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1.
The greatest sources of atmospheric emissions of SO2 in Estonia are caused by power plants (TP) which use oil shale. Since 1990 the amount of SO 2 discharges has continuously decreased due to fall in production of electric energy, and it was from TP as follows: in 1990–1991 about 180–200 thousand tons, in 1992 about 140 and in 1993–1994 about 100 thousand tons. In 1990 the annual mean emission intensity of SO 2 from all North-East (NE) Estonian pollution sources was fixed to be about 6.kg/s, with a maximum of 9.5–11 kg/s in winter period. In 1992–1993 the corresponding values were 3.5–4.6 and 5.1–6.8 kg/s. The single maximum concentrations (MC, per 30 min.) of SO 2 in the overground air layer would be in the ranges 25–450 μg/m 3 depending on emission intensity and wind parameters. The annual mean concentrations are below 25 μg/m 3 on the main territory, but may be up to 50–75 μg/m 3 near the power plants. In Kohtla-Järve town the annual mean values of 15.8–19.1 μg/m 3 and MC values of 271–442 μg/m 3 were fixed during 1991–1994 by automatic air monitoring system. Many arable lands, forest areas and wild-life preserves are subjected to relatively high sulphur precipitation loads, exceeding 0.5 g S/m2 per year, of which the role of emissions from local sources is about 60–95%. On the basis of air pollution concentration maps, the landscape of NE Estonia is classified into zones of high, moderate and low pollution level. 相似文献
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为了解覆盖栽培与施用石灰氮对早竹林土壤重金属污染的潜在生态风险以及对早竹笋重金属健康风险的影响,选择浙江省德清县3个主要早竹笋产区作为试验点,采用电感耦合等离子体质谱(ICP-MS)法检测了3种不同处理(不覆盖、覆盖和覆盖后施用石灰氮)下早竹林土壤和笋中的Cr、As、Hg、Ni、Cd和Pb等6种重金属的含量。结果表明,各试验点土壤中重金属含量排序均为Cr>Pb>Ni>As>Cd>Hg,覆盖栽培使土壤酸化,重金属富集,而覆盖栽培后施用石灰氮则可改善重金属的富集水平;覆盖栽培后笋中Cr、As、Hg、Ni、Cd、Pb 6种重金属含量最大值分别为0.23、0.06、0.006、0.65、0.04、0.10 mg·kg-1, 均未超出标准森林食品质量安全通则(LY/T 1777-2008)和食品安全国家标准食品中污染物限量(GB 2762-2012)中的限值。覆盖栽培后施用石灰氮能够降低笋中重金属的积累,同时明显降低土壤重金属综合潜在生态危害指数,通过食用笋摄入6种重金属的健康危害指数(HI)均低于美国环保署(US EPA)推荐的最大可接受水平1.0,无明显健康风险。研究表明,施用石灰氮有助于缓解覆盖栽培所引起的重金属污染现象。本研究为石灰氮在林业生产上的应用提供了科学依据。 相似文献
3.
A long-term modelling (1991–1994) of oxidised sulphur, bound nitrogen and some heavy metals has been carried out by MSC-E/EMEP for the Northern Hemisphere. The transport unit of the model is an Eulerian scheme which could be classified as Pseudo-Lagrangian one. Vertical distribution described by means of Gaussian approximation and the exchange with the free troposphere are taken into account. Vertical movement is calculated proceeding from local mixing conditions, state of the surface, its height (topography) etc. The chemical unit for acid compounds contains 25 reactions and 14 compounds including sulphur and nitrogen compounds peroxyacetylnitrate, tropospheric ozone, volatile hydrocarbons (but methane) are considered as a whole via ozone creation potential. The model time step is 1 hour, meteorological data (winds, temperature, precipitation etc.) cover 6-hour intervals. The model results show that very significant part of the Arctic and West Asian acid pollution is produced by European countries. On the whole the Arctic pollution by SOx, NOx and NHx comes from sources of Old World. The main source of sulphur pollution is located in Russia and of nitrogen compound — in Central and Northern Europe. About 50% SOx, 70% NOx and 40% NHx deposition in Central Asia and Kazakhstan is-imported from external sources. A similar situation is observed in European and Asian parts of Russia. 相似文献
4.
