Browsing by Author "Oremo, Jane"
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Publication Assessment of Available Phosphates and Nitrates Levels in Water and Sediments of River Isiukhu, Kenya(Science and Education Publishing, 2020-06-22) Oremo, Jane; Orata, Francis; Owino, Joseph; Shivoga, WilliamSurface water contamination has become one of the main environmental issues of concern and achallenge to the world population, especially in the developing world, that face potable or usable water security. Inthis study concentrations of available nutrients (PO43- and NO3-) in sediments and water along River Isiukhu, withinLake Victoria catchment area in Kenya are presented. Sediments and water samples were collected from 11sampling sites along River Isiukhu. Available phosphorus was determined by a Spectrophotometric method in whichthe ammonium phosphomolybdate complex, was reduced by ascorbic acid in the presence of antimony to give adistinct blue color complex. Available nitrate was measured spectrophotometrically at 420nm using UVI609PCUV/VIS Spectrophotometer. Physicochemical parameters such as temperature, pH, dissolved oxygen, turbidity,salinity, conductivity, were measured on-site using mobile Hydrolab Quanta. Phosphates concentrations rangedfrom 1.18 ± 0.09 to 3.28 ± 0.5 in water (mg/l) and 2.30 ± 0.03 to 4.51 ± 0.31 in sediment (mg/kg) andnitrates concentrations ranged from 0.15 ± 0.04 to 0.75 ± 0.03 in water (mg/l) and 0.75 ± 0.02 to 1.93 ± 0.05 insediment (mg/kg). The coefficient of variation (CV) depicted that all the physical-chemical parameters measuredvaried widely except pH and temperature. Pearson's correlation matrix was used to show the relationship betweennutrients concentrations in sediments and water and also for the physical-chemical parameters at significantdifferences accepted at P ≤ 0.05 . There was variation in Pearson correlation coefficient analysis for all theparameters tested.Publication Assessment of heavy metals in benthic macroinvertebrates, water and sediments in River Isiukhu, Kenya(Springer, 2019-10-16) Oremo, Jane; Orata, Francis; Owino, Joseph; Shivoga, WilliamA major ecological challenge facing freshwater resources such as rivers is the influx of chemical contaminants from anthropogenic sources. A report on the levels of heavy metals, namely Zn, Cu, Cr, Cd and Pb in benthic macroinvertebrates, sediments and water along River Isiukhu, within Lake Victoria catchment area in Kenya is presented. Families of benthic macroinvertebrates that were investigated included Gerridae, Baetidae and Unionidae. Samples were digested using the appropriate acid combination and analysed using Spectra AAS Varian 200. Physicochemical parameters were measured on-site using mobile Hydrolab Quanta. Pearson’s correlation matrix and post hoc Tukey’s test were used to show the relationship between metal concentrations in the various matrices at significant differences accepted at p ≤ 0.05. Positive correlations were obtained for heavy metal concentrations in sediments and benthic macroinvertebrates with significant correlations observed for Zn (r = 0.655, p = 0.029) and Cu (r = 0.641, p = 0.034). Sediments presented the highest range of heavy metal concentrations compared to water and benthic macroinvertebrates and presented the only matrix with quantifiable Pb levels. The range in heavy metal concentration in benthic macroinvertebrates samples were as follows: Zn, 30.73–46.64, 21.93–38.17, and 26.85–41.69 mg/kg, Cu, 1.17–6.54, 1.11–3.87 and 1.15–5.79 mg/kg, Cr, 0.47–1.61, 0.22–0.74 and 0.25–0.92 mg/kg, for families Unionidae, Baetidae and Gerridae respectively. Heavy metal concentration profile along the river indicated an influx of pollutants from anthropogenic sources due to rapid urbanization along the river.