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Recent Submissions
Effects of Catchment Land Use on Nutrients and Heavy Metals Inflows into Maragua and Mathioya Wetlands in Murang’a County, Kenya
(International Journal of Research and Innovation in Applied Science (IJRIAS), 2025-05-08) Evans Kipkemoi, Warren Andrew Andayi, B.M. Mwangi, Eric C. Njagi and Margaret W. Kariuki
etland ecosystems in Murang’a County are diminishing due to increased catchment land use practices. Part of
wetlands have been converted into farmlands where various agricultural activities are carried out while some
parts have been converted into settlement points. Agricultural practices carried out along wetland ecosystems
involve the use of excessive agrochemicals during crop production which later contribute to wetland pollution
through nutrients and heavy metals inflows. This study aimed at assessing the effects of catchment land use on
nutrient and heavy metals inflows into Maragua and Mathioya river basins in Murang’a County. Water samples
were collected using the Grab technique, packed in plastic containers, kept in cool boxes, and transported to the
research laboratory for analysis. Phosphate and nitrate concentrations were analyzed across different seasons,
sampling stations, and sampling levels. During dry season, the mean phosphate concentration was 0.0259 ±
0.0051 mg/L with a standard deviation of 0.0124 mg/L. In wet conditions, the mean phosphate concentration
increased to 0.1631 ± 0.1509 mg/L with a standard deviation of 0.3697 mg/L. For nitrate, the mean concentration
during dry conditions was 9223.37 ± 2672.33 mg/L with a standard deviation of 6545.84 mg/L, and during wet
conditions, it remained the same at 9223.37 ± 2008.17 mg/L with a standard deviation of 4919.00 mg/L.
Elemental analysis was performed using Microwave Plasma-Atomic Emission Spectroscopy (MP-AES)
instrument. Mean concentrations of lead during dry seasons were 0.005 ± 0.002 mg/L and during wet season,
they increased to 0.012 ± 0.004 mg/L. Zinc concentrations were 0.01 ± 0.003 mg/L during dry season and
increased to 0.015 ± 0.004 mg/L during the wet season.
The mean concentrations of zinc in the water samples were significantly lower than the maximum residue
concentrations set for drinking water by the World Health Organization (WHO). However, lead (Pb)
concentrations were above the WHO recommended maximum residue level. ANOVA analysis indicated no
significant seasonal differences in phosphate (F=0.825, p=0.385) and nitrate (F=3.090, p=0.109) levels.
Similarly, no significant differences were found between different sampling stations for phosphate (F=1.081,
p=0.323) and nitrate (F=0.478, p=0.505). Analysis by sampling levels showed no significant differences noted
for phosphate (F=0.979, p=0.412) and nitrate (F=1.949, p=0.198). For heavy metals, no significant differences
were found for lead (F=1.234, p=0.271), cadmium (F=0.893, p=0.348), and zinc (F=1.567, p=0.223) across
different seasons and sampling stations.
These findings suggest that nutrient and heavy metal inflows into the wetlands are relatively stable and uniform
across different spatial and temporal scales. The study highlights the importance of consistent land use practices
and the effective buffering capacity of wetlands in maintaining ecological balance.
Removal of Nitrites from Wetland Waters Based on Diazonium Silica
(American Journal of Chemistry, 2025) Aquiline Kathambi, Peter W. Njoroge, Sylvia A. Opiyo, Isaac Waweru, Benson M. Mwangi
Diazonuim silica was prepared and used to remove nitrites in wetland waters. Raw silica was chlorinated using
phosphorous pentachloride (PCl5). Chlorinated silica was further reacted with ethylenediamine (EDA) under reflux to give
aminated silica. Thereafter, aminated silica was protonated to yield diazonium silica which was used as the adsorbent. The
prepared diazonium silica material was characterized using Fourier Transform Infrared (FT-IR) showing bands at
wavenumbers 1049 and 791 cm-1 of the anti-symmetric and symmetric stretching modes (Si-O-Si) of SiO4. The shift in
spectra band of Si-O-Si from 1051cm-1 in raw silica to 1049cm-1, was attributed to diazonium silica. Additionally, a new open
chain azo (N=N) group band was found in the region 1575cm-1 -1630cm-1. The physical adsorption parameters examined
using batch adsorption system including: pH, initial concentration, contact time and temperature were made using sorption
models, adsorption kinetics and thermodynamics. The results obtained showed 3.0 as the optimal pH for adsorption of NO2-,
303K as the optimal temperature, optimum contact time as 60 minutes and optimal initial concentration as 20ppm. The
adsorption capacity of nitrites using diazonium silica adsorbent was achieved at 16.45mg/g. For sorption of nitrites in
diazonuim silica, Langmuir isotherm model was obeyed according to correlation coefficient R2 = 0.97182 close to unity.
Adsorption kinetics of nitrites in diazonium silica pseudo second order was best obeyed while, thermodynamic parameters
revealed that the sorption of nitrites into diazonium silica was exothermic in nature. From the results obtained, diazonium
silica is an efficient adsorbent for adsorption of nitrites compared to raw silica.
