Browsing by Author "Twinomuhwezi, Hannington"

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    Aflatoxin B1 Production, Toxicity, Mechanism of Carcinogenicity, Risk Management, and Regulations
    (Archives of Animal and Poultry Sciences, 2021) Awuchi, Chinaza God.; Ondari, Erick N.; Twinomuhwezi, Hannington; Igwe, Victory S.; Amagwula, Ikechukwu O.
    parasiticus. It is well known strong carcinogenic substance with median lethal dose (TD50) of 3.2 μg per kg a day in rat model. Mechanism of AFB1 carcinogenicity has been defined. The carcinogenicity of AFB1 differs from species with certain species, e.g. monkeys and rats, reportedly mostly susceptible compared to the other species. In animals and humans, aflatoxin B1 has been shown to be teratogenic, mutagenic, and immunosuppressant. The worldwide maximum tolerated aflatoxin B1 levels was reported by the FAO to be in within 1 to 20 µg per kg in food; 5 to 50 µg per kg in cattle feed. Aflatoxin B1 permeates via skin. Dermal exposures to AFB1 in specific conditions usually result in concerning health risk. Liver is organ mostly vulnerable to the toxicity of AFB1. AFB1 is a genotoxic hepatocarcinogen that has its exposures linked to hepatocellular carcinoma development, tumors of the liver, particularly when simultaneously occurred with hepatitis B viral infection. The hepatocellular carcinoma prevalence in people exposed to aflatoxins, has shown to increase with simultaneous occurrence of hepatitis B viral infection. Oral median lethal dose (LD50) of AFB1 is 0.3 to 17.9 mg per kg bw for many animals. Embryonic deaths and weakened development of embryo of Fabricius bursa in chicken by AFB1 was reported. Exposures to aflatoxin B1 is mostly taken care of with the measures directed at the prevention of crop contamination in field, handling in post-harvest, and also in storage,
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    Variations in the contents of heavy metals in arable soils of a major urban wetland inlet drainage system of Lake Victoria, Uganda
    (Lakes & Reservoirs: Research & Management, 2010) Mbabazi, Jolocam; Bakyayita, Grace; Wasswa, John; Muwanga, Andrew; Twinomuhwezi, Hannington; Kwetegyeka, Justus
    Little is known about the effects of urbanization on the chemical quality of soils in suburban wetland inlet drainage systems to the Uganda side of Lake Victoria, on which food crops are extensively grown. It is feared that pollution in the soils might eventually enter food chains through such crops being consumed by urban populations unaware of their occurrence. Soil samples were collected from cultivated areas of a major wetland drainage system (Nakivubo Channel), at Kampala, Ubanda, near Lake Victoria and from a rural control wetland site (Senge). The soil from this site had similar properties as those from the urban test site (i.e., soil texture; porosity; humus content). Analysis of heavy metals with atomic absorption spectrophotometry (AAS) yielded the following soil concentration ranges: manganese (190–780), cadmium (<0.001–1.0), zinc (6.0–10.0) and lead (10–20 mg kg)1) dry weight for the control site, and 450–900, 1.0–2.0, 131– 185, 40–60 mg kg)1 dry weight, respectively, for the urban wetland, indicative of relatively heavy metal pollution in the suburban drainage system. Heavy metal levels in cocoyam (Colocasia Esculenta) and sugarcane (Saccharum Officinarum) grown on both wetland soils also were evaluated via AAS with a modified wet-acid-digestion technique. The results highlighted high cadium and lead levels (P £ 0.0003) in the crops from urban wetland cultivation. Cadmium and lead concentrations in cocoyam from urban wetland soils exceeded those from the control site by 0.17 and 3.54 mg kg)1, respectively. The corresponding results for sugarcane indicated a similar increase of 0.56 and 2.14 mg kg)1 of juice extract. Cadmium and lead levels in both urban wetland crops were higher than the maximum permissible limits of the Codex Alimentarius Commission, indicating that these concentrations pose potential health risks to urban consumers, and call for early counter-measures to combat urban pollution entering the lake.