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吉林省土壤—水稻系统环境质量分析评估及重金属复合污染研究

Soil Quality and Heavy Metals Contamination in Soil-rice System in Jilin Province

【作者】 王恒

【导师】 刘景双;

【作者基本信息】 中国科学院研究生院(东北地理与农业生态研究所) , 环境科学, 2014, 博士

【摘要】 农产品产地环境质量对农产品质量安全具有直接、重大影响;是农业产品质量安全的最基本的保障。为了更合理地分析评估土壤--水稻系统环境质量及预测稻田土壤重金属污染的环境风险,本论文系统地研究吉林省两个代表性水田区域土壤中重金属(Pb、Cr、 Cu、Ni、Zn、Cd)的污染现状和来源解析;分析土壤性质、土壤重金属含量对水稻吸收重金属的影响,进而探讨其模型预测;对研究区土壤环境质量进行评价,并表征重金属对该地区土壤生态风险;通过实际田间模拟试验,探讨在不同污染浓度条件下Pb、Cd和Cu单一及其复合污染对水稻生长和重金属吸收的影响。对了解研究区水稻灌区土壤污染状况、研究区水稻灌区水稻质量安全,提出安全农产品的基地规划和对不同污染程度的土壤进行规避或修复都是具有重要的理论和现实意义。本论文主要得出以下结论:第二松花江流域灌区耕层土壤中Pb、Cr、Cu、Ni、Zn、Cd含量分别有85.33%、80.67%、48%、63.33%、76.67%和95.3%超过吉林省土壤背景值,延边州灌区耕层土壤中Pb、Cr、Cu、Ni、Zn、Cd含量超过吉林省背景值比例显著高于第二松花江流域灌区,分别有100%、92.85%、61.14%、77.14%、97.14%和22.85%,说明第二松花江流域灌区和延边州灌区耕层土壤重金属元素含量已经受到人类活动影响,且延边州灌区受到影响比第二松花江流域灌区更加严重。其中,前郭灌区、饮马河灌区、伊通河灌区、安图灌区、布尔哈通河灌区和珲春灌区多种重金属超标。第二松花江流域水稻土重金属元素主成分分析结果表明:重金属Cr、Cu和Ni主要来源为自然因素和人类活动;重金属Pb和Zn元素主要来源于人类活动;重金属Cd元素受人类农业活动影响显著。延边州水稻土重金属元素主成分分析结果表明:重金属Pb、Cu、Zn和Cd元素主要来源于人类活动;重金属Cr元素主要来源于自然因素和人类活动的影响;重金属Ni元素含量主要受成土母质的影响。延边州灌区稻米中Pb、Cr元素有个别样点超过国家食品标准最大限值(GB2762-2012)。说明延边州灌区产出的部分稻米可能对人体产生危害,值得引起关注。延边州灌区水稻对土壤中Pb、Cr、Cu、Ni、Zn和Cd富集系数大小顺序为Zn﹥Cd﹥Cu﹥Ni﹥Cr﹥Pb。