procedures at
Kenya Water Institute (KeWTI), Water Resources Management Authority (WRMA) and
the National Materials Testing and Research Division (NMTRD) laboratories. The
outcomes were compared to the established requirements for drinking water quality by
both WHO (2017) and NEMA (2006). Produced Water was found to be highly
contaminated with heavy metals and salts whose levels were found to exceed the set
drinking water quality standards by WHO and NEMA as follows: Lead by 15,680%, Zinc
by 22%, Iron by 16,567%, Chlorides by 8,128%, Fluorides by 2,500%, and Nitrates by
480%. This was attributed to the usage of production chemicals to enhance oil recovery
through hydraulic fracturing. The heavy metals present and salts in levels not within the
set drinking water quality standards by both WHO and NEMA were observed at the
following boreholes: Nalemsekon borehole whose Iron level exceeded these standards by
250%, Chloride level by 10.4%, and Fluoride level by 148%; RCEA borehole whose
Lead level exceeded these standards by 1,500% while Fluoride level exceeded by 56%;
Nakwakipi borehole whose Lead level exceeded by 5,180% and Nitrate level by 287%;
Nakukulas 10 borehole whose Zinc level exceeded by 51% and Nitrate level by 111%;
Nakwakitela borehole whose Fluoride level exceeded by 36% and Nitrate level by 428%;
Nitrates levels at Irir 1, Chinese 1 and Nawoyatira boreholes exceeded these standards by
604%, 463% and 322% respectively. The study discovered that the high concentrations
of salts and heavy metals observed in these boreholes could be as a result of
contamination from Produced Water. Therefore, strategies on safe handling and disposal
of Produced Water should be put in place to safeguard the study area's groundwater
supplies.
Description
A Thesis Submitted in Partial Fulfillment of the Requirement for the Award of the Degree of Master of Science (Integrated Watershed Management) in the School of Pure and Applied Sciences of Kenyatta University. January, 2023