水中全氟化合物电化学去除技术研究进展

全氟化合物(perfluorinated compounds,PFCs)是一类人工合成的难降解有机污染物.PFCs长期大量使用导致其在水环境中普遍存在,并且已在人体中检出.传统的生物处理技术对PFCs几乎没有去除效果,研究高效去除水体中PFCs的实用化技术成为了环境领域的研究热点.本文综述了电化学氧化、电絮凝和电吸附等电化学技术在PFCs废水处理中的研究进展,详细阐述了不同电化学处理技术对PFCs的去除效率、影响因素以及去除机理,并对今后水体中PFCs电化学去除技术研究提出了展望.     

植物修复重金属与多环芳烃污染土壤强化措施研究进展

重金属和多环芳烃是土壤环境中的重要污染物,其复合污染土壤的修复已成为环境科学研究的热点问题。植物修复技术是目前修复土壤复合污染重要方法之一,但植物本身修复能力有限,需借助化学、微生物、基因工程等手段对其修复效果进行强化。本文对国内外近几年来植物修复重金属-多环芳烃复合污染强化措施研究成果进行综述,并重点讨论了植物根际生长促进菌及菌根在强化修复中的应用,在此基础上对未来该领域需要深入研究的科学问题进行了阐述。     

河流水沙条件对水质评价的影响

世界上许多河流具有高泥沙含量特征,我国河流的高泥沙含量特征尤为显著.河流水沙条件包括悬浮泥沙的含量、粒径和组成以及溶解性有机质的含量和组成等参数.河流中的许多污染物倾向于与泥沙和有机质结合,泥沙和有机质的存在不仅影响了污染物的迁移转化过程,同时还影响了污染物的生态环境风险.本文归纳总结了河流水沙条件特征及其对耗氧性有机污染物和有毒有机污染物迁移转化的影响,详细阐述了河流水沙条件对耗氧性有机物和有毒有机物污染评价的影响,指出由于化学氧化剂能氧化泥沙中在自然条件下耗氧过程极为缓慢的天然有机质,现有的化学需氧量可能高估水体耗氧性有机物的污染;又由于与泥沙结合的有毒有机污染物部分具有生物有效性,现有的基于有毒有机污染物溶解态浓度的水质评价方法可能低估水体有毒有机物的污染.并提出怎样考虑水沙条件影响对现有水质评价方法进行改进的思路,为完善水质评价方法提供参考,对于“碳中和”目标的实现也具有重要的意义.     

苯并(a)芘的环境污染、健康危害及研究热点问题

本文主要介绍了多环芳烃类中致癌性最强的化合物之一－苯并（a)芘对人体健康的危害，污染来源和程度，环境质量和污染排放标准，以及目前的科研热点问题。     

生物膜滴滤床降解低浓度有机废气的理论模型

将生物膜滴滤塔内的多孔填料简化为由多个管内覆盖有生物膜的竖直毛细管并行排列构成的填料, 建立了一个净化低浓度有机废气的毛细管模型. 运用两相流理论获得了毛细管内液膜厚度分布, 然后考虑气液界面、液膜和生物膜内的传质阻力以及氧对微生物生化反应的限制, 并结合生化反应动力学理论, 建立了气相、液相的传质方程以及生物膜内的传质与生化反应动力学方程. 对离散后的方程进行了迭代求解. 模型的理论预测值与净化低浓度甲苯废气的实验值基本吻合. 计算结果表明: 在一定的进口污染物浓度条件下, 滴滤塔的净化效率随气体流量和液体流量的增加而下降. 降解有机废气的速率主要受液膜传质阻力控制, 越接近滴滤塔废气, 进口的污染物降解率越高.     

