Analysis of Heavy Metal Concentration Data in Different Geochemical Fractions

Statistical studies on the correlation analysis and multiple linear stepwise regression analyses based on the different geochemical fractions of metals (Cd, Cu, Pb and Zn) in the sediments of the Straits of Malacca were conducted. Significant (P< 0.001) correlation matrices were found among total concentrations of Cd, Cu, Pb and Zn indicating that they had a common source of anthropogenic origin. The nonresistant fractions of Cd, Cu, Pb and Zn were mainly due to the ‘oxidisable-organic’ fractions (Cd: R= 0.91; Cu: R= 0.99; Pb: R= 0.97 and Zn: R= 0.99) of the sediments which were considered to be related to anthropogenic activities. The assumption that the elevated metal concentrations were due to anthropogenic sources (nonresistant) in the sediments was found to be true for Cd (R= 0.83, P< 0.001), Cu (R= 0.69, P< 0.001) and Pb (R= 0.87, P< 0.001) but not for Zn (P> 0.05). The total concentrations of Cd, Cu, Pb and Zn were also significantly correlated with and related to their resistant fractions (with R values are Cd: 0.68; Cu: 0.96; Pb: 0.85 and Zn: 0.96). Multiple linear stepwise regression analysis revealed that the total concentrations of metals were influenced by the geochemical fractions of the metals that resulted in highly significant (p< 0.001) of all models and some of them are also significantly (at least P< 0.05) correlated by performing the Pearson’s correlation analysis. Based on the present data, the relationships and behaviours of the geochemical fractions of Cd, Cu, Pb and Zn in the surface sediment of the Straits of Malacca could be understood by using correlation analysis and multiple linear stepwise regression analysis.