长春市绿地铅污染评价及其植物修复研究

发布时间：2018-05-07 15:13

本文选题：长春市 + 铅污染　；参考：《吉林农业大学》2011年博士论文

【摘要】：城市土壤重金属污染日趋严重,特别是铅(Pb)污染已导致城市儿童血Pb含量升高。植物修复技术以其低成本和环境友好等优点成为污染土壤修复行之有效的方法,成为国内外研究的热点。超积累植物筛选是植物修复能否成功的关键,也是植物修复技术的难点所在。本文以长春市为例,首先对城市表层土壤理化性质与Pb污染进行评价；其次通过分析12个绿化植物叶片对铅的吸收量,筛选出对大气铅吸收力强的植物种,为城市土壤铅污染的植物修复提供理论依据；以杨树叶片为代表,初步判断植物大气铅污染等级；土壤Pb污染主要来源于交通污染等人为活动,人们往往忽略了自然落叶或人为施用有机肥带给土壤的影响,因此初步探讨了城市土壤中外源有机物料对Pb吸附的影响,充分肯定了花卉植物修复具有巨大潜力；然后通过砂培、水培和土培试验,研究了32种常见花卉植物(包括一串红、绣线菊、紫花玉簪、鸭跖草、马蔺、石碱花、石竹、波斯菊、福禄考、四季海棠、金鱼草、金盏菊、天竺葵、雁来红、红王子锦带、紫茉莉、蜀葵、茶花凤仙、百日草、万寿菊、大丽花、八仙花、月季、美人蕉、银边天竺葵、彩叶草、金边天竺葵、矮牵牛、孔雀草、八宝景天、君子兰、射干)对Pb胁迫的生长反应及Pb在植物体内的富集特征,筛选出了Pb富集能力较强且适于北方种植的的花卉品种,为探索花卉植物修复城市Pb污染土壤的技术提供理论和实践依据。主要研究结果归纳如下： 1、以长春市为例,对城市表层土壤的理化性质与Pb污染评价结果表明,城市表层土壤物理性质略差,但多数有利于植物根系的正常生长；化学指标总体上处于较高水平。长春城区表层土壤Pb含量差异性很大,变幅为18.7～125.8 mg·kg-1,平均含量为57.1 mg·kg-1。采用Pb污染指数法和地积累指数评价法,长春城区表层土壤Pb总体上处于轻度向偏中度污染水平。 2、通过14个主要街路两侧12种植物叶片中Pb的含量测定,采用单项污染指数法计算污染指数进行大气质量等级评价结果表明：运用聚类分析得出,12种植物对Pb吸收能力最强的是绣线菊,其次是杨树、油松、矮牵牛和彩叶草；而对Pb吸收能力最弱的树种是榆树、女贞、小叶女贞、八宝景天。采用单项污染指数评价法计算大气质量等级,长春市红旗街和同志街大气Pb污染达到严重污染程度,火车站北口属于重度污染区,会展大街已达到中度污染,人民大街和南湖大路属于轻度污染区,无污染的是凯旋路、前进大街和延安大路。 3、城市土壤外源有机物料原样及其HLA、HLM对Pb2+的等温吸附曲线研究结果表明,树叶、草坪草和牛粪原样及其HLA、HLM对Pb2+的吸附量随平衡溶液中Pb2+浓度的增加而增加；在相同初始浓度下,对于Pb2+的吸附量的顺序是树叶牛粪草坪草,对于同一有机物料来说,草坪草、树叶对Pb2+的吸附量的顺序是HLMHLA原样,HLAHLM原样。各组分的吸附等温线可以用Freundlich、Langmiur和Temkin方程很好的描述,且都呈显著线性相关,且与吸附等温曲线所表述的规律性一致,最大吸附量的顺序为HLAHLM原样。 4、种子萌发试验分析结果显示,供试花卉植物中对Pb胁迫的耐性最强的是马蔺种子,其次是百日草种子和紫茉莉种子,耐性最差的是黑心菊种子。与对照相比,孔雀草和百曰草的根长分别下降了66.2%、55.1%,黑心菊下降了85.2%。说明种子幼根对Pb的耐性最强的花卉是孔雀草和百日草,最弱的是黑心菊。Pb胁迫对萌发后幼苗生长影响研究进一步证实植物根系对Pb的耐受能力较强的四种为马蔺、茶花凤仙、百日草和孔雀草,强弱顺序为马蔺茶花凤仙百日草孔雀草。 5、水培试验结果表明,供试花卉植物中四季海棠、百日草、紫茉莉和紫花玉簪的地上部最大Pb含量达到了超富集植物的临界含量标准,并且所有处理中它们的地上部Pb含量和富集系数数值最大,均显著高于其它花卉植物。供试花卉植物中,Pb转移系数最高值可达0.8以上的有四季海棠、百日草、紫茉莉、紫花玉簪和鸭跖草,并且百日草在200 mg Pb/L时的转移系数仍高于100 mg Pb/L时的转移系数。这说明四季海棠、百日草、紫茉莉、紫花玉簪和鸭跖草不仅对Pb胁迫具有较强的耐性,而且具有较高的Pb富集能力和转移能力。 6、土培试验结果表明,1)供试花卉植物中,紫茉莉、蜀葵、四季海棠和茶花凤仙的地上部最大Pb含量都超过了100 mg-kg-1,其顺序为紫茉莉蜀葵四季海棠茶花凤仙,并且它们的地上部Pb含量和Pb富集系数均显著高于其它花卉植物。2)供试花卉植物中,Pb转移系数最高值可达0.45以上的有紫茉莉、银边天竺葵、金边天竺葵、八宝景天,同时它们高浓度Pb处理下的转移系数均显著高于低浓度的。从花卉植物地上部修复能力来看,四季海棠的修复效率和Pb迁移总量最高,其次是紫茉莉、蜀葵、茶花凤仙、万寿菊、百日草,但都没有超过0.2%。3)综合以上研究结果可知,紫茉莉不仅对Pb胁迫具有较强的耐性,而且具有较高的Pb富集能力和转移能力,在Pb污染土壤的修复方面具有较大的应用价值。从花卉植物地上部修复能力来看,四季海棠、紫茉莉、百日草、茶花凤仙对Pb污染土壤有良好的修复潜力,蜀葵、茶花凤仙和万寿菊的修复潜力亦不可忽视。综上所述,通过系统研究适于长春市种植的32种常见花卉植物对Pb的生长反应及富集特征,从中发现了4种具备Pb超富集潜力的花卉植物,即四季海棠、百日草、紫茉莉和紫花玉簪,这4种花卉植物的Pb富集量均超过1000 mg-kg-1,富集系数均大于1,证明能够从花卉植物中筛选出对Pb具有较强耐性和富集能力的品种,利用花卉植物进行Pb污染土壤的修复是可行的,在降低土壤Pb含量的同时美化了城市环境,这为长春市Pb污染土壤的修复提供了新的模式。
[Abstract]:Heavy metal pollution in urban soil is becoming more and more serious, especially lead (Pb) pollution has led to the increase of blood Pb in urban children. Plant remediation has become an effective method for remediation of contaminated soil with its advantages of low cost and environmental friendliness, which has become a hot topic at home and abroad. This paper takes Changchun as an example to evaluate the physical and chemical properties of the urban surface soil and Pb pollution. Secondly, through the analysis of the absorption of lead in the leaves of 12 greening plants, the plant species with strong absorbability to the air lead can be selected to provide a theoretical basis for the remediation of urban soil lead pollution. As the representative of the leaves, the grade of lead pollution in the atmosphere was preliminarily judged. The soil Pb pollution was mainly due to traffic pollution and others. People often ignored the natural deciduous or artificial application of organic manure to the soil. Therefore, the effect of organic materials on the adsorption of Pb in the urban soil was preliminarily