Investigation of Cd, Pb, and Ni contamination in soil and wheatplant in alluvial lands of Tigris River in southern Baghdad, Iraq

Accurate information on the concentration of heavy metals in the soil is essential to manage soilcontamination. the objective of this study was to investigate the contamination of soil and wheat plantswith ni, cd, and pb in the alluvial plain of tigris river in southern baghdad. a total of hundred surfacesoil samples (0-30 cm) and aerial parts of the wheat plant were taken in an area of ~100 km2 at aninterval distance of 1000 meters. heavy metals in air-dried soil samples and plant were extracted by theaqua regia solution and wet digestion method, respectively. the mean concentration of cd in soil andwheat plant was 0.4 and 1.1 mg kg-1, respectively. the amount of plant-cd was higher than the allowablestandards of fao and who. mean pb concentration in the soil of the study area was 14.5 mg kg-1. theconcentration of pb in the plant was less than the detection limit of the device. the mean concentrationof ni in the soil and plant was 214 and 17 mg kg-1, respectively, which was more than the allowablestandards of fao and who. the source of ni is fine sediments transferred from eroded ultramaficrocks in the upper part of the river. a positive correlation between pb and cd in the soil indicates asimilar origin. they were added to the soil by agricultural activities and vehicles. the results showedthat the studied soils are at the beginning of the contamination with cd and pb, which needs to beconsidered to prevent more contamination.