From six ombrotrophic mires located far from distinct local sources in Sweden and Norway, a core was sampled in bog hummocks in 1988 and dated by 210Pb. Ten slices from each core were analyzed for Cd, Cu, Pb, and Zn. Based on the datings, the accumulation rates of Cd, Cu, Pb, and Zn have been estimated for the last 150 years. A reasonable agreement exists in the comparison between the recent deposition in the peat bog and nearby bulk deposition measurements. Highest deposition has been measured in southern Norway and the western part of Sweden. Generally, deposition has increased during the last 150 years, except at a station on the east coast of Sweden. In a study in Sweden where heavy metals have been measured in mosses every five years time since 1970, significant decreases in the concentrations of heavy metals have been found. Similar decreases have not been measured in the present study, although both methods are expected to reflect atmospheric deposition. Several studies have indicated that peat bogs are not suitable for measuring the historical evolution of trace metals. However, despite the disagreement, the recent literature suggests that it can be done with reasonable accuracy when performed with samples from hummocks in the peat bog. 相似文献
5.
Bulk precipitation and throughfall analyses in 50–100-year-old Scots pine stands revealed decreasing sulphur, nitrogen, calcium and magnesium deposition gradients, which extend from the St. Petersburg-Leningrad region and N.-E. Estonia to S.-E. Finland. The Ca and Mg deposition alleviate the acidifying effect of sulphur and nitrogen. The Scots pine canopies acted as a sink for ammonium and nitrate, while the canopy interactions increased sulphur, calcium and magnesium content in throughfall. Foliar S, N and Ca concentrations correlated positively with the corresponding deposition loads. In contrast, low foliar magnesium concentrations were detected in the vicinity of St. Petersburg. The results indicate that the sulphur and calcium deposition may have increased soil leachate S and Ca concentrations in the most polluted Scots pine stands. 相似文献
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模拟降水和氮沉降对准噶尔盆地南缘梭梭光合生理的影响 总被引：1，自引：1，他引：0
氮沉降和降水格局变化是目前全球气候变化背景备受关注的热点研究课题,也是荒漠生态系统的两个主要限制因子。因此,研究两者对荒漠植物的效应有助于深入了解荒漠生态系统对全球变化的响应。本文选择准噶尔盆地南缘荒漠地区的建群种梭梭(Haloxylon ammodendron)作为研究对象,设置自然降水(W0)与增加降水30%(W1)两个水分条件和自然氮沉降(N0)、增加氮素30 kg(N)·hm~(-2)·a~(-1)(N1)与增加氮素60kg(N)·hm~(-2)·a~(-1)(N2)3个施氮水平,连续处理2年,以探究降水、氮沉降及其交互作用对梭梭光合日变化及生理生态特征的影响。结果表明:降水、氮沉降及其交互作用对梭梭的净光合速率(Pn)日变化产生极显著正相关影响;同时根据梭梭Pn、胞间CO2浓度(Ci)及气孔限制值(Ls)的变化方向,推测梭梭光合"午休"主要由非气孔因素引起。此外,W0条件下,梭梭丙二醛(MDA)含量、抗氧化酶(POD、CAT、SOD)活性、可溶性蛋白(Pr)和可溶性糖(SS)含量均随施氮量增加而显著降低,脯氨酸(Pro)含量则呈先降低后增加的趋势;而W1条件下,梭梭MDA含量、抗氧化酶(POD、CAT、SOD)活性及渗透调节物质(Pro、Pr、SS)含量均随施氮量增加呈显著先增加后降低的趋势。两种水分条件下,除W1N1处理梭梭的Pro含量高于对照组外,其余处理均显著低于对照组;同时梭梭的MDA含量、抗氧化酶活性、Pr及SS含量也均显著低于对照组。综合分析结果表明:降水、增氮及其交互作用均有利于梭梭的生长,但其交互作用效应的强弱则取决于二者间的比例。 相似文献
8.
N. K. Vestergaard U. Stephansen L. Rasmussen K. Pilegaard 《Water, air, and soil pollution》1986,27(3-4):363-377
A survey of heavy metal deposition was carried out in the vicinity of a Danish steel plant. Bulk precipitation and transplanted lichen (Hypogymnia physodes (L.) Nyl.) were sampled at 12 stations in the environment before and after the production had been converted from open-hearth furnaces to electric-arc furnaces. The samples were analyzed for Cd, Cr, Cu, Fe, Mn, Pb and Zn. The results show that heavy metal pollution from the steelworks still is severe and that it follows a decreasing power curve when the distance to the steelworks is increased. However, a reduction in the deposition of heavy metals close to the steelworks has been observed, pointing to the conclusion that the change from a situation of emission through a 46 m stack without any filter to emission from the electric arc furnaces equipped with bag-filters has lead to changes in the emission. At the sampling stations with the highest deposition levels measured in bulk precipitation the corresponding concentrations in the lichens were relatively lower indicating a change in particle size distribution. Within each station there was a direct proportionality of metal concentrations in lichens and atmospheric fallout measured in bulk precipitation. 相似文献
9.
