Abstract
This study investigated two digestion methods (USEPA 3051: microwave, HNO3 or Hossner: hot plate, HFH2SO4HClO4) for heavy metals analysis in contaminated soil surrounding Mahad AD'Dahab mine, Saudi Arabia. Moreover, contamination metal levels were estimated. The Hossner and USEPA 3051 methods showed, respectively, average total contents of 17.2 and 18.1mgkg(1) for Cd, 11.6 and 10.6mgkg(1) for Co, 45.7 and 34.7mgkg(1) for Cr, 1030 and 1100mgkg(1) for Cu, 33,300 and 27,400mgkg(1) for Fe, 963 and 872mgkg(1) for Mn, 33.2 and 22.8mgkg(1) for Ni, 791 and 782mgkg(1)for Pb, and 6320 and 2870mgkg(1) for Zn. A lack of significant differences and a high correlation coefficient (>90%) for Cd, Pb and Cu between the two digestion methods suggest that the total-recoverable method (USEPA 3051) may be equivalent to the total-total digestion method (Hossner) for determining these metals in the studied soil. However, significantly higher concentrations of Cr, Fe, Ni and Zn were found by the Hossner method comapred with the USEPA 3051 method. The soil samples have very or extremely high levels of Zn, Cu, Cd and Pb contamination, indicating very high potential ecological risk.