Xuzhou City is an important base for coal production and coal-fired power. To evaluate selenium contamination in this area, we sampled agricultural soil, soil profile, irrigation water, bedrock, coal, fly ash, paddy r...Xuzhou City is an important base for coal production and coal-fired power. To evaluate selenium contamination in this area, we sampled agricultural soil, soil profile, irrigation water, bedrock, coal, fly ash, paddy rice, and vegetables from the north of Xuzhou City, and determined their selenium contents. The background level of selenium in the soil profile was 0.08 mg/kg. The selenium concentrations in agricultural soils and irrigation water were in the range of 0.21-4.08 mg/kg and 0.002-0.29 mg/L, respectively. Soils with high selenium content were located closely to coalmines and power plants. The average selenium concentrations in coal and coal fly ash were 5.46 and 2.81 mg/kg, respectively. In contrast, the concentrations of selenium in bedrock and in the soil profile were very low. These results imply that the high selenium level in agricultural soils is mainly caused by anthropogenic activities, rather than by parent material. The arithmetic mean of selenium concentration in paddy rice was 0.116 mg/kg, and in cabbage was 0.05 mg/kg. The selenium concentration in rice was positively correlated with total selenium concentration in soil, suggesting that selenium in soil is readily transferred into the crops. Furthermore, the estimated dietary intake （88.8 μg） of selenium from paddy rice and cabbage exceeds the recommended dietary allowance （55 μg）. Therefore, there is a potential health risk from consumption of local staple food in the study area.展开更多
Deformation experiments of Carrara marble were conducted under increasing temperatures (temperatures 300℃ - 550℃, confining pressure 0. 5Mpa, strain - rate 5 × 10- 6 s-1 ). The experiments reveal that calcite r...Deformation experiments of Carrara marble were conducted under increasing temperatures (temperatures 300℃ - 550℃, confining pressure 0. 5Mpa, strain - rate 5 × 10- 6 s-1 ). The experiments reveal that calcite rocks show different deformation behaviors and corresponding microstructural characteristics under different temperatures. By analyzing microstructural characteristics, preferred grain shape orientation variation of the primary rocks and deformed specimen, the deformation features of Carrara marble are summarized: twinning, fracturing dominates deformation of the rocks at temperatures between 300℃ and 450℃; dynamic recrystallization occurs in the temperature range of 450- 550℃; the brittle to crystalline plasticity transition deformation is observed at around 450℃, twinning and crystal - plastic deformation become dominant with further increasing temperature.展开更多
基金supported by the Geological Survey of China and the Jiangsu Province Program "Multipurpose Geochemical Survey of Jiangsu Province" (No.200312300008)
文摘Xuzhou City is an important base for coal production and coal-fired power. To evaluate selenium contamination in this area, we sampled agricultural soil, soil profile, irrigation water, bedrock, coal, fly ash, paddy rice, and vegetables from the north of Xuzhou City, and determined their selenium contents. The background level of selenium in the soil profile was 0.08 mg/kg. The selenium concentrations in agricultural soils and irrigation water were in the range of 0.21-4.08 mg/kg and 0.002-0.29 mg/L, respectively. Soils with high selenium content were located closely to coalmines and power plants. The average selenium concentrations in coal and coal fly ash were 5.46 and 2.81 mg/kg, respectively. In contrast, the concentrations of selenium in bedrock and in the soil profile were very low. These results imply that the high selenium level in agricultural soils is mainly caused by anthropogenic activities, rather than by parent material. The arithmetic mean of selenium concentration in paddy rice was 0.116 mg/kg, and in cabbage was 0.05 mg/kg. The selenium concentration in rice was positively correlated with total selenium concentration in soil, suggesting that selenium in soil is readily transferred into the crops. Furthermore, the estimated dietary intake （88.8 μg） of selenium from paddy rice and cabbage exceeds the recommended dietary allowance （55 μg）. Therefore, there is a potential health risk from consumption of local staple food in the study area.
基金National Natural Science Foundation of China(49872071)
文摘Deformation experiments of Carrara marble were conducted under increasing temperatures (temperatures 300℃ - 550℃, confining pressure 0. 5Mpa, strain - rate 5 × 10- 6 s-1 ). The experiments reveal that calcite rocks show different deformation behaviors and corresponding microstructural characteristics under different temperatures. By analyzing microstructural characteristics, preferred grain shape orientation variation of the primary rocks and deformed specimen, the deformation features of Carrara marble are summarized: twinning, fracturing dominates deformation of the rocks at temperatures between 300℃ and 450℃; dynamic recrystallization occurs in the temperature range of 450- 550℃; the brittle to crystalline plasticity transition deformation is observed at around 450℃, twinning and crystal - plastic deformation become dominant with further increasing temperature.
