不同种植密度对春小麦积累土壤重金属的影响研究及人体健康风险评价
发布时间：2018-10-21 20:28
【摘要】：白银地区是我国重要的重金属采矿与冶炼基地,悠久的采矿历史和过度的工农业活动使得该地区农田土壤系统受到了严重的污染,其中以重金属污染最为严重。土壤重金属可通过土壤-植物系统在作物中积累,进而通过食物链进入到人体并对人体健康造成危害。虽然当地的土壤污染修复工作已在开展中,但收效甚微。作为主要粮食作物的春小麦(Triticum aestivum)在当地被广泛种植,但污染环境条件下,春小麦对土壤中重金属的积累情况如何仍不清楚,长期食用对当地居民健康有何潜在风险也未见详细报道。因此,开展污染环境条件下春小麦对土壤重金属的积累效应及其影响因素的研究,对当地农作物安全生产和尽可能降低当地居民健康风险具有重要意义。本研究选择白银四龙镇东大沟沿岸农田为研究地点,以不同种植密度的春小麦为研究对象,通过测定研究地常见的重金属铜(Cu)、锌(Zn)、铅(Pb)、镉(Cd)的浓度以及土壤速效氮、速效磷和pH等因子,以及通过采集和测定春小麦各期(三叶期、分蘖期、拔节期、抽穗期、开花期、灌浆期和成熟期)不同组织(根、茎、叶、颖壳和籽粒)中重金属的浓度,旨在阐明当地春小麦不同组织对重金属的积累效应及其影响因素、揭示春小麦不同组织对重金属的积累随生长时期的变化规律、探寻通过增加种植密度来降低春小麦籽粒重金属浓度和居民所受健康风险的可行性。研究结果显示：1.白银东大沟排污沟沿岸农田土壤中Cu、Zn、Cd污染严重,远超过国家土壤安全标准限值(Cu 100 mg kg-1, Zn 300 mg kg-1, Cd 1 mg kg-1),而Pb浓度在上游土壤中超过安全标准限值(300 mg kg-1),下游相应浓度则在安全浓度以内。白银当地春小麦组织中的重金属浓度与土壤速效氮浓度呈显著正相关(p0.05),与土壤速效磷浓度相关性不显著(p0.05)。土壤重金属的可交换态和碳酸盐结合态处于较高水平,促进了春小麦各组织尤其是籽粒中的重金属浓度。2.在春小麦生长的三叶期到分蘖期,小麦根、茎、叶中的重金属浓度达到了峰值,然后逐渐下降。单株春小麦积累重金属的量随生长时间增加而增加。春小麦各个组织积累重金属的能力分别为：对Cu,根颖壳叶茎籽粒；对Zn,根籽粒叶颖壳茎；对Pb,根叶颖壳籽粒茎；对Cd,根叶茎颖壳籽粒。3.增加种植密度可以在一定程度上降低重金属在春小麦组织尤其是Pb和Cd在籽粒中的积累,从而降低重金属对当地居民可能造成的健康风险,说明增加种植密度可以作为当地春小麦更为安全的生产方式。4.随着种植密度的增加,单位面积内春小麦所积累的重金属量有所下降,在种植密度最大时具有显著降低,显示在使用植物进行土壤重金属原位修复时,植物或作物的种植密度是影响移除效果的关键因素之一综上所述,白银东大沟沿岸农业区土壤受重金属污染严重,生长于其上的春小麦各组织中的重金属浓度主要与土壤速效氮、土壤重金属可交换态及碳酸盐结合态的浓度相关,且都呈正相关关系(p0.01)；春小麦对重金属的积累能力具有组织差异性,并且会随着春小麦的种植密度的增加和生长期的延长而降低；春小麦籽粒中重金属积累浓度对当地居民健康具有潜在风险,但是,可在不显著降低产量的前提下,通过提高种植密度的方式降低这种风险。总之,本研究结果对长期受重金属污染的白银农业区春小麦安全生产及降低当地居民健康风险具有参考意义。
[Abstract]:Baiyin region is an important heavy metal mining and smelting base in China. The long mining history and excessive industrial and agricultural activities have caused serious pollution to farmland soil system in this area, among which heavy metal pollution is the most serious. Soil heavy metals can accumulate in crops through soil-plant systems, and then enter the human body through the food chain and pose a hazard to human health. Although local soil pollution remediation efforts have been carried out, little success has been achieved. Spring wheat (spring wheat), which is the main food crop, has been widely cultivated locally, but the accumulation of heavy metals in soil under the condition of environmental pollution is still unclear, and the potential risks of long-term consumption to the health of local residents have not been reported in detail. Therefore, the research on the accumulation effect of spring wheat on soil heavy metals and its influencing factors under the condition of environmental pollution is of great significance to the safe production of local crops and to reduce the health risk of local residents as much as possible. In this study, we select the farmland as the research site in Donggugou, Baiyin, and study the concentration of heavy metal copper (Cu), zinc (Zn), lead (Pb), Cd (Cd) and quick-acting nitrogen in soil by measuring the common heavy metal copper (Cu), zinc (Zn), lead (Pb), Cd (Cd). The concentrations of heavy metals in different tissues (roots, stems, leaves, glumes and seeds) of spring wheat (root, stem, leaf, glume and kernel) are determined by collecting and measuring the factors such as phosphorus and pH, The effects of different tissues of spring wheat on the accumulation of heavy metals and their influencing factors are expounded, and the changes of the accumulation of heavy metals in different tissues of spring wheat with the growth period are revealed. To explore the feasibility of reducing the heavy metal concentration and health risk of spring wheat grains by increasing planting density. The results showed that: 1. The pollution of Cu, Zn and Cd in farmland soil along the Daogou sewage ditch of Baiyin is serious, far exceeding the national soil safety standard limit (Cu 100 mg kg-1, Zn 300 mg kg-1, Cd 1 mg kg-1), while the Pb concentration exceeds the