Adsorptive removal of phosphates from wetland waters using silica molyb date adsorbent
(Journal of Emerging Technologies and Innovative Research, 2025-02) Aquiline Kathambi, Peter W. Njoroge, Sylvia A. Opiyo, Isaac Waweru, Benson M. Mwangi
World’s most productive and valuable ecosystem is the wetlands. Quality and functions of wetlands have been
affected adversely by deforestation, fertilizers, and pesticides among others. Pollution by phosphates affect aquatic
life as they have serious side effects at very low levels. Silica molybdate was prepared by first chlorinating silica
sand using phosphorous pentachloride (PCl5) to give chlorinated silica. Amination of chlorinated silica was done
using Ethylenediamine (EDA) and later molybdate was chemically grafted to the aminated silica to yield silica
molybdate. Silica molybdate was used to reduce the levels of PO4 3- residues from wetland ecosystem.. Molecular
structure of the silica molybdate material was characterized using Fourier Transform Infrared (FT-IR). FT-IR results
showed Adsorption bands at 854cm-1 and 542cm-1 which were attributed to Mo=O and Mo-O stretching in
molybdate. Peaks observed at 1388 and 1662cm-1 were attributed with the vibration mode of Mo-OH bond and
bending mode of adsorbed water. Spectra peaks observed at 542, 634.58 and 898.97 cm-1 were attributed to the
adsorption of molybdate. The physical adsorption parameters which were examined using batch adsorption system
were; temperature, pH, contact, time, initial concentration using sorption models, adsorption kinetics and
thermodynamics. Results showed that optimum pH for biosorption of PO4 2- was 6.0, optimal contact time was 30
minutes, optimum temperature was 45 ℃. The experimental results obtained showed that the maximum phosphate
adsorption of silica molybdate was achieved at 194.93mg/g at adsorption optimal conditions of pH, temperature
and contact time. The phosphate removal based on silica molybdate will offer several benefits such as low cost,
effectiveness and reliability to lower the levels of phosphates in wetland waters as compared to commercial
activated carbon. Based on the adsorption efficiency values obtained from this study and comparing them with
adsorption efficiency reported in the literature, it can be concluded that silica molybdate is super adsorbent for the
removal of phosphates from wetland waters.
Sustainability of Livelihood Strategies of Riparian Communities in Murang’a County, Kenya.
(nternational Journal of Humanities and Social Science Invention (IJHSSI), 2021-06) Isaiah Ochieng Abillah, Dr. Benson Mwangi, Prof. Richard Juma, Prof. Clifford Machogu
Wetlands have played a key role in support of the riparian community’s livelihoods and
development and have been the source of forest, wildlife, minerals, agriculture, recreation, water and energy.
Murang’a County in Kenya, is endowed with many such wetlands that provide water to nearby towns
of Thika and Nairobi city. Despite these important roles, wetlands conservation and management in the county
continue to attract little attention from scientists and policy makers. This study aims at investigating the
livelihood strategies of riparian communities in Murang’a County, Kenya. This study aimed at investigating
how sustainable the livelihoods strategies are of the riparian communities are in Murang’a County. The study
was conducted in four purposively selected sub-counties, due to their richness in wetlands: Kiharu, Kangema,
Mathioya, and Maragua. Data was collected using household’s survey questionnaires, key informant interviews,
and focus group discussion. Questionnaire were administered to a randomly selected sample of 404 respondents
from the riparian community in the four sub-counties. Data was analyzed using SPSS software version 26.0.
Chi-squared test was used to test for association between livelihood strategies and effects of encroachment into
wetlands. Rejection value for statistical tests was set at P< 0.05. Results showed an encroachment rate into the
wetlands by the riparian communities of 60.4%. It is concluded that livelihood strategies of riparian
communities were not sustainable due to a high rate of encroachment, inadequate enforcement of laws and
policies, On the other hand, over exploitation of wetlands resources, lack of knowledge on wise use of wetlands
and conflict of interest among different environmental conservation institutions among other factors, were
impacting negatively on wetlands conservation in Murang’a County. The study recommends enhanced
sustainability of livelihood strategies of riparian communities through empowerment, capacity building and
well-coordinated livelihood strategies by all stakeholders in wetlands management that will lead to the wise use
of wetlands ecosystems in Kenya and in other parts of the world.
Gender Roles in Wetlands Conservation and Restoration in Murang’a County, Kenya
(International Journal of Humanities and Social Science Invention (IJHSSI), 2021-06) Isaiah Ochieng Abillah, Dr. Benson Mwangi, Prof. Richard Juma, Prof. Clifford Machogu
Women are the majority vulnerable in wetlands access and control, yet livelihood provisioning
services bring her in direct contact with and control of wetlands on a daily basis. Murang’a County is majorly a
patriarchal society and women continue to experience the worst forms of oppression and exploitation in
environmental management. Therefore, the purpose of this paper is to determine the gender roles in community-
based strategies aimed at Wetlands conservation and restoration in Murang’a County, Kenya. It adopted a
descriptive survey design with a target population of 144,376 divided into four Sub-Counties of Murang’a.
Simple random sampling was used for each stratum to select a sample of 404 respondents. Key Informant
interviews, focus group discussion, and documentary analysis were used to corroborate responses from the
questionnaires. Qualitative data were coded before the analysis. Quantitative and qualitative data were
analyzed using SPSS software version 26.0. Continuous variables were analyzed using a Chi-Square test and P
values of <0.05 at 95% confidence interval level was considered significant. The study revealed that there is
gender inequality in conservation efforts due to poor policies, beliefs, lack of knowledge, and skills. The study
thus recommends effective gender role equity in wetlands conservation efforts.
