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湖泊重金属污染的植物修复研究
Alternative TitleStudies on the phytoremediation of heavy metal pollution in lakes
吴灵琼
Subtype硕士
Thesis Advisor成水平
2008-06-18
Degree Grantor中国科学院水生生物研究所
Place of Conferral水生生物研究所
Degree Discipline环境科学
Keyword湖泊 重金属污染 美人蕉 窄叶香蒲 旱柳 植物修复 底泥堆场
Abstract我国水体重金属污染问题十分突出,特别是底泥的重金属污染给环境造成了潜在的生态危害。在治理水体重金属污染的过程中,植物修复技术是目前最受关注的修复措施之一。本文针对城市湖泊水体与底泥的重金属污染,开展了武汉市汉阳区月湖、莲花湖和三角湖等三个浅水湖泊重金属污染现状的调查与评价、美人蕉 (Canna indica Linn.) 修复环境重金属污染 (Cd和Cu) 的能力和抗重金属胁迫的耐性机制等研究、植物修复湖泊疏浚底泥中重金属污染的实践分析等,为湖泊重金属污染的植物修复可行性与实施提供参考依据。主要研究结果如下: 1) 月湖、莲花湖和三角湖水中重金属的含量均未超出我国地表水环境质量III类标准 (GB3838-2002),但Cd和Pb含量都超过长江河源区背景值 (其中Cd含量高出背景值22.9~45.5倍,Pb含量高出背景值的2.6~6.4倍),表现出一定程度的富集。沉积物中Cd、Pb、Cu和Cr的最大含量分别为44.1、33.7、124和158 mg/kg DW,其中Cd和Cu分别高出武汉湖泊背景值219和2.8倍。Cd在所有湖区都达到重污染级别,而Cu和Cr在部分湖区也达到重污染级别。对重金属的潜在生态危害评价的结果表明,Cd在所有湖区的表层沉积物中均具有极强的潜在生态危害,而Pb、Cu和Cr的潜在生态危害比较轻微。以上结果表明,湖泊水体Cd污染最严重,无论是在水中还是在沉积物中,Cd都表现出明显的富集,且沉积物中Cd表现出极强的潜在生态危害。虽然Cu和Cr在水体中有不同程度的富集,在个别采样点达到重污染级别,但其潜在生态危害性不强。 2) 在20和100 µM Cd和Cu处理下,美人蕉 (Canna indica Linn) 根部Cd含量分别为对照的12和40倍 (其含量分别为1.82和5.98 mg/kg DW),而Cu含量分别为对照的22和108倍 (其含量分别为1.53、7.60 mg/kg DW),表现出良好的吸收能力。进一步研究重金属在植物体内的分布,发现Cu处理下的转运系数显著降低,说明Cu基本都滞留在根部。 3) Cd和Cu均使美人蕉H2O2和MDA含量显著提高,对植物造成了氧化胁迫。在Cu胁迫浓度不高的情况下 (20 µM),美人蕉叶部SOD和APX活性显著增强 (分别增加31.0%和23.4%)。而在20和100 µM Cd处理下,植物根部GR活性和GSH/GSSG比值较对照分别增加40.0%和70.0%、33.3%和75.0%;与此同时,根部酸溶性SH和PCs含量也较对照有明显提高 (分别提高了66%和207%、98%和132%)。从植物对重金属的耐受机制来看,限制Cu向植物地上部组织的转运,使叶部含量维持在正常水平,可能是美人蕉耐受Cu胁迫的一种机制;而通过有效调节根部GR的活性,提高GSH的水平,并合成PCs使Cd储存在液泡中可能是美人蕉解毒,并提高对Cd耐受性的主要方式。 4) 在琴断口堆场所调查的六种植物 (即窄叶香蒲 (Typha angustifolia Linn)、旱柳 (Salix matsudana Koidz.)、荆三棱 (Scirpus yagara Ohwi)、水蓼 (Polygonum hydropiper Linn)、一年蓬 (Erigeron annuus (Linn.) Pers) 和石龙芮 (Ranunculus sceleratus Linn)) 中,窄叶香蒲和旱柳为优势种,且窄叶香蒲、荆三棱和旱柳对重金属具有较好的吸收能力。窄叶香蒲根对Pb、Cu和Cd的吸收能力最强,其根中Pb、Cu和Cd含量分别为13.6、35.6和4.67 mg/kg DW。荆三棱对Cr的吸收最强,其叶中Cr含量高达13.3 mg/kg DW。旱柳茎中Cd含量最高,达到2.65 mg/kg DW。三种植物中,旱柳将重金属转运到地上部的能力最强。综合重金属吸收和富集的能力以及富集和转运重金属的特点,窄叶香蒲和荆三棱可考虑用于堆场Cu、Pb和Cd的植物固定技术中;同时,荆三棱也在Cr污染的植物吸收技术中有较好的应用前景。而旱柳可用于Cd污染环境的植物吸收技术中。窄叶香蒲和旱柳是堆场主要的植物种类,对这两种植物进行收割(包括地下部),可一次性从环境中分别收获Cr 16.5和10.5 g/ha、Pb 69.7和19.4 g/ha、Cu 201.4和137.9 g/ha、Cd 2.3和13.8 g/ha。 以上研究表明,月湖、莲花湖和三角湖已受到重金属Cd、Cu和Cr的污染,其中Cd污染最严重,且沉积物中Cd表现出极强的潜在生态危害,湖泊重金属污染亟待解决。美人蕉对Cd和Cu具有很好的吸收和净化能力,在Cd和Cu胁迫下表现出不同的响应和耐受机制。植物对湖泊疏浚底泥中重金属污染的修复作用明显,应用窄叶香蒲、旱柳和荆三棱等修复湖泊疏浚底泥重金属污染是可行的。
Other AbstractOne of the major environmental problems caused by industrialization is the increment in the concentration of heavy metals in waters and sediments and the heavy metal pollution in sediments has caused potential risk on environment. On the other hand, phytoremediation is emerging cleanup technology for remedying of heavy metal polluted waters. In view of these considerations, studies were carried out from three aspects, namely a) the pollution of heavy metal in water and water sediments in three shallow lakes in Wuhan (Lake Yuehu, Lake Lianhuahu and Lake Sanjiaohu) and their ecological risk to environment; b) the ability of Canna indica Linn. for phytoremediation of Cd and Cu pollution and its potential resistance mechanism to Cd and Cu; c) the possibility for plants lived in the sediment deposited site at Qinduankou to remedy the heavy metal pollution. The main results were summarized as follows: 1) The concentrations of heavy metals (include Hg, Cd, Cr, Pb, Zn, Cu) in the water of Lake Yuehu, Lake Lianhuahu and Lake Sanjiaohu did not exceed category III from the Surface Water Environment Quality Criterion, but the concentrations of Cd and Pb were significantly higher than the background of Yangtze River Basin (being 22.9-45.5 and 2.6-6.4 times higher than the background concentration of Cd and Pb respectively). The highest concentrations of Cd, Pb, Cu and Cr in sediments were 44.1, 33.7, 124 and 158 mg/kg DW, respectively, and the concentrations of Cd and Cu were 219 and 2.8 times higher than the background of lake sediments in Wuhan, respectively. Severe pollution of Cd was detected in all sampling sites and the pollution of Cu and Cr was strong in several sampling sites. There was extremely high potential ecological risk of Cd pollution, while the potential ecological risk of the other heavy metals was slight. The results indicated that Cd pollution was the most serious heavy metal pollution in both waters and sediments, and it also showed extremely high potential ecological risk in sediments. Although there was different pollution of Cu and Cr in sediments, their potential ecological risks were still slight. 