Use of wild plant species as indicator of some heavy metals in the soil of General Company for tire industry in Najaf Governorate

Abstract

Concentration of seven metals (Pb, Cu, Zn, Mu, Ni, Cr, and Cd) in the samples of soil and some plant species collected from General Company for tire industry in Najaf were determined. The mineral ions were assayed using the acid digestion method and atomic absorption spectrophotometry (AAS). Physicochemical parameters (pH, EC, Bulk density, water holding capacity and Total Nitrogen) of the soil samples were also determined of the 7 metals determined in the soils samples, the concentration of Pb (15.25 ± 5.79 mg/kg−1) was the highest compared to the concentrations of other metals.Physicochemical parameters were within the range that allows effective use of wild plant species as indicator of some heavy metals in the soil. Cu showed the lowest concentration (0.65 ± 1.78 mg/kg−1). Ni was below the detectable limit in most of the samples. Similarly, concentrations of Pb (12.35 mg/kg−1) in the shoot of Sonchus asper (L.)Vill. among other metals were higher than those of the other metals in the plant tissues. Concentration of Cd (0.01 mg/kg−1) in the root of Rumex cyprius Murb. was the lowest. Generally, metal ion concentration in the soil and plant samples of the General Company for tire industry in Najaf(polluted site) significantly differed from those of the non-polluted site (P<0.05). Plantago boissieri Hausska.et Bornm. among the plant species had the highest translocation factor (TF = 2.91). Although the TF was higher in the plant of the polluted site (TF >1), reasonable amount of them were retained within the underground tissues (roots).