Abstract：To study the dynamic characteristics, aging factors and its’ influence factors of Cd added to paddy soil, five kinds of paddy soil with various properties were collected, the soils were artificially polluted by cadmium with 6 different addition levels. A pot experiment was performed to investigate the Cd phytotoxicity to the rice growth characterised with different sensitivity to Cd stress in paddy soils, meanwhile, the effect of five ageing times (i.e. 14d, 30d, 60d, 90d and 180d) on the Cd phytotoxicity was investigated using Log-logistic dose-response distribution model. The results showed that the content of the 0.05mol/L EDTA-2Na extracted Cd decreased with the increasing of the aging time in all the soils, the maximum decrement of the 0.05mol/L EDTA-2Na extracted Cd ranged from 21.5% (for the red soil) to 38.0% (for the black soil) respectively, as compared with the treatment of 14d-incubation time. After aging for 90d, the adsorption of Cd in the soil solution reached the slow reaction stage. According to the fitting parameters of the two-order kinetics equation, the aging of Cd in soil was characterized with the extracted Cd content decreased fast in 30d to 60d stage, then the process became slow and reached the balance in the soil solution after 90d incubation. The analysis of the correlation between the kinetic equation parameters (C∞ and K2) and soil properties indicated that, soil pH was the main control factors affecting the fraction of bio-available Cd content in soils, followed by soil CEC and OC content. The 50%inhibiting concentration (EC50) of Cd toxicity to rice growth increased significantly (P<0.05) with the aging time in soils, the EC50 of the treatments with 180d ageing time increased 72.1% to 195.0% as compared with the treatments of 14d aging time. The effects of soil pH on the Cd aging processes decreased gradually, and the influence of CEC increased gradually in thelong-term ageing greater than the treatment of 90d, however, the key factor that affecting the Cd ageing process in the soil was still the soil pH, and no effect of the selected rice cultivars on the Cd ageing process was observed in the soils for this study.
刘彬, 孙聪, 陈世宝, 张晓晴, 宋文恩, 李宁. 水稻土中外源Cd老化的动力学特征与老化因子[J]. 中国环境科学, 2015, 35(7): 2137-2145.
LIU Bin, SUN Cong, CHEN Shi-Bao, ZHANG Xiao-Qing, SONG Wen-恩, LI Ning. Dynamic characteristics and ageing factors of Cd added to paddy soils with various properties. CHINA ENVIRONMENTAL SCIENCECE, 2015, 35(7): 2137-2145.