污染胁迫下的蛋白质组学研究

近年来,以双向电泳技术、生物质谱和生物信息学为核心的蛋白质组学技术飞速发展,其大规模高通量的特点,使得这项技术逐渐在环境科学领域,尤其是对污染胁迫下差异蛋白表达和污染物特异性的生物标志物的筛选研究中得到了广泛的应用。本文简要介绍了蛋白质组学的基本概念和技术方法,对蛋白质组学在微生物、植物和动物对于无机污染物和有机污染物胁迫的响应机制和分子生物标志物探究等方面的研究进展进行了概述,并对蛋白质组学技术今后在生态环境领域的需求、应用与发展进行了展望。     

生物炭对土壤中农药的吸附-解吸行为和生物有效性的影响综述

生物炭是生物质在缺氧条件下热解产生的一种多孔富炭物质,由于其巨大的比表面积和表面理化性质,生物炭对水土环境介质中的有机污染物有较强的吸附能力。本文说明了生物炭的施用对土壤中农药吸附-解吸行为以及生物有效性的影响;由于自身疏松多孔、比表面积和表面能较大等性质,以及高度芳香化结构使其能够强烈的吸附土壤中残留的农药污染物;并且使解吸滞后现象增强,减少农药的解吸量。另外,生物炭的施用减弱了土壤中农药的生物有效性及药效。同时,总结了目前在生物炭对在农药迁移机理的影响与其在农药污染控制中的应用研究中存在的不足之处,提出需要解决的主要科学问题。最后,对生物炭在农药污染控制中的应用前景进行了展望。     

持久性有机污染物研究的国际发展动态

持久性有机污染物(POPs)是指对于生物代谢、光解、化学分解等具有很强的抵抗能力的天然或人工合成的有机污染物。本文全面介绍了从有机化学品开始广泛应用到POPs成为研究热点和国际行动的焦点这一历史过程，其中详细介绍了联合国环境署18／92号决议通过后展开的国际行动。并列举了当今POPs研究的热点问题和发达国家在该领域的研究计划。     

一种能同时吸附水中多种污染物的新型吸附材料:表面活性剂改性沸石

表面活性剂改性沸石是指将粉煤灰合成沸石后,使用十六烷基三甲基溴化铵进行表面修饰获得的一种新型吸附材料.本文评估了表面活性剂改性沸石从水中同时去除多类污染物的多功能性.目标污染物包括无机离子型污染物(氨氮和磷酸盐)、有机离子型污染物(亚甲基蓝和腐植酸)、可离子化有机污染物(不同pKa的双酚A,-氯酚和苯酚)和不可离子化的有机污染物(不同疏水性的苯胺,硝基苯,萘).与合成沸石相似,表面活性剂改性沸石吸附氨氮和磷的能力也较强.沸石内部孔隙中的负电荷可以去除氨氮;粉煤灰中的CaO,Al2O3和Fe2O3等成分经过沸石合成过程中的修饰可以吸附磷.研究结果还表明:尽管合成沸石对腐植酸,可离子化和不可离子化的有机污染物没有亲和性,表面活性剂改性沸石却对上述污染物具有很强的吸附能力.表面活性剂在沸石表面形成了双层胶束,使沸石外表面具有了疏水性,因此,可以吸附有机污染物.本研究表明表面活性剂改性沸石是一种很有前途的多功能水处理吸附剂.     

基于专利分析的甲醇生物利用及转化技术趋势研究

以Thomson Innovation数据库和国家知识产权局的中国专利数据库收录的甲醇生物利用及转化相关专利文献作为研究对象,探讨了该技术领域专利申请的整体态势、重点技术分布、地域分布、主要申请人和在华专利申请,全面揭示了甲醇生物利用及转化技术创新现状和发展趋势。研究发现:以1999年为界,甲醇生物利用及转化技术全球专利活动分为两个阶段;日本是全球最大的技术输出国;日、美、欧是最受重视的市场保护地;methan*或methy*类菌株及其基因改造手段是一直以来的研发热点;甲醇生物利用及转化技术专利申请人集中度较高;在华技术分布与全球基本一致。     

