Contamination of Soil and Vegetables by Heavy Metals and the Associated Health Risks in Khartoum North

Abstract

The concentration of metals in soil and vegetables grown in farms around Khartoum North urban area was determined for estimated contamination of soil, vegetable and health risk. The metals investigated are Al, As, Cu, Fe, Ni, Pb and V, their concentrations are found in soil below WHO permissible limit accept Fe levels 182.57 mg/kg, where permissible limit is 4.25. Metals Al, As, Cu, Fe, Ni, Pb and V content in vegetables range (0.80 – 2.30), (0.07 – 0.18), (0.11 – 0.21), (1.89 – 5.05), (0.06 – 0.08), (0.10 – 2.15) and (0.09 – 0.10) mg/kg respectively. Plant transfer coefficient % (PTC) calculated high metals transmit As 66.52, 55.01 and 52.45 for watercress, purslane, mallow and tomatoes respectively. The PTCs of Cu are 99.77, 86.65, 73.54 and 70.73 for tomatoes, mallow, purslane and okra, while the PTCs of Pb were moderated except purslane 828.46% and watercress 64.23%. The daily intake of metals (DIM) estimated for adult, the values found below the permitted maximum tolerable daily intake PMTDI in most vegetables studied, but it was found that Al consumed in purslane and watercress above PMTDI. The DIMs of As were above PMTDI in all samples, except cucumbers was equal the PMTDI value 0.01 mg/person per day. The DIM of Pb for purslane was estimated to be 0.305 mg/person/day above PMTDI. The health risk index (HRI) values ranged as As 3.40 – 8.689, Cu 0.386 – 0.754, Fe 0.382 – 1.022, Ni 0.404 – 2.154, Pb 0.101 – 6.760 and V 1.480 – 1.621. When HRI˂1, the exposed population is safe of metals health risk, while HRI>1 means the exposed population is unsafe of metals health risk.