ABSTRACT
The bioavailability of copper in contaminated soils has received more attention due to the safety concern of food chain. The bioavailability of metals is determined by its fractions which are affected by the soil properties and its aging time. This paper focused on the aging effect on the bioavailability of copper added to the soil. The garden soil [fluvo aquic soil] was treated with 100mg/kg and 1000 mg/kg of CuSO4 and incubated for 14, 21, 28, 42, 63, 120, 200, 300 and 400 days in the laboratory respectively. The sequential extraction procedure was used to characterize copper bioavailability in the soil. Meanwhile, the barley was cultured on the same soil incubated and its toxicity was assessed according to the guideline of International Organization for Standardization. The findings show that the exchangeable and carbonate-bound copper decreased with the aging time after addition of CuSO4 in to soil. Meanwhile, the percentages of Fe-Mn oxides and organic bound copper increased. The residual copper was changed little during the aging course. The copper fractions became stable in soils after 60 days. The kinetic equations showed that the Power function and the Elovich equation were fitted well to the experimental data, and the r2 values ranged from 0.840 to 0.982 and 0.741 to 0.975 respectively. The barley test showed that the barley root length was more sensitive to reflect copper toxicity than the shoot biomass. And the exchangeable and carbonate-bound copper were significantly correlated with the barley root length