Level,distribution and pollution assessment of heavy metals in urban community garden soils in Baghdad City, Iraq

Abstract

Fourteen composite samples were collected from the gardens soils in Baghdad City in order to determine concentrations, spatial distribution and contamination assessment of heavy metals such as Cd, Cr, Cu, Ni, Fe, Pb and Zn. The mean concentrations are as follows: 18.64 mg/kg for Cd, 3.65 mg/kg for Cr, 15.64 mg/kg for Cu, 9114.28 mg/kg for Fe, 30.71 mg/kg for Ni, 1.99 mg/kg for Pb and 23.71 mg/kg for Zn. The mean concentrations of heavy metals were compared with USEPA soil guideline and the world reference value. The mean concentrations of Cd and Ni exceeded the guidelines while the other metals did not exceed. Positive and negative significant correlation relationships between the metals were reported. ANOVA showed that there were significant differences (at p < 0.5) in concentrations Cd, Ni and Zn metals between the sampling sites and insignificant (at p < 0.5) in concentrations of Cr, Cu and Pb. The metal contamination in the garden soils was also evaluated by Appling enrichment factor (EF), pollution load index (PLI), integrated pollution load index (IPLI) and geoaccumulation index (Igeo). Based on enrichment factor (EF) , the gardens soils in Baghdad city are extremely high enrichment with Cd and moderate enrichment with Cu and Ni. Pollution load index (PLI) and geoaccumulation index (Igeo) indicated that Baghdad gardens soils are polluted by Cd and unpolluted by other metals. The integrated pollution load index (IPLI) values showed that the gardens soils in Baghdad are polluted with heavy metals. The sources of Cd in Baghdad gardens soils may be from traffic and industrial emissions and may be from phosphate fertilizers.