discussed, and the flower plants were fully affirmed. It has great potential, and then through sand culture, hydroponics and soil culture experiments, 32 kinds of common plants (including a string of red, embroidered chrysanthemum, purple flower jade hairpin, orin, iris, chrysanthemum, Ishi Take, chrysanthemum, floret, chrysanthemum, calendula, geranium, geranium, Red Prince, brocade, mabanus, camellia, pimentum, and roentgrass) are studied. Marigold, dahlia, Ba, Chinese rose, Canna, silvery geranium, color leaf grass, Phnom Penh, pennilus, Petunia, peacock grass, eight treasure Sedum, Rhizoma orchid, shoot dry), the growth response of Pb stress and the enrichment of Pb in plants, and the selection of Pb enriched and suitable flower varieties suitable for Northern plants to explore flowers and plants. The theoretical and practical basis for the technology of Pb contaminated soil in complex cities is summarized.
1, taking Changchun as an example, the results of the physical and chemical properties of the urban surface soil and the evaluation of Pb pollution show that the physical properties of the surface soil of the city are slightly poor, but most of them are beneficial to the normal growth of plant roots, and the chemical indexes are at a high level in general. The Pb content of the surface soil in the urban area of Changchun is very different, and the average variation is from 18.7 to 125.8 mg. The content of 57.1 mg. Kg-1. was evaluated by Pb pollution index method and geo accumulation index method. The surface soil Pb in Changchun city was generally at a mild to moderate pollution level.
2, by determining the content of Pb in the leaves of 12 plant species on both sides of 14 main streets, the results of air quality evaluation of the pollution index were calculated by single pollution index method. The results showed that by cluster analysis, the 12 plants had the strongest absorption ability to Pb, followed by poplar, Pinus tabulaeformis, Petunia and color leaf grass, and the absorption energy of Pb The weakest tree species are elm, Ligustrum lucidum, Ligustrum lucidum, and eight treasure Sedum. The air quality grade is calculated by the single pollution index evaluation method. The atmospheric Pb pollution of Hongqi Street and Comrade Street in Changchun is seriously polluted, the north entrance of the railway station is a severe polluted area, the exhibition Avenue has reached moderate pollution, the people's street and the nanhu road are mild. Pollution area, no pollution is triumphant Road, Qianjie street and Yanan road.
3, the original samples of urban soil organic materials and the isothermal adsorption curves of HLA and HLM to Pb2+ showed that leaves, turf grass and cow dung and HLA, HLM adsorption of Pb2+ increased with the increase of Pb2+ concentration in the equilibrium solution; at the same initial concentration, the order of Pb2+ adsorption was leaf cow dung turfgrass, for the same initial concentration. In the same organic material, the order of the adsorption of Pb2+ in turf grass and leaves is HLMHLA, HLAHLM. The adsorption isotherms of each component can be described well with Freundlich, Langmiur and Temkin equations, and all have significant linear correlation. The order of adsorption isotherms is consistent with the regularity of the adsorption isotherm curves, the order of maximum adsorption is HLAHLM It's the original.
