Long range trans-Pacific transport and deposition of Asian dust aerosols

The deposition of Asian dust aerosols during their trails-Pacific Uansport might cause significant marine phytoplankton biomass increases.However,the knowledge of the trans-Pacific dust transport,deposition,and spatial distribution is still poor due to a lack of continuous and simultaneous observations in the Asian subcontinent,the north Pacific Ocean,and North America.The severe Asian dust storm during 6 to 9 April 2001 provided an opportunity to gain a better understanding of trans-Pacific dust transport and deposition,using a comprehensive set of observations from satellites,ground-based light detection and ranging,aircraft,and surface observation networks.The observations and model simulations outline the general pattern of dust transport,deposition,vertical profile,and spatial distribution.The following points were observed(1)the surface dust concentrations decreased exponentially with the increasing dust transport distance from 80°E to 120°W along the transport pathway;(2)the altitude of the dust concentration peak increased with increasing transport distance in the north Pacific region;and (3) the spatial distribution of dust deposition mainly depended on the trans-Pacific transport route.     

低DO与化学控制相结合的半亚硝化运行

针对厌氧氨氧化工艺（ANAMMOX）的进水需求以及污水中氮素的存在形态,增强前置半亚硝化工艺的运行稳定性是十分有必要的。研究发现：在温度（30±1）℃、进水pH在8.0以上、DO在0.3 mg·L-1左右、HRT=8 h的情况下;逐步增加进水氨氮（NH4+-N）与碳酸氢盐浓度,经过19 d成功启动亚硝化反应（以亚硝硝酸盐积累率达到50%为限）;为了进一步提升亚硝酸盐积累率,间歇投加5 mmol·L-1氯酸钾,后又改加联氨作为硝化反应的选择性抑制剂,经过大约90 d的反复调试运行,使得出水中NH4+-N与亚硝态氮（NO2--N）的摩尔比近似1：1,基本符合厌氧氨氧化工艺进水需求。通过Miseq测序结果发现：氨氧化菌（AOB）在添加氯酸钾之后,已经成为绝对优势菌种,所占比例为54.99%;在添加联氨之后,AOB所占比例能够达到63.92%,其中包括Nitrosomonas sp和Nitrosomonas europaea这两种亚硝化菌;只有痕量亚硝酸盐氧化菌（NOB）的存在。     

Different effects of foliar application of silica sol on arsenic translocation in rice under low and high arsenite stress

Foliar application of Si can generally reduce As translocation from roots to shoots in rice; however, it does not always work, particularly under high As stress. Here, the effects of foliar application of nanoscale silica sol on As accumulation in rice were investigated under low (2 μmol/L) and high (8 μmol/L) arsenite stress. The results revealed that foliar Si application significantly decreased the As concentration in shoots under low arsenite stress, but showed different effects under high arsenite stress after 7 days of incubation. The reduction in root-to-shoot As translocation under the 2As+Si treatment was related to the down-regulation of OsLsi1 and OsLsi2 expression and up-regulation of OsABCC1 expression in roots. In the 8As+Si treatment, the expressions of OsLsi1, OsLsi2, and OsABCC1 were significantly promoted, which resulted in substantially higher As accumulation in both the roots and shoots. In the roots, As predominantly accumulated in the symplasts (90.6%–98.3%), in which the majority of As was sequestered in vacuoles (79.0%–94.0%) under both levels of arsenite stress. Compared with that of the 8As treatment, the 8As+Si treatment significantly increased the As concentration in cell walls, but showed no difference in the vacuolar As concentration, which remained constant at approximately 69.1–71.7 mg/kg during days 4–7. It appeared that the capacity of root cells to sequester As in the vacuoles had a threshold, and the excess As tended to accumulate in the cell walls and transfer to the shoots via apoplasts under high arsenite stress. This study provides a better understanding of the different effects of foliar Si application on As accumulation in rice from the view of arsenite-related gene expression and As subcellular distribution in roots.     

紫外消毒对城市污水处理厂耐药菌去除的影响研究

通过选取假单胞杆菌、鲍曼不动杆菌以及芽孢杆菌3种耐药菌作为研究对象,研究紫外光变化对这3种耐药菌的去除效果,得出较好的紫外消毒条件,应用到实际的污水处理厂消毒过程中。结果表明,紫外消毒对3种耐药菌都有很好的灭活效果。     

废旧阴极射线管(CRT)显示器玻壳中铅浸出特性研究

CRT显示器玻壳中含有大量的铅,废旧CRT显示器玻壳被列为危险废物。采用4种浸提方法(水平振荡法(GB5086.2-1997)、翻转法(GB5086.1-1997)、硫酸硝酸法(HJ/T299-2007)、醋酸缓冲溶液法(HJ/T300-2007))研究CRT显示器玻壳中铅的浸出特性。同时探讨浸提液pH和pH缓冲能力、振荡方式、CRT玻壳颗粒粒径、液固比、浸提时间对CRT玻壳颗粒中的Pb浸出的影响。结果表明:上述4种方法浸提液中Pb的平均浓度分别为0.07、0.69、1.64、11.33 mg/L。随着醋酸缓冲液初始pH值从4.0升高到7.0,其浸提的Pb的含量呈现出逐渐下降的趋势。而去离子水的pH值低于5时,其浸提的Pb的含量才明显升高。Visual MINTEQ模型计算结果表明:在去离子水和硫酸硝酸混合液浸提过程中,主要以酸碱反应为主;而在醋酸缓冲液浸提过程中,以酸碱反应和络合反应为主。前3种浸提方法使用的浸提液类似于天然水环境或降水,其浸提的Pb浓度高于地下水环境质量III标准。第4种浸提方法模拟垃圾填埋场环境,其浸提的Pb的浓度高于工业固废最高容许浸出浓度。因此,废旧CRT玻壳无论填埋处置或直接进入土...     

