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1.
This study focused on the changes of soil microbial diversity and potential inhibitory effects of heavy metals on soil enzymatic activities at different application rates of Cd andor Pb. The soil used for experiments was collected from Beijing and classified as endoaquepts. Pots containing 500 g of the soil with different Cd andor Pb application rates were incubated for a period of 0, 2, 9, 12 weeks in a glasshouse and the soil samples were analyzed for individual enzymes, including catalase, alkaline phosphatase and dehydrogenase, and the changes of microbial community structure. Results showed that heavy metals slightly inhibited the enzymatic activities in all the samples spiked with heavy metals. The extent of inhibition increased significantly with increasing level of heavy metals, and varied with the incubation periods. The soil bacterial community structure, as determined by polymerase chain reaction-denaturing gradient gel electrophoresis techniques, was different in the contaminated samples as compared to the control. The highest community change was observed in the samples amended with high level of Cd. Positive correlations were observed among the three enzymatic activities, but negative correlations were found between the amounts of the heavy metals and the enzymatic activities.  相似文献   

2.
Effects of cadium, zinc and lead on soil enzyme activities   总被引:5,自引:0,他引:5  
Heavy metal (HM) is a major hazard to the soil-plant system. This study investigated the combined effects of cadium (Cd), zinc (Zn) and lead (Pb) on activities of four enzymes in soil, including calatase, urease, invertase and alkalin phosphatase. HM content in tops of canola and four enzymes activities in soil were analyzed at two months after the metal additions to the soil. Pb was not significantly inhibitory than the other heavy metals for the four enzyme activities and was shown to have a protective role on calatase activity in the combined presence of Cd, Zn and Pb; whereas Cd significantly inhibited the four enzyme activities, and Zn only inhibited urease and calatase activities. The inhibiting effect of Cd and Zn on urease and calatase activities can be intensified significantly by the additions of Zn and Cd. There was a negative synergistic inhibitory effect of Cd and Zn on the two enzymes in the presence of Cd, Zn and Pb. The urease activity was inhibited more by the HM combinations than by the metals alone and reduced approximately 20%--40% of urease activity. The intertase and alkaline phosphatase activities significantly decreased only with the increase of Cd concentration in the soil. It was shown that urease was much more sensitive to HM than the other enzymes. There was a obvious negative correlation between the ionic impulsion of HM in soil, the ionic impulsion of HM in canola plants tops and urease activity. It is concluded that the soil urease activity may be a sensitive tool for assessing additive toxic combination effect on soil biochemical parameters.  相似文献   

3.
Bacterial diversity in soils around a lead and zinc mine   总被引:1,自引:0,他引:1  
Five samples of soil collected from a lead and zinc mine were used to assess the effect of combined contamination of heavy metals on soil bacterial communities using a polyphasic approach including characterization of isolates by culture method, community level catabolic profiling in BIOLOG GN microplates, and genetic community fingerprinting by denaturing gradient gel electrophoresis of 16S rDNA fragments amplified by PCR from community DNA (PCR-DGGE). The structure of the bacterial community was affected to a certain extent by heavy metals. The PCR-DGGE analysis of 16S rRNA genes showed that there were significant differences in the structure of the microbial community among the soil samples, which were related to the contamination levels. The number of bacteria and the number of denaturing gradient gel electrophoresis (DGGE) bands in the soils increased with increasing distance from the lead and zinc mine tailing, whereas the concentration of lead (Pb) and cadmium (Cd) was decreased. Heavily polluted soils could be characterized by a community that differs from those of lightly polluted soils in richness and structure of dominating bacterial populations. The clustering analysis of the DGGE profiles showed that the bacteria in all the five samples of soil belonged to three clusters. The data from the BIOLOG analysis also showed the same result. This study showed that heavy metal contamination decreased both the biomass and diversity of the bacterial community in soil.  相似文献   

4.
Batch experiments were conducted with a heavy metals and arsenic co-contaminated soil from an abandoned mine to evaluate the feasibility of a remediation technology that combines sieving with soil washing.Leaching of the arsenic and heavy metals from the different particle size fractions was found to decrease in the order: 0.1,2–0.1,and 2 mm.With increased contact time,the concentration of heavy metals in the leachate was significantly decreased for small particles,probably because of adsorption by the clay soil component.For the different particle sizes,the removal efficiencies for Pb and Cd were75%–87%,and 61%–77% for Zn and Cu,although the extent of removal was decreased for As and Cr at 45%.The highest efficiency by washing for Pb,Cd,Zn,and As was from the soil particles 2 mm,although good metal removal efficiencies were also achieved in the small particle size fractions.Through SEM-EDS observations and correlation analysis,the leaching regularity of the heavy metals and arsenic was found to be closely related to Fe,Mn,and Ca contents of the soil fractions.The remediation of heavy metal-contaminated soil by sieving combined with soil washing was proven to be efficient,and practical remediation parameters were also recommended.  相似文献   

