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1.
Heavy metal contamination in an area immediately surrounding a zinc smelter has resulted in destruction of over 485 hectares of forest. The elevated levels of heavy metals in these soils have had significant impacts on the population size and overall activity of the soil microbial communities. Remediation of these soils has resulted in increases in indicators of biological activity and viable population size, which suggest recovery of the microbial populations. Questions remain as to how the metal contamination and subsequent remediation at this site have impacted the population structure of the soil microbial communities. In the current study, microbial communities from this site were analyzed by the phospholipid fatty acid (PLFA) procedure. Principal component analysis of the PLFA profiles indicated that there were differences in the profiles for soils with different levels of metal contamination, and that soils with higher levels of metal contamination showed decreases in indicator PLFAs for mycorrhizal fungi, Gram-positive bacteria, fungi, and actinomycetes. PLFA profiles for remediated sites indicated that remediated soils showed increases in indicator PLFAs for fungi, actinomycetes, and Gram-positive bacteria, compared to unremediated metal contaminated soils. These data suggest a change in the population structure of the soil microbial communities resulting from metal contamination and a recovery of several microbial populations resulting from remediation. 相似文献
2.
On numerous occasions, rhizosphere microbial activities have been identified as a key factor in metal phytoavailability to various plant species and in phytoremediation of metal-contaminated sites. For soil bioremediation efforts in heavy metal contaminated areas, microbes adapted to higher concentrations of heavy metals are required. This study was a field survey undertaken to examine rhizosphere microbial communities and biogeochemistry of soils associated with Zn accumulation by indigenous willows (Salix purpurea L.) in the naturally metalliferous peat soils located near Elba, NY. Soil and willow leaf samples were collected from seven points, at intervals 18 m apart along a willow hedgerow, on four different dates during the growing season. Soil bacterial community composition was characterized by terminal restriction fragment length polymorphism (T-RFLP) analysis and a 16S clone library was created from the rhizosphere of willows and soils containing the highest concentrations of Zn. Bacterial community composition was correlated with soil sulfate, but not with soil pH. The clone library revealed comparable phylogenetic associations to those found in other heavy metal-contaminated soils, and was dominated by affiliations within the phyla Acidobacteria (32%), and Proteobacteria (37%), and the remaining clones were associated with a wide array of phyla including Actinobacteria, Gemmatimonadetes, Planctomycetes, Verrucomicrobia, Bacteriodetes, and Cyanobacteria. Diverse microbial populations were present in both rhizosphere and bulk soils of these naturally metalliferous peat soils with community composition highly correlated to the soil sulfate cycle throughout the growing season indicative of a sulfur-oxidizing rhizosphere microbial community. Results confirm the importance of soil characterization for informing bioremediation efforts in heavy metal contaminated areas and the reciprocity that microbial communities uniquely adapted to specific conditions and heavy metals may have on an ecosystem. 相似文献
3.
Large accumulation of heavy metals in organic layers of forest soils may adversely affect the structure and diversity of microbial communities. The objective of this study was to assess the influence of different soil chemical properties on structure and diversity of microbial communities in soils polluted with different levels of heavy metals. The soil samples were taken at ten sites located in the vicinity of the cities of Legnica and Olkusz, differently polluted with Cu, Zn and Pb. The samples were measured for pH and the contents of organic C (Corg), total N (Nt), total S (St) and total Zn, Cu and Pb. The measured gross microbial properties included microbial biomass (Cmic) and soil respiration (RESP). The structure of soil microbial communities was assessed using phospholipid fatty acid (PLFA) analysis and the structure of soil bacterial communities using pyrosequencing of 16S rRNA genes. To assess diversity of the bacterial communities the Chao1 index was calculated based on the pyrosequencing data. For Cmic and RESP the most important factors were Nt and Corg, respectively. The structure and diversity of soil microbial communities revealed by PLFA profiles and pyrosequencing depended mainly on soil pH. The effect of high heavy metal contents on soil microbial properties was weaker compared with other soil properties. High concentrations of heavy metals negatively affected RESP and the Chao1 diversity index. The heavy metal pollution altered the structure of microbial communities measured with PLFA analysis, but the effect of heavy metal pollution was not observed for the structure of soil bacteria measured by pyrosequencing. The obtained results indicate that the use of soil microbial properties to study heavy metal effects may be difficult due to confounding influences of other environmental factors. In large-scale studies local variability of soil properties may obscure the effect of heavy metals. 相似文献
4.