铁还原菌介导的氧化铁还原与硝酸盐还原的竞争效应研究

中性厌氧条件下,脱色希瓦氏菌Shewanella decolorationis(S12)能够使用多种电子受体进行厌氧呼吸,包括溶解态的硝酸盐以及难溶态的氧化铁基质。因此,本文通过构建"脱色希瓦氏菌/铁氧化物/硝态氮"的交互反应体系,研究这一体系中铁还原与硝态氮还原的相互作用过程,并对相互作用机制进行初步探讨。结果表明,交互反应体系中氧化铁还原与硝酸盐还原存在明显的竞争关系;随着氧化铁比表面积、可利用态铁含量的增大,硝酸受抑制作用逐渐增强;通过不同温度煅烧而得到的不同结晶度的赤铁矿对硝态氮的抑制作用也被研究。结果还表明,氧化铁结晶度越高,S12对硝态氮的还原抑制作用越小。循环伏安电化学测试结果发现,加入硝酸条件下,铁氧化峰几乎完全消失,表明硝态氮存在条件下,铁还原受到明显抑制。针对以上结果,初步探讨了铁还原与硝态氮还原竞争的原因,即:(1)Fe(Ⅲ)与NO3–同时作为电子受体,因竞争电子而受到抑制;(2)吸附态Fe(Ⅱ)物种还原NO3–,导致Fe(Ⅱ)累积减少,NO3–还原因产生的Fe(Ⅱ)的低速率而被抑制。     

三元复合驱采出水中悬浮固体的控制方法

采用向三元复合驱采出水中加入水质稳定剂的方法有效降低采出水中悬浮固体的质量浓度。实验结果表明,将100 g采出水依次经滤纸和孔径为0.45μm的醋酸纤维素膜过滤后,加入1.0 g WSBL-3型水质稳定剂,混合均匀后置于80℃的水浴中静置4 h,取出后再置于40℃的水浴中静置5 min,由此可将采出水中的悬浮固体质量浓度由107 mg/L降至2 mg/L。     

水深梯度对荆三棱(Scirpus yagara)生长的影响

研究湿地植物对水深梯度的响应对于湿地修复具有重要的指导意义.在南四湖湖边滩地上的人工修复湿地中开展水深梯度对荆三棱(Scirpus yagara)生长的影响研究,试验观测水深分别为-10、0、10、20、30 cm共5个梯度.结果显示:随着水位的升高,1)荆三棱的株高、基茎、叶长和叶宽均有所增加,当水位大于10 cm时各项指标增加更为显著;2)生物量呈增加趋势,而根茎比则逐渐减小,水位为30 cm时的生物量和根茎比分别为-10 cm时的2.67倍和58.15%;3)叶绿素含量总体呈增加趋势,但在不同水位间的差异不明显(P>0.05);4)叶绿素荧光方面,最大光化学量子产量Fv/Fm均在0.75以上,光化学淬灭qP和非光化学淬灭qN分别呈现出升高和下降的趋势.结果表明,在试验所设置的水位条件下(-10～30 cm),荆三棱的生长没有受到水深梯度增加的显著影响,相反表现出随着水深的增加而生长更好的趋势.可见,在试验设置的水深梯度范围内,相对较高的水位有利于荆三棱的生长,因此在湿地管理中应控制适当的高水位以利于其种群的生长和稳定.     

蚯蚓和堆肥固定化添加模式对漆酶降解土壤五氯酚的影响

利用土壤五氯酚（PCP）污染模拟实验,研究两种不同生态型蚯蚓（赤子爱胜蚓Eisenia foetida和壮尾环毛蚓Amynthas robustus E.Perrie）和堆肥固定化添加模式对漆酶降解土壤PCP的影响。在42 d培养期内,测试了不同处理下PCP质量分数、漆酶活性,以及土壤呼吸和微生物碳氮等微生物指标。结果表明：堆肥固定化漆酶降解土壤PCP的效果优于壳聚糖固定化漆酶和自由漆酶,主要原因是堆肥固定化漆酶能够有效地提高漆酶稳定性,减缓其活性下降速度。此外,堆肥还能提高土壤微生物的数量与活性,显著提升土壤漆酶的活性。添加两种生态型蚯蚓对漆酶活性影响不显著,但均可以显著提高土壤微生物的数量与活性,加速土壤中PCP的降解。壮尾环毛蚓对土壤微生物数量与活性的提升效果优于赤子爱胜蚓。     

我国环境规划的回顾与展望

本文回顾了我国环境规划的发展历程,指出在我国环境规划是一门新兴的学科分支.20年来经过了孕育时期和探索时期,“七五”期间得到较快的发展进入了发展时期。环境规划成为我国环境科学和环境管理工作中的重要组成部分,在我国环境科学工作中发挥了先导作用。文章用大量实例总结了环境规划方法的进展,说明了随着环境规划的迅速发展,我国环境规划方法论也逐步得到完善和丰富,初步形成了一个完整的体系。文章最后展望了我国环境规划的发展趋势,分析了环境规划未来发展的新特点。