5.
The nature of microbial communities and their relation to enzyme activities in desert soils is a neglected area of investigation. To address this, the bacterial diversity and distribution and soil physico-chemical factors were investigated in the soil crust, the soil beneath the crust and rhizosphere soil at the southeast edge of the Tengger Desert, using the denaturing gradient gel electrophoresis of 16S rRNA genes amplified by the polymerase chain reaction. Phylogenetic analysis of the sequenced DGGE bands revealed a great diversity of bacteria. The Proteobacteria, consisting of the α, β, and γ subdivisions, were clearly the dominant group at all depths and in rhizosphere soil. Analysis of the enzyme activities indicated that the rhizosphere soil of Caragana korshinskii exhibited the highest protease and polyphenol oxidase activities, and in the soil crust there were increased activities of catalase, urease, dehydrogenase and sucrase. The bacterial community abundance closely correlated with soil enzyme activities in different soils. The presence of Cyanobacteria correlated with significant increases in protease, catalase and sucrase in the soil crust, and increased urease in the rhizosphere soil of Artemisia ordosica. The occurrence of Acidobacteria was associated with significant increases in urease, dehydrogenase, and sucrase in the rhizosphere soil of C. korshinski. The presence of γ-Proteobacteria correlated with a significant increase in polyphenol oxidase in the rhizosphere soil of A. ordosica. The study indicated a close relationship between the soil bacterial community and soil enzymes, suggesting the necessity of further investigations into bacterial function in this desert ecosystem.  相似文献   

6.
The soil moisture regime can affect the release of heavy metals in soil. In the previous studies, slightly polluted soils or artificially contaminated soil samples were considered to investigate the effect of soil moisture. We used highly smelter-contaminated and aged soils to study the release of typical heavy metals(Cu, Zn, Cd and Pb) induced by water incubation in batch experiments with characterization via speciation and X-ray diffraction analyses(XRD). The results show that the leachable concentrations of the heavy metals increased slightly in the first 30 days, decreased drastically between 30 and 90 days, and immobilized relatively constant thereafter. The fluctuation was ascribed to the changes of soil Eh and pH, the reductive dissolution of crystalline iron oxides, the formation of new amorphous iron oxides, the absorption of dissolved organic matter and the precipitation of metal sulfide. Speciation analysis indicated that a proportion of the soil heavy metals was transformed from an exchangeable fraction to a less labile fraction after water incubation. And the presence of a lead iron oxide phase and the peak increasing of zinc sulfide were observed via XRD analyses. Finally, water incubation restrained the release of heavy metals after 180 days of incubation, and reduced the leachability of Cu, Zn, Cd and Pb by as much as 1.61%–7.21% for soil A and 0.43%–3.36% for soil B, respectively. The study findings have implications for the formulation of risk control and management strategies for heavy metals in smelter-contaminated soils.  相似文献   

7.
The ecotoxicological effects of heavy metals and petroleum hydrocarbons (PHCs) on ragworms are still vague. The relationships between toxicological indices (mortality and acetylcholinesterase (ACHE) activity) and concentrations of toxicants (Cu, Cd, and PHCs) were examined in the estuary keystone species Perinereis aibuhitensis in laboratory conditions. The results of single toxicant indicated that three toxicants had potentially physiological toxicity to P. aibuhitensis. The estimated 4-d and 10-d LC50 for Cu, Cd, and PHCs was derived from the relationships between mortality and toxicants concentrations. Notable changes in the morphological signs and symptoms of P. aibuhitensis exposed to PHCs were observed. The ACHE activity of P. aibuhitensis was more sensitive to the toxicity of PHCs than the others. The results of combined toxicants implied that the combined toxicity of Cu or Cd and PHCs to P. aibuhitensis was related to the concentration combination of toxicants. Compared to single PHCs treatment, the addition of Cu or Cd significantly mitigated the neurotoxicity of PHCs to ACHE activity in P. aibuhitensis, which showed an antagonistic effect.  相似文献   

