森林生态系统汞的生物地球化学过程

森林系统占全球陆地总面积的31%,是全球生物地球化学循环最活跃的地区之一。认识森林系统汞的生物地球化学过程对确立大气-森林系统汞的相关归趋,及进一步定量分析全球汞的生物地球化学循环过程至关重要。然而,当前森林系统在全球大气汞的循环中的角色认识还不清楚,即无法确定森林系统是大气汞的汇还是源。本文基于森林系统汞的质量平衡、土壤汞的累积过程及汞的同位素地球化学的研究,阐述了当前关于汞在全球森林生态系统多介质间汞的相互耦合作用过程及其迁移转化规律的认识。在此基础上,针对当前森林系统汞的生物地球化学过程研究的关键科学问题,提出了未来该领域的研究重点和方向。     

我国水质监测行业前景可期外资企业加速国内市场布局

正水质监测是指对水环境中的悬浮物、化学物质、生态系统等进行检测、监视和测定。其细分领域包括水质监测设备和水质监测运营服务。在政策驱动和需求升级的双重加持下,我国水质监测产业迎来发展机遇期,行业前景值得期待众所周知,我国水质监测行业起步较晚,在步入21世纪之前,我国的水质监测分析设备基本是从国外进口,随着行业的不断发展,我国不断引进、吸收新的技术,国产设备逐渐     

利用改进的内梅罗指数法模型评价苏州市内外城河水质

采用改进的内梅罗指数法评价苏州市内外城河的水质污染状况。计算水质的分级标准临界值,以此作为评价水质污染状况的依据。研究结果表明,苏州市内外城河6个采样点的水质污染状况不同,各个点位的水质随时间变化显著(5月、9月、11月较好)。通过Pearson相关性分析可知,影响水质的主要因素是营养元素(氨氮、总氮和总磷)及重金属(6价铬)。对比改进前后的两种评价方法,改进的内梅罗指数法对水质污染状况的评价更为科学客观。     

贡嘎山东坡森林土壤有效微量元素分布特征

对青藏高原东缘贡嘎山东坡森林土壤有效微量元素的含量、分布及影响因子进行了研究。结果表明,四种典型土壤土层中有机质、水解氮、有效磷和速效钾的含量基本表现为由上而下逐渐降低的趋势;且在不同林型条件下,土壤养分含量分布也有差异;位于不同海拔高度的土层中,有机质等常量养分的分布表现出两头高、中间低的态势。土壤中B、Zn、Mn三种元素的含量均低于或远远低于各自的临界值;除Mn以外,有效态微量元素B、Cu、Zn、Fe含量均呈现出自上而下逐渐减少的趋势,即为表层富集型。     

纳米零价铁富集水溶液中铀的表面化学及应用展望

由于铀矿采冶、核能利用等类活动的影响, 铀引起的水体污染问题日益严重. 纳米零价铁(nanoscale zero-valent iron, nZVI)及其复合材料可高效富集水溶液中低浓度的铀, 在放射性废水的处理与铀的资源回收方面具有巨大的应用潜力. 但是, 不同研究对nZVI分离铀的机理和性能尚未形成一致的解释. 因此, 本综述归纳了nZVI分离铀的研究进展, 概括了溶液及固相反应机理(如吸附作用、还原作用、沉淀作用), 重点分析了水质因素(如pH、U(VI)浓度、阳离子、阴离子、溶解氧)的影响机制. 后续研究可注重分析铀废水中nZVI的结构转化规律及水质因素的协同作用对nZVI固定铀的机理、性能的影响; 并基于放射性废水的水质或水处理工艺的特征, 优化nZVI材料结构且评估其处理放射性废水的长期稳定性和生态毒性; 确定nZVI固定铀的性能与水质组分及水处理工艺运行参数的数学相关性, 建立监测和调控工艺的方法.     

