长三角农田土壤典型重金属污染特征及生物有效性调控

发布时间：2018-09-19 06:46

【摘要】：我国局部地区农田土壤重金属污染较为严重,影响农产品安全,并通过食物链危害人类健康。本文系统调查了长三角农田土壤重金属的污染现状,应用荟萃分析(Meta-analysis)方法阐明了过去15年农田土壤重金属的时空变化趋势;通过室内模拟实验和现场农田试验相结合,研究了膨润土-生物炭对土壤重金属生物有效性的调控作用,试图发展基于生物有效性调控的土壤重金属污染缓解阻控技术。论文取得了以下主要结果:(1)发现长三角地区15%的点位重金属含量超过我国农田土壤二级标准,其中Cd超标最为严重。浙江、上海和江苏交界处金属含量均呈现较高浓度,富阳市、临安和省界处(嘉善市、宝山区、太仓市)表层土壤中Cd含量较高;嘉善市Cu含量较高。过去15年间表层土壤中Cd含量呈逐年上升趋势(p0.05;0.0081mg kg~(-1) yr~(-1)1),Cu则呈逐年下降趋势(p0.05;-0.80mg kg~(-1) yr~(-1))。(2)膨润土-生物炭复合材料能降低农田土壤重金属生物有效态含量,阻控重金属在土壤水稻间的迁移。盆栽实验表明,膨润土-生物炭(4:1)复合材料阻控土壤中重金属迁移积累的效果最显著。2%投加量下,水稻地上部分Cd、Pb和Cr含量分别下降41.64%、42.02%和35.61%。农田试验表明,2%膨润土投加下,稻米中Cd与Cr的含量分别下降17.29%和27.39%,而膨润土-生物炭(4:1)复合材料使稻米Pb含量下降84.53%。
[Abstract]:The heavy metal pollution of farmland soil in some areas of China is more serious, which affects the safety of agricultural products and endangers human health through the food chain. In this paper, the present situation of heavy metals pollution in farmland in Yangtze River Delta is systematically investigated, and the temporal and spatial trends of heavy metals in farmland over the past 15 years are illustrated by meta-analysis (Meta-analysis). The effects of bentonite-biochar on the bioavailability of heavy metals in soil were studied in this paper. The main results are as follows: (1) it was found that 15% of the heavy metals in the Yangtze River Delta area exceeded the second grade standard of farmland soil in China, and the Cd exceeded the standard most seriously. The metal content in the surface soil of Fuyang City, Lin'an and provincial boundaries (Jiashan City, Baoshan District, Taicang City) was higher than that in Jiashan City, and the content of Cu in Jiashan City was higher than that in Jiashan City. In the past 15 years, the content of Cd in surface soil increased year by year (p0.05 + 0.0081mg kg~ (-1) yr~ (-1) 1) and Cu decreased year by year (p0.05- 0.80mg kg~ (-1) yr~ (-1). (2) bentonite-biochar composite) could reduce the bioavailability of heavy metals in farmland soil. The migration of heavy metals between soil and rice. Pot experiment showed that the effects of bentonite-biochar (4:1) composite materials on controlling the accumulation of heavy metals in soil were the most significant, and the contents of Cd,Pb and Cr in the aboveground part of rice decreased 42.02% and 35.61% respectively. The results showed that the content of Cd and Cr in rice decreased by 17.29% and 27.39%, respectively, and the content of Pb in rice decreased 84.53% by bentonite-biochar (4:1) composite material under the addition of 2% bentonite.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53

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