长期重金属胁迫对农田土壤微生物生物量、活性和种群的影响

调查了沈阳张士灌区长期污水灌溉造成的原位农田土壤重金属污染状况,从土壤微生物生物量、微生物活性和微生物种群数量的角度评价了长期重金属污染对农田土壤生态系统的影响.结果表明,张士灌区土壤存在严重的Cd污染,土壤Cd含量达1.75～3.89 mg·kg ^-1,部分区域还伴有Cu、Zn复合污染.在目前污染程度下,土壤微生物生物量碳(C_mic)、微生物商(qM)、土壤脱氢酶活性以及自生固氮菌数量随土壤重金属含量增加呈下降趋势,代谢商(qCO₂)随土壤重金属含量增加显著升高,而底物诱导呼吸强度(SIR)、纤维素酶活性以及细菌、放线菌和真菌数量无明显变化.相关性分析表明,土壤Cd含量变化是影响微生物参数变化的主要因素,在微生物参数中微生物商和代谢商对重金属污染最敏感.     

Relationship between decomposition of cellulose strips and chemical properties of humus layer in natural boreal forests

The relationships between the decomposition of cellulose strips buried completely within the humus layer (Of + Oh) for two 1-year periods and humus layer properties were studied at forested sites with minimal anthropogenic influence. The 18 study sites are clustered in four catchments located between 61° and 69° N in Finland. The stands were composed of varying proportions of Scots pine, Norway spruce and deciduous species. Of the 23 humus layer properties studied, significant correlations were found between decomposition and soil pH, effective cation exchange capacity, base saturation, C/N ratio, the concentrations of P, Mn, Pb, Zn and Cu. The relationships, however, were inconsistent except for heavy metal concentrations which were positive in all cases. Decomposition was more strongly and consistently correlated to tree stand characteristics (mean height and stem volume) than to the humus layer properties. Both the decomposition of cellulose strips and the concentrations of heavy metals were intercorrelated with climate and the stand characteristics. Partial correlation analysis revealed that the relationships between decomposition and humus layer heavy metal concentrations were more strongly affected by the tree stand characteristics than by climate. After the statistical elimination of the effects of stand characteristics, no significant positive correlations between decomposition and humus layer heavy metal concentrations remained and, in some cases for total and extractable Zn, the correlations became significant and negative. Results from litterfall chemistry (nutrients and heavy metals) also underlined that any specific effects of humus layer heavy metal concentrations on decomposition may be masked if the effects of stand characteristics are not accounted for. We conclude that the relationships between decomposition and soil chemical properties can not be elucidated without considering stand structure and composition of the forest stand.     

土壤中水溶性有机质及其对重金属化学与生物行为的影响

土壤水溶性有机质是陆地生态系统和水生生态系统中一种重要的、很活跃的化学组分,已成为环境科学、土壤学和生态学等学科的研究热点．土壤DOM对重金属化学与生物行为有重要影响。但其机理尚不清楚．文中从土壤性质、环境条件、人为因素等方面阐述了土壤DOM产生及影响因素,总结评述了DOM对重金属化学行为和生物有效性的影响,将DOM对重金属的影响机制归纳为络合机制、竞争吸附机制、酸碱缓冲机制．在此基础上,提出了DOM研究存在的问题及其展望．     

Influence of heavy metals in spruce forest soil on amylase activity,CO2 evolution from starch and soil respiration

Summary Starch decomposition and soil respiration is partly inhibited in spruce needle mor contaminated with heavy metals (Cu, Zn, Pb and Cd) from a brass foundry at Gusum, Southern Sweden. The total decomposition of starch was measured as CO₂ evolution rate and the hydrolysis of starch as increase in glucose concentration during incubation according to the methods of Hoffman and Pallauf and that of Nelson. In order to measure the effects of the Na-acetate buffer (pH 5.5) during incubation, amylase activity was also determined without buffer. Only the Hoffmann and Pallauf method without buffer was significantly different (p<0.001) from the other three methods. Application of stepwise regression showed that 43 to 62 per cent of the variability in amylase activity was accounted for by the metal- and hydrogen concentration of the soil. Corresponding figures for the total starch decomposition and soil respiration were 47 and 66 per cent respectively. re]19751213     