8.
Preparing materials for simultaneous remediation of anionic and cationic heavy metals contamination has always been the focus of research. Herein a biochar supported FeMnMg layered double hydroxide (LDH) composites (LB) for simultaneous remediation of copper and arsenic contamination in water and soil has been assembled by a facile co-precipitation approach. Both adsorption isotherm and kinetics studies of heavy metals removal by LB were applied to look into the adsorption performance of adsorbents in water. Moreover, the adsorption mechanisms of Cu and As by LB were investigated, showing that Cu in aqueous solution was removed by the isomorphic substitution, precipitation and electrostatic adsorption while As was removed by complexation. In addition, the availability of Cu and As in the soil incubation experiments was reduced by 35.54%–63.00% and 8.39%–29.04%, respectively by using LB. Meanwhile, the addition of LB increased the activities of urease and sucrase by 93.78%–374.35% and 84.35%–520.04%, respectively, of which 1% of the dosage was the best. A phenomenon was found that the richness and structure of microbial community became vigorous within 1% dosage of LB, which indirectly enhanced the passivation and stabilization of heavy metals. These results indicated that the soil environment was significantly improved by LB. This research demonstrates that LB would be an imaginably forceful material for the remediation of anionic and cationic heavy metals in contaminated water and soil.  相似文献   

9.
Degradation of soil and water from discharge of untreated industrial effluent is alarming in Bangladesh. Therefore, buildup of heavy metals in soil from contaminated effluent, their entry into the food chain and effects on rice yield were quantified in a pot experiment. The treatments were comprised of 0, 25%, 50%, 75% and 100% industrial effluents applied as irrigation water. Effluents, initial soil, different parts of rice plants and post-harvest pot soil were analyzed for various elements, including heavy metals. Application of elevated levels of effluent contributed to increased heavy metals in pot soils and rice roots due to translocation effects, which were transferred to rice straw and grain. The results indicated that heavy metal toxicity may develop in soil because of contaminated effluent application. Heavy metals are not biodegradable, rather they accumulate in soils, and transfer of these metals from effluent to soil and plant cells was found to reduce the growth and development of rice plants and thereby contributed to lower yield. Moreover, a higher concentration of effluent caused heavy metal toxicity as well as reduction of growth and yield of rice, and in the long run a more aggravated situation may threaten human lives, which emphasizes the obligatory adoption of effluent treatment before its release to the environment, and regular monitoring by government agencies needs to be ensured.  相似文献   

10.
Lateral transportation of soil heavy metals in rainfall events could significantly increase the scope of pollution. Therefore, it is necessary to develop a model with high accuracy to simulate the migration quantity of heavy metals. A model for heavy metal migration simulation was developed based on the SWAT(Soil and Water Assessment Tool) model. This model took into consideration the influence of soil p H value, soil particle size, runoff volume, sediment amount,concentration of water-soluble heavy metals dissolved in runoff and insoluble absorbed to the soil particles. This model was reasonable in Huanjiang watershed, Guangxi Zhuang Autonomous Region, south China, covering an area of 273 km~2. The optimal drainage area threshold was determined by analyzing the effects of watershed subdivision on the simulation results to ensure the simulation accuracy. The main conclusions of this paper were:(1) watershed subdivision could affect simulation migration quantity of heavy metals;(2) the quantity of heavy metals transported by sediment accounted for 97%–99% of the total migration quantity in the study watershed. Therefore, sediment played the most important role in heavy metal migration;(3) the optimal drainage area threshold percentage to ensure high simulation accuracy was determined to be 2.01% of the total watershed;(4) with the optimal threshold percentage, this model could simulate the migration quantity of As, Pb and Cd accurately at the total watershed and subwatershed level. The results of this paper were useful for identifying the key regions with heavy metal migration.  相似文献   

11.
研究了浙江省绍兴银山铅锌矿周围农田的污染情况及其对土壤酶活性的影响。该污染区域内主要的污染元素为砷和铅,其含量与区内土壤脱氢酶、过氧化氢酶、过氧化物酶、转化酶、脲酶和磷酸酶呈显著的复相关关系,其中砷的影响是主要的。土壤脱氢酶、过氧化氢酶和转化酶活性的变化能够反映供试土壤类型受砷和铅复合污染的程度。  相似文献   