从防止土壤重金属污染对人体产生危害角度出发,延边州灌区土壤Zn、Cd、Cu等元素污染需要优先关注。应用多元回归分析,可以得到延边州稻米吸收重金属元素的预测模型,对于稻米中Pb、Cu、Ni元素,本研究得到相应线性模型可以较好的预测其在稻米中含量。对于稻米中Cr元素,应用对数模型可以较好的预测稻米中Cr元素含量。单一Pb和Cd的低浓度重金属添加条件下除对水稻的株高生长具有轻微的毒害作用外,对水稻的分蘖和茎叶生长发育反而具有一定程度的促进作用;重金属复合污染对水稻生长毒害作用明显。重金属污染不同添加水平对水稻产量均有影响,单一污染条件下水稻产量降低8~35.4%;复合污染条件下水稻产量降低23.4~62.6%。外源重金属污染物进入水稻体后在不同器官进行再分配,其不同部位重金属含量及重金属在不同部位分配有很强的分异特性。对稻米中Pb、Cd和Cu含量进行了分析,发现所有Pb、Cd和Cu单一和复合添加水平土壤其水稻稻米中Pb、Cd和Cu含量均显著增加,外源Pb、Cd的加入显著增加了稻米中Pb、Cd的含量,其含量均超过食品安全国家标准(GB2762-2012)中规定的最大允许限值。复合污染添加时,水稻稻米中Cu元素含量均未超过国家食品卫生标准。说明Cu元素的生物有效性不仅与土壤中Cu元素含量有关,同时可能受到土壤组分以及环境条件等因素共同影响。不同添加水平的水稻各部位生物富集系数大小遵循根系﹥茎叶﹥稻米的顺序,生物富集系数(BCF)随着添加浓度的升高而减小。复合污染显著高于单一污染生物富集系数(BCF)。第二松花江流域灌区土壤中重金属元素已经出现累积现象。延边州灌区土壤样品与第二松花江流域灌区土壤样品相比单因子指数除Cd元素外处于尚清洁等级和轻度污染等级的样品比例普遍偏高。延边州灌区土壤各重金属积累高于第二松花江流域灌区,值得更多关注,防止污染进一步加重。第二松花江流域灌区和延边州灌区土壤重金属含量绝大部分未超过国家土壤质量二级标准,研究区域土壤质量基本上对作物和环境不造成危害。但国家土壤质量标准为全国统一标准,对于吉林省土壤来讲以国家土壤标准作为评价标准,有可能存在对污染评价不准确的现象,今后研究应该进一步确立有针对性的土壤质量标准。第二松花江流域灌区和延边州灌区土壤尼梅罗综合污染指数评价结果表现出在个别样点上已受到了一定程度的重金属污染,但整体情况尚好,需要特别注意的是永舒榆灌区、饮马河灌区、伊通河灌区、布尔哈通河灌区和安图灌区由于处于警戒级和轻污染比例偏高,不适宜建立绿色食品产地。地累积指数评价结果表明两个研究区域各重金属元素均有不同比例的轻度污染。与单因子污染指数相比,地累积指数对研究区域土壤外源重金属污染评价更加灵敏。第二松花江流域灌区和延边州灌区土壤虽然各有不同重金属出现积累现象,并且达到轻度污染水平,但是研究区域土壤总体处于轻度生态风险水平。