Th. Beck 《植物养料与土壤学杂志》1981,144(6):613-627
The toxic effects of heavy metals, commonly found in urban wastes on the soil microflora In several series the influence of soluble salts of Cd, Cr, Zn, Cu, Ni and Hg in various concentrations was tested on the development of bacteria and fungi in cultural studies and in soil model systems. In addition the changes in microbial biomass, in the activity of oxidoreductases and hydrolases, and in nitrification were measured in five soils. Comparison of the results of bacteria-plate-counts in the presence of heavy metals in agar-media and in soils demonstrated that all tested elements have a more toxic effect on isolated soil microorganisms under culture conditions than when tested after heavy metal application to soils. Beside Hg, eucaryotic soil fungi proved to be 10 – 50 fold more resistant to heavy metals in vitro as well as in situ. For calculating the effect of heavy metals on soil microbial activity soil enzymatic methods are not reliable and can be used only to some extent, because some cellfree encymes in the soil are activated or inactivated immediately by heavy metals. In long-term experiments, the microbial biomass and nitrification in soil is not significantly influenced by the elements Cd, Cu and Ni in the concentration range of the tolerable limit content. In contrast, Cr, Zn and Hg reduced these microbiological properties more or less distinctly. 相似文献
5.
综述了铁锰氧化菌诱导成矿对重金属环境行为的影响,分别从铁/锰氧化菌与生物成矿、铁/锰氧化菌诱导铁锰氧化物沉淀耦合重金属稳定化以及铁锰氧化物对土壤中重金属的作用方面进行阐述;并从铁/锰氧化菌生物成矿方式、铁/锰氧化菌诱导生物成矿过程对土壤重金属的稳定化机制等方面进一步总结了铁/锰氧化菌在不同重金属生物成矿修复中的应用,以及微生物诱导成矿过程的调控因素,分析胞外聚合物、温度与酸碱度、共存离子和其他因素对成矿过程的影响,以期为微生物诱导成矿修复重金属污染提供理论参考。未来工作可进一步关注生成矿物稳定重金属的长效性,不同微生物菌群组合对成矿效果的调控,以及铁/锰氧化菌在重金属复合污染场地土壤修复中的应用等方面。 相似文献
6.
南京栖霞重金属污染区植物富集重金属效应及其根际微生物特性分析 总被引：1，自引：0，他引：1
以南京栖霞重金属污染区5种植物及其根际土壤为研究对象,对植物富集重金属特征以及重金属含量与根际土壤细菌数量、土壤酶活性等的相关性进行了调查分析。结果发现,植物根际重金属污染物以Zn和Cd为主;重金属污染地区的植物有较强的吸收重金属能力,龙葵和茼草具备了超积累植物的基本特征;植物根际细菌和Pb抗性细菌的数量达到了107CFU g-1土;根际土壤酶活性未受到重金属的毒害或受到的毒害很小;植物体中重金属含量与土壤重金属含量及其存在状态、土壤酶、土壤重金属抗性细菌有显著的正相关性。根际土壤细菌尤其是具有重金属抗性的活性细菌可能会促进土壤重金属的活化,由此促进植物体对重金属的吸收和转运。 相似文献
7.
Axel Gzik Matthias Kuehling Ingo Schneider Bernd Tschochner 《Journal of Soils and Sediments》2003,3(1):29-34
In soils, animals and plants from selected sites in the Rustenburg mining area, a part of the South African ore belt, the
heavy metal burden was examined. These sites belong to different soil types and are characterized by different land-use (agriculture,
grassland). The heavy metal contamination of the soil samples is relatively high and is dominated by chromium and nickel,
metals, which are extracted in the mine near the sampling sites. These high heavy metal concentrations had no clear inhibitory
influence on micro-organisms or the enzyme activity of soils. It appears that the high clay content of the soils may counteract
the influence of heavy metals. On the other hand, tolerant microbial populations may have been established. In addition, the
investigated culture plants there was no correlation between the heavy metal content of the soils and the concentrations in
roots and shoots. The dangerous, potential contamination of organs in humans seems to be modest, with the exception of tobacco
leaves. The heavy metal content of tissues in the examined animals reflect the environmental habitat in situ with no obvious
influence on the health of the animals. 相似文献
8.