体内和体外生物测定在环境监测中的应用

生物测定在环境毒物学研究中普遍用于检测人为污染物对个别生物体和生态系统的影响.这些测定适用于个别化学品或复杂的混合物(如废水)对有代表性的生物系统或整个生物体所引起的影响,并普遍应用于环境监测项目.生物测定可在生物体外或生物体内进行,前者是在实验室内利用细胞培养技术,后者除可在实验室内进行还可应用在真实的环境中.体外生物测定往往是用来研究环境样品中的污染物对生物机制的具体影响,如受体结合特性.而体内活性生物测定则提供了一个更加具体化的综合生物反应.然而,这两种类型的生物测定法可以测量许多不同的生物指标,如对生物生长及发育的影响、内分泌功能和DNA损伤.无论是在体内和体外生物测定都分别有其特有的优点和缺点,其中一些测定法可以使用于毒性鉴定和评价程序.本文简要介绍了体内和体外生物测定方法的基本特点及其在环境监测中的应用实例,指出化学物质如何影响有机体及生态系统的结构和功能,认为广泛发展更能充分反映生态系统生物多样性的生物测定方法,将有助于更准确地了解环境污染物对环境的潜在影响.     

垃圾场渗滤液中十二烷基硫酸钠的光度测定

三峡库区令人担忧的严重问题之一是城市生活垃圾填埋场渗滤液的迁移污染.渗滤液成分复杂,水质变化大,色度深、有恶臭.高浓度有机废水会污染地表水和地下水,破坏原有水体的用途,甚至危及原有的生态系统,若不妥善处理渗滤液,有害成分发生迁移转化,就会带来严重的二次污染,对库区环境构成严重危胁.     

天然河床渗滤取水滤膜研究

滤膜在渗滤取水水质净化中起重要作用,其生长特点关系到工程能否持久运行。通过实验测试及工程监测数据分析了滤膜的微观物质组成、演化特点,提出了滤膜对净化水质的贡献和对滤水能力的影响。     

四川省重点河段水环境安全性评价

为研究四川省重点河段水环境的安全性,利用综合评价指数法和模糊综合评价决策的数学模型对主要水系干流和支流河段的水质安全性做出了评价.结果显示,岷江流域的水质安全性较差,主要的污染物为重金属汞和铁,沱江和涪江流域的水质安全性较好.     

The Application of Water Feature Model for Water-bursting Source Judgment at the First Mining Face of Under-group Coal Seams

通过对淄博矿业集团公司岱庄煤矿影响下组煤开采的3个主要含水层以前所做的大量水质化学成分化验结果的资料整理,建立了该矿下组煤主要充水水源的水质特征模型。根据最近突水点水质特征指标与已建立的水质特征模型进行综合对比,准确及时地确定了突水水源。     

Tritium in a Pine Forest Ecosystem: Relation between Fresh Pine Needles, Organic Materials on a Forest Floor and Atmosphere

Tritium concentrations were analyzed in organic and water fractions of fresh pine needles, dead and degraded pine needles accumulating on a pine forest floor to examine tritium cycle in a forest ecosystem. Tritium concentration was higher in the organic fraction of dead and degraded pine needles compared to others, suggesting two tritium sources. Rain is responsible for water fractions in the samples, while atmospheric hydrogen and methane are speculated to be responsible for high tritium level in the organic fraction of dead and degraded pine needles.     

Implementation of the EU Water Framework Directive in monitoring of small water bodies in Hungary, I. Establishment of surveillance monitoring system for physical and chemical characteristics for small mountain watercourses

The EU Water Framework Directives (WFD) prescribes to achieve a good status of surface waters by 2015. To keep this deadline of a new three level (surveillance, operational and investigative) monitoring system is required, including hydro-morphological, biological and chemical elements. The status of a water body should be related to the reference conditions, depending on surface water types. In Hungary, the standard monitoring network for surface water quality has been operated for rivers and large lakes; however no satisfactory information is available for small water bodies. Therefore, there is an urgent need to design a methodology to develop a monitoring network for small watercourses. For this purpose a slightly impacted mountain stream (Nagy Stream in Mátra Mountains), was selected and intensively monitored during three years (May 2002 → May 2005). Hydrological, biological and chemical parameters required by WFD were monitored in this program. Variability of parameters vs. time and space was also investigated. The minimum frequency of sampling was determined for chosen physico-chemical components to meet the WFD standards for confidence. It was found that the minimum frequency of sampling suggested by WFD in space and time may not be adequate for precise and accurate characterization of water quality.     

