烟草产地重金属污染风险评估与迁移特征的研究
发布时间：2019-06-10 23:54
【摘要】：目前,土壤污染越来越严重,其中重金属的污染问题尤为严峻。土壤中的重金属经过植物根系吸收和体内转运,最终在植物可利用部分中积累,通过食物链进入到人体中,危害人体健康。烟叶中重金属会伴随烟气进入人体,对人体健康构成威胁。为了减少烟叶中有害重金属的含量,对植烟区土壤环境质量的评估和土壤-烟叶重金属迁移影响因素的研究可以为重金属污染控制和烟叶安全生产提供科学依据。本研究以湖南省东部某县级植烟区土壤为研究对象,野外定点采集土壤和烟叶样品。在实验室分析了土壤、烟叶重金属含量及土壤相关参数,对土壤和烟叶重金属含量进行了污染评价。通过相关分析研究了土壤有效态含量及其影响因素。回归分析和通径分析土壤-烟叶重金属含量的影响因素,拟合了烟叶重金属预测模型。本文主要结果：(1)研究区植烟土壤重金属Cu、Zn、Pb、Cd、As、Hg平均含量分别为36.25、82.82、37.66,0.36、12.71、0.27mg·kg-1。利用地统计学方法,研究植烟区土壤重金属空间分布特征为Cu、Zn、Pb、Cd为东北烟区土壤重金属含量比西南烟区重金属含量高,As和Hg呈斑点状分布。以国家土壤环境二级标准和湖南省土壤重金属背景值为参考,利用单因子指数法得到的结果为植烟区土壤主要受到Cd污染,其次为Hg、Cu和Pb、Zn和As属于清洁水平；潜在生态风险系数法分析结果表明植烟区土壤重金属Cu、Zn、Pb和As基本未受污染,Cd和Hg有较强生态风险。(2)研究区土壤有效态Cu、Zn、Pb、Cd、As和Hg平均含量分别为12.21、17.34、10.71、0.23、1.46和0.061mg·kg-1。研究区植烟土壤Cu、Zn、Pb、Cd、As和Hg的生物有效性系数分别为32.4%、19.8%、26.7%、54.1%、11.8%和24.9%。生物有效性系数大小依次为CdCuPbHgZnAs。 Cd的生物有效性系数最大,说明土壤中Cd的潜在生态危害最大。土壤重金属全量和有效态含量有一定的正相关性。土壤pH、阳离子交换量、总Ca、总Mg、总Fe与重金属生物有效性呈负相关。土壤有机质、氯离子、总氮、有效态Fe、交换态Ca、交换Mg与重金属生物有效性呈正相关。(3)研究区烟叶中Cu、Zn、Pb、Cd、As和Hg含量平均值分别为11.34 mg·kg-1, 105.59mg·kg-1、3.58 mg·kg-1、8.29 mg·kg-1、0.94mg·kg-1和0.125 mg·kg-1。单因子污染评价显示研究区烟叶Cd超标严重,超标率分别为Cd(88.21%),富集系数大小依次为CdZnHgCuPbAs o相关性分析表明,烟叶土壤重金属含量本身及其有效态含量、pH、有机质、阳离子交换量、Ca、Mg、Fe、Mn、总磷及其有效态含量是影响烟叶吸收重金属的主要因素,土壤pH值、阳离子交换量、Ca、Mg、Fe、Mn对重金属向烟草迁移有抑制作用。重金属全量及其有效态含量、有效Fe、交换态Ca、交换态Mg、有机质、氯离子含量对重金属向烟草迁移有促进作用。通过多元线性回归分析法得到烟叶重金属迁移累积量与土壤重金属和土壤理化性质等环境因子的定量模型,结果表明,除了As和Hg外,拟合模型相关系数呈极显著。
[Abstract]:At present, soil pollution is becoming more and more serious, especially heavy metal pollution. Heavy metals in soil are absorbed by plant roots and transported in vivo, and finally accumulate in the available parts of plants and enter the human body through the food chain, which is harmful to human health. Heavy metals in tobacco leaves will be accompanied by smoke into the human body, posing a threat to human health. In order to reduce the content of harmful heavy metals in tobacco leaves, the assessment of soil environmental quality in tobacco growing areas and the study on the influencing factors of heavy metal transport between soil and tobacco leaves can provide scientific basis for heavy metal pollution control and safe production of tobacco leaves. In this study, soil and tobacco leaf samples were collected in a county-level tobacco planting area in eastern Hunan Province. The content of heavy metals in soil and tobacco leaves and related parameters were analyzed in laboratory, and the pollution of heavy metals in soil and tobacco leaves was evaluated. The content of soil available state and its influencing factors were studied by correlation analysis. Regression analysis and path analysis were used to analyze the influencing factors of heavy metal content in soil and tobacco leaves, and the prediction model of heavy metals in tobacco leaves was fitted. The main results are as follows: (1) the average content of heavy metal Cu,Zn,Pb,Cd,As,Hg in tobacco planting soil is 36.25, 82.82, 37.6, 12.71, 0.27mg kg-1., respectively. The spatial distribution characteristics of heavy metals in tobacco growing areas were studied by geostatistics. The