Browsing by Author "Nyamweya, Chrisphine"

Now showing 1 - 2 of 2
  • Publication
    Publication
    Occurrence and distribution of Organochlorine Pesticide Residues in Water and Sediments of Earthen Fish Ponds in South Western Kenya
    (Africa Journals Online, 2019) Nyaundi, Joseph Kiyuka; Getabu, Albert; Onchieku, James; Kinaro, Zachary; Bassa, Samuel; Nyamweya, Chrisphine; Nyaboke, Hilda; Getenga, Zachary
    Persistent organochlorine residues in the environment are a threat to ecological health of aquatic organisms and pose a health risk to both animals and human consumers. Organochlorine pesticides were determined in water and sediments collected during wet and dry season from selected riverine and earthen fish pond sites in high altitude catchment areas within Kuja River (Kenya) between August 2016–May, 2017. Analysis of DDT and metabolites, Hexachlorocyclohexanes (HCHs) isomers and cyclodienes using a gas chromatograph (GC), and electron capture detector (ECD), confirmed using GC - Mass Spectrometry (MS). Mean (± Standard error) results of DDTs, cyclodienes and HCHs in pond waters were:- below detection level (BDL) to 0.27±0.03µg/L, BDL to 0.11±0.00µg/L, and 4.39±1.01µg/L respectively; and BDL to 0.23±0.01µg/L, 1.20±0.005µg/L, and 1.71±0.02µg/L in river water respectively. Sediment mean OCPs contents were significantly (p<0.05) higher for Dieldrin (3.043±0.43µg/kg), Endrin (2.56±0.460µg/kg), Heptachlor (3.61±0.02µg/kg) DDT (2.97±1.32µg/kg), Endosulfan (6.31.27±1.051µg/kg), Methoxychlor (2.15±1.641µg/kg) and Lindane (2.96±1.32µg/kg), respectively. A longitudinal spatial distribution pattern was noted for both water and sediment OCPs contents, demonstrating that cyclodienes are predominant contaminants in point and non-point sources in water courses. The study recommends continuous monitoring of OCPs in upstream catchment areas for informed management and policy decisions on pesticide use.Keywords: Kuja-Migori River; Organic contaminants; Organochlorine Pesticide.
  • Publication
    Publication
    Using the Multi-metric Index of Biotic Integrity methodological approach to determine the major river catchment that most pollutes a lake
    (Aquatic Ecosystem Health, 2021-12-20) Aura, Christopher; Nyamweya, Chrisphine; Njiru, James; Omondi, Reuben; Manyala, Julius; Musa, Safina; Owiti, Horace; Guya, Fredrick; Ongore, Collins; Ogari, Zachary; Mwamburi, Job; Health and Management, Aquatic Ecosystem
    We present the Multi-metric Index of Biotic Integrity methodological approach that allows for the ranking of major river catchments based on pollution status in the Kenyan portion of Lake Victoria, Africa. The study has a broader applicability to all of Lake Victoria, other African Great Lakes, and all lakes that have riverine discharge. The method presented utilizes water quality and environmental data, local knowledge, and pre-existing literature. The parameters considered were sampled from 2016 to 2018 during the dry season (July sampling) and the wet season (March sampling). Separation power of Mann-Whitney U test (p < 0.05) qualified 11 discriminant metrics for both macroinvertebrate and fish samples into the scoring system of 1, 3 and 5 in the formulation of final Multi-metric Index of Biotic Integrity methodological approach. Rivers in the northern section had lower Multi-metric Index of Biotic Integrity methodological approach scores, as compared to southern counterparts. The Multi-metric Index of Biotic Integrity methodological approach ranking herein was validated by community perceptions on pollution levels. River Nzoia catchment emerged as the most polluted, followed by River Yala, River Kuja, and Sondu-Miriu. Siltation, domestic washing, litter and refuse emerged as the main agents of pollution. Management authorities ought to reinforce a balanced utilization of the vital water resources to minimize future impacts, and promote catchment wide practices that ensure ecological health sustainability of the lake ecosystem.