含氟有机化合物的生态迁移及转化

含氟有机化合物的众多特性使得其在各方面得到越来越广泛的应用,同时也成为了一种较普遍的环境污染物。本文列举了含氟有机化合物的应用类型及相应的应用特点;指明其污染途径和毒性特征;从含氟有机物的分子结构特征、降解茵的类型、外部因素三方面阐明了其生物降解特性;总结了酶作用于碳氟键使得含氟有机物发生降解的四种作用;并介绍了含氟有机污染物的生物处理和生态修复的一般方法。     

应用植物重金属超富集机理修复土壤复合污染的研究现状与展望

超积累植物在修复土壤重金属污染中起着重要的作用,但由于重金属复合污染的存在,许多植物并未能完全适用于实际修复中。本文通过阐述土壤重金属复合污染,参考近年来国际上对超积累植物富集机理的研究,从土壤重金属复合污染自身的交互作用,超积累植物根系活化机理,吸收和运输通道机制,金属配位体的运输与解毒作用,以及细胞分室化现象等各个阶段探讨与展望土壤重金属复合污染修复研究问题。     

Ammonia in the environment: from ancient times to the present

Recent research on atmospheric ammonia has made good progress in quantifying sources/sinks and environmental impacts. This paper reviews the achievements and places them in their historical context. It considers the role of ammonia in the development of agricultural science and air chemistry, showing how these arose out of foundations in 18th century chemistry and medieval alchemy, and then identifies the original environmental sources from which the ancients obtained ammonia. Ammonia is revealed as a compound of key human interest through the centuries, with a central role played by sal ammoniac in alchemy and the emergence of modern science. The review highlights how recent environmental research has emphasized volatilization sources of ammonia. Conversely, the historical records emphasize the role of high-temperature sources, including dung burning, coal burning, naturally burning coal seams and volcanoes. Present estimates of ammonia emissions from these sources are based on few measurements, which should be a future priority.     

Sequential sorption of lead and cadmium in three tropical soils

It is important to examine mechanisms of Pb and Cd sorption in soils to understand their bioavailability. The ability of three tropical soils to retain Pb, Cd, and Ca was evaluated. The objectives of this study were to (1) determine the extent to which soil sorption sites are metal specific, (2) investigate the nature of reactions between metals and soil surfaces, and (3) identify how metals compete for sorption sites when they are introduced to soils sequentially or concurrently. Lead was shown to be much less exchangeable than Cd and inhibited Cd sorption. Cadmium had little effect on Pb sorption, though both Ca and Cd inhibited the adsorption of Pb at exchange sites. Lead appears to more readily undergo inner-sphere surface complexation with soil surface functional groups than either Cd or Ca. Thus, regardless of when Pb is introduced to a soil, it should be less labile than Cd.     

自来水厂污泥的流动电流特性

以水厂混合污泥为对象,采用流动电流为特征参数分析加药量和pH对污泥沉降性能和脱水性能的影响,探讨流动电流技术在污泥处理中的适用性.结果表明,在污泥沉降性能方面,等电点处的投药量和pH值分别为8.9mg/L和7.25,实际最佳投药量和最佳pH为9.0mg/L和6.90.在污泥脱水方面,等电点处的投药量和pH值分别为25.0mg/L和9.25,实际最佳投药量和最佳pH为26.0mg/L和9.0.表明污泥调节的最佳投药量和最佳pH均处于流动电流值稍正的位置,可以用流动电流值作为单因子来控制污泥处理中的加药量,实现污泥加药的连续反馈控制.     

Social foraging in stingless bees: how colonies of Melipona fasciata choose among nectar sources

In an experimental set-up, a colony of the stingless bee Melipona fasciata demonstrated its ability to choose the better of two nectar sources. This colony pattern was a result of the following individual behavioural decisions: continue foraging, abandon the feeder, restart foraging and initiate foraging. Only very rarely did individuals switch from one feeder to the other. With the first combination of a rich (2.7 M) and a poor (0.8 M) feeder M. fasciata behaved differently from Apis mellifera. Recruitment occurred to both feeders and the poor feeder was not abandoned completely. When the poor feeder was set to 0.4 M, M. fasciata abandoned the poor feeder rapidly and allocated more foragers to the rich feeder. These patterns were similar to those reported for A. mellifera with the first combination of feeders. Over a sequence of 4 days, experienced bees increasingly determined the colony patterns, and the major function of communication between workers became the reactivation of experienced foragers. The foragers modulated their behaviour not only according to the profitability of the feeder, but also according to previous experience with profitability switches. Thus, experience and communication together regulated colony foraging behaviour. These findings and the results of studies with honeybees suggest that M. fasciata and honeybees use similar decision-making mechanisms and only partly different tools. Received: 21 December 1998 / Accepted: 5 January 1999     