Transfer of137Cs from soil to plants in a wet montane forest in subtropical Taiwan

The distribution of¹³⁷Cs in an undisturbed, multistoried, subtropical wet montane forest ecosystem surrounding Yuanyang Lake (lake surface level ca. 1670m, in northeastern Taiwan), was investigated. The mossy forest here represents a currently-rare perhumid temperate environment in subtropical region. The radioactivity concentration of¹³⁷Cs was determined by γ-spectroscopy with a Ge(Li) detector. Although the soil is extremely acidic (pH 3.3 to 3.6) and the rainfall is high,¹³⁷Cs is evidently retained in the organic layer. The radioactivity concentration of¹³⁷Cs in surface soil ranges from 28 to 71 Bq·kg⁻¹. The concentrations of¹³⁷Cs in the ground moss layer and litter were much lower than that in the soil organic layer, this suggests that¹³⁷Cs detected is not from the newly deposited radioactive fallout. The radioactivity concentration and transfer factor (TF) of¹³⁷Cs varied with plant species. Shrubs and ferns have higher values than a coniferous tree (Taiwan cedar). The TF in this ecosystem is as high as 0.21 to 1.88. The high values of TF is attributed to the abundance of the organic matter in the forest soils. The rapid recycling of¹³⁷Cs through the soil-plant system of this undisturbed multistoried ecosystem suggests the existence of an internal cycling that help the accumulation of¹³⁷Cs in this ecosystem.     

云南省龙陵地区温泉水化学特征及其成因分析

高黎贡山地区越岭隧道施工过程中可能遇到高热流体等地质灾害,为了在施工过程中对可能遇见的水体的来源和水质特性有一个总体的把握,利用比例系数法,结合同位素水化学资料,对云南省龙陵地区的温泉水的化学特性进行了分析。结果显示,龙陵地区的温泉水的矿化度较低;水-岩作用主要为溶滤、溶解作用和同离子效应;地下水循环和径流条件良好,温泉水补给来源为大气降水;温泉水为未变质水。     

Sulphonamide Residues in Italian Surface and Drinking Waters: A Small Scale Reconnaissance

The occurrence of antibiotics in the aquatic environment is an important emerging issue due to potential adverse effect of these compounds on ecosystem and human health. For a correct environmental risk assessment there is a need for appropriate analytical methods for monitoring antibiotic residues in a variety of water matrices. This paper describes a method for the determination of eleven sulphonamide compounds in surface and drinking waters using solid-phase extraction and liquid chromatography-tandem mass spectrometry. Recoveries of the analytes in both surface and drinking water matrices at different fortification levels, always exceed 87%; the limits of quantification in surface water samples are between 0.005 and 0.021 μg L⁻¹ depending on the compound, and the interday method precision is less than 12%. Matrix effects were evaluated in drinking and surface water samples. The method has been applied to a small scale reconnaissance of river, lake, mineral and municipal water samples; results indicate the occurrence of sulphonamides in some surface and mineral waters analyzed.     

Distribution and circulation of radionuclides originating from fallout in a forest

Water, plant and soil samples from forested area were analyzed in order to study the behavior of radionuclides in the forest ecosystem. The concentration of ¹³⁷Cs in the soil decreased with depth, while stable Cs and ⁴⁰K were almost constant. It is suggested that most of the ¹³⁷Cs once entered in the forest ecosystem is trapped in the upper part of the soil.     