Metal Toxicity Affects Fungal and Bacterial Activities in Soil Differently

Although the toxic effect of heavy metals on soil microorganism activity is well known, little is known about the effects on different organism groups. The influence of heavy metal addition on total, bacterial, and fungal activities was therefore studied for up to 60 days in a laboratory experiment using forest soil contaminated with different concentrations of Zn or Cu. The effects of the metals differed between the different activity measurements. During the first week after metal addition, the total activity (respiration rate) decreased by 30% at the highest level of contamination and then remained stable during the 60 days of incubation. The bacterial activity (thymidine incorporation rate) decreased during the first days with the level of metal contamination, resulting in a 90% decrease at the highest level of contamination. Bacterial activity then slowly recovered to values similar to those of the control soil. The recovery was faster when soil pH, which had decreased due to metal addition, was restored to control values by liming. Fungal activity (acetate-in-ergosterol incorporation rate) initially increased with the level of metal contamination, being up to 3 and 7 times higher than that in the control samples during the first week at the highest levels of Zn and Cu addition, respectively. The positive effect of metal addition on fungal activity then decreased, but fungal activity was still higher in contaminated than in control soil after 35 days. This is the first direct evidence that fungal and bacterial activities in soil are differently affected by heavy metals. The different responses of bacteria and fungi to heavy metals were reflected in an increase in the relative fungal/bacterial ratio (estimated using phospholipid fatty acid analysis) with increased metal load.     

Assessment of Heavy Metals Contamination in Agricultural Soil of Southwestern Nile Delta,Egypt

The spatial and vertical distributions of heavy metals were quantitatively determined for organic-rich agricultural soils in the Southwestern Nile Delta. This study aims to undertake an assessment of heavy metals contamination in the soils of Quessna district using the inductively coupled plasma-optical emission spectroscopy, remote sensing, and geographic information system techniques. In this study, 24 soil samples were collected at 12 sites representing the main suburbs in the Quessna district. The concentrations of the studied metals decreased in the order of Zn > Cr > Pb > Cu > Ni > Co. The contamination degree and ecological risk assessment for metals in soil samples were evaluated using the enrichment factor, geoaccumulation index, improved Nemerow's pollution index, Pollution load index, and potential ecological risk index. The spatial and vertical distribution of heavy metals concentrations were affected by soil properties such as clay and organic matter content and scavenger metals (Fe and Mn). The intensive urbanization, industrial activity, and agricultural practices are thought to be the main anthropogenic sources of heavy metals contamination. Further studies especially human health risk assessment are recommended to investigate possible risks for humans from heavy metals in this area.     

有机肥连续施用对菜田重金属行为的影响——基于地球化学模型研究

2017年起,农业部连续多年出台化肥减量增效行动工作方案,要求适当增加有机肥投入,发展循环农业。但连续施用的有机肥进入土壤后,会对土壤pH、有机质和重金属含量等产生影响,改变土壤重金属行为。科学评估有机肥料施用的影响至关重要。仅通过总含量评估重金属污染风险被认为是片面的,不同化学提取剂提取的重金属含量不能完全代表实际污染状况。地球化学模型具有良好的适用性,比传统的提取方法能够更全面地解释重金属的行为。在集约化农业种植区黄淮海平原,多次施用不同比例的粪源有机肥于旱地菜田,并引入地球化学模型,结合pH依赖性浸出试验,明确连续施肥对菜田土壤重金属行为的主要影响机制。研究发现,有机肥中的铜锌含量远高于土壤中的含量,施用后,它们在土壤中的淋溶浓度随着施用比例增加而显著增加,最多可超过十倍以上,并且活性大大增加,与施肥后溶解性有机物含量的升高呈正相关。不同处理条件下的土壤重金属浸出趋势相似：在中性pH下浸出浓度最低,然后逐渐向强酸和强碱增加,呈现出V型变化。地球化学模型LeachXS展示出较好的模拟结果,其模拟值与实测浓度具有良好的相关性(71.02%)。模拟结果显示,有机肥的施用不会明显改变重金...     

土壤重金属生物毒性研究进展

世界范围内土壤重金属污染不断加重,由污染所带来的问题以及如何治理污染已经受到人们越来越多的关注.土壤重金属将对土壤生物产生影响,而土壤生物在重金属的胁迫下也会产生不同的响应.综述了国内外近年来土壤重金属生物毒性的研究进展,介绍了土壤重金属污染对陆地生态系统中植物、动物和微生物生长的影响;土壤重金属生物毒性的影响因素;土壤重金属生物毒性的研究方法;土壤重金属生物毒性的预测模型,最后提出了问题和展望.     