12.
Hg作为环境的主要污染重金属之一,其对土壤酶的影响是表征其环境效应的重要方面,结果可为土壤环境监测等提供生物学依据.因此,本文通过室内模拟试验,较系统地分析了全国14种主要类型18个土样的脲酶和脱氢酶活性在Hg胁迫下的响应.结果表明,Hg会抑制土壤酶活性,其降幅随土壤类型的不同有明显差异;随着Hg含量的升高,土壤脲酶和脱氢酶活性均显著降低;模型U=A/(1+B×C)可较好地拟合酶活性(U)与汞含量(C)之间的关系,揭示出土壤脲酶和脱氢酶在一定程度上可监测土壤Hg污染的程度,且机理为完全抑制(包括竞争性抑制和非竞争性抑制)作用.同时,实验获得的供试土样脲酶的生态剂量(ED10)范围为0.08~0.77 mg·kg-1,脱氢酶ED10范围为0.11~2.58mg·kg-1,从土壤酶角度获得的土壤汞轻度污染临界值为0.08 mg·kg-1,此值要小于国家土壤质量标准中的二级标准.有机质、pH、CEC和粘粒显著影响了汞与土壤脱氢酶的关系,上述4个土壤性状参数值越高,汞对土壤酶的毒害作用就越弱;酸性土壤中汞的毒害作用强于碱性土壤.表明在我国主要土壤类型上,土壤脲酶、脱氢酶对Hg毒性均较为敏感,可在更广范围内作为Hg污染程度的监测指标之一.  相似文献   

13.
The ultimate purpose of phytoextraction is not only to remove heavy metals from soil but also to improve soil quality. Here, we evaluated how the joint effect of Streptomyces pactum (strain Act12) and inorganic (Hoagland's solution) and organic (humic acid and peat) nutrients affected the phytoextraction practice of cadmium (Cd) and zinc (Zn) by potherb mustard, and the microbial community composition within rhizosphere was also investigated. The results indicated that the nutrients exerted synergistically with Act12, all increasing the plant biomass and Cd/Zn uptakes. The inoculation of Act12 alone significantly increased dehydrogenase activity of rhizosphere soil (P < 0.05), while urease and alkaline phosphatase activities varied in different dosage of Act12. Combined application of microbial strain with nutrients increased enzymatic activities with the elevated dosage of Act12. 16S ribosomal RNA high-throughput sequencing analysis revealed that Act12 inoculation reduced the diversity of rhizosphere bacteria. The Act12 and nutrients did not change dominant phyla i.e., Proteobacteria, Bacteroidetes, Gemmatimonadetes, Actinobacteria and Acidobacteria, but their relative abundance differed among the treatments with: Peat > Act12 > Humic acid > Hoagland's solution. Comparatively, Sphingomonas replaced Thiobacillus as dominant genus after Act12 application. The increase in the Sphingomonas and Flavisolibacter abundances under Act12 and nutrients treatments gave rise to growth-promoting effect on plant. Our results revealed the important role for rhizosphere microbiota in mediating soil biochemical traits and plant growth, and our approach charted a path toward the development of Act12 combined with soil nutrients to enhance soil quality and phytoextraction efficiency in Cd/Zn-contaminated soils.  相似文献   

14.
土壤的重金属污染与土壤酶活性   总被引:101,自引:5,他引:101       下载免费PDF全文
本文根据模拟研究,论述了不同用量的重金属Hg、Cd和Pb对不同肥力水平的棕壤和红壤的过氧化氢酶、转化酶、脲酶和磷酸酶活性的影响.重金属对土壤酶抑制作用的顺序为:Hg>Cd>Pb.且随金属浓度的增大而增强.实验表明,重金属对土壤酶活性的抑制是一种暂时现象、由于脲酶活性恢复得较少较慢,故建议用土壤的脲酶活性作为土壤Hg污染程度的指标.  相似文献   

15.
不同金属矿山选冶活动造成的矿区及周边土壤中重金属的分布累积特征不同.为了解密云水库上游金矿和铁矿矿区土壤中重金属地球化学特征的异同及污染状况,对区域内典型的金矿和铁矿矿区进行土壤样品采集,应用地球化学方法研究了2种土壤中重金属的污染特征,并应用地累积指数法评价了其污染状况.结果表明,2种土壤中除As外的其它重金属含量明显高于北京市土壤重金属背景值,金矿矿区土壤重金属含量普遍高于铁矿矿区.相关性分析表明,金矿矿区土壤中Cu含量与Pb、Zn(p<0.01)及Cr、有机质(OM)含量(p<0.05)之间显著相关,pH值与Pb含量(p<0.01)及Hg含量(p<0.05)呈显著负相关,而铁矿矿区土壤中重金属含量之间的相关性不显著.金矿尾砂中重金属含量明显高于铁矿尾砂,与矿区土壤污染状况一致.地累积指数法评价结果显示,金铁矿区土壤中重金属的污染程度均已十分严重,金矿矿区土壤污染程度高于铁矿,金矿矿区土壤重金属的污染程度由高到低依次为:Pb>Hg>Cd>Cr>Cu>Zn>Co>As;铁矿矿区土壤重金属的污染程度由高到低依次为:Pb>Cd>Cr>Co>Cu>Zn>Hg>As.该研究数据可为同一区域内不同金属矿区重金属污染的有效监控与治理提供科学依据.  相似文献   

