Quantification of heavy metal levels in imported rice (Oryza sativa) consumed in the Northern Parts of Nigeria

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Research Paper 01/04/2014
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Quantification of heavy metal levels in imported rice (Oryza sativa) consumed in the Northern Parts of Nigeria

G.T.O. Otitoju, O. Otitoju, C.J. Igwe
J. Bio. Env. Sci.4( 4), 202-207, April 2014.
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Dietary exposure to heavy metals, namely Cadmium (Cd), Lead (Pb), Chromium (Cr), Mercury (Hg), Arsenic(As), has been identified as a risk to human health through the consumption of some major food substances. This study was designed to investigate five (5) heavy metals (As, Cd, Cr, Hg, Pb) in ten (10) imported rice (Oryza sativa) samples consumed in the Northern parts of Nigeria. The study areas were Kubwa in Abuja (FCT), Jos town in Plateau state, Wukari in Taraba state, Jaba in Kano and Central market in Kaduna town, Kaduna state. The result showed the average mean lead concentration in some imported rice samples to be 0.152mg/kg with variations in different areas which when compared with the Provisional Tolerable Weekly Intake (PTWI) of heavy metals set by WHO/FAO at 25μ/kg (0.025mg/kg) body weight far exceed the permissible limit for human health. All the rice samples had lead concentrations above the permissible limit except for “Par Excellence Premium Long Grain rice” (0.014mg/kg) produced in USA which is below the permissible limit. “Royal stallion” produced in Thailand had the highest lead concentration of 0.383mg/kg which also when compared with the Provisional Tolerable Weekly Intake (PTWI) far exceeded the permissible limit. Other heavy metals such as As, Cd, Cr, Hg was undetectable at 0.001mg/kg. Hence, imported rice consumed in the Northern parts of Nigeria may contain toxic levels of heavy metals which should be monitored as it may be deleterious to health.


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