铜尾矿污染区土壤酶活性研究

对浙江省哩浦铜尾矿污染区土壤酶活性进行了研究,结果表明,尾矿区及其周边土壤环境受到不同程度的Cu、Zn、Pb、Cd污染,从尾矿库中心到外围重金属污染程度逐渐减轻,而土壤酶活性则不断提高,其中以脱氢酶和脲酶活性增加最明显,回归分析表明,单一脱氢酶、脲酶、酸性磷酸酶以及蛋白酶活性与重金属复合元素含量之间存在显著线性关系,主成分分析结果显示,尾矿区土壤酶信息系统的第一、二主成分方差贡献率之和达98．24％,以第一、二主成分建立了两个土壤总体酶活性指标,并用此指标对各供试样本进行空间分类,其结果与以重金属含量为依据的划分结果基本吻合,可见,采用酶活性构筑的土壤信息系统的总体酶活性来表征矿区土壤的重金属污染状况是可行的。     

工矿区不同类型生物结皮对大气降尘重金属的富集规律及其影响因子

大气降尘是矿区土壤重金属的主要来源,而生物结皮对大气降尘重金属有显著的富集作用。为探究不同类型生物结皮对大气降尘重金属的富集规律及其影响因子,选取宁东典型火电厂周边生物结皮广布区作为试验样地,3类生物结皮作为研究对象,并以临近裸土作为对照,对比分析了生物结皮富集大气降尘过程中土壤理化性质、酶活性及重金属含量的变化,采用相关分析、冗余分析和方差分解方法探讨了不同类型生物结皮的结皮层(A层)和层下土壤(B层)重金属含量与其土壤物理、化学性质及酶活性之间的关系。结果表明：燃煤烟尘是矿区大气降尘重金属污染的主要来源,涉及重金属元素包括Cd、Cr、Hg、Pb、Zn、As。生物结皮对源自大气降尘的重金属元素均具有显著的富集作用,且在不同演替阶段生物结皮间的富集规律完全一致：藓结皮>混生结皮>藻结皮;重金属综合污染指数评价结果显示：生物结皮对重金属具有表层富集效应,表现为A层污染程度高于B层。不同类型生物结皮A、B层综合污染指数存在显著差异,排序为：藓结皮>混生结皮>藻结皮;和对照相比,三类生物结皮均能通过富集大气降尘增加其A、B层养分和细颗粒物含量并改善土壤质地。方差分解结...     

重金属在土壤生态系统中的富集及毒性效应

对清水塘重金属污染区土壤生态系统重金属的富集及毒性效应的研究结果表明,土壤中 主要富集的重金属元素为生物毒性较强的Cd、Hg、As以及具有一定毒性的Zn、Pb、Cu,平均综 合污染指数为640.大型土壤动物重金属含量的分析结果表明,重金属富集量随污染程度的 增加而增加,尤其某些巨蚓科种类对Cd表现高富集,富集系数为1196.通过染毒试验进一 步证明,土壤动物种类和数量随Cd浓度的增加而减少.同工酶分析表明,Cd对蚯蚓同工酶活性 有明显的毒性效应.污染区主要种植蔬菜作物,而重金属在蔬菜体内的富集量也随污染 程度的增加而增加,其中蔬菜对Cd的富集有明显的品种间差异.     

Changes in antioxidant enzyme activity in the fine roots of black poplar (Populus nigra L.) and cottonwood (Populus deltoides Bartr. ex Marsch) in a heavy-metal-polluted environment

The effect of heavy metal deposition onto soil from a copper smelter on lipid peroxidation and antioxidant enzyme activity in the fine roots of two poplars (Populus nigra L. and Populus deltoides Bartr. ex Marsch) was analyzed. The subjects were mature trees growing in real environments. In both analyzed species, heavy metals stimulated the overproduction of free radicals in fine roots (measured as malondialdehyde level), which was directly proportional to advancing senescence. In young fine roots, heavy metals caused a decrease in guaiacol peroxidase activity and presumably disturbed the lignification process. Catalase was highly sensitive to the presence of heavy metals in the soil. In contrast, ascorbate peroxidase and glutathione reductase activities were unaffected by heavy metals. In the case of superoxide dismutase, a clear increase in enzyme activity was observed only in P. nigra under drought conditions, whereas it was inhibited in polluted stands.     