为增加粮食可食用部分有益元素的浓度,同时减少有毒重金属元素的含量,需要更好地了解元素在植株和籽粒内的运输和分布。在温室盆栽条件下,以春小麦为供试材料,设置对照（不添加重金属）和重金属复合处理（同时添加铜、锌、镍、镉,以不影响小麦生长为前提）,研究锌（Zn）、铜（Cu）、镍（Ni）、镉（Cd）在成熟植株和籽粒不同部位的分布特点。结果表明,重金属复合处理对小麦成熟期籽粒和秸秆产量、收获指数以及粒重均无显著影响,但使小麦各器官重金属浓度均显著增加,增幅因不同器官和不同元素而异,籽粒中Zn、Cu、Ni和Cd浓度分别增加1.8、0.5、48.1倍和45.3倍。重金属复合处理还显著改变了Zn和Ni在地上部各器官中的分配模式：对照小麦吸收的Zn更易向生殖器官中转运,处理植株则更多地滞留在营养器官中,而Ni呈相反的趋势。激光剥蚀电感耦合等离子体质谱仪（LA-ICP-MS）对籽粒糊粉层和胚乳的定量分析表明,重金属复合处理使糊粉层Zn和Cu浓度仅增加了78%和86%,而糊粉层Ni和Cd浓度分别增加了30倍和121倍。重金属复合处理使胚乳Zn和Cu浓度分别增加了49%和48%,使Ni和Cd浓度均超出小麦标准中Ni和Cd的最大允许浓度（对照籽粒胚乳中没有检验到Ni和Cd）。以上结果表明,在小麦生物强化实践中,在增加有益营养元素（如Cu和Zn）的同时亦存在有毒重金属（如Ni和Cd）超标的巨大风险。 相似文献
9.
Ioannis Massas Constantinos Ehaliotis Dionisios Kalivas Georgia Panagopoulou 《Water, air, and soil pollution》2010,212(1-4):51-63
This study reports on the concentrations, distribution, and availability of heavy metals in the children’s playground soils of Athens. Playgrounds were chosen because they are open city areas; they show relatively even spatial distribution within the district of Athens and are used by a great number of young children and their escorts on a regular basis. Samples were collected from 70 playground surface soils, representing more than 70% of the city’s playgrounds. Cu, Zn, Pb, Cr, Ni, Co, Mn, and Fe were extracted by aqua regia and by diethylene triamine pentaacetic acid (DTPA) to estimate total and available metal forms, respectively. Their mean total concentrations were 43, 174, 110, 80, 82, 22, 312, and 17?×?103?mg kg?1, respectively. The DTPA-extracted fraction showed much lower values, with means of 2.5, 7.8, 5.8, 1.5, 1.3, 0.4, 8.4, and 2.0 mg kg?1 respectively, which, however, should be carefully monitored since they relate directly to the bioavailable fraction of heavy metals. Though mean values of metal concentrations are not particularly high, the calculated enrichment factors indicate site-specific cases of high enrichment with heavy metals. Considering that the bioavailable fraction of a metal is possibly a more appropriate indicator for the recent soil pollution history, availability ratios were calculated and their distribution was visualized over the entire city profile using the appropriate GIS software. It was shown that recent metal pollution events appear to have affected mostly playground sites in the southern and eastern part of the municipality. 相似文献
10.
