Comparative Analysis of Some Digestion Methods Used in the Determination of Metals in Soil and Sediments

Analytical study was carried in order to compare the accuracy of three (3) frequently used digestion methods, in the determination of metals in soil and sediments. Samples of soil and sediments were taken from three different locations namely; Bakalchi, Batare, and Anguwan Honna in Girei Local Government Area in Adamawa State Nigeria. Sample matrix was formed from the three samples and the three digestion methods was carried out on each of the sample matrix formed, the methods are, Method I: Roast before digestion using aqua regia as used by Ehi-Eromosele and coworkers [1], Method II: Air dried and digest using Aqua-regia similar to the work of Saxena [2], and Method III; Roast using ammonium chloride before digestion with aqua regia similar to the work of Voica et al [3]. The metal elements Calcium and Iron were chosen because of their relative abundance in natural soil and sediments. Results obtained shows that the soil and sediment samples contain the metal element calcium and Iron which were used to examine the frequently used digestion methods. Based on the result obtained from the analysis, method III (Roast with NH4Cl and digest with aqua regia) appears to be the most promising, given the higher concentration of the elements in all the matrix samples examined.