【Abstract】 Environmental quality of agricultural producing area has a direct and significantimpact on the quality and safety of agricultural products, is the most basic agriculturalproduct quality safety guarantee. In order to better evaluate the soil-rice paddy soilenvironment quality and the estimate of heavy metal pollution,this thesissystematically studies two representative paddy field areas in Jilin province in the soilheavy metal (Pb, Cr, Cu, Ni, Zn, Cd) pollution present situation and the sourceapportionment.Analyses the impact of soil properties and soil heavy metalconcentration on rice absorbs heavy metals,and then explores the model predictions.To evaluate soil environmental quality and characterization of heavy metals on soilecological risk in the study area. By actual field simulation, discusses impact on ricegrowth and absorption of heavy metals of pollution of Pb, Cd and Cu single andcombined pollution under different concentrations condition. It has the importanttheoretical and practical significance to understand irrigation area soil pollutioncondition, the quality and safety of rice in rice irrigation area and to put forward thesafe agricultural base planning, to avoid or repair different pollution degree of soil.The Second Songhua River Basin Irrigation topsoil in Pb,Cr,Cu,Ni,Zn,Cdcontents were85.33%,80.67%,48%,63.33%,76.67%and95.3%more than theproportion of soil Jilin background values,Irrigation in Yanbian topsoil Pb, Cr, Cu, Ni,Zn, Cd content of more than Jilin background values were significantly higher thanthe proportion of the Second Songhua River Irrigation, respectively100%,92.85%,61.14%,77.14%,97.14%and22.85%, implied that the Second Songhua RiverIrrigation and Yanbian Irrigation heavy metals in the topsoil has been impact ofhuman activities, and Yanbian Irrigation affected more severely than the secondSonghua River Irrigation District. Among them, a variety of heavy metals exceededJilin background values in Qianguo Irrigation, Yinma Irrigation, Yitong RiverIrrigation, Antu Irrigation, Hunchun Irrigation and Buerhatong River Irrigation. Principal component analysis of heavy metals in the Second Songhua RiverIrrigation topsoil results indicates that: heavy metal Cr, Cu and Ni are main source ofnatural factors and human activities; Pb and Zn mainly from human activities; Cd isaffected by human agricultural activities significantly. Yanbian paddy soil heavymetals principal component analysis showed that: heavy metal Pb, Cu, Zn and Cdelements mainly from human activities; major source of heavy metal elements Crnatural factors and human activities; heavy metal elements Ni mainly by soil parentmaterial impact.Yanbian irrigation rice Pb, Cr elements have some samples exceed the maximumlimit of national food standards (GB2762-2012). It is cause for concern that Yanbianirrigation rice output may cause harm to humans. Yanbian irrigation rice in soil Pb, Cr,Cu, Ni, Zn and Cd enrichment factor in the order of Zn> Cd> Cu> Ni> Cr> Pb.Yanbian irrigation soil Zn, Cd, Cu and other elements of pollution need priorityattention to prevent soil contamination from heavy metals harmful to humanperspective.Multiple regression analysis can get predictive models of the rice to absorb heavymetals in Yanbian, for rice Pb, Cu, Ni elements of this study are the correspondinglinear model can better predict. Exponential model [5] can better predict rice Crelement content.Single low concentrations of Cd and Pb added conditions have slightly toxiceffect on the growth of the rice plant height, but have a role in promoting on ricetillers and leaf growth. Combined pollution has obviously toxic effects on rice growth.Add different levels of heavy metal pollution has different effects on rice yield, undersingle conditions reduced rice yield8~35.4%; under the combined pollution reducerice yields23.4~62.6%. Exogenous heavy metal pollutants enter the body indifferent organs of rice redistribution, and its heavy metal content and distribution indifferent parts has a strong differentiation features.For rice Pb, Cd and Cu were analyzed and found that all Pb, Cd and Cu singleand composite added level of soil its rice grain Pb, Cd and Cu levels weresignificantly increased. Exogenous Pb, Cd adding significantly increased rice grainsPb, Cd content, and the contents more than the national food safety standards (GB2762-2012) in the maximum allowable limits. Under combined pollution situations,Cu content in rice grain did not exceed the national food hygiene standards.Bioavailability of Cu element is not only related to the Cu element content in soil, at the same time may be affected by soil components and factors such as environmentalconditions. Each part of the different levels of add rice biological concentration factorfollow the order of roots﹥stem leaf﹥grain. Biological concentration factor ofcombined pollution are significantly higher than the single pollution.Second Songhua River Basin Irrigation of heavy metals in soil accumulationphenomenon has emerged. The ratios in clean and light pollution level of single factorindex Yanbian irrigation were higher than that in the Second Songhua River Basinirrigation, except Cd.Yanbian irrigation various heavy metal accumulation in soil ishigher than the Second Songhua River irrigation; it is worth more attention toprevention and control of pollution further.The most part of the Second Songhua River basin irrigation and Yanbian irrigation ofsoil heavy metal content does not exceed the national secondary standard of soilquality, the study area soil quality basically does not cause harm to the crops and theenvironment. But the national soil quality standard is the unified national standards,for Jilin province soil on national soil as evaluation standard, evaluation of possiblepollution not accurate phenomenon; future research should establish targeted soilquality standards.Second Songhua River Basin Irrigation and Yanbian Irrigation soil Nemerowpollution index evaluation results showed on individual samples has been a certaindegree of heavy metal pollution, but the overall situation is still good.In particular,Yongshuyu District, Yinma River District, Yitong River District,Buerhatong river District andAntu District due to high alert level and the proportion of light pollution, are not suitable toestablish green food production. The geo-accumulation index results showed that the twostudy regions have different proportions of light pollution. Compared with the singlefactor pollution index, the geo-accumulation index is more sensitive. Although therewere different heavy metal accumulation phenomenon and achieve the level of lightpollution in the Second Songhua River Basin Irrigation and Yanbian Irrigation soil,the overall study area is mild soil ecological risk levels.

【关键词】 土壤水稻环境重金属复合污染
【Key words】 soilriceenvironmentheavy metalcombined pollution
  • 【分类号】X82;X53;X173
  • 【被引频次】1
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