ENVIRONMENTAL AUDITING: Exceedance of Critical Loads for Lakes in Finland,Norway, and Sweden: Reduction Requirements for Acidifying Nitrogen and Sulfur Deposition

/ The main objectives of this study were to identify the regions inFennoscandia where the critical loads of sulfur (S) and acidifying nitrogen(N) for lakes are exceeded and to investigate the consequences for depositionreductions, with special emphasis on the possible trade-offs between S and Ndeposition in order to achieve nonexceedance. In the steady-state model forcalculating critical loads and their exceedances, all relevant processesacting assinks for N and S are considered. The critical loads of N and S areinterrelated (defining the so-called critical load function), and therefore asingle critical load for one pollutant cannot be defined without makingassumptions about the other. Comparing the present N and S deposition withthe critical load function for each lake allows determination of thepercentage of lakes in the different regions of Fennoscandia where: (1) Sreductions alone can achieve nonexceedance, (2) N reductions alone aresufficient, and (3) both N and S reductions are required but to a certaindegree interchangeable. Secondly, deposition reduction requirements wereassessed by fixing the N deposition to the present level, in this wayanalyzing the reductions required for S, and by computing the percentage oflakes exceeded in Finland, Norway and Sweden for every possible percentdeposition reduction in S and N, in this way showing the (relative)effectiveness of reducing S and/or N deposition. The results showed clearregional patterns in the S and N reduction requirements. In practically thewhole of Finland and the northern parts of Scandinavia man-made acidificationof surface waters could be avoided by reducing S deposition alone. In thesouthern parts of Sweden some reductions in N deposition are clearly neededin addition to those for S. In southern Norway strong reductions are requiredfor both N and S deposition.KEY WORDS: Acidification; Critical load; Exceedance; Sulfur; Nitrogen;Deposition; Lake     

有机磷阻燃剂甲状腺干扰效应及其作用机制研究——以磷酸三(2-氯丙基)酯(TCPP)为例

以典型有机磷阻燃剂磷酸三（2-氯丙基）酯（TCPP）为研究对象,应用GH3细胞增殖实验检测TCPP对甲状腺激素的干扰效应;应用重组甲状腺激素受体（TR）基因酵母实验和GH3（TRβ-）细胞增殖实验结合实时定量PCR技术初步探究TCPP甲状腺激素干扰作用机理.结果表明,TCPP在1×10^-4mol/L和2×10^-4mol/L浓度下对甲状腺激素T3诱导的GH3细胞增殖产生抑制效应;重组TR基因酵母实验和GH3（TRβ-）细胞增殖实验测试结果表明TCPP可能通过TR介导的基因组途径和非基因组途径诱导甲状腺激素干扰效应;实时定量PCR测试结果表明TCPP下调相关基因如：c-fos、TRβ、integrin-av和k-ras的mRNA表达,初步认为TCPP可能通过影响TRβ基因表达和激活α_vβ₃-ERK-1/2信号通路产生甲状腺激素干扰效应.     

EDDS强化Fe0-Al0体系降解废水中4-氯酚的性能和机理

采用乙二胺二琥珀酸（EDDS）强化Fe⁰-Al⁰体系还原水溶液中的O₂产生H₂O₂和·OH等活性氧（ROS）的绿色高级氧化工艺,以4-氯酚（4-CP）模拟废水为研究对象,考察了溶液的初始pH值、铁铝的质量比、EDDS投加量和4-CP的初始浓度等因素对4-CP降解的影响.采用电子自旋共振（ESR）法、苯甲酸捕捉法以及4-CP的降解产物等证实了ROS的产生及4-CP的降解机制.结果表明：EDDS强化Fe⁰-Al⁰/O₂体系对4-CP的去除率随溶液初始pH的升高而降低,但在pH=2.5～9范围内,始终具有较好的4-CP去除率;随Fe⁰：Al⁰质量比增加4-CP的去除率先增大后减小,最佳质量比为4：1;随EDDS投加量和4-CP初始浓度增加,4-CP的去除率增大;EDDS可使体系的高级氧化能力提高9倍,在初始pH=2.5、Fe⁰=8g/L、Al⁰=2g/L、EDDS=1.5mmol/L条件下,反应3h后100mg/L 4-CP的去除率和脱氯率均达到近100%..     

微生物絮凝剂及其在污水处理中的应用

综述了微生物絮凝的种类，性质，产生条件。讨论了影响微生物絮凝剂絮凝活性的主要因素和絮凝机理的多样性；列举了徽生物絮凝剂在水处理中的应用；最后，展望了微生物絮凝剂的研究发展方向。