沿海滩涂区土壤重金属含量分布及其有效态影响因素 总被引：2，自引：1，他引：1
为揭示沿海地区土壤重金属含量的空间分布特征及其与自然、人为因素的关联,以近年来围垦开发强度较大的江苏沿海某滩涂区为研究对象,采用经典统计与地统计相结合的方法研究了表层土壤主要重金属Pb、Cr、Cd、As全量与有效态含量状况及其空间分布,分析了沿海滩涂区土地利用方式对重金属含量的影响,探讨了重金属有效态含量与土壤理化性质的相关性。结果表明:目前研究区土壤环境质量状况良好,土壤Pb、Cr、Cd、As均呈累积趋势但基本都低于土壤环境质量一级标准值;土地利用方式不同程度地影响了Pb、Cr、Cd全量与有效态含量,As全量与有效态含量受土地利用方式影响较小;研究区土壤Pb、Cr、Cd全量与Pb、Cr有效态含量具有明显的趋势效应,且研究区土壤重金属全量与有效态含量的空间分布受大尺度的潮汐作用与小尺度的人为因素的共同控制;土壤Pb、Cr、Cd有效态含量与黏粒含量、阳离子交换量和p H显著负相关,与有机质呈显著正相关,土壤As有效态含量仅与土壤p H显著正相关。本研究为沿海滩涂区土壤重金属源头减量、活性钝化、污染消减与风险防范提供科学依据。 相似文献
11.
Yu. N. Vodyanitskii A. T. Savichev S. Ya. Trofimov E. A. Shishkonakova 《Eurasian Soil Science》2012,45(10):977-982
X-ray fluorescence and X-ray radiometry represent easy and simple methods to determine concentrations of heavy metals in the ash of peat soils contaminated with oil and can be applied for soil monitoring purposes. Oil spills on peat bogs produce two contamination zones differing in the composition of heavy metals. In the zone of primary contamination, the peat surface is covered by a bitumen crust with V, Ni, Sr, Ba, Ce, and La accumulating there. This zone adjoins the zone of secondary peat contamination, where heavy alkaline-earth metals (Sr, Ba) and lanthanides (Ce and La) are accumulated to a lesser extent. Biological preparations recommended for remediation of oil-contaminated peat soils should be tolerant to high concentrations of heavy metals, particularly, V, Ni, and Ba that are present in the oil contaminated soils in relatively high amounts. 相似文献
12.
Jose Escarr�� Claude Lef��bvre Stephan Raboyeau Anabelle Dossantos Wolf Gruber Jean Claude Cleyet Marel Helene Fr��rot Nausicaa Noret Stephanie Mahieu Christian Collin Folkert van Oort 《Water, air, and soil pollution》2011,216(1-4):485-504
Mining activities generate spoils and effluents with extremely high metal concentrations of heavy metals that might have adverse effects on ecosystems and human health. Therefore, information on soil and plant metal concentrations is needed to assess the severity of the pollution and develop a strategy for soil reclamation such as phytoremediation. Here, we studied soils and vegetation in three heavily contaminated sites with potential toxic metals and metalloids (Zn, Pb, Cd, As, TI) in the mining district of Les Malines in the Languedoc region (southern France). Extremely high concentrations were found at different places such as the Les Aviniéres tailing basins (up to 160,000 mg kg?C1 Zn, 90,000 mg kg?C1 Pb, 9,700 mg kg?C1 of As and 245 mg kg?C1 of Tl) near a former furnace. Metal contamination extended several kilometres away from the mine sites probably because of the transport of toxic mining residues by wind and water. Spontaneous vegetation growing on the three mine sites was highly diversified and included 116 plant species. The vegetation cover consisted of species also found in non-contaminated soils, some of which have been shown to be metal-tolerant ecotypes (Festuca arvernensis, Koeleria vallesiana and Armeria arenaria) and several Zn, Cd and Tl hyperaccumulators such as Anthyllis vulneraria, Thlaspi caerulescens, Iberis intermedia and Silene latifolia. This latter species was highlighted as a new thallium hyperaccumulator, accumulating nearly 1,500 mg kg?C1. These species represent a patrimonial interest for their potential use for the phytoremediation of toxic metal-polluted areas. 相似文献
13.
