| 1 | Predicting Cadmium Safety Thresholds in Soils Based on Cadmium Uptake by Chinese Cabbage显示文摘Cadmium(Cd), a common toxic heavy metal in soil, has relatively high bioavailability, which seriously threatens agricultural products. In this study, 8 different soils with contrasting soil properties were collected from different regions in China to investigate the Cd transfer coefficient from soil to Chinese cabbage(Brassica chinensis L.) and the threshold levels of Cd in soils for production of Chinese cabbage according to the food safety standard for Cd. Exogenous Cd(0–4 mg kg^(-1)) was added to the soils and equilibrated for 2 weeks before Chinese cabbage was grown under greenhouse conditions. The influence of soil properties on the relationship between soil and cabbage Cd concentrations was investigated. The results showed that Cd concentration in the edible part of Chinese cabbage increased linearly with soil Cd concentration in 5 soils, but showed a curvilinear pattern with a plateau at the highest dose of exogenous Cd in the other 3 soils. The Cd transfer coefficient from soil to plant varied significantly among the different soils and decreased with increasing soil p H from 4.7 to 7.5. However, further increase in soil pH to > 8.0 resulted in a significant decrease in the Cd transfer coefficient. According to the measured Cd transfer coefficient and by reference to the National Food Safety Standards of China, the safety threshold of Cd concentration in soil was predicted to be between 0.12 and 1.7 mg kg^(-1) for the tested soils. The predicted threshold values were higher than the current soil quality standard for Cd in 5 soils, but lower than the standard in the other 3 soils. Regression analysis showed a significant positive relationship between the predicted soil Cd safety threshold value and soil p H in combination with soil organic matter or clay content. | LU Junhe YANG Xinping MENG Xuchao WANG Guoqing LIN Yusuo WANG Yujun ZHAO Fangjie | 2017 | Pedosphere2017，27，3： | 13 |
| 2 | Remediation of Organochlorine Pesticide-Contaminated Soils by Surfactant-Enhanced Washing Combined with Activated Carbon Selective Adsorption显示文摘Remediation of organochlorine pesticide (OCP)-contaminated soils is urgently required especially in China. The present study investigated the removal of OCPs from two soils by triton X-100 (TX- 100)-enhanced washing coupled with powdered activated carbon (PAC) adsorption treatment of the solution. Two contaminated soils, including a silt clay contaminated w计h chlordene, dichloro- 2,2-6is(p-chlorophenyl)ethanes (DDDs), and dichlorodiphenyltrichloroethane (DDT) and a sandy loam containing chlordanes and mirex, were selected. Effects of varied operating parameters, including TX-100 dosage, liquid/soil (L/S) ratio, and extraction time, on the contaminant removal were examined. For both soils, OCP removal was clearly enhanced with increasing TX-100 in extraction solution and L/S ratio. Meanwhile, the removal efficacy was also impacted by soil texture and characteristics and contents of the contaminants. Moreover, by using PAC as an absorbent, a significant decrease in the contaminants in the extraction solutions was detected, and TX-100 could be further reused. Our investigation suggests that surfactant-enhanced washing combined with activated carbon selective adsorption would be an alternative to remediate OCP-contaminated soils. | ZHANG Shengtian HE Yue WU Linna WAN Jinzhong YE Mao LONG Tao YAN Zhou JIANG Xin LIN Yusuo LU Xiaohua | 2019 | Pedosphere2019，29，3： | 1 |
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