Abstract:
Samples of soils and plants were collected from 3 electroplating plant contaminated areas in Chongqing for analysis in laboratory to investigate concentrations of chromium(Cr),nickel(Ni),zinc(Zn) and copper(Cu) therein and to further explore characteristics of the 23 dominant plants accumulating and translocating heavy metals.Results show that in the soils,the average concentration of Cu,Zn,Cr,and Ni was 560.0,722.6,1 364.3 and 735.7 mg·kg
-1,respectively,and about 1.40,1.45,3.90,and 3.68 times,respectively,the threshold value in Grade Ⅲ of the "Standard for Soil Environmental Quality"(GB 15618-1995).The characteristics of plants absorbing,accumulating and transferring heavy metals varied with species and parts of plant,location of contaminated area and kind of metal.Most of the plants in these areas had heavy metals accumulated in the roots.Only
Hemarthria compressa and
Mentha haplocalyx displayed their characteristics of being Cr hyperaccumulators,with Cr concentration in shoots reaching 1 559.2 and 1 914.6 mg·kg
-1,respectively,on average,BTC(biological transfer coefficient) 1.29 and 1.58,respectively,and BAC(biological accumulating coefficient) 1.58 and 1.79,respectively.Besides the two,there were 14 other plants whose Cr concentrations in shoots were over 100 times higher than those of ordinary plant species,with Cr concentrations ranging from 121.2 to 694.3 mg·kg
-1 and averaging 376.4 mg·kg
-1,and 8 others whose Ni concentrations in shoots were over 100 times higher than those of ordinary plant species,with Ni concentrations ranging from 220.3 to 532.1 mg·kg-
1 and averaging 344.1 mg·kg
-1.In summary,the findings indicate that these plants are ideal species of plants for phytoremedying soils polluted with multi-heavy metals from electroplating plants.