عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Arsenic (As) toxicity in soil, plant and water is a major global environmental problem. This research was carried out to measure the concentration of arsenic in soil and to compare the arsenic uptake by maize, wheat and rapeseed planted in a natural contaminated calcareous soil. The level of arsenic was identified in 20 naturally polluted soil samples which had been randomly selected in north of Qhorve using concentrated nitric acid, 0.05 M (NH4)2SO4, and water extractants. Then greenhouse experiments based on a completely randomized design were used to grow maize, wheat and rapeseed for 120 days in the selected As polluted calcareous soils with three replications. The maximum total As concentration in the selected soils was 3470 mg/kg and the level of As was significantly correlated with the clay, silt and CaCO3 contents. The average levels of concentrated HNO3, 0.05 M (NH4)2SO4- and water-extractable As in the soil selected for greenhouse planting were 990 mg/kg, 0.4 mg/kg and 0.5 mg/kg, respectively. The levels of As concentration were 7, 15 and 16 mg/kg in the maize, wheat and rapeseed shoots and 51, 102 and 84 mg/kg in their roots, respectively. In addition, the As uptaks by maize, wheat and rapeseed were 0.728, 0.350 and 0.198 mg/pot respectively. The bioaccumulation factors were 0.006, 0.015, and 0.016 and the translocation factors were 0.129, 0.148 and 0.181, in maize, wheat and rapeseed respectively. The As concentration in maize was highly correlated with the water and 0.05 M (NH4)2SO4 extractable As compared to concentrated HNO3. Because of higher As bioaccumulation factor, wheat can create higher risk to animals and human than to maize in the agricultural lands of north of Ghorveh.