Assessment Effect of Organic Matter and Arsenic on Transfer Coefficient, Tolerance Index and Phytoremediation in Cress (Lepidium sativum L.)

Soil contamination with heavy metals such as arsenic has harmful effects on human health and agricultural products. Arsenic (AS) is one of the heavy metals which are highly toxic and carcinogenic. This research was conducted to study the effect of organic manure on increasing the Arsenic absorption ability by Cress plant in the greenhouse of the Agriculture and Natural Resources Research Center, Khuzestan, Iran, according factorial experiment based randomized completely design with three replications. Main factor included two levels of organic substance (0 and 10 tons per hectar) and three levels of arsenic concentration (0, 20 and 40 ppm) belonged to sub factor. Mean comparison result revealed increasing arsenic concentration led to increase arsenic accumulation in shoot plant (14.1 ppm), also this trend seems in transfer coefficient trait so cress can be used as a purifier plant to reduce arsenic contamination of the soil. It need to mention by increase arsenic concentration, shoot dry weight decreased (0 ppm arsenic concentration had 20.1 gr per flowerpot but 40 ppm treatments had 0.7 gr). Finally according to contamination symptoms (Necrosis and chlorosis) on cress plant at 40 ppm concentrations and reduced plant shoot dry weight at this concentration, it is recommended to use the cress plant for purification of soil contaminated less than 40 ppm arsenic concentrations. It is noteworthy advised according plant's ability to absorb arsenic and other heavy elements, sowing of this plant as food should be avoided in the contaminated fields.