Short- and long-term effects of heavy metals on phosphatase activity in soils: An ecological dose-response model approach 总被引：7，自引：0，他引：7
Summary The aim of this study was to provide manageable data to help establish permissible limits for the pollution of soil by heavy metals. Therefore the short-and long-term effects of heavy metal pollution on phosphatase activity was studied in five different soil types. The results are presented graphically as logistic dose-response curves. It was possible to construct a curve for sand and silty loam soil but it was more difficult to establish a curve for sandy loam and clay soil and nearly impossible (except for Cu) for peat. The toxicity of the various metals can be compared on the basis of mmol values. In clay soils, for Cd, Cr, Cu, and Zn, the 50% effective ecological dose (ED50) values were comparable (approximately 45 mmol kg–1), but the ED10 values were very different, at 7.4, 41.4, 15.1, and 0.55, respectively. At the ED50 value, toxicity did not decrease with time and, in sandy soils, was approximately 2.6 mmol kg –1 dry soil for Cd, Cu, and Zn. In four out of five soils, the Cd toxicity was higher 1.5 years after the addition of heavy metal salts than after 6 weeks. Toxicity was least in the sandy loam, silty loam, and clay soil, and varied in general between 12 and 88 mmol kg–1. In setting limits, the criteria selected (no-effect level, ED10 or ED50) determine the concentration and also the toxicity of the sequence. It is suggested that the data presented here could be very useful in helping to set permissible limits for heavy metal soil pollution. 相似文献
10.
H.-S. Helmisaari J. Derome H. Fritze T. Nieminen K. Palmgren M. Salemaa I. Vanha-Majamaa 《Water, air, and soil pollution》1995,85(3):1727-1732
Distribution and fluxes of copper within Pinus sylvestris stands were studied during 1992–1994 along a heavy-metal pollution gradient in south-western Finland. The stands are situated at distances of 0.5, 4 and 8 km from a copper-nickel smelter that started operating in 1945 at Harjavalta. According to the results, copper concentrations in the soil, in the understorey vegetation and in the trees increased steeply towards the smelter. Almost 50 years' accumulation of heavy metals in the soil has caused direct toxic effects to soil microbes, thus decreasing decomposition and nutrient mineralisation. During the past few years, sulphur and heavy metal emissions from the copper and nickel smelter have been radically decreased. However, the heavy metals which have been accumulating in the soil for decades continue to affect the vegetation for a long time through soil processes. Consequently, long-term accumulation in the soil has to be taken into account when determining the critical loads of forest ecosystems for heavy metals. 相似文献
11.
This study investigated the effect of anions on the uptake of heavy metals and aluminum by Brassica rapa L. from non-contaminated, Cd-contaminated, and sewage sludge compost (SSC)-amended sandy soil. Four types of artificial precipitation were applied: deionized water (pH 5.7) as a control, and solutions of HNO3, H2SO4, and HCl prepared to pH 4.5. Precipitation was applied daily during the last 20 d of cultivation. The pH of the Cd-treated soil after harvest was not affected by any precipitation treatment. Shoot concentrations of heavy metals and Al were unaffected by any treatments on non-contaminated soil. In contrast, all acid treatments increased the Cd concentration in shoots grown on Cd-contaminated soil, but only HNO3 precipitation increased it in SSC-amended soil. These results indicate, even without large soil pH change, there is a possibility that the Cd uptake by B. rapa L. depends on anions in precipitation and chemical form of Cd in the soil under conditions of heavy metal enrichment. 相似文献
12.