spatial distribution characteristics of heavy metals in soils in tobacco growing areas were as follows: the contents of heavy metals in soils in northeast tobacco areas were higher than those in southwest tobacco areas, and As and Hg were punctate distribution. Based on the national secondary standard of soil environment and the background value of heavy metals in Hunan Province, the results obtained by single factor index method showed that the soil in tobacco planting area was mainly polluted by Cd, followed by Hg,Cu, Pb,Zn and As. The results of potential ecological risk coefficient method showed that heavy metals Cu,Zn,Pb and As in tobacco growing area were basically unpolluted, and Cd and Hg had strong ecological risk. (2) soil available Cu,Zn,Pb,Cd, in the study area. (2) soil available Cu,Zn,Pb,Cd, The average contents of As and Hg were 12.21, 17.34, 10.71, 0.23, 1.46 and 0.061mg kg-1., respectively. The bioavailability coefficients of Cu,Zn,Pb,Cd,As and Hg were 32.4%, 19.8%, 26.7%, 54.1%, 11.8% and 24.9%, respectively. The bioavailability coefficient is CdCuPbHgZnAs. in turn. The bioavailability coefficient of Cd is the largest, which indicates that Cd has the greatest potential ecological harm in soil. There is a positive correlation between the total amount of heavy metals in soil and the content of available state. Soil pH, cation exchange capacity and total Ca, total Mg, total Fe were negatively correlated with bioavailability of heavy metals. Soil organic matter, chlorine ion, total nitrogen and available Fe, exchange Mg were positively correlated with the bioavailability of heavy metals. (3) the average contents of Cu,Zn,Pb,Cd,As and Hg in tobacco leaves in the study area were 11.34 mg kg-1, respectively. 105.59mg kg-1,3.58 mg kg-1,8.29 mg kg-1, 0.94mg kg-1 and 0.125 mg kg-1. The single factor pollution evaluation showed that the Cd of tobacco leaves in the study area exceeded the standard seriously, the exceeding standard rate was Cd (88.21%), and the enrichment coefficient was CdZnHgCuPbAs o correlation analysis. The results showed that the content of heavy metals in tobacco soil and its available content, pH, Organic matter, cation exchange capacity, Ca,Mg,Fe,Mn, total phosphorus and its available content are the main factors affecting the absorption of heavy metals by tobacco leaves. Soil pH value, cation exchange capacity and Ca,Mg,Fe, are the main factors affecting the absorption of heavy metals by tobacco leaves. Mn can inhibit the migration of heavy metals to tobacco. The total amount of heavy metals and their effective content, effective Fe, exchange Ca, exchange Mg, organic matter and chloride ion content can promote the migration of heavy metals to tobacco. The quantitative models of heavy metal migration accumulation in tobacco leaves and environmental factors such as soil heavy metals and soil physical and chemical properties were obtained by multivariate linear regression analysis. The results showed that except As and Hg, the correlation coefficient of the fitting model was very significant.