M. Belén Hinojosa Benjamín Viñegla Jose A. Carreira 《Soil biology & biochemistry》2004,36(10):1637-1644
This study focused on the potential of using soil enzyme activities and general microbiological rates (respiration, N-mineralisation, nitrification) to evaluate the quality of soils affected by a pyrite mud spill which contained high concentrations of heavy metals. The quality of soils after restoration was estimated by comparing enzyme activities and general microbiological rates in three different types of experimental field plots: (i) non-polluted, (ii) polluted but restored, and (iii) polluted but un-restored soils. Non-polluted soils showed the highest levels of enzyme activity. Significant differences were detected for acid phosphatase, β-glucosidase and urease activities between all types of plots. However, arylsulfatase and alkaline phosphatase activities showed no significant differences between the restored plots and polluted but un-restored plots. Geometric mean statistics were used as an index of soil quality in terms of overall: (i) bioavailable heavy metal concentrations, (ii) assayed enzyme activities, and (iii) general microbiological rates, in order to compare plots differing in the degree of pyritic mud pollution. The results indicate that it is important to consider these three criteria in to estimate the soil quality of heavy-metal contaminated soils. Typically, enzyme activities were negatively correlated with bioavailable Cd, Cu and Zn concentrations, but positively with soil pH values. In contrast, pH values were negatively correlated with bioavailable concentrations of Cd, Cu and Zn. It is unclear if the generalised lower enzyme activities found in restored soils, compared to non-polluted soils, is promoted by pH or bioavailable heavy metals concentrations, or a combination of both. 相似文献
14.
采集南方几种重金属污染下的水稻土,通过室内培养的方法研究土壤CO2排放的动态变化以及微生物学指标的差异。结果表明,在60d的培养期内,前7d土壤呼吸速率较高,占了整个排放量的30．89％～64．37％,并且这一阶段重金属对土壤呼吸速率的影响最大。重金属对土壤微生物生物量的影响表现出增加、抑制与无显著性差异的结果,而重金属对微生物熵及微生物代谢熵（qCO2）的影响却是极显著的,同时表现出增加与降低的不同结果。这说明土壤呼吸以及不同的微生物学指标,在长期的复合重金属污染条件下,其表现并不一致,微生物熵与代谢熵用于基本性质差异较大的土壤时,对重金属的响应更为灵敏。此外,土壤重金属的累积还能提高土壤中有机碳的含量。 相似文献
15.
《Communications in Soil Science and Plant Analysis》2012,43(13-14):1867-1884
Abstract Soils developed on serpentinitic rocks have serious limitations for agriculture. They have high levels of magnesium (Mg) and heavy metals [copper (Cu), manganese (Mn), nickel (Ni), and chromium (Cr)] and are deficient in some macronutrients. In parts of Northwestern Spain, serpentine soils have been subjected to intensive management, based on the use of manure and harvesting residues. Although these practices have allowed the growth of crops, plants may have accumulated high amounts of metals. This study was carried out to assess the effect of the management practices on the uptake of heavy metals by crops, and to analyze the relationship between the concentrations of these metals in plants, and soil properties. Moderate levels of Ni and Mn and low levels of Cr and Cu were found in soil extractable fractions of these metals. In spite of this, analysis of plant tissues revealed high levels of Cr and Ni and moderate contents of Mn. Concentrations of Mn and Ni in foliage were correlated to soil extractable contents, whereas simple linear regression between concentration of Cr in plants and the soil‐extractable Cr showed a poor relationship, possibly because the availability of this metal, as Cr(VI), is determined by temporal environmental conditions. To assess the effects of the management on the uptake of heavy metals by plants, a complementary bioassay experiment was carried out in the laboratory in which Festuca rubra and Agrostis stolonifera were sown on serpentine soil with low organic matter content, and amended with peat and/or lime. This experiment confirmed that there is a reduction in heavy metal concentration in plants after organic amendment and suggested that the lower metal availability is partly due to the higher soil microbial activity, produced as a consequence of addition of organic matter. 相似文献
16.