Changes in organic carbon and nitrogen in soil with metal pollution by Cd,Cu, Pb and Zn: a meta‐analysis 
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下载免费PDF全文 T. Zhou L. Li X. Zhang J. Zheng J. Zheng S. Joseph G. Pan 《European Journal of Soil Science》2016,67(2):237-246
Organic carbon (OC) and nitrogen (N) storage in soil plays an important role in global climate change and in maintaining food security. Pollution of soil with heavy metals has occurred in many parts of the world, but their effects on soil OC and N have not been well addressed. Relevant data were extracted from peer‐reviewed journal papers and analysed by a meta‐analysis to determine how long‐term heavy metal pollution affected soil OC and N status. Plant biomass decreased significantly because heavy metals in soil decreased soil OC and N concentrations by 5.0 and 17.9%, respectively, but increased the C/N ratio by 5.1%. The largest reductions in soil OC and N concentrations were in soil more strongly polluted by metals. The changes in soil OC and N with metal pollution varied with climatic conditions. More substantial decreases in OC and N concentrations were likely to occur in polluted soil with large background contents of OC and low pH. Overall, heavy metals were linked to greater reductions in soil OC and N concentrations in natural ecosystems than in agro‐ecosystems. These results provided a quantitative evaluation of the effects of heavy metal pollution on the decrease in soil C and N concentrations and, therefore, on global climate change. Further consideration should be given to changes in the cycling of C and N in soil polluted with metals in natural and agro‐ecosystems. 相似文献
13.
重金属污染农田安全利用:进展与展望 总被引：3，自引：1，他引：2
我国耕地土壤污染面积广,污染情况复杂,农产品重金属超标问题已经关系到国计民生。常用的物理化学修复方法成本高,不适用于大面积的中低污染农田。植物提取修复方法成本低,环境友好,但修复时间长,推广困难。总的来讲,基于重金属移除的诸技术在解决农田重金属污染方面还没有太大优势。相较而言,农田安全利用在不移除或缓慢移除土壤重金属的条件下,以生产安全农产品为目标,具有更加坚实的现实意义和推广价值。种植低吸收农作物是安全利用的重要措施,基因工程手段在低吸收农作物品种筛选中具有巨大的潜力,但其可能带来的生态环境风险使得这些通过基因工程得到的低吸收作物的田间种植面临着巨大挑战。土壤添加剂可以改变土壤重金属形态,降低重金属的生物有效性,但会对土壤质量产生影响。微生物尤其是土著微生物的利用越发受到关注,改变微生物的生存环境与基因工程手段能够强化微生物的钝化效果。施肥、水分管理、间作等农艺措施也能改变土壤重金属的形态,抑制作物对重金属的吸收。未来以加强推广为目的,多种技术手段的联合应用是重金属污染农田安全利用的重要发展方向,其中以生物技术为核心的利用模式具有十分重要的意义。 相似文献
14.
The 23-year-long dynamics of actual acidity (pHwater) and acid-soluble heavy metals (Cu, Pb, Cd, Zn) in the forest litter and humus horizon of soils in spruce-fir forests were studied in the area subjected to the long-term (since 1940) pollution with atmospheric emissions from the Middle Ural Copper Smelter (Revda, Sverdlovsk oblast). For this purpose, 25 permanent sample plots were established on lower slopes at different distances from the enterprise (30, 7, 4, 2, and 1 km; 5 plots at each distance) in 1989. The emissions from the smelter have decreased since the early 1990s. In 2012, the emissions of sulfur dioxide and dust decreased by 100 and 40 times, respectively, as compared with the emissions in 1980. Samples of litter and humus horizons were collected on permanent plots in 1989, 1999, and 2012. The results indicate that the pH of the litter and humus horizons restored to the background level 10 and 23 years after the beginning of the reduction in emissions, respectively. However, these characteristics in the impact zone still somewhat differ from those in the background area. In 2012, the content of Cu in the litter decreased compared to 1989 on all the plots; the content of Cu in the humus horizon decreased only in the close vicinity of the smelter. The contents of other metals in the litter and humus horizons remain constant or increased (probably because of the pH-dependent decrease in migration capacity). The absence of pronounced removal of metals from soils results in the retention of high contamination risk and the conservation of the suppressed state of biota within the impact zone. 相似文献
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Heavy Metal Pollution in Air-Water-Soil-Plant System of Zhuzhou City,Hunan Province,China 总被引：2，自引：0，他引：2
The sources, distribution and mobility of heavy metals in Zhuzhou City, Hunan Province, China were systematically studied based on environmental monitoring data and random sampling from fields and markets. The significant positive correlations between some pairs of heavy metals (total Cd–Hg, total Cu–Pb) within the Zhuzhou section of the Xiang River may indicate that they are coming from the same pollution sources with similar pollution channels and removal patterns in the water bodies. Heavy metals from wastewater partly settled in the sediment after entering the Xiang River, which caused an inconsistent change in heavy metal concentrations over time in the middle and lower parts of the Xiang River. There was no significant difference in total Pb and Zn in topsoil between years in the period 1990–1997, which showed the balance between input and output. Heavy metals accumulated mainly in the topsoil with little downward movement. Heavy metals in the vegetables and rice were higher than the edible standard and background value to some degree with minor exceptions. The maximum heavy metal level observed divided by the acceptable level was in the order of Cd > Pb > Cu > Zn. Significant positive correlations were only found between cabbage uptake and total soil content for Hg, Pb and Cd, with no significant correlationfor the other elements. The plant uptake of a heavy metal was somewhat influenced by the co-existence of other elements. 相似文献
17.
