Evaluating spatio-temporal soil erosion dynamics in the Winam Gulf catchment, Kenya for enhanced decision making in the land-lake interface

Humphrey, Olivier S.; Osano, Odipo; Aura, Christopher Mulanda; Marriott, Andrew; Dowell, S; Blake, William; Watts, Michael J.

doi:10.1016/j.scitotenv.2021.151975

Cited by 13 publications

(8 citation statements)

References 60 publications

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“…Similarly, an increase in urban settlements, combined with industrialisation and agricultural land clearance/use along the shores, could see a general rise in water contamination from PHEs. The impacts of this are seen through increased turbidity and eutrophication effects from erosion in the catchment area (Campbell et al, 2003 ; Okungu et al, 2005 ; Okely et al, 2010 ; Nyamweya et al, 2016 ; Humphrey et al, 2022 ). The implications from anthropogenic inputs with regards water quality whether riverine or coastal have the potential to become problematic when considering sustainable aquaculture in the Winam Gulf and for the local communities who manage and rely on these systems for food.…”

Section: Discussionmentioning

confidence: 99%

Considerations for environmental biogeochemistry and food security for aquaculture around Lake Victoria, Kenya

Marriott

Osano

Coffey

et al. 2023

Environ Geochem Health

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The impact of population expansion through economic growth and development has been identified as one of the key drivers of both water and sediment contamination from potentially harmful elements (PHEs). This presents a major hazard not only to aquatic ecosystems but local riparian communities and beyond who rely heavily on this natural resource for drinking water and fish—a valuable source of dietary micronutrients and protein. The present study measured biogeochemical concentration of PHEs in water, sediment and fish from locations pooled into four zones within Winam Gulf and Lake Victoria area of Kenya. Captured fish were used as a sentinel receptor of lake health to evaluate potential risks to fisheries and aquaculture food security. In water, concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu) and lead (Pb) were observed above the United States Environmental Protection Agency (US EPA) maximum contamination level drinking water guidelines (MCL), with aluminium (Al) observed above the Aquatic Life Criteria in all four zones. Similarly, sediment concentrations in all four zones exceeded the US EPA Effects range low (ERL) threshold guidelines for Cu, nickel (Ni), zinc (Zn) and Pb, with Cu, Zn and Pb classed at moderate contamination levels using the contamination factor. Fish tissue concentrations from the four zones were calculated using recommended daily intakes (RDI) and for PHEs as provisional maximum tolerable intakes (PMTIs) and indicated most macro- and micronutrients were at or below 10% RDI from aquaculture and wild fish, with Se indicating a greater RDI (16–29%) in all the zones. Contributions of PHEs to PMTIs were below threshold guidelines for both aquaculture and wild fish with only Cd, Cr and Pb levels being above the PMTI thresholds. There is a need to assess the long-term effects of persistent anthropogenic PHE input into Winam Gulf and the wider Lake Victoria basin. Continued monitoring of PHEs using both historical and more recent data will enable future management policies to be implemented through improved mitigation strategies to reduce their impact on water quality, fish health and subsequent human health.

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Section: Discussionmentioning

confidence: 99%

Considerations for environmental biogeochemistry and food security for aquaculture around Lake Victoria, Kenya

Marriott

Osano

Coffey

et al. 2023

Environ Geochem Health

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“…3-5 (areas contributing the largest nutrient flux rates). Given the climate of Kenya, the fluxes of sediments and associated nutrients from rivers into Lake Victoria are likely to be greatest during the rainy seasons (March-May and August-October), which Humphrey et al (2022) demonstrated using the RUSLE model at monthly resolution. Alewell et al (2020) highlighted that Africa has some of the highest soil P depletion rates in the world, driven by the challenges of fertiliser affordability and exacerbated by high soil erosion rates.…”

Section: Erosion Implications and Mitigation In Kenyamentioning

confidence: 93%

Agricultural practices drive elevated rates of topsoil decline across Kenya, but terracing and reduced tillage can reverse this

Feeney

Robinson

Thomas

et al. 2023

Science of The Total Environment

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“…Both counties are well drained with permanent rivers such as Isiukhu, Izava, Yala and Nzoia, which drain their waters into Lake Victoria and are the primary water sources for drinking, domestic use and supplying fishponds and irrigation. The mean annual rainfall ranges from 2000 to 2200 mm in Kakamega county and 1800 to 2000 mm in Vihiga county and is bimodal with long (March–July) and short (September–October) rainy seasons (Humphrey et al, 2022 ). The geology of Vihiga and Kakamega counties has the formation of the Kavirondian and the Nyanzian volcanic systems.…”

Section: Methodsmentioning

confidence: 99%

Artisanal gold mining in Kakamega and Vihiga counties, Kenya: potential human exposure and health risk

Ondayo

Watts

Hamilton

et al. 2023

Environ Geochem Health

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Artisanal and small-scale gold mining (ASGM) represents 20% of gold supply and 90% of gold mining workforce globally, which operates in highly informal setups. Pollutants from mined ores and chemicals introduced during gold processing pose occupational and inadvertent health risks to the extent that has not been well elucidated in Africa. Trace and major elements were analysed using inductively coupled plasma mass spectrometry in soil, sediment and water samples from 19 ASGM villages in Kakamega and Vihiga counties. Associated health risks for residents and ASGM workers were assessed. This paper focuses on As, Cd, Cr, Hg, Ni and Pb for which 96% of soil samples from mining and ore processing sites had As concentrations up to 7937 times higher than the US EPA 12 mg kg−1 standard for residential soils. Soil Cr, Hg and Ni concentrations in 98%, 49% and 68% of the samples exceeded respective USEPA and CCME standards, with 1–72% bioaccessibility. Twenty-five percentage of community drinking water sources were higher than the WHO 10 µg L−1 drinking water guideline. Pollution indices indicated significant enrichment and pollution of soils, sediment and water in decreasing order of As > Cr > Hg > Ni > Pb > Cd. The study revealed increased risks of non-cancer health effects (98.6) and cancer in adults (4.93 × 10−2) and children (1.75 × 10−1). The findings will help environment managers and public health authorities better understand the potential health risks in ASGM and support evidence-based interventions in ASGM processes, industrial hygiene and formulation of public health policy to protect residents and ASGM workers’ health in Kenya.

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Evaluating spatio-temporal soil erosion dynamics in the Winam Gulf catchment, Kenya for enhanced decision making in the land-lake interface

Cited by 13 publications

References 60 publications

Considerations for environmental biogeochemistry and food security for aquaculture around Lake Victoria, Kenya

Considerations for environmental biogeochemistry and food security for aquaculture around Lake Victoria, Kenya

Agricultural practices drive elevated rates of topsoil decline across Kenya, but terracing and reduced tillage can reverse this

Artisanal gold mining in Kakamega and Vihiga counties, Kenya: potential human exposure and health risk

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