effects of some soil properties on arsenic and cadmium uptake by silybum marianum

in this study the effects of some soil properties on uptake arsenic and cadmium by silybum marianum was studied. to this end surrounding area asphalt plant of city kalaleh, was divided to 6 pieces (a, b, c, d, e, f), with an area of approximately one hectare. plots a and d on both sides of the river, are the nearest areas asphalt plant. also a non-polluting area as a control was considered. arsenic accumulation in plants collected from plots a and d (6.83 and 6.18 mg arsenic per kg of plant dry weight) is greater than the plant permitted limit. the highest uptake of cadmium was observed in plot a (1.58 mg cd per kg of plant dry weight) and then plot d (1.41 mg cd per kg of plant dry weight) that in both plots were more than permitted standard limits. in the present study, between the cec and soil organic carbon, with arsenic and cadmium uptake by the plant, a negative correlation was observed, so that areas with lower cec and soil organic carbon, arsenic and cadmium levels were higher in plants. in the present study, the arsenic amount in plants in areas with high acidity and salinity was higher. considering that bioaccumulation factor in the roots and shoots for both metal, in all plots was smaller than one, the plant can not be as a hyper accumulator for these metals.