外源六价铬在土壤中的有效性及其小麦毒性效应  

The Bioavailability of Exogenous Cr(Ⅵ) in Soils and Its Toxic Effect on Wheat

作　　者：彭叶棉 杨阳[1,2,3] 侯素霞 程鹏飞[2] 宋旭昕 杨泽胜 刘同旭 PENG Yemian;YANG Yang;HOU Suxia;CHENG Pengfei;SONG Xuxin;YANG Zesheng;LIU Tongxu(Guangzhou Institute of Geochemistry,Chinese Academy of Science,Guangzhou 510640,China;Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management,Guangdong Institute of Eco-environmental Science&Technology,Guangzhou 510650,China;University of Chinese Academy of Sciences,Beijing 100039,China;Department of Resource and Environmental Engineering,Xingtai Polytechnic College,Xingtai 054000,China;National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China,Guangzhou 510650,China)

机构地区：[1]中国科学院广州地球化学研究所,广东广州510640 [2]广东省生态环境技术研究所/广东省农业环境综合治理重点实验室,广东广州510650 [3]中国科学院大学,北京100039 [4]邢台职业技术学院资源与环境工程系,河北邢台054000 [5]华南土壤污染控制与修复国家地方联合工程研究中心,广东广州510650

出　　处：《生态环境学报》2020年第2期369-377,共9页Ecology and Environmental Sciences

基　　金：国家重点研发计划项目(2016YFD0800404);广东省重点领域研发计划项目(2019B110207002)。

摘　　要：土壤中的铬(Cr)进入植物体内,易对动植物以及人体健康造成危害,而中国农田土壤中关于铬污染防治的研究较少。土壤环境中的铬主要以Cr(Ⅲ)、Cr(Ⅵ)两种化学价态存在,而Cr(Ⅵ)毒性远大于Cr(Ⅲ)。该研究在外源添加Cr(Ⅵ)溶液的6种土壤上种植小麦(Triticum aestivum L.),探究其对土壤中重金属铬的富集作用及植物有效性。研究结果表明苗期的小麦富集的铬质量浓度达到约200 mg·kg-1时开始抑制小麦根的生长。几种土壤中小麦富集系数均随着外源铬含量的升高而下降,导致该结果的原因为低铬处理下(5 mg·kg-1)对小麦根长抑制较小,此时铬的富集系数较高;随着土壤中铬含量的增加,各土壤中小麦根系的生长均受影响,富集能力则逐渐降低。此外,研究结果表明土壤提取态铬(乙酸铵提取剂)与小麦相对根伸长具有较好的相关性(R2=0.741,P<0.01)。相比土壤全量铬,有效态铬更适宜作为有效性模型的预测因子。通过回归分析,建立了基于提取态总铬含量、Cr(Ⅲ)与Cr(Ⅵ)的分配值预测相对生长量的有效性预测模型(R2>0.75,P<0.001)。受土壤理化性质的综合影响,供试土壤中的重庆土壤有效态铬含量低、Cr(Ⅵ)占比低,故在6种农田土壤中铬毒害最轻。土壤理化性质等参数对有效态Cr(Ⅲ)与Cr(Ⅵ)含量的影响固然不可忽视,但是直接测定提取态总铬和Cr(Ⅵ)含量以建立生物有效性模型的方法更简便。The transport of chromium(Cr) from soil to plant can cause harm to animal, plant, and human health. However, few studies focus on Cr pollution control of farmland soil in China. Chromium in soil environment mainly exists in Cr(Ⅲ) and Cr(Ⅵ) whereas Cr(Ⅵ) toxicity is much greater than Cr(Ⅲ). In this study, wheat was grown in six types soils with exogenous Cr(Ⅵ) solution to investigate the bioaccumulation and bioavailability of Cr. The results showed that Cr inhibited root elongation when the Cr content in wheat reached about 200 mg·kg-1 in seedling stage, and the bioaccumulation factor of wheat decreased with Cr concentration, probably because in the low concentration(5 mg·kg-1), root elongation of wheat is less inhibited, while Cr bioaccumulation factor were relatively high. The growth of wheat root in each soil is affected by the increase of Cr contents, and the bioaccumulation capacity is gradually reduced. Meantime, the bioavailability of Cr in soil was studied using wheat root elongation as the end point of test. The results showed that extracted Cr(ammonium acetate) in soil was significantly correlated with the relative root elongation of wheat(R2=0.741, P<0.000 1). Compared with total Cr content in soil, effective Cr is more suitable as a predictor of the bioavailability model. A bioavailability prediction model was established by regression analysis to predict the relative root elongation based on the extracted Cr content and the ratio of Cr(Ⅵ) or Cr(Ⅲ) to the total Cr(R2>0.75, P<0.001). The extracted Cr content and Cr(Ⅵ) proportion of the soil in Chongqing was relative low, and the Cr toxicity was the least among six soils. While the effect of physical and chemical properties of soil on the available Cr(Ⅲ) and Cr(Ⅵ) content cannot be ignored, the bioavailability model could easily conducted by direct determination of extracted Cr and Cr(Ⅵ).

关 键 词：土壤铬 Cr(Ⅵ) Cr(Ⅲ) 有效态 植物毒害 

分 类 号：X52[环境科学与工程—环境工程]