Investigation of Heavy Metals Accumulation in Plants Growing in Contaminated Soils (Case Study: Qazvin Province, Iran)

Environmental pollution with heavy metals is a global disaster that is related tohuman activities. This study was conducted to determine the extent of heavy metalsaccumulation by plant species in Lia industrial city (Qazvin, Iran) and to investigate theremediative capacity of native plant species grown in the contaminated soils. Soil andindustrial wastewater sampling was done radially along transects with 300 m intervalsfrom exit point of wastewater at three sites. In each sampling point, along 100 m transectswithin 5×2 m plots, the plant samples and soil samples were collected in depth of 0-20 cmand 20-40 cm from rhizosphere zone. Concentration of copper, zinc and chromium in rootand shoot of 11 plant species, soil and wastewater were analyzed in three sits formentioned metals. Bio Concentration factors and translocation factor were determined toensure phytoremediation availability. Results showed that the concentrations of metals inthe soil and wastewater greatly exceeded the threshold limit values. The contents of metalsin soils ranged in the order of Cr>Zn>Cu and in wastewater were in the order ofZn>Cr>Cu, respectively. Results showed that Scirpus maritimus L. and Phragmitesaustralis (Cav.) Trin. ex Steudel presented the highest accumulation of Zn, Cu and Cr intheir root tissues which were suitable for phytostabilization (with a high BCF couple withlow TF). The lowest extractable Zn (7.24 and 3.29 mgkg-1 for shoot and root respectively,BCF=0.07) and extractable Cu (2.56 and 2.80 mgkg-1 for shoot and root respectively,BCF=0.14) were related to Hordeum glaucum L. Moreover, the relatively lowest values ofCr were measured for Taraxacum officinale L. Results indicated that the species, whichhad low metal bioaccumulation in their roots and high TF, could play important roles forremoval of heavy metals through phytoextraction.