safety standard limit value (300 mg kg-1) in the upstream soil. The downstream corresponding concentration is within the safe concentration. The concentration of heavy metals in the local spring wheat tissues of Baiyin was positively correlated with the soil available nitrogen concentration (P0.05). The exchangeable state of heavy metals in soil and the state of carbonate leaching are at a higher level, which promotes the concentration of heavy metals in the tissues of spring wheat, especially in grains. The concentrations of heavy metals in wheat roots, stems and leaves reached the peak value during the three-leaf period of spring wheat growth and then gradually decreased. The amount of heavy metal accumulated in spring wheat increased with increasing growth time. The ability to accumulate heavy metals in various tissues of spring wheat was: for Cu, root and leaf stem grains, Zn, root, glutin stem, Pb, root, glutin seed stem, Cd, root stem glum kernel. Increasing the planting density can reduce the accumulation of heavy metals in the grain of spring wheat, especially Pb and Cd, so as to reduce the possible health risks of heavy metals to local residents, and indicate that increasing planting density can be used as a safer production mode for local spring wheat. As the planting density increases, the amount of heavy metal accumulated in the spring wheat in the unit area is reduced, The planting density of plants or crops is one of the key factors that affect the effect of removal. In conclusion, the heavy metal concentration in the soil is heavily polluted by heavy metal, and the heavy metal concentration in the tissues of the spring wheat growing on it is mainly related to soil available nitrogen. The exchangeable state of heavy metal in soil and the concentration of carbonate salt state were positively correlated (P0.01); the accumulation ability of spring wheat to heavy metals had organizational difference, and decreased with the increase of planting density of spring wheat and the extension of growth phase; The accumulation concentration of heavy metals in grain of spring wheat has potential risk to the health of local residents. However, this risk can be reduced by raising the planting density without significantly reducing the yield. In conclusion, the result of this study is of reference to safe production of spring wheat and reduce the health risk of local residents.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;S512.12
本文编号：2286281
[Abstract]:Baiyin region is an important heavy metal mining and smelting base in China. The long mining history and excessive industrial and agricultural activities have caused serious pollution to farmland soil system in this area, among which heavy metal pollution is the most serious. Soil heavy metals can accumulate in crops through soil-plant systems, and then enter the human body through the food chain and pose a hazard to human health. Although local soil pollution remediation efforts have been carried out, little success has been achieved. Spring wheat (spring wheat), which is the main food crop, has been widely cultivated locally, but the accumulation of heavy metals in soil under the condition of environmental pollution is still unclear, and the potential risks of long-term consumption to the health of local residents have not been reported in detail. Therefore, the research on the accumulation effect of spring wheat on soil heavy metals and its influencing factors under the condition of environmental pollution is of great significance to the safe production of local crops and to reduce the health risk of local residents as much as possible. In this study, we select the farmland as the research site in Donggugou, Baiyin, and study the concentration of heavy metal