对巢湖湖区不同位点的表层沉积物中的Fe、Cr、Pb、Cu、Co、Zn、Ni7种重金属含量进行的分析表明,湖泊沉积物中重金属含量分布呈现一定的区域特征,由于巢湖西半湖靠近合肥市区,大量的工业废水和生活污水通过河道排入巢湖,引起西半湖区中重金属含量高于东半湖区。采用富集因子法和地积累指数法对巢湖沉积物重金属污染现状进行了评价,结果表明,巢湖沉积物中存在Pb、Cu污染,个别地区已相当严重,并呈现沿湖心区至东半湖区逐渐降低趋势。研究表明,两种方法均能对人为污染行为做出较为科学的评价,且两种方法得到的评价结果基本一致。由于重金属元素有很强的毒性,并且能够在食物链中传递,有关部门应及早从流域环境综合规划入手,对重金属污染问题采取有力的控制对策,保护沿湖地区居民免受危害。此外,对巢湖表层沉积物中重金属污染物来源进行了初步分析,据分析结果判断,巢湖沉积物中重金属总量Co、Fe、Cr的来源相似,Zn和Cu的来源相似。 相似文献
18.
The influence of mesoscale weather patterns on the chemical composition of daily precipitation samples is analysed. The data of pH, sulphur from sulphates and total nitrogen are analysed for two rural sites: Plitvice station in forested part of Central Croatia (1981 to 1990) and Puntijarka suburban station on the mountain near Zagreb, the capital of Croatia (1982–1991). The two prevailing weather types in precipitation days are selected and the comparison of chemical composition of precipitation is made for each of them. The frequency distributions of pH, sulphur and nitrogen show that concentration of major ions in precipitation apparently depends on the regional scale weather type. It is shown that the seasonal variation of deposition is related to the seasonal variation in precipitation amount. In both weather types Plitvice receives more pollution than Puntijarka that is closer to urban and industrial pollution sources. Both locations are under the prevailing influence of regional pollution sources. 相似文献
19.
通过查阅文献数据库,统计发表的我国各地污灌污水中的重金属含量,并对数据进行统计分析,总结近30a来我国污灌污水中重金属的含量特征及年代变化规律。文献数据统计结果表明,近30a来我国污灌污水中重金属Pb、Cr、Zn、Ni的含量均值或中位值随年代逐步降低,Hg、As平均含量呈先上升后下降的趋势,Cu、Cd平均含量则是呈现先下降后上升的趋势;近30a来污灌污水中8种重金属浓度的平均值或中位值均低于农田灌溉水质标准（GB5084—2005）,但污灌污水中重金属浓度的90%分位值均超过该农田灌溉水质标准,污灌污水中重金属浓度75%分位值20世纪80年代Hg、Pb、Cd超标,90年代Hg、Cr、As超标,近10aCd、As超标。对污灌污水中Hg、Cd、As在污染源头控制中需要优先控制。 相似文献
20.
扬中地区农田土壤重金属污染调查与评价 总被引：7，自引：1，他引：6
对扬中地区主要农田土壤进行了采样监测,按照国家无公害农产品产地的环境质量标准,采用单项污染指数法和尼梅罗综合指数法对土壤的8个重金属污染指标进行了环境质量评价。结果表明,扬中农田土壤均受到重金属轻污染,其中Cd、Hg污染主要与化肥、农药等大量施用有关;As、Pb、Cu、Zn污染可能与工厂废气及汽车尾气排放有关;而Cr、Ni污染主要与长江石灰性冲积母质特征有关。结合1990年的土壤数据,计算了重金属的累积速率,反映近年来重金属的不断输入。污染区的农产品生态效应研究表明,重金属污染已经威胁到农产品安全。 相似文献