Daystar University Publications

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Browsing Daystar University Publications by Author "Admiraal, Wim"

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    Contribution of Soil, Water and Food Consumption To Metal Exposure of Children From Geological Enriched Environments in The Coastal Zone of Lake Victoria, Kenya
    (International Journal of Hygiene and Environmental Health, 2012) Oyoo-Okoth, Elijah; Admiraal, Wim; Osona, Odipo; Manguya-Lusega, David; Ngure, Veronica; Kraak, Michiel H. S.; Chepkirui-Boit, Victoria; Makwali, Judith
    Geologically enriched environments may contain high concentrations of some metals. In areas where industrial exposures remain super cial, children may be exposed to these geological metals through soil, drinking water and consumption of food locally grown. The aim of this study was to assess the contribution of soil, water and food consumption to cadmium (Cd), chromium (Cr), copper (Cu), zinc (Zn), cobalt (Co) and titanium (Ti) body burden of children in the geologically metal rich coastal zone of Lake Victoria, Kenya. We evaluated the relationship between the metal body burden of children by analyzing the hair samples and the estimated metal intake through exposure to soil, drinking water, and food consumption. The body burdens of all metals in children at the exposed sites were high, suggesting environmental exposure. Most of the foods consumed resulted in metal intake below the maximum recommended daily intake. However, the net contribution of all food items jointly exceeded the recommended maximum daily intake at some of the exposure sites. Our results further demonstrated that the highest intake of metals occurred via ingestion of high quantities of the cyprinid sh Rastrineobola argentea. Positive linear relationships between the metal body burden in children and estimated daily intake were observed for Cd, Cr, Ti in children consuming high quantity of R. argentea; for Zn and Co in children highly exposed to soils and consuming high quantity of Brassica oleraceae, while Co burden in the body was associated with high consumption of maize meal. This study demonstrated that exposure to soil and consumption of higher quantities of some foods contributed to the increased metal body burdens of children in a geologically exposed region.
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    Dynamics of Metal Uptake and Depuration in a Parasitized Cyprinid Fish (Rastrineobola argentea)
    (Aquatic Taxocology, 2012) Oyoo-Okoth, Elijah; Admiraal, Wim; Osano, Odipo; Kraak, Michiel H. S; Were-Kogogo, Pamela J. A; Gichuki, John; Ngure, Veronica; Makwali, Judith; Ogwai, Caleb
    Infestation of fish by endoparasites may potentially influence metal uptake and elimination by the host. We quantified the metal uptake rate constant (ku) and efflux rate constants (ke) of radiolabeled Cd and Co in the cyprinid fish Rastrineobola argentea experimentally infected with the parasite Ligula intestinalis. During 24 h, the accumulation of Cd and Co increased linearly with no evident steady state in uninfected fish, infected fish and in the parasite. Following aqueous exposures, the ku for Cd in parasites was about 3× higher than that of infected fish and 6× higher than for the uninfected fish. The ku for Co was up to 15× higher in the parasites than that of infected fish and 7.5× higher than for the uninfected fish. The ke for excretion of Cd were consistently higher for the uninfected fish than for the infected fish and also higher for uninfected fish than the parasite. The ke for Co for the uninfected fish was 1.4–2.0× lower than in the infected fish, but higher for parasites compared to uninfected fish (1.3–2.3×). Pulse-chase feeding experiments with radiolabeled copepods showed that Cd assimilation efficiency from food was higher in infected fish, while Co was assimilated more effectively by uninfected fish. The observed differences in metal dynamics between infected and uninfected R. argentea in the laboratory concord with differences in metal concentrations measured in natural populations in Lake Victoria. Our findings provide evidence that L. intestinalis infection enhances Cd accumulation, but depletes the essential Co in the cyprinid fish R. argentea. We conclude that the combined stress of parasites and pollution changes metal risks to fish hosts in a metal specific manner.