Induced Geophagy with Local Kaolin from Cameroon Market and Heavy Metals (Lead, Cadmium and Mercury) Profile of Rat Blood, Liver, Placentas and Litters
Bonglaisin Julius Nsawir
Scientific findings revealed that local kaolin from the Cameroon market is contaminated with lead, mercury and cadmium. This study was carried out to assess the bioavailability of these heavy metals as well as their transplacental transport and their passage into rat litters. Eighty pregnant female albino rats were fed with kaolin for 21 consecutive days and on days 0, 7, 14 and 21, four of them were sacrificed from each group by cervical dislocation to obtain blood and liver samples. Kaolin dosage was calculated per body mass considering daily human consumption range (w/w). Whole blood and liver samples were digested with concentrated nitric acid. Based on results obtained in the first study, a second experimental study consisting of 10 pregnant albino rats verified the trans-placental transport of lead and the passage of lead to litters at birth and during breastfeeding. In the first study results, values of blood lead in the control group compared to the various test groups were statistically significant. No statistical significance occurred for cadmium and mercury. The values of liver lead in the control group compared to the other test groups on average bases were statistically significant. Results of the second study showed that transplacental transport of lead occurred only for high kaolin consumption and the passage of lead to litters occurred during breastfeeding. The study revealed that lead in kaolin is bioavailable. Cadmium and mercury are absorbed from the digestive tract but are both managed at the level of the liver.
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