2) Under the treatments of 20 and 100 μM Cd and Cu, the concentrations of Cd in roots were 1.82 and 5.98 mg/kg DW (being 12 and 40 times higher than control) and the concentrations of Cu were 1.53 and 7.60 mg/kg DW (being 22 and 108 times higher than control), respectively, showing a good absorption of both Cd and Cu by C. indica.. In addition, the transolocation factor of Cu was decreased significantly in Cu treated plants, indicating Cu absorbed by C. indica was largely stranded in roots. 3) Both Cd and Cu had caused oxidative stress in C. indica, but the plant showed various responses under different treatments. The activities of APX and SOD were increased 31.0% and 23.4% at 20 μM Cu, while under the treatment of 20 and 100 μM Cd, there was an increase of GR activity (increased 70.0% and 40.0%, respectively) and GSH/GSSG ratio (increased 33.3% and 75.0%, respectively) in roots. In addition, the concentrations of both acid soluble SH (increased 66% and 207%, respectively) and PCs concentration (increased 98% and 132%, respectively) were also found to increase in Cd treated roots. C. indica showed different tolerance mechanisms in responses of Cd and Cu treatments. It was possible for C. indica to protect itself against Cu stress by restricting Cu translocation from roots to aboveground tissues in order to keep Cu concentration of aboveground tissues at a normal level, while it could be supposed that the high amount PCs can be associated with the detoxification processes in response to Cd by quenching Cd in the vacuole. 4) Typha angustifolia Linn, Salix matsudana Koidz., Scirpus yagara Ohwi, Polygonum hydropiper Linn, Erigeron annuus (Linn) Pers and Ranunculus sceleratus Linn were found in the sediment deposited site at Qinduankou and T. angustifolia and S. matsudana were the dominant species. T. angustifolia, S. matsudan and S. yagara showed a good ability to remedy the heavy metal pollution from the deposited sediments. The highest Pb, Cu and Cd concentrations were found in roots of T. angustifolia (being 13.6, 35.6 and 4.67 mg/kg DW, respectively), while the highest concentration of Cr was detected in leaves of S. yagara (13.3 mg/kg DW). In addition, there was a quite high concentration of Cd in stems of S. matsudana (2.65 mg/kg DW) and the plant also showed a good ability to transfer heavy metals from underground to aboveground tissues. According to different capacities of metal uptake and accumulation, T. angustifolia and S. yagara could be good candidates for phytostabilization of Cu, Pb and Cd, while S. yagara would be a good choice for phytoextraction of Cr and S. matsudana for Cd in the sediment deposited site. If T. angustifolia and S. matsudana were harvested (including underground tissues), there would be 16.5 and 10.5 g/ha Cr, 69.7 and 19.4 g/ha Pb, 201.4 and 137.9 g/ha Cu, 2.3 and 13.8 g/ha Cd taken away from the the sediment deposited site, respectively. These results showed Lake Yue, Lake Lianhuahu and Lake Sanjiaohu had been polluted by Cd, Cu and Cr. The most severe pollution in lakes was caused by Cd and its potential ecological risk in the sediments was extremely high. C. indica had an excellent absorption of Cd and Cu in waters and the plant showed different tolerance mechanisms under Cd and Cu treatments. There was a potential for phytoremediation of heavy metal pollution from the deposited sediment and it is recommended that T. angustifolia, S. matsudan and S. yagara could be applied.
Pages86
Language中文
Document Type学位论文
Identifierhttp://ir.ihb.ac.cn/handle/342005/12368
Collection学位论文
Recommended Citation
GB/T 7714
吴灵琼. 湖泊重金属污染的植物修复研究[D]. 水生生物研究所. 中国科学院水生生物研究所,2008.
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