试谈环境区划中的地质地貌因素

近几十年来,由于工业和科学技术的迅猛发展,环境和环境保护问题日益引起了人们的关注。环境的严重污染和破坏使各国的环境工作者在相当长的一段时间中,把主要的精力放在“三废”的治理上,而对原生环境的保护、规划和改造重视不够,因而疲于治理,事倍功半。为了制定环境保护规划,指导工农业生产的合理布局和城市建设,为了从根本上改善和保护环境,预防环境污染,环境区划的工作就越来越显得迫切和重     

关于土壤环境背景值的研究现状

土壤是重要的环境要素,是人类赖以生存的最基本资源,是农业生产环境的构成基础。我国已开始进行专门的土壤环境污染调查和质量初步评价工作。要正确判断土壤是否污染,给污染广度、范围、程度及其对生态系统的影响予以正确而适当的评价,都必须以可靠的土壤环境背景值为基础。土壤环境背景值是环境(尤是土壤环境)质量评价、环境区划与规划(特别是农业区划与规划)以及利用和改造环境的一个很重要的基础因子,也是以后对比环境污染历史演变趋势之重要资料。目前,国际上,如美、英、日、加拿大、澳大利亚等较重     

Estimating species richness and accumulation by modeling species occurrence and detectability

A statistical model is developed for estimating species richness and accumulation by formulating these community-level attributes as functions of model-based estimators of species occurrence while accounting for imperfect detection of individual species. The model requires a sampling protocol wherein repeated observations are made at a collection of sample locations selected to be representative of the community. This temporal replication provides the data needed to resolve the ambiguity between species absence and nondetection when species are unobserved at sample locations. Estimates of species richness and accumulation are computed for two communities, an avian community and a butterfly community. Our model-based estimates suggest that detection failures in many bird species were attributed to low rates of occurrence, as opposed to simply low rates of detection. We estimate that the avian community contains a substantial number of uncommon species and that species richness greatly exceeds the number of species actually observed in the sample. In fact, predictions of species accumulation suggest that even doubling the number of sample locations would not have revealed all of the species in the community. In contrast, our analysis of the butterfly community suggests that many species are relatively common and that the estimated richness of species in the community is nearly equal to the number of species actually detected in the sample. Our predictions of species accumulation suggest that the number of sample locations actually used in the butterfly survey could have been cut in half and the asymptotic richness of species still would have been attained. Our approach of developing occurrence-based summaries of communities while allowing for imperfect detection of species is broadly applicable and should prove useful in the design and analysis of surveys of biodiversity.     

Modeling the long-term transport and accumulation of radionuclides in the landscape for derivation of dose conversion factors

To evaluate the radiological impact of potential releases to the biosphere from a geological repository for spent nuclear fuel, it is necessary to assess the long-term dynamics of the distribution of radionuclides in the environment. In this paper, we propose an approach for making prognoses of the distribution and fluxes of radionuclides released from the geosphere, in discharges of contaminated groundwater, to an evolving landscape. The biosphere changes during the temperate part (spanning approximately 20,000 years) of an interglacial period are handled by building biosphere models for the projected succession of situations. Radionuclide transport in the landscape is modeled dynamically with a series of interconnected radioecological models of those ecosystem types (sea, lake, running water, mire, agricultural land and forest) that occur at present, and are projected to occur in the future, in a candidate area for a geological repository in Sweden. The transformation between ecosystems is modeled as discrete events occurring every thousand years by substituting one model by another. Examples of predictions of the radionuclide distribution in the landscape are presented for several scenarios with discharge locations varying in time and space. The article also outlines an approach for estimating the exposure of man resulting from all possible reasonable uses of a potentially contaminated landscape, which was used for derivation of Landscape Dose Factors.     

The use of a sequential leaching procedure for assessing the heavy metal leachability in lime waste from the lime kiln at a caustizicing process of a pulp mill

A five-stage sequential leaching procedure was used to fractionate 13 heavy metals (Cd, Cu, Pb, Cr, Zn, Fe, Mn, Al, Ni, Co, As, V, Ba) and sulphur (S) in lime waste from the lime kiln at the causticizing plant of Stora Enso Oyj Veitsiluoto Pulp Mills at Kemi, Northern Finland, into the following fractions: (1) water-soluble fraction (H₂O), (2) exchangeable fraction (CH₃COOH), (3) easily reduced fraction (HONH₃Cl), (4) oxidizable fraction (H₂O₂ + CH₃COONH₄), and (5) residual fraction (HF + HNO₃ + HCl). Although metals were leachable in all fractions, the highest concentrations for most of the metals were observed in the residual fraction (stage 5). It was also notable that the total heavy metal concentrations in lime waste did not exceed the maximal allowable heavy metal concentrations for soil conditioner agents set by the ministry of the Agricultural and Forestry in Finland. The heavy metals concentrations in lime waste were also lower than the maximal allowable heavy metals concentrations of the European Union Directive 86/278/EEC on the protection of environment, and in particular of the soil, when sewage sludge is used in agriculture. The Ca concentration (420 g kg⁻¹; d.w.) was about 262 times higher than the typical value of 1.6 g kg⁻¹ (d.w.) in arable land in Central Finland. However, the concentration Mg (0.2 g kg⁻¹; d.w.) in lime waste was equal to the Mg concentration in arable land in the Central Finland. The lime waste has strongly alkaline pH (12.8) and a neutralizing value (i.e. liming effect) of 47.9% expressed as Ca equivalents (d.w.). This indicates lime waste to be a potential soil conditioner and improvement as well as a pH buffer.     

