EVAPOTRANSPIRATION FROM A BULRUSH‐DOMINATED WETLAND IN THE KLAMATH BASIN,OREGON1

ABSTRACT: Growing‐season evapotranspiration and surface energy and water balances were investigated for an extensive, bulrush‐dominated wetland in the Upper Klamath National Wildlife Refuge of south‐central Oregon, a semi‐arid region with competing demands for scarce water resources. Turbulent fluxes of sensible and latent heat were measured by eddy covariance for 1.2 to 1.9 days during each of four site visits during late‐May to mid‐October 1997. Mean daytime latent heat flux and the Bowen ratio ranged from 148 to 178 W m^?2 and from 0.38 to 0.51, respectively, during late May, mid‐July, and late August site visits. By mid‐October, when the