4, the results of seed germination test showed that the strongest resistance to Pb stress in the plant was the seeds of iris root, followed by the seeds of herb and purple jasmine, and the worst tolerance was the seed of chrysanthemum. Compared with the control, the root length of the peacock grass and the hundred Japanese grass decreased by 66.2%, 55.1% respectively, and the chrysanthemum declined by 85.2%. to explain the seed young roots. The most resistant flowers to Pb are peacock grass and herb, the weakest is the influence of.Pb stress on the growth of the seedlings after germination, and further confirmed that the four strong tolerance of plant roots to Pb are Iris japonica, Camellia Impatiens, sachergrass and peacock grass, and the order of strength and weakness is the malachite grass peacock.
5, the results of hydroponic test showed that the maximum Pb content in the upper ground of Begonia, herb, purple jasmine and purple flower hairpin reached the critical content standard of the hyperaccumulator, and the Pb content and enrichment coefficient of the above ground were the largest in all the treatments. All of the plants were significantly higher than those of other plants, P. The maximum value of B transfer coefficient is more than 0.8, such as four seasons Begonia, herb, purple jasmine, purple flower hairpin and jalgrass, and the transfer coefficient of B. Purea at 200 mg Pb/L is still higher than that of 100 mg Pb/L. It has high Pb enrichment ability and transfer ability.
6, the results of soil culture test showed that 1) the maximum Pb content of purple jasmine, marshmus, crabapple, and Camellia Impatiens were more than 100 mg-kg-1, and the order of them was the Camellia sinensis, and the Pb content in the upper ground and the Pb rich coefficient were significantly higher than those of the other flower plants.2). In the compound, the highest Pb transfer coefficient was more than 0.45: purple jasmine, silver side geranium, Phnom pennum, geranium and eight treasure Sedum, and the transfer coefficient of the high concentration Pb was significantly higher than that of low concentration. From the top of the plant, the repair efficiency and the total migration of Pb were the highest, followed by the purple jasmine and the Shu. Sunflower, Camellia Impatiens, marigold, Herba Herba, but not more than 0.2%.3), the results of the comprehensive study show that the purple jasmine not only has strong resistance to Pb stress, but also has a higher Pb enrichment and transfer ability, and has great application value in the remediation of Pb contaminated soil. From the upper repair ability of flower plants, four Ji Haitang, mirabilis Jones, day lily and Camellia balsam have good potential to restore Pb contaminated soil, and the restoring potential of marshmallow, Camellia Impatiens and marigold flowers should not be neglected.
To sum up, through the systematic study of the growth response and enrichment characteristics of 32 common flower plants planted in Changchun, 4 kinds of flower plants with the potential of Pb hyperenrichment have been found, that is, Begonia, eriergrass, purple jasmine and purple flower hairpin, and the Pb enrichment of the 4 plants is more than 1000 mg-kg-1, and the enrichment coefficient is all greater than that of the 4 flower plants. 1, it is proved to be able to screen the varieties with strong resistance and enrichment to Pb from flowers and plants. It is feasible to use flowers and plants to repair Pb contaminated soil. It can reduce the Pb content of soil and beautify the urban environment, which provides a new model for the remediation of Pb contaminated soil in Changchun.

【学位授予单位】：吉林农业大学
【学位级别】：博士
【学位授予年份】：2011
【分类号】：X53;X825;X173

【引证文献】