16.
The relationship between plant species coexistence and soil microbial communities under heavy metal pollution has attracted much attention in ecology. However, whether plant species coexistence could o set the impacts of heavy metal combined pollution on soil microbial community structure and soil enzymes activities is not well studied. The modified ecological dose model and PCR-RAPD method were used to assess the e ects of two plant species coexistence on soil microbial community and enzymes activities subjected to Cd and Pb combined stress. The results indicated that monoculture and mixed culture would increased microbe populations under Cd and Pb combined stress, and the order of sensitivity of microbial community responding to heavy metal stress was: actinomycetes > bacteria > fungi. The respirations were significantly higher in planted soil than that in unplanted soil. The plant species coexistence could enhance soil enzyme activities under Cd and Pb combined. Furthermore, planted soil would be helpful to enhance soil genetic polymorphisms, but Cd and Pb pollution would cause a decrease on soil genetic polymorphisms. Mixed culture would increase the ecological dose 50% (ED50) values, and the ED50 values for soil enzyme activities decreased with increasing culture time. The dehydrogenase was most sensitive to metal addition and easily loses activity under low dose of heavy metal. However, it was di cult to fully inhibit the phoshpatase activity, and urease responded similarly with phosphatase.  相似文献   

17.
赵兴青  朱旭炎  黄兴  孙雨  侯颖 《环境科学研究》2019,32(12):2139-2147
为揭示土壤微生物及酶活性与重金属污染的内在关系,并建立土壤重金属污染水平的酶活性及生物学参数表征体系,以安徽铜陵狮子山矿区周边土壤为研究对象,测定矿区内不同功能区域(采矿区、选矿区、堆矿区、尾矿库以及菜园)土壤中w(Cu)、w(Zn)、w(Cd)、w(Pb)和基础呼吸、微生物量碳含量、代谢熵等理化性质以及6种土壤酶(脲酶、蔗糖酶、纤维素酶、过氧化氢酶、中性磷酸酶和碱性磷酸酶)的活性.结果表明,所选矿区不同功能区域的内梅罗综合污染指数(PN)依次为堆矿区(10.77)>采矿区(4.38)>选矿区(4.06)>尾矿库(2.55)>菜园(1.35);4种重金属(Cu、Zn、Cd和Pb)的单因子指数(Pi)依次为Cd > Cu > Zn > Pb.不同功能区域内6种土壤酶活性之间有显著差异并呈不同程度变化,且均以菜园土壤酶活性为最大,其中,过氧化氢酶、中性磷酸酶和蔗糖酶活性均可以有效地表征w(Cu)、w(Zn)、w(Cd)和w(Pb)的水平.与基础呼吸或者微生物量碳含量指标相比,代谢熵能更好地表征土壤环境污染状况.研究显示,土壤酶活性、代谢熵与Cu、Zn、Cd、Pb这4种重金属含量均呈极显著相关,因此可通过测定土壤酶活性和代谢熵等生物学参数为矿区土壤环境质量评价及生态修复提供参考依据.   相似文献   

18.
重金属Cd、Zn、Pb复合污染对土壤酶活性的影响   总被引:81,自引:2,他引:81  
采用回归正交设计方案 ,研究了潮褐土中Cd、Zn、Pb复合污染对 4种土壤酶活性 (过氧化氢酶、脲酶、碱性磷酸酶、转化酶 )的影响 .结果表明 ,在复合效应影响中 ,重金属对土壤酶活性的抑制效应顺次为Cd >Zn >Pb ;同时 ,Cd、Zn、Pb复合污染对 4种土壤酶活性的影响效应存在着明显差异 .其复合污染对脲酶表现出协同抑制负效应的特征 ;对过氧化氢酶表现出一定的屏蔽作用 ;对转化酶和碱性磷酸酶活性影响则主要随着Cd浓度的增加而显著降低 .离子冲量与土壤脲酶活性之间呈显著负相关 ,用脲酶活性作为预测土壤重金属Cd、Zn、Pb复合污染程度的主要生化指标具有一定的可行性  相似文献   

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