【作者】 王建坤；

【导师】 张小平；

【作者基本信息】 四川农业大学 ， 环境工程， 2009， 硕士

【摘要】 我国西南地区铅锌矿资源十分丰富,虽然矿产资源的开发为我国经济发展做出了巨大贡献,然而大量土壤遭到采矿破坏或重金属污染退化,造成土壤生态系统的严重破坏,由此产生的土壤重金属污染已成为当前面临的最严重的环境问题之一。在环境中,重金属单一污染是很少的,绝大多数污染是多种重金属造成的复合污染。本文通过对四川省汉源县富泉乡万顺铅锌矿区的土壤进行了采集,研究了自然状态下重金属复合污染对土壤微生物数量、结构、活性的影响,旨在探索重金属复合污染对土壤微生物多样性的影响,为重金属污染土壤的修复、环境质量评价提供有益的参考。本研究取得如下结果:1.铅锌矿区土壤中Zn、Pb、Cd、Cu几种重金属含量明显高于非矿区土壤,且其基本理化性质相应变差。2.重金属复合污染对土壤微生物主要类群的生长数量影响表现为抑制作用。八个采样区微生物多样性指数大小不一致,非矿区土壤的多样性指数最大,重金属越高的地区,多样性指数越小。土壤重金属有效量与微生物数量呈一定程度的负相关趋势。3.铅锌矿污染最重和污染较轻的区域在各自细菌优势菌属构成上有相似之处,矿区土壤中出现频率较高为芽孢杆菌属(Bacillus)、微球菌属(Micrococcaceae)和棒状杆菌属(Corynebacterium),说明这三种菌对铅锌矿的耐性较好。不管是矿区土壤与非矿区土壤之间,还是矿区不同污染程度之间,放线菌类群组成上差别较大,说明放线菌比细菌和真菌对铅锌矿更敏感。矿区土壤与非矿区土壤之间,在真菌优势菌属构成上有所不同,而矿区土壤中真菌优势种属构成有相似性,木霉(Trichoderma)、曲霉(Aspergillus)、镰刀霉(Fusarium)是矿区土壤中出现频率最高的真菌种属,说明它们对铅锌矿耐性较好。4.土壤中重金属的积累导致了微生物活动的反常性,抑制了微生物的生命活动,使微生物生物量碳、纤维素分解作用的值降低,从而引起土壤肥力的减弱。处于这种逆境中,微生物为了维持其正常的生命活动,就会加大其代谢强度,表现为土壤基础呼吸随着重金属Zn、Pb、Cd、Cu含量的增加而增加。有效Zn、Pb与微生物生物量碳、纤维素分解作用呈显著负相关,与土壤基础呼吸呈显著正相关。5.Zn、Pb、Cd、Cu胁迫对不同土壤酶活性的影响存在一定差异,土壤脲酶、碱性磷酸酶、多酚氧化酶对铅锌矿较为敏感,是能反映重金属污染状况的灵敏生物学指标,而蔗糖酶和过氧化氢酶受到的抑制作用不明显。本研究表明脲酶、碱性磷酸酶、多酚氧化酶的活性可以作为同类矿区污染的生物学评价指标。更多还原

【Abstract】 Zinc-lead mine resources are very rich in the southwest of china, although the development of mineral resources for economic development in our country has made tremendous contributions, however, mining was a large number of soil damage or degradation of heavy metals pollution, causing soil ecosystem damage seriously, the resulting soil heavy metals pollution has now become the most serious environmental problems. In the environment, few contamination of heavy metals is solitary, which are combined in most cases.This research collected soil polluted by heavy metals, studied the influence of combined pollution of heavy metals to biomass, structure, and activities of soil microorganisms in natural state. This research was focused on effects of soil microbial diversity by combined heavy metals contamination, which was supposed to support the ecological remediation of contaminated by heavy metals. The conclusions are as following:1. Zn, Pb, Cd, Cu content of zinc-lead mine in the soil was significantly higher than that of non-mining, and their basic physical and chemical properties were corresponding varied.2. From the test result, we can find that combined pollution of heavy metals influence on the growth quantity of the chiefly kind of soil microorganisms is main restrictive. The microbial diversity index of eight sampling areas was inconsistent, non-mining diversity index of soil was greatest, the higher heavy metals in regions, the smaller the diversity index. Available dose of heavy metals in soils and the number of microorganisms were to some extent the trend of negative correlation. 3. Most polluted and less polluted regions of zinc-lead mine in their respective species composition of bacteria is quite similar. Bacillus, micrococcaceae and corynebacterium are the highest frequency of occurrence of mine soil, that they have good patience with zinc-lead mine. Between mine soil and non-mining soil, and between different pollution levels of mining, the composition of actinomyce is different larger than that bacteria and fungi, so they are more sensitive to zinc-lead mine. Between mine soil and non-mining soil, the composition of advantages fungi species is different, and the advantages fungi species mine soil have a similar composition. Trichoderma, aspergillus, fusarium are the highest frequency of occurrence of mine soil, that they have good patience with zinc-lead mine.4. The accumulation of the heavy metals has caused biological activity abnormal in the soil, life activation suppressed, and microbial carbon and cellulose decomposition reduced. Thus it causes of soil fertility subsided. In order to maintain its normal life activity in adverse circumstance, the microorganisms can strengthen metabolizing intensity. Available Zn, Pb and microbial biomass carbon, cellulose decomposition was negatively correlated with soil respiration based on a significant positive correlation.5. Zn, Pb, Cd, Cu stress on different soil enzyme activities there are certain differences, soil urease, alkaline phosphatase, polyphenol oxidase on the zinc-lead mine were more sensitive, and invertase, catalase were not obvious by inhibition. Activities of urease, alkaline phosphatase, polyphenol oxidase can be effective biochemical evaluation indexes to indicate pollution degree of heavy metals.更多还原