Trichloroacetic acid in the foliage of forest trees

Trichloroacetic acid (TCA) is an atmospheric oxidation product of airborne C₂-chlorocarbons and a widespread air pollutant. It was widely used as a herbicide in the fifties and sixties, in some countries, still today. It occurs in the foliage of conifers and deciduous trees of mountain forests in Germany, e. g. the Black Forest, the Northern Alps or the Erzgebirge. Quantitative determination in the ppb-range is achieved by gas chromatography using thick film capillary columns and electron-capture detection. The levels in spruce needles at two forest sites correlate with the extent of needle loss. The data are supportive of the hypothesis that TCA is causally involved in the induction of mountain forest decline.     

Removal of226Ra(II) from uranium mining and processing effluents

The activity of¹³⁷Cs was determined in mosses and their surrounding soils in three Venezuelan cloud forests. The concentration of¹³⁷Cs in both the mosses and their respective soils were correlated with elevation (m.a.s.l.). This relationship was the result of the cloud forest effect, no direct deposition by condensation below the base of the clouds and increasing deposition of¹³⁷Cs with the density of the clouds. The ratio of the activity of¹³⁷Cs in the mosses to their surrounding soils was in general the same for sites near the top of the mountains, but the ratio at the Altos de pipe location was 3.5 times higher than that of the La Sierra mountain. This was explained by the difference in the water content of the surface and the top soil layer. It was concluded that the¹³⁷Cs measured in the mosses was from the soil effect rather than new deposition of¹³⁷Cs in the last three years.     

Potential of Climate Change and Herbivory to Affect the Release and Atmospheric Reactions of BVOCs from Boreal and Subarctic Forests

Compared to most other forest ecosystems, circumpolar boreal and subarctic forests have few tree species, and are prone to mass outbreaks of herbivorous insects. A short growing season with long days allows rapid plant growth, which will be stimulated by predicted warming of polar areas. Emissions of biogenic volatile organic compounds (BVOC) from soil and vegetation could be substantial on sunny and warm days and biotic stress may accelerate emission rates. In the atmosphere, BVOCs are involved in various gas-phase chemical reactions within and above forest canopies. Importantly, the oxidation of BVOCs leads to secondary organic aerosol (SOA) formation. SOA particles scatter and absorb solar radiation and grow to form cloud condensation nuclei (CCN) and participate in cloud formation. Through BVOC and moisture release and SOA formation and condensation processes, vegetation has the capacity to affect the abiotic environment at the ecosystem scale. Recent BVOC literature indicates that both temperature and herbivory have a major impact on BVOC emissions released by woody species. Boreal conifer forest is the largest terrestrial biome and could be one of the largest sources of biogenic mono- and sesquiterpene emissions due to the capacity of conifer trees to store terpene-rich resins in resin canals above and belowground. Elevated temperature promotes increased diffusion of BVOCs from resin stores. Moreover, insect damage can break resin canals in needles, bark, and xylem and cause distinctive bursts of BVOCs during outbreaks. In the subarctic, mountain birch forests have cyclic outbreaks of Geometrid moths. During outbreaks, trees are often completely defoliated leading to an absence of BVOC-emitting foliage. However, in the years following an outbreak there is extended shoot growth, a greater number of leaves, and greater density of glandular trichomes that store BVOCs. This can lead to a delayed chemical defense response resulting in the highest BVOC emission rates from subarctic forest in the 1–3 years after an insect outbreak. Climate change is expected to increase insect outbreaks at high latitudes due to warmer seasons and arrivals of invasive herbivore species. Increased BVOC emission will affect tropospheric ozone (O₃) formation and O₃ induced oxidation of BVOCs. Herbivore-induced BVOC emissions from deciduous and coniferous trees are also likely to increase the formation rate of SOA and further growth of the particles in the atmosphere. Field experiments measuring the BVOC emission rates, SOA formation rate and particle concentrations within and above the herbivore attacked forest stands are still urgently needed.