Effect of aging on bioavailability of copper on the fluvo aquic soil|
Guo, G.; Yuan, T.; Wang, W.; Li, D. & Wang, J.
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 100 mg/kg and 1000 mg/kg of copper(II) sulfate 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 copper(II) sulfate 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 well fitted 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.
Aging effect; Bioavailability; Copper; Kinetics; Soil fractions