Bioaccumulation processes in ecosystems

The fate of environmental pollutants — the various isotopes of elements, and inorganic or organic compounds — is a fundamental aspect of ecology and ecotoxicology, and bioaccumulation is a phenomenon often discussed in this context. Human activities have drastically altered natural concentrations of many substances in the environment and added numerous new chemicals. An understanding of the processes of bioaccumulation is important for several reasons. 1) Bioaccumulation in organisms may enhance the persistence of industrial chemicals in the ecosystem as a whole, since they can be fixed in the tissues of organisms. 2) Stored chemicals are not exposed to direct physical, chemical, or biochemical degradation. 3) Stored chemicals can directly affect an individual's health. 4) Predators of those organisms that have bioaccumulated harmful substances may be endangered by food chain effects. While former theories on the processes of bioaccumulation focused on single aspects that affect the extent of accumulation (such as the trophic level within the food chain or the lipophilicity of the chemical), modern theories are based on compartmental kinetics and the integration of various environmental interactions. Concepts include results from quantitative structure-activity relationships (QSAR), pharmacokinetics, ecophysiology and general biology, molecular genetic aspects and selection, and finally the structure of communities and man-made alterations in them.     

Pistia stratiotes L. in Nigerian waters

Summary Pistia stratiotes L., a perennial water weed found in natural water bodies in Nigeria, removes organic and inorganic nutrients as it grows and spreads in the waters. In a lake which received a variety of pollutants, the plant reduced oxidizable organic matter (4-h permanganate value) by 61%, the biochemical oxygen demand by 85.3%, ammonia nitrogen by 95.3% and water soluble phosphorus by 85%. The plant also removed other mineral matter.     

Use of aggregating cell cultures for toxicological studies

Summary Relatively simple techniques are now available which allow the preparation of large quantities of highly reproducible aggregate cultures from fetal rat brain or liver cells, and to grow them in a chemically defined medium. Since these cultures exhibit extensive histotypic cellular reorganization and maturation, they offer unique possibilities for developmental studies. Therefore, the purpose of the present study was to investigate the usefulness of these cultures in developmental toxicology. Aggregating brain cell cultures were exposed at different developmental stages to model drugs (i.e., antimitotic, neurotoxic, and teratogenic agents) and assayed for their responsiveness by measuring a set of biochemical parameters (i.e., total protein and DNA content, cell type-specific enzyme activities) which permit a monitoring of cellular growth and maturation. It was found that each test compound elicited a distinct, dose-dependent response pattern, which may ultimately serve to screen and classify toxic drugs by using mechanistic criteria. In addition, it could be shown that aggregating liver cell cultures are capable of toxic drug activation, and that they can be used in co-culture with brain cell aggregates, providing a potential model for complementary toxicological and metabolic studies.     

Use of aggregating cell cultures for toxicological studies

Relatively simple techniques are now available which allow the preparation of large quantities of highly reproducible aggregate cultures from fetal rat brain or liver cells, and to grow them in a chemically defined medium. Since these cultures exhibit extensive histotypic cellular reorganization and maturation, they offer unique possibilities for developmental studies. Therefore, the purpose of the present study was to investigate the usefulness of these cultures in developmental toxicology. Aggregating brain cell cultures were exposed at different developmental stages to model drugs (i.e., antimitotic, neurotoxic, and teratogenic agents) and assayed for their responsiveness by measuring a set of biochemical parameters (i.e., total protein and DNA content, cell type-specific enzyme activities) which permit a monitoring of cellular growth and maturation. It was found that each test compound elicited a distinct, dose-dependent response pattern, which may ultimately serve to screen and classify toxic drugs by using mechanistic criteria. In addition, it could be shown that aggregating liver cell cultures are capable of toxic drug activation, and that they can be used in co-culture with brain cell aggregates, providing a potential model for complementary toxicological and metabolic studies.     

