中文关键词Cr(Ⅲ)Cr(Ⅵ)土壤特性大麦生态毒性 英文关键词Cr(Ⅲ)Cr(Ⅵ)soil propertybarleyecotoxicity

作者	单位	E-mail
付平南	中国农业大学资源与环境学院, 农田土壤污染防控与修复北京市重点实验室, 北京 100193	pingnanfu@qq.com
贡晓飞	中国农业大学资源与环境学院, 农田土壤污染防控与修复北京市重点实验室, 北京 100193
罗丽韵	中国农业大学资源与环境学院, 农田土壤污染防控与修复北京市重点实验室, 北京 100193
王琪	中国农业大学资源与环境学院, 农田土壤污染防控与修复北京市重点实验室, 北京 100193
李花粉	中国农业大学资源与环境学院, 农田土壤污染防控与修复北京市重点实验室, 北京 100193	lihuafen@cau.edu.cn

中文摘要 三价铬和六价铬的化学性质不同，对植物的毒性也不同，但我国土壤质量标准中铬的限值未区分三价和六价.因此，选取8种土壤，基于土壤溶液中铬的变化趋势，通过模型计算，分析8种土壤中土壤性质对大麦根部Cr（Ⅲ）和Cr（Ⅵ）毒性阈值的影响.结果表明，不同价态铬和土壤性质对大麦根长的影响均显著.同一土壤条件下，Cr（Ⅲ）的10%抑制浓度的毒性阈值（EC₁₀）、半抑制浓度（EC₅₀）和无观察效应浓度（no-observed-effect concentrations，NOEC）显著高于Cr（Ⅵ），Cr（Ⅲ）的EC₅₀比Cr（Ⅵ）高2.8~101.7倍.添加Cr（Ⅲ）时，EC₅₀的变化范围为298.8~2014.1 mg·kg^-1，8种土壤间相差6.7倍；添加Cr（Ⅵ）时，EC₅₀的变化范围为8.0~126.6 mg·kg^-1，8种土壤间相差15.8倍.回归分析结果表明，土壤pH和土壤有机质是影响铬对大麦根部毒害的主要因子，而土壤阳离子交换量和土壤黏粒含量对铬的毒性无显著影响.当Cr（Ⅲ）添加量低于1280 mg·kg^-1时，其土壤溶液中铬的质量浓度均低于检测限；而在Cr（Ⅵ）添加量高于40 mg·kg^-1时土壤溶液中能检测到铬的存在.因此，土壤固定Cr（Ⅲ）的能力显著强于Cr（Ⅵ），土壤中Cr（Ⅵ）的生物毒性显著高于Cr（Ⅲ），土壤理化性质对铬的生物毒性影响显著. 英文摘要 Tri-and hexavalent chromium have different chemical properties, and their levels of toxicity to plants are different. However, there is no limit set by the soil environmental quality risk control standard for Cr(Ⅲ) or Cr(Ⅵ). Therefore, studying the ecological toxicity of Cr has important implications for protecting the environment. Based on the dynamics of the Cr(Ⅲ) and Cr(Ⅵ) levels in soil solution collected from eight soils, the toxicity thresholds of the two Cr forms to barley roots were investigated through model calculation and correlation analysis under different soil properties. The results showed that both Cr forms and the soil properties had significant effects on the root length of barley. The effective concentrations of Cr(Ⅲ) added to the soils that led to 10% inhibition (EC₁₀), 50% inhibition (EC₅₀), and no-observed-effect concentrations (NOEC) were significantly higher than those of Cr(Ⅵ). The EC₅₀ of Cr(Ⅲ) ranged from 298.8 to 2014.1 mg·kg^-1 (6.7-fold variation); the EC₅₀ of Cr(Ⅵ) ranged from 8.0 to 126.6 mg·kg^-1 (15.8-fold variation). Under the same soil conditions, the EC₅₀ of Cr(Ⅲ) was 2.8 to 101.7 times higher than that of Cr(Ⅵ), suggesting the higher phytotoxicity of Cr(Ⅵ) than Cr(Ⅲ). Correlation analysis showed that the pH and soil organic matter were the main factors that influenced the Cr toxicity thresholds, as indicated by the root length of barley. The concentration of chromium in the soil solution was below the detection limit of the TAS-990 when Cr(Ⅲ) was applied at 1280 mg·kg^-1 (or less) to soils, whereas for Cr(Ⅵ), the level was 40 mg·kg^-1 (or less). Cr(Ⅲ) adsorption to the soil was significantly stronger than that of Cr(Ⅵ). The toxicity of Cr(Ⅵ) was significantly higher than that of Cr(Ⅲ), which was also influenced by soil properties.

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