Browsing by Author "Kamau, Luna"

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    Levels of heavy metals in wastewater and soil samples from open drainage channels in Nairobi, Kenya: community health implication
    (Scientific Reports, 2020) Kamau, Luna; Kinuthia, Geoffrey K.; Ngure, Veronica; Beti, Dunstone; Lugalia, Reuben; Wangila, Agnes
    Levels of Mercury (Hg), Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni) & Thallium (Tl) were established in wastewater & soil samples obtained from 8 sites in open drainage channels at Nairobi industrial area, Kenya. Ultra-trace inductively coupled plasma mass spectroscopy (ICP-MS) was used for metal analysis. Temperature, pH & turbidity of wastewater ranged from 16.75 to 26.05 °C; 7.28 to 8.78; 160.33 to 544.69 ppm respectively and within World Health Organization (WHO) allowable limits. Wastewater conductivities in 4 sites ranged from 770 to 1074 μS/cm and above WHO limits at 25 °C. The mean concentrations of the metals in wastewater ranged from 0.0001 to 0.015 ppm in an ascending order of Tl
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    Mosquito Diversity in the Nairobi – Kenya Urban Environment and Implications for Disease Transmission
    (2020-05-23) Kinuthia, Geoffrey K.; Ngure, Veronica ; Kamau, Luna; Beti, Dunstone; Lugalia, Reuben; Wangila, Agnes; Ngari, Florence Wanja; Mburu, Faith W.; Kiarie, Martha
    Mosquito surveillance and control efforts especially those carried out under programmatic settings by mosquito control departments of governments in many situations in Africa tend to focus on rural locales, mainly because this is where mosquito transmitted diseases have been found to be prevalent. In a recent study, we found an abundance of mosquitogenic conditions conducive for mosquito breeding in Nairobi in areas in close proximity to informal settlements, similar to previous studies. Thirteen different mosquito species were identified with Culex pipiens accounting for over 97% of the 7,605 mosquitoes sampled. Implications for disease transmission within the context of climate change and other factors are discussed. The evidence points to the need for enhanced vector surveillance and control in urban environments to minimize the risk of emergence and resurgence of mosquito-borne diseases.
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    Urban mosquitoes and filamentous green algae: their biomonitoring role in heavy metal pollution in open drainage channels in Nairobi industrial area, Kenya
    (BMC Ecology and Evolution, 2021) Kamau, Luna; Kinuthia, Geoffrey K.; Ngure, Veronica
    Background: Industrial wastewater is a human health hazard upon exposure. Aquatic organisms in contaminated wastewater may accumulate the toxic elements with time. Human population living in informal settlements in Nairobi industrial area risk exposure to such toxic elements. Biomonitoring using aquatic organisms in open drainage channels can be key in metal exposure assessment. Levels of Mercury (Hg), Lead (Pb), Chromium (Cr), Cadmium (Cd), Thallium (Tl), and Nickel (Ni) were established in samples of wastewater, filamentous green algae (Spirogyra) and mosquitoes obtained from open drainage channels in Nairobi industrial area, Kenya. Results: Pb, Cr, & Ni levels ranged from 3.08 to 15.31 μg/l while Tl, Hg, & Cd ranged from 0.05 to 0.12 μg/l in wastewater. The Pb, Cr, Ni, & Cd levels were above WHO, Kenya & US EPA limits for wastewater but Hg was not. Pb, Cr, Tl, & Ni levels in assorted field mosquitoes were 1.3–2.4 times higher than in assorted laboratory-reared mosquitoes. Hg & Cd concentrations in laboratory-reared mosquitoes (0.26 mg/kg & 1.8 mg/kg respectively) were higher than in field mosquitoes (0.048 mg/kg & 0.12 mg/kg respectively). The levels of Pb, Cr, & Ni were distinctively higher in field mosquito samples than in wastewater samples from the same site. Pb, Cr, Ni, Cd & Hg levels in green filamentous Spirogyra algae were 110.62, 29.75, 14.45, 0.44, & 0.057 mg/kg respectively. Correlation for Pb & Hg (r (2) = 0.957; P < 0.05); Cd & Cr (r (2) = 0.985; P < 0.05) in algae samples was noted. The metal concentrations in the samples analyzed were highest in filamentous green algae and least in wastewater. Conclusion: Wastewater, mosquitoes, and filamentous green algae from open drainage channels and immediate vicinity, in Nairobi industrial area (Kenya) contained Hg, Pb, Cr, Cd, Tl, and Ni. Mosquitoes in urban areas and filamentous green algae in open drainage channels can play a role of metal biomonitoring in wastewater. The potential of urban mosquitoes transferring heavy metals to human population from the contaminated wastewater should be investigated.