Analysis heavy metals in different regions in the Sultanate of Oman

Abstract

Heavy metals can enter the food chain through water, soil and plant pollutions. It was therefore of interest to conduct a study to estimate the levels of these heavy metals in water, soil and plants of different regions of the Sultanate of Oman. This is the first comprehensive study for the analysis of heavy metals in soil, water and plant in the Sultanate of Oman. Samplings were conducted from four regions i.e. Batinah North (BN), Batinah South (BS), Dakhliyah (DH) and Sharqiyah (SH) between November 2009 and July 2010. For this purpose, five farms were selected from each region. Eleven heavy metals analyzed were cadmium (Cd), cobalt (Co), copper (Cu), chromium (Cr), iron (Fe), lead (Pb), manganese (Mn), molybdenum (Mo), nickel (Ni), vanadium (V) and zinc (Zn) using inductively coupled-plasma emission spectroscopy (ICP-OES). For soil samples, high levels of Mn (3.406 ?g/g) and Fe (2.494 ?g/g) were detected, but not exceeding MPL, while Cd (0.006 ?g/g) recorded the lowest concentration in all regions. For well water samples, only Ni (0.035 ?g/mL) exceeded the Omani specifications standard for unbottled drink. Fe was detected at high concentration (170.554 ?g/g) and Cd (0.058 ?g/g) was the lowest detectable element for the animal grass plant samples. The proposed maximum permissible limit (MPL) of ten heavy metals (Cd, Co, Cu, Cr, Pb, Mn, Mo, Ni, V and Zn) in Omani soil was 0.8, 20, 10.0, 63.0, 100.0, 85.0, 500.0, 40.0, 50.0, 50.0 and 200.0 µg/g respectively. While for well water, MPL of most elements proposed followed the WHO guidelines except Cu and Mn that followed the lower Malaysian guideline of 1.0 and 0.1 ?g/mL respectively. All heavy metals in soil and water samples analyzed were well below the limit of the proposed Omani MPL. There was no correlation found of the content of heavy metals in the soil, water and plant samples.