Effects of atmospheric pollution on human health

Most air pollutants do not lead to specific diseases. Depending on the pollutant, the concentration and the duration of exposure, some organs are more affected than others. The most frequent disorders are those caused by irritant gases and particulates on the mucous membranes and respiratory organs. The consequences are eye, nose and throat inflammations, diminished lung function, increased susceptability to respiratory infection and a higher incidence of chronic bronchitis. These disorders and diseases are, of course, influenced by other factors as well, such as immune deficiency, allergies, occupational exposure to pollutants, and particularly smoking. The effects of air pollutants are, therefore, multifactorially conditioned and nonspecific disorders are placed in the foreground. Evidence for an association of air pollution with adverse effects on human health is drawn from three sources: animal experiments, experimental human exposures, and epidemiologic studies of exposed human populations. The burden of atmospheric pollution must be reduced to protect human health by an adequate safety margin. In particular, the increased sensitivity of sick and aged people as well as children should be taken into account. In defining the maximum emmission levels, preventive aspects should have priority so as to keep the risk of damage to health and the harmful influences on the environment to a minimum.This article Effects of atmospheric pollution on human health by H. U. Wanner is a revised version of the same article that was first published in the Proceedings of the 1990 European Aerosol Conference; special issue of the J. Aerosol Sci., Vol. 21, Suppl. 1 (1990) 389–396.Reprinted with kind permission from Pergamon Press Ltd, Headington Hill Hall, Oxford OX3 0BW, Great Britain.     

Microbial potential in deep-sea sediments

Summary In spite of high pressures and low temperatures in abyssal sediments of the North Atlantic Ocean, bacterial activity is evident and highest in the top 10 cm. At these locations the input of degradable organic material to the deep-sea bottom is low. Oxygen, therefore, remains the dominant oxidant in surface sediments. Although alternative electron acceptors like nitrate, oxidized manganese and sulfate are present in large amounts, they are not utilized in this natural habitat. In sediment cores which were collected from the site for laboratory perturbation studies, it was possible to stimulate microbially mediated processes which are dormant in situ. When the oxygen supply was cut off, nitrate and manganese reduction occurred. Denitrification was the major process observed in the upper anoxic layers, while nitrate-ammonification and manganese reduction occurred in deeper sediment strata (4–8 cm). This is evidence for the presence of a variety of different bacteria and of an anaerobic heterotrophic potential. Most of the activity is located in the top 10 cm of these sediments. The shift to anaerobiosis initiates microbial activities through which metals are converted into their mobile species at the lowered redox potential. Evaluation of the suitability of the deep sea as a repository for waste materials will have to account for the large dormant potential of microbial activities and the consequences of their release by changing the environmental conditions at the sea floor.     

Transformations and dynamic linear models

The dynamic linear model (DLM) with additive Gaussian errors provides a useful statistical tool that is easily implemented because of the simplicity of updating a normal model that has a natural conjugate prior. If the model is not linear or if it does not have additive Gaussian errors, then numerical methods are usually required to update the distributions of the unknown parameters. If the dimension of the parameter space is small, numerical methods are feasible. However, as the number of unknown parameters increases, the numerial methods rapidly grow in complexity and cost. This article addresses the situation where a state dependent transformation of the observations follows the DLM, but a priori the appropriate transformation is not known. The Box-Cox family, which is indexed by a single parameter, illustrates the methodology. A prior distribution is constructed over a grid of points for the transformation parameter. For each value of the grid the relevant parameter esitmates and forecasts are obtained for the transformed series. These quantities are then integrated by the current distribution of the transformation parameter. When a new observation becomes available, parallel Kalman filters are used to update the distributions of the unknown parameters and to compute the likelihood of the transformation parameter at each grid point. The distribution of the transformation parameter is then updated.     

The dental amalgam issue. A review

Summary Using an interdisciplinary approach, the current position in the dental amalgam controversy and the potential impact of amalgam mercury on human health are reviewed. Aspects of materials science, corrosion, mercury exposure, toxicology, neurology and immunology are included.New data on mercury exposure from corroded amalgam fillings in vivo are presented. The exposure can reach levels considerably over known threshold limit values. Also, measurements of mercury absorption from intraoral air are presented. The vital importance of avoiding a galvanic amalgam-gold coupling is emphasized. The symptomatology of a disabled patient, who recovered after amalgam removal, has been included.It is concluded that discussion of the dental amalgam issue has suffered from the lack of an interdisciplinary approach. It would be wise to learn from the lesson of acrodynia, and consider amalgam mercury among other possible factors in neurological and immunological diseases of unclear etiology.