土壤重金属污染生态过程、效应及修复

本文探讨了重金属在土壤中的行为特性及其生态化学过程作用的特点,不同的重金属元素在土壤胶体颗粒表面的吸附特性及不同元素间的交互作用类型有所不同,自然对重金属迁移积累的影响有所不同。土壤重金属污染影响了种子萌发、幼苗生长、作物产量及体内重金属含量,探讨了污染土壤的酶学评价方法。阐述了重金属污染土壤生物修复的特点,展望了重金属污染生态过程研究的未来发展趋势。     

节节草生长对铜尾矿砂重金属形态转化和土壤酶活性的影响

通过盆栽模拟栽培试验,研究了节节草生长对铜尾矿砂重金属形态转化和土壤酶活性的影响。结果表明,节节草生长显著提高了尾矿砂中有机物结合态重金属比例(P0.01),降低了交换态和残渣态重金属比例(P0.05)。土壤过氧化氢酶、脲酶、多酚氧化酶和蔗糖酶活性均随着节节草的生长而不同程度的升高,其中过氧化氢酶和脲酶活性均与植物生长时间呈显著正相关(r过氧化氢酶=0.911,P0.05;r脲酶=0.957,P0.01),多酚氧化酶和蔗糖酶活性在植物生长旺盛期达到峰值,分别是对照组的2.40和2.02倍,随后迅速下降;而磷酸酶活性却显著下降(r磷酸酶=-0.923,P0.05)。土壤酶活性与节节草地下部分干重的相关性大于地上部分;且与土壤有机物结合态重金属的含量呈显著正相关,与交换态和残渣态重金属含量呈显著负相关。节节草生长不仅促进了铜尾矿砂重金属朝螯合态方面转化,有效降低重金属的生物有效性,同时还显著地改善了铜尾矿砂的基质环境和土壤肥力。因此,节节草在铜尾矿废弃地恢复实践中具有较大的应用潜力。     

Diversity of Arbuscular Mycorrhizal Fungus Populations in Heavy-Metal-Contaminated Soils

High concentrations of heavy metals have been shown to adversely affect the size, diversity, and activity of microbial populations in soil. The aim of this work was to determine how the diversity of arbuscular mycorrhizal (AM) fungi is affected by the addition of sewage-amended sludge containing heavy metals in a long-term experiment. Due to the reduced number of indigenous AM fungal (AMF) propagules in the experimental soils, several host plants with different life cycles were used to multiply indigenous fungi. Six AMF ecotypes were found in the experimental soils, showing consistent differences with regard to their tolerance to the presence of heavy metals. AMF ecotypes ranged from very sensitive to the presence of metals to relatively tolerant to high rates of heavy metals in soil. Total AMF spore numbers decreased with increasing amounts of heavy metals in the soil. However, species richness and diversity as measured by the Shannon-Wiener index increased in soils receiving intermediate rates of sludge contamination but decreased in soils receiving the highest rate of heavy-metal-contaminated sludge. Relative densities of most AMF species were also significantly influenced by soil treatments. Host plant species exerted a selective influence on AMF population size and diversity. We conclude based on the results of this study that size and diversity of AMF populations were modified in metal-polluted soils, even in those with metal concentrations that were below the upper limits accepted by the European Union for agricultural soils.     

Characterization of Heavy Metals in Soil by High Gradient Magnetic Separation

In recent years forecasting soil cleaning efficiencies of polluted soil, especially those contaminated with heavy metals, has become an important issue. Failure of the methods to predict the right efficiency has resulted in financial losses and penalties. This article describes an addition to the traditional characterization methods for soils contaminated by heavy metals, improving the quality of the basic decisions to be made. The method is based on magnetic separation using a Frantz Isodynamic Separator (FIS) for this study. The FIS isolates soil particles containing heavy metals so that these particles, which are relevant for soil cleaning, can be studied in more detail. Four contaminated soils were tested, for example, soils that were a problem for the soil-cleaning industry. The experiments indicate that each soil has its own magnetic properties that should be regarded as a fingerprint. Density measurements of two soils show that densities approach the quartz density separated at moderate and high magnetic fields suggesting that some of the heavy metals cannot be removed by density separation techniques. A pilot plant scale test supports this conclusion. It also shows that a part of the heavy metals are found in particles lighter than quartz. Based on the results, a qualitative model is proposed to account for the presence of the heavy metals in soil.     