Mycorrhizae are ubiquitous symbiosis which can mediate uptake of some plant nutrients. In polluted soils they could be of great importance in heavy metal availability and toxicity to plants. Mycorrhizae have also been reported to protect plants against toxic metals. We investigated the occurrence and infectivity of arbuscular mycorrhizal (AM) spores as affected by heavy metal levels and other soil properties in Norwegian soils collected from heavy metal polluted, high natural background and non-polluted areas. Spore numbers, mycorrhizal infectivity and spore germination of indigenous mycorrhizal fungi and of a reference strain (Glomus mosseae) in soils showed lower values in two soils with high metal concentrations and in one soil with a low pH. Mycorrhizal infectivity was negatively correlated with extractable metals. Spore number and mycorrhizal infectivity in a soil with naturally high heavy metal content were not different to in non-polluted soils, and indigenous AM fungi appeared more tolerant to metals than those in non-polluted soils. Mycorrhizal infectivity, expressed as MSI50 values, was significantly correlated (r′=0.89, P< 0.05) with the percentage of germinating G. mosseae spores in the soils. However, the number of spores per volume of soil was not significantly correlated with infectivity or spore germination of the reference strain. The spore germination method is discussed as a bioassay of heavy metal toxicity in soil. 相似文献
17.
Background, Aim and Scope Environmental contamination by heavy metals affects microbial communities. The number of single and multiple heavy metal resistant bacteria may be an indictor of the level of contamination. This paper details the isolation and characterisation of metal resistant microorganisms isolated from rhizosphere/soil samples obtained from an abandoned zinc, lead and copper mine and a local unaffected site. This data was compared to the level of heavy metal in the soils to establish the effect of metals on the microbial community and to determine the relationship between pollutant levels and resistant strains. This paper outlines the diversity of transferable resistance determinants between both sites and details the levels of heavy metal resistant bacteria and those expressing transferable multiple heavy metal tolerance.Methods The sample sites were located in Co. Galway, Ireland. The first sample site (site A) was a former lead, zinc and copper mine, which was closed in 1961 due to exhaustion of ore. The second site (site B) was located two and a half kilometres from the mining site and was not affected by the mining operations. Composite soil samples were characterised for general soil matrix composition, organic content, pH and general chemical parameters. The soil was also enumerated for the total viable heterotrophic counts and tested on Pseudomonas selective agar (PSA) for total Pseudomonas counts and Sucrose Asparagine (SA), which is semi-selective for fluorescent Pseudomonas.Results and Discussion Samples from both site A and site B were analysed by atomic absorption spectrophotometry for the presence of heavy metals. In the case of copper, which has a Dutch list recommended minimum permissible level of 190 µg/Kg dry weight, the levels detected at site A were 1270 µg/Kg dry weight while site B was detected at 36 µg/Kg. The arsenic levels detected at site A were eight times the permissible level (416 µg/Kg) while only half the permissible level was found at site B (13 µg/Kg). Zinc concentrations were also high at site A (4460 µg/Kg) while at site B (553 µg/Kg) they were well below the Dutchlist guidelines (720 µg/Kg). A large number of heavy metal tolerant strains were isolated from both sites. 270 isolates (site A (170) and site B (100)) were screened against 8 metals to examine the extent of multiple resistance. 82% of the strains from site A were found to be resistant to 5 metals. A total of 18% showed resistance to all 8 metals and of those examined only 4% were resistant to only one metal. In contrast isolates from site B showed no multiple resistance to more than 5 metals, while 62% showed resistance to individual metals only. Site A had a higher level of multiple heavy metal resistance strains. Stains isolated from site A had 23 (14%) isolates resistant to zinc, copper, nickel, arsenic and cobalt and site B had no bacteria resistant to all five of these selected metals. The transferability of heavy metal resistance was investigated in the case of 60 multiple heavy metal resistant isolates taken from site A and 50 multiple resistance isolates from site B. Transfer was only detected in isolates from site A, 13% showed transfer and expression of copper, zinc and arsenic resistance determinants. In most cases the transconjugants only expressed resistance to copper, zinc and arsenic, which were the metals, used for selection. This co-transfer of all three determinants suggests a genetic link between these resistance determinants.Conclusion Heavy metal resistant bacteria are present in both sites, however, the number and presence of multiple transferable resistance phenotypes are confined to the isolates from the heavy metal contaminated site. The presence of high levels of heavy metals selects these multiple resistance phenotypes. Within these communities there seems to be little diversity between the microorganisms, which provides a hugely preferable environment for gene transfer of such metal resistant determinants.Recommendation and Perspective The experiments have shown a microbes ability to mobilize heavy metal determinants and a relationship between heavy metal resistance and metal contamination has been identified These multiple heavy metal resistant bacteria could eventually be used for detection and qualification of the level of heavy metal-polluted soil/water environments. 相似文献
18.