copper (Cu), zinc (Zn), lead (Pb), Cd (Cd) and quick-acting nitrogen in soil by measuring the common heavy metal copper (Cu), zinc (Zn), lead (Pb), Cd (Cd). The concentrations of heavy metals in different tissues (roots, stems, leaves, glumes and seeds) of spring wheat (root, stem, leaf, glume and kernel) are determined by collecting and measuring the factors such as phosphorus and pH, The effects of different tissues of spring wheat on the accumulation of heavy metals and their influencing factors are expounded, and the changes of the accumulation of heavy metals in different tissues of spring wheat with the growth period are revealed. To explore the feasibility of reducing the heavy metal concentration and health risk of spring wheat grains by increasing planting density. The results showed that: 1. The pollution of Cu, Zn and Cd in farmland soil along the Daogou sewage ditch of Baiyin is serious, far exceeding the national soil safety standard limit (Cu 100 mg kg-1, Zn 300 mg kg-1, Cd 1 mg kg-1), while the Pb concentration exceeds the safety standard limit value (300 mg kg-1) in the upstream soil. The downstream corresponding concentration is within the safe concentration. The concentration of heavy metals in the local spring wheat tissues of Baiyin was positively correlated with the soil available nitrogen concentration (P0.05). The exchangeable state of heavy metals in soil and the state of carbonate leaching are at a higher level, which promotes the concentration of heavy metals in the tissues of spring wheat, especially in grains. The concentrations of heavy metals in wheat roots, stems and leaves reached the peak value during the three-leaf period of spring wheat growth and then gradually decreased. The amount of heavy metal accumulated in spring wheat increased with increasing growth time. The ability to accumulate heavy metals in various tissues of spring wheat was: for Cu, root and leaf stem grains, Zn, root, glutin stem, Pb, root, glutin seed stem, Cd, root stem glum kernel. Increasing the planting density can reduce the accumulation of heavy metals in the grain of spring wheat, especially Pb and Cd, so as to reduce the possible health risks of heavy metals to local residents, and indicate that increasing planting density can be used as a safer production mode for local spring wheat. As the planting density increases, the amount of heavy metal accumulated in the spring wheat in the unit area is reduced, The planting density of plants or crops is one of the key factors that affect the effect of removal. In conclusion, the heavy metal concentration in the soil is heavily polluted by heavy metal, and the heavy metal concentration in the tissues of the spring wheat growing on it is mainly related to soil available nitrogen. The exchangeable state of heavy metal in soil and the concentration of carbonate salt state were positively correlated (P0.01); the accumulation ability of spring wheat to heavy metals had organizational difference, and decreased with the increase of planting density of spring wheat and the extension of growth phase; The accumulation concentration of heavy metals in grain of spring wheat has potential risk to the health of local residents. However, this risk can be reduced by raising the planting density without significantly reducing the yield. In conclusion, the result of this study is of reference to safe production of spring wheat and reduce the health risk of local residents.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;S512.12
【参考文献】
相关期刊论文 前3条
1 肖昕;朱子清;王晨;于文超;魏欣;;重金属Cd在小麦中的富集特征[J];安徽农业科学;2009年20期
2 杨海霞;李涛;;含锌废水对小麦种子萌发和幼苗生长的影响[J];环境科学与管理;2008年04期
3 王晓瑞;周生路;吴绍华;;长江三角洲地区小麦植株的重金属分布及其相关性——以昆山市为例[J];地理科学;2011年02期
，本文编号：2286281
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