【学位授予单位】：湖南农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X820.4
[Abstract]:At present, soil pollution is becoming more and more serious, especially heavy metal pollution. Heavy metals in soil are absorbed by plant roots and transported in vivo, and finally accumulate in the available parts of plants and enter the human body through the food chain, which is harmful to human health. Heavy metals in tobacco leaves will be accompanied by smoke into the human body, posing a threat to human health. In order to reduce the content of harmful heavy metals in tobacco leaves, the assessment of soil environmental quality in tobacco growing areas and the study on the influencing factors of heavy metal transport between soil and tobacco leaves can provide scientific basis for heavy metal pollution control and safe production of tobacco leaves. In this study, soil and tobacco leaf samples were collected in a county-level tobacco planting area in eastern Hunan Province. The content of heavy metals in soil and tobacco leaves and related parameters were analyzed in laboratory, and the pollution of heavy metals in soil and tobacco leaves was evaluated. The content of soil available state and its influencing factors were studied by correlation analysis. Regression analysis and path analysis were used to analyze the influencing factors of heavy metal content in soil and tobacco leaves, and the prediction model of heavy metals in tobacco leaves was fitted. The main results are as follows: (1) the average content of heavy metal Cu,Zn,Pb,Cd,As,Hg in tobacco planting soil is 36.25, 82.82, 37.6, 12.71, 0.27mg kg-1., respectively. The spatial distribution characteristics of heavy metals in tobacco growing areas were studied by geostatistics. The spatial distribution characteristics of heavy metals in soils in tobacco growing areas were as follows: the contents of heavy metals in soils in northeast tobacco areas were higher than those in southwest tobacco areas, and As and Hg were punctate distribution. Based on the national secondary standard of soil environment and the background value of heavy metals in Hunan Province, the results obtained by single factor index method showed that the soil in tobacco planting area was mainly polluted by Cd, followed by Hg,Cu, Pb,Zn and As. The results of potential ecological risk coefficient method showed that heavy metals Cu,Zn,Pb and As in tobacco growing area were basically unpolluted, and Cd and Hg had strong ecological risk. (2) soil available Cu,Zn,Pb,Cd, in the study area. (2) soil available Cu,Zn,Pb,Cd, The average contents of As and Hg were 12.21, 17.34, 10.71, 0.23, 1.46 and 0.061mg kg-1., respectively. The bioavailability coefficients of Cu,Zn,Pb,Cd,As and Hg were 32.4%, 19.8%, 26.7%, 54.1%, 11.8% and 24.9%, respectively. The bioavailability coefficient is CdCuPbHgZnAs. in turn. The bioavailability coefficient of Cd is the largest, which indicates that Cd has the greatest potential ecological harm in soil. There is a positive correlation between the total amount of heavy metals in soil and the content of available state. Soil pH, cation exchange capacity and total Ca, total Mg, total Fe were negatively correlated with bioavailability of heavy metals. Soil organic matter, chlorine ion, total nitrogen and available Fe, exchange Mg were positively correlated with the bioavailability of heavy metals. (3) the average contents of Cu,Zn,Pb,Cd,As and Hg in tobacco leaves in the study area were 11.34 mg kg-1, respectively. 105.59mg kg-1,3.58 mg kg-1,8.29 mg kg-1, 0.94mg kg-1 and 0.125 mg kg-1. The single factor pollution evaluation showed that the Cd of tobacco leaves in the study area exceeded the standard seriously, the exceeding standard rate was Cd (88.21%), and the enrichment coefficient was CdZnHgCuPbAs o correlation analysis. The results showed that the content of heavy metals in tobacco soil and its available content, pH, Organic matter, cation exchange capacity, Ca,Mg,Fe,Mn, total phosphorus and its available content are the main factors affecting the absorption of heavy metals by tobacco leaves. Soil pH value, cation exchange capacity and Ca,Mg,Fe, are the main factors affecting the absorption of heavy metals by tobacco leaves. Mn can inhibit the migration of heavy metals to tobacco. The total amount of heavy metals and their effective content, effective Fe, exchange Ca, exchange Mg, organic matter and chloride ion content can promote the migration of heavy metals to tobacco. The quantitative models of heavy metal migration accumulation in tobacco leaves and environmental factors such as soil heavy metals and soil physical and chemical properties were obtained by multivariate linear regression analysis. The results showed that except As and Hg, the correlation coefficient of the fitting model was very significant.
【学位授予单位】：湖南农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X820.4
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1 毛海立;龙成梅;杨艳;邹洪涛;;贵州牛角塘矿区土壤重金属形态分布特征研究[J];环境科学与技术;2014年S2期
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