Some Heavy Metals Content in Plants Grown on Serpentinitic Soil from Penjwin and Mawat Area at Kurdistan Region – Iraq

摘要

Plants absorb a number of elements from soil, some of which have no known biological function and some are known to be toxic at low concentrations. There are substantial areas of serpentine soils at many locations in Iraq, but there is little information on their flora and biogeochemistry. The aim of this study was to assess the accumulation of heavy metals (Ni, Mn, Cu, Cr, Co, Cd, Fe, and Zn) in some natural plant species grown in serpentintic soils. Concentrations of heavy metals were measured also in soils, near the root of plant species. Four stations were chosen to assess the effect of growth environment in metal accumulation by each plant depending on variation in parent material composition. The plants species Conium maculatum L., Euphorbia helioscopia L., Scrophularia deserti, Onosma sericeum and Teucrium polium were collected from Penjwin area. Daucus carota and Lotus gebelia, were collected from Mawat area (Betwat), while plants species Lepidium draba L. and Salvia viridis were collected from Kunjrin in Mawat area. The total accumulation of selected elements in studied plants species showed variation in amount of elements accumulation, and the variation in ability of studied plants to accumulate metals in their organs. The results showed that the Euphorbia helioscopia was able to accumulate all studied elements in their root, in contrast, it was noticed that Salvia viridi showed high ability to accumulate all elements in aerial parts (foliage). So, concern rose about the possibility of toxic concentrations of certain elements being transported from plants to higher strata of the food chain. All studied plants were able to accumulate very high levels of Ca, and Mg, and the values of Ca accumulated in roots were ranged between 166.62 to 4277.59 mg kg-1, while the ranged in shoots were 367.69 to 2121.94 mg kg-1. Whereas the Mg values were raned between 73.21 to 2669.98 mg kg-1 in roots, while in shoots were ranged from 76.79 to 1270.01 mg kg-1.