Comparative Analysis of Leachable Heavy Metals in Earthenware Clay Deposits in the Central and Volta Regions of Ghana

摘要

This paper, sought to compare and contrast the potential leachable heavy metals in earthenware clay deposits in the Central and Volta regions of Ghana, using the Atomic Absorption Spectrophotometer (AAS). The study also tried to establish the suitability of which clay deposit is the ideal raw material for earthenware products used as food wares, based on toxic heavy metal and micro nutrient/essential metal levels. The toxic metals determined were Pb, As, Hg, and Cd, while the micronutrients/essential elements examined were Cr, Zn, Mn, Cu, and Fe. The results showed that, apart from Hg and Cr, there was no statistical difference in heavy metal levels in the two regions. Earthenware clay deposits in the two regions were found to be suitable raw materials for food ware products based on their heavy metal levels. The reproducibility of the analytical method was assessed by analysis of the standard reference material IAEA soil-7. The values obtained, compared favourably well with the recommended values as Spearman correlation coefficient was +0.96%. The experimental values were within ± 4% of the recommended values. The measurement precision specified by the relative standard deviation was within ± 5%. The error margins are standard deviations. A two -tailed student’s t-test was used to establish any statistical differences between the mean concentrations of the two earthenware clay deposits. The level of probability at which significant differences existed between the deposits was set at p < 0.05 at 95% confidence level. In general, the two clay deposits were found to be suitable sources of raw materials for food ware products.