Chen Qi, Deng Xiao, Chen Shan, Hou Hong-Bo, Peng Pei-Qin, Liao Bo-Han
College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
Huan Jing Ke Xue. 2017 Jun 8;38(6):2538-2545. doi: 10.13227/j.hjkx.201610158.
Pot experiments were used to study the correlations between different extractable cadmium levels in typical soil and cadmium accumulation in rice. To analyze the pH, Cd in soil solution(SSE-Cd), TCLP extractable Cd level(TCLP-Cd), and Cd accumulation in rice at different growth stages of rice, we conducted pot experiments which selected the reddish clayey soil(developed from quaternary red clay parent materials) and purple paddy field(developed from purple sandy shale parent materials), meanwhile added with exogenous Cd with the gradients of 0, 0.5, 1, 2, 5, 10 mg·kg. The results showed that, during the rice growth period, the content of SSE-Cd in reddish clayey soil was in the range of 0 and 2.5 μg·L, and the average content was 0.57 μg·L; TCLP-Cd was in the range of 0 and 0.25 μg·L with the average content of 0.10 mg·kg;The content of SSE-Cd in purple paddy field was in the range of 0 and 1.6 μg·L with the average content of 0.48 μg·L; TCLP-Cd was in the range of 0 and 0.2 mg·kg, and the average content was 0.07 mg·kg. It showed that the cadmium concentrations in soil solution and the TCLP extractable Cd levels were both significantly reduced in two types of soil with the extension of rice growth period, and the content in reddish clayey soil was higher than that in purple paddy. The TCLP extractable Cd level was significantly positively correlated with Cd concentration in soil solution. The total Cd accumulation in rice plants gradually increased with increasing exogenous Cd concentration. There were significant positive correlations between Cd concentration in soil solution and Cd concentration in rice, Cd concentration in soil extracted by TCLP method and Cd concentration in rice and total Cd accumulation in rice plant. The soil environmental capacities of the two different parent materials varied greatly,and the safety threshold of Cd in purple paddy field was 2.06 times of that of reddish clayey soil. There were significant differences in Cd uptake and accumulation in different soils, so different measures may be needed to control Cd pollution in different parent materials. TCLP extractable Cd was more relevant with total Cd accumulation in rice, and had more extraction amount. Therefore, the TCLP method can more accurately evaluate the biological availability of soil Cd.
采用盆栽试验研究典型土壤中不同形态镉含量与水稻镉积累的相关性。为分析水稻不同生育期土壤pH值、土壤溶液镉（SSE-Cd）、TCLP提取态镉含量（TCLP-Cd）及水稻镉积累情况，选取发育于第四纪红粘土母质的红壤性粘土和发育于紫色砂页岩母质的紫色稻田土进行盆栽试验，同时设置0、0.5、1、2、5、10 mg·kg外源镉梯度。结果表明，水稻生育期内，红壤性粘土中SSE-Cd含量在02.5 μg·L之间，平均含量为0.57 μg·L；TCLP-Cd含量在00.25 μg·L之间，平均含量为0.10 mg·kg；紫色稻田土中SSE-Cd含量在在01.6 μg·L之间，平均含量为0.48 μg·L；TCLP-Cd含量在00.2 mg·kg之间，平均含量为0.07 mg·kg。表明随着水稻生育期延长，两种土壤中土壤溶液镉浓度和TCLP提取态镉含量均显著降低，且红壤性粘土中含量高于紫色稻田土。TCLP提取态镉含量与土壤溶液镉浓度显著正相关。水稻植株总镉积累量随外源镉浓度增加而逐渐增加。土壤溶液镉浓度与水稻镉浓度、TCLP法提取土壤镉浓度与水稻镉浓度及水稻植株总镉积累量之间均存在显著正相关。两种不同母质土壤环境容量差异较大，紫色稻田土镉安全阈值是红壤性粘土的2.06倍。不同土壤镉吸收积累存在显著差异，治理不同母质镉污染可能需采取不同措施。TCLP提取态镉与水稻总镉积累相关性更强，提取量更大。因此，TCLP法能更准确评价土壤镉生物有效性。