The objective of the present study was to determine whether substrate-induced priming effects in soils are sensitive to increasing levels of Cu and Zn. Soils were collected from ten plots of two Australian field experiments (Spalding and Avon) where increasing amounts of Cu or Zn had been added 2?years prior to sampling, reaching maximum values of 5,880?mg?kg?1 for Cu and 7,400?mg?kg?1 for Zn. In a 21-day incubation experiment, the effect of uniformly 14C-labeled fructose and alanine on the mineralization of the soil organic carbon (SOC) was investigated. With increasing heavy metal content, the initial peak of soil respiration after substrate addition was retarded, indicating that the microorganisms utilizing these substrates were inhibited in soils highly contaminated with heavy metals. Both substrates strongly changed the mineralization of the soil organic matter (SOM), i.e., priming effects were induced. In the soil samples with high Cu concentrations from Spalding, fructose induced a stronger additional mineralization of the SOC than in the lower contaminated samples. In the samples with the highest Zn contamination level, negative priming effects, i.e., a reduced mineralization of SOM, were observed. In contrast, heavy metal effects in the Avon soil (pH?7.6) were less pronounced since substrate mineralization and priming effects were not directly related to the increasing heavy metal content. Apart from direct toxic heavy metal effects, the tested microbial activity parameters were also indirectly affected through the toxic heavy metal effects on plant growth. At the highest heavy metal contaminations, no fresh biomass inputs occurred during the past 2?years so that microorganisms in these soils were highly substrate-limited. As a consequence, complex interactions between different levels of heavy metal contamination, the microbial activity, and the input of SOC via plant biomass have to be considered. 相似文献
19.
南通市城市边缘带土壤重金属污染现状及评价 总被引：8，自引：0，他引：8
通过对不同土地利用方式下的7个样区进行系统的采样测定,对南通城市边缘带土壤重金属富集与污染状况进行了分析与评价。结果显示,研究区土壤未发生明显的重金属污染。但3个样区的土壤有轻度的重金属污染现象,Zn是发生富集最普遍的元素,约76%的样点土壤Zn富集指数>1,18%的样点土壤出现Zn的轻度污染。Cu、Pb等重金属元素导致的污染也在零星样点被发现。方差分析表明,土地利用方式不是导致研究区土壤重金属含量空间差异的主要因素,而土壤类型、样区空间环境与土壤重金属含量及富集、污染有相对密切的关系。 相似文献
20.
长期重金属胁迫下的土壤微生物特征: 沈阳张士污灌区的案例研究 总被引：2，自引：0，他引：2
Soil samples were collected from Zhangshi Wastewater Irrigation Area in the suburb of Shenyang City, China, an area with a 30-year irrigation history with heavy metal-containing wastewater. The chemical properties and microbial characteristics of the soils were examined to evaluate the present situation of heavy metal pollution and to assess the soil microbial characteristics under long-term heavy metal stress. In light of the National Environmental Quality Standards of China, the soil in the test area was heavily polluted by Cd and to a lesser degree by Zn and Cu, even though wastewater irrigation ceased in 1993. Soil metabolic quotient （qCO2） had a significant positive correlation, while soil microbial quotient （qM） had a negative correlation with content of soil heavy metals. Soil microbial biomass carbon （MBC） had significantly negative correlation with Cd, but soil substrate~induced respiration （SIR）, dehydrogenase activity （DHA）, cellulase activity, and culturable microbial populations had no persistent correlations with soil heavy metal content. Soil nutrients, except for phosphorous, showed positive effects on soil microbial characteristics, which to a certain degree obscured the adverse effects of soil heavy metals. Soil Cd contributed more to the soil microbial characteristics, but qM and qCO2 were more sensitive and showed persistent responses to heavy metals stress. It could be concluded that qM and qCO2 can be used as bioindicators of heavy metal pollution in soils. 相似文献