公路源重金属对青藏高原高寒草甸土壤线虫群落的影响

为了解重金属对青藏高原高寒草甸土壤线虫群落的影响,在邦杰塘草原利用公路源重金属含量差异,采用高通量测序技术,分析重金属对高寒草甸土壤线虫群落多样性及群落组成的影响。结果表明：在重金属含量较低样本中,土壤线虫群落Shannon指数、Ace指数、Chao指数比重金属含量较高样本均要小,且整体上Shannon指数、Ace指数、Chao指数与重金属含量较高样本差异显著（P<0.05）。重金属含量升高改变了高寒草甸土壤线虫纲水平和目水平的群落结构,使近自然状况下的色矛纲（Chromadorea）、小杆目（Rhabdtida）优势土壤线虫群落转变为一类未分类线虫纲（unclassified_p_Nematoda）、一类未分类线虫目（unclassified_p_Nematoda）的优势土壤线虫群落。重金属Cu、Pb、Zn、Cd与线虫门（Nematoda）和刺嘴纲（Enoplea）正相关,但与色矛纲（Chromadorea）负相关,且对土壤线虫Chao指数的变异解释比例依次减小。研究表明土壤重金属含量对青藏高原高寒草甸土壤线虫群落多样性及组成产生很大影响,但仍需对高寒草甸区域进行系统的土壤线虫调查,并丰富土壤线虫生物信息数据库。     

土壤－植物系统中多环芳烃和重金属的行为研究

对土壤中多环芳烃和重金属的行为研究表明,与对照相比,０—２０ｃｍ以上表土层存在多环芳烃和重金属积累,２０ｃｍ以下土层未发现积累;与春、秋两次采样结果相比,土壤中多环芳烃的含量有所下降,表明土壤微生物对多环芳烃有一定降解作用,且其降解程度与土壤－植物系统的生态结构有关．菲在地下水中检出浓度较高,表明这一污染物有向下迁移的可能性．此外,柳树对土壤中重金属Ｃｄ的积累有明显的削减与净化作用．本研究表明,严格限制污水中多环芳烃和重金属的污染负荷以及设计合理的生态结构是避免多环芳烃和重金属在土壤中积累的关键．     

Effect of carbide sludge (lime) on bioavailability and leachability of heavy metals during rotary drum composting of water hyacinth

Abstract

The bioavailability and leachability of heavy metals play a major role in the toxicity of heavy metals in the compost applied for soil conditioning. A rotary drum composter was used for the study of heavy metal bioavailability and leachability during water hyacinth composting with a mixture of cattle manure, sawdust and lime. Lime was added in 1, 2 and 3% to the mixture of water hyacinth, cattle manure and sawdust at a ratio of 6:3:1 respectively. Influences of physico-chemical parameters on heavy metal bioavailability and leachability were studied during the process. The bioavailability of heavy metals solubility and diethylene triamine penta-acetic acid extractability was examined. The toxicity characteristics leaching procedure (TCLP) test was performed for assessing the hazardous properties of compost. The nutrients and the total concentration of heavy metals were increased during the composting process. The lime was very effective in reducing water solubility, plant availability and leachability of the selected heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd and Cr) during the process. The addition of lime provided a buffer against the decrease in pH and a sufficient amount of Ca that would improve the metabolic activity during composting. The addition of an excess amount of lime slowed the metabolic activity of the microbes due to its high alkalinity. The TCLP test confirms that the heavy metals concentrations in the control and in the lime-amended compost were below the threshold limits.     

生物质炭添加对红壤性水稻土重金属有效性及土壤质量的影响

通过田间定位试验探讨了不同生物质炭添加量对红壤性水稻土理化性质、重金属有效性和土壤质量的影响。生物质炭于2017年水稻种植前一次性添加于耕作层(0～17cm),分别设置5个不同处理:CK:0 t·hm^-2,A10:10 t·hm^-2,A20:20 t·hm^-2,A30:30t·hm^-2和A40:40 t·hm^-2,经种植两季水稻后于2018年9月采集耕作层(0～17 cm)和犁底层(17～29 cm)土壤,计算土壤质量指数(SQI),评价土壤质量。结果表明:在耕作层(0～17 cm)和犁底层(17～29 cm),随着生物质炭添加量的增加,土壤容重逐渐降低;土壤孔隙度、pH值、有机质和可溶性有机碳含量增加,铵态氮和有效磷分别在添加量为20和30 t·hm^-2时达到最大值;土壤中脲酶、过氧化氢酶和蔗糖酶的活性降低;生物质炭能够降低有效态Cd、As和Pb的含量,在生物质炭添加量为40 t·hm^-2时最低;在土壤耕作层(0～17cm),有效态...