摘要
基于野外田间采样和室内分析，研究了凤凰铅锌矿区耕层土壤中Pb、Cd、Hg、As等重金属的质量状况及其在水稻不同部位的迁移富集情况。结果表明，该地区的土壤和稻米均受到多种重金属不同程度的污染：耕层土壤中Ph、Cd、Hg、As的平均含量分别达到875、10．70、4．25租62．24mg·kg^-1，与国家规定的土壤环境质量二级标准（GB15618--1995）相比，分别超标2．9、35．7、8．5、2．5倍；稻米中Pb、As污染严重，与国家粮食卫生标准（GB2715--2005）相比，Pb、As分别超标2．0～7．7倍和0．9～2．9倍，而稻米№、Cd污染相对较轻。植株各部位重金属的含量顺序除Cd为稻根〉茎秆〉稻叶〉稻米外，Pb、Hg、As均表现为稻根〉稻叶〉茎秆〉稻米。土壤重金属含量与土壤有机质含量和砂粒含量正相关，与硅铝铁率、粉砂粒和粘粒含量负相关，并显著影响其在稻根中的含量水平。相较土壤而言，稻叶与稻米中重金属含量间的相关性更强，且大多达到显著性水平，表明在凤凰铅锌矿区，除从土壤摄取外，叶面传输也是稻米中重金属累积的重要途径。
Fenghuang lead-zinc deposit is one of the major production bases of nonferrous metals in Hunan Province. The ores in the deposit are characterized not only by base-metals content but also by the presence of other metals such as Cd, Hg and As as impurity elements. Intensive mining-refining operations and random disposal of tailings in addition to little governmental control cause heavy metals discharging into argo-ecosystem, which may in particular cause a widespread occurrence of heavy metals in the entire food chain and bring a series of toxicosis symptoms in animals and human beings. Therefore, monitoring of those elements and understanding their behaviors in soil-plant system are critical to establish the risk assessment of local and regional ecosystems. In this study, concentrations of lead （Pb）, cadmium （Cd）, mercury （Hg） and arsenic（As） in plough horizon soils as well as their translocation and accumulation by paddy in Fenghuang lead-zinc deposit area were studied based on field systematic sampling and laboratory analysis. The average concentration of Pb, Cd, Hg and As in plough horizon soils were 875, 10.70, 4.25 and 62.24 mg·kg^-1, respectively, which were 2.9, 35.7, 8.5 and 2.5 times higher than the benchmark value of Grade Ⅱ environmental quality standard for soil. The concentrations of Pb and As in local paddy rice were 2.0-7.7 times and 0.9-2.9 times higher than those in the National Environmental Quality Standard for Grain, respectively, suggesting that rice in the deposit area was seriously polluted by Pb and As. However, Hg and Cd contamination were less severe in local paddy rice. The average concentrations of Pb, Hg and As in different organs of paddy followed the trend： root 〉 leaf 〉 stalk 〉 rice, whereas the average concentration of Cd followed the trend of root 〉 stalk 〉 leaf 〉 rice. The concentrations of Pb, Cd, Hg and As in plough horizon soils were significant positively correlated with those in paddy roots. Moreover, the concentrations of those soil heavy metals were positively correlated with the soil organic matter contents and sand contents but negatively correlated with the soil silica-sesquioxide ratio, silt contents and clay contents. Compared with the concentrations of heavy metals in plough horizon soil, their concentrations in the leaf have higher correlation with their concentrations in paddy rice, suggesting that, besides the uptake from soil, the translocation from the leaf was also an important transmitting channel for heavy metals accumulation in grains in the study area.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2008年第6期2143-2150,共8页
Journal of Agro-Environment Science
基金
中国科学院知识创新工程重要方向性项目(KZCX3-SW-437)
国家自然科学基金项目(40571008)
中国科学院地理科学与资源研究所知识创新工程三期项目
科技部国际科技合作与交流专项(20072630)
关键词
铅锌矿
重金属
土壤-植物系统
迁移
富集
lead-zinc deposit
heavy metals
soil-plant system
translocation
accumulation