Perfluorinated chemicals in relation to other persistent organic pollutants in human blood

In order to evaluate blood levels of some perfluorinated chemicals (PFCs) and compare them to current levels of classical persistent organic pollutants (POPs) whole blood samples from Sweden were analyzed with respect to 12 PFCs, 37 polychlorinated biphenyls (PCBs), p,p'-dichlorodiphenyl-dichloroethylene (DDE), hexachlorobenzene (HCB), six chlordanes and three polybrominated diphenyl ethers (PBDEs). The median concentration, on whole blood basis, of the sum of PFCs was 20-50 times higher compared to the sum of PCBs and p,p'-DDE, 300-450 times higher than HCB, sum of chlordanes and sum of PBDEs. Estimations of the total body amount of PFCs and lipophilic POPs point at similar body burdens. While levels of for example PCBs and PBDEs are normalized to the lipid content of blood, there is no such general procedure for PFCs in blood. The distributions of a number of perfluorinated compounds between whole blood and plasma were therefore studied. Plasma concentrations were higher than whole blood concentrations for four perfluoroalkylated acids with plasma/whole blood ratios between 1.1 and 1.4, whereas the ratio for perflurooctanesulfonamide (PFOSA) was considerably lower (0.2). This suggests that the comparison of levels of PFCs determined in plasma with levels determined in whole blood should be made with caution. We also conclude that Swedish residents are exposed to a large number of PFCs to the same extent as in USA, Japan, Colombia and the few other countries from which data is available today.     

Urban Geochemistry: A Multimedia and Multielement Survey of a Small Town in Northern Europe

The concentrations and distributions of chemical elements (Ag, Al, As, Au, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Se, Sr, Te, Th, Ti, Tl, U, V, W and Zn) were studied in till, humus and urban soil in Jakobstad, a small town (20,000 inhabitants) in W. Finland. The analyses were performed with ICP-MS after aqua regia leaching of till (n = 37), urban topsoil (n = 32) and subsoil (n = 32), and HNO3 leaching of humus (n = 37). The till and humus samples, collected at the same sites, were divided into urban and rural samples. The urban till was not significantly enriched in metals. In contrast, a majority of the elements occurred in higher concentrations in the urban than the rural humus samples. Statistical and spatial interpretations of the humus data revealed that traffic (Pb, V and Ni), metal industry (Pb, Zn, Bi, Sb and Cr), an abandoned shooting range (Pb and Sb) and other sources contribute to higher metal levels in the urban humus. The urban soil samples were collected at parks, yards, abandoned industrial sites, roadsides, etc. The topsoil samples were enriched in most elements, also by elements not enriched in the urban humus (e.g. Cd). At several sites, the concentrations far exceeded the limit concentrations for contaminated soils in Finland. A large variety of sources were identified or indicated.     

美国环境保护局宣布对汞污染的5年研究计划

由于汞及其化合物是生物积累性毒物,汞污染一直是国际环境保护界关注的重要污染物.2000年12月底美国环境保护局(EPA)研究和开发办公室宣布一项为期5年的研究计划,目的是更好地了解汞对环境和人群健康的影响.该项研究将由EPA的科学家领导,并得到EPA资助的局外研究人员的支持.EPA表示,研究计划细节将在今后几个月内出台.该研究项目将补充过去几年EPA和国家科学院关于汞的研究报告的不足,因为现在对汞污染的关注日益增加,特别是汞对儿童的影响.该研究项目将考察汞的人群健康影响、其在环境中的输送和归宿、燃烧源和非燃烧源的危险性管理、生态影响和危险性信息交流等问题.据EPA文件透露,该研究项目将着重研究儿童健康和汞的关系.详细信息可查阅因特网:http://www.epagov/ord/nrmarl/mercury/. 江刚摘自《Chemical & Engineering News》, January 8,18(2001)     

有害农药侵袭原始生态系统

一些发展中国家仍在使用一些有害的、禁用的农药,如DDT等.世界上一些原始生态系统将受到损害.尽管大多数国家已禁用DDT,其大气沉降仍然在损害世界边远地区.例如,非洲和印度较高的气温使DDT蒸发并以降水形式落到了奥地利阿尔卑斯山区,这一过程称作“全球性蒸馏”.这是一项新的国际调查透露的.阿尔卑斯山区周围环境像一块磁铁那样吸引这些有毒污染物.因斯布鲁克大学教授Roland Psenner最近说:“DDT从较暖地区开始循环并在较冷地区降落.我们知道在极地区域有DDT踪影,但不知道它们在比利牛斯山脉和阿尔卑斯山也常见.”Psenner说,虽然DD…     

电子束辐照烟气脱硫脱硝机理研究现状

电子束辐照烟气脱硫脱硝技术是一种新兴的烟气净化技术。本文对该技术涉及的机理研究做了较全面的介绍 ,并对影响SO2 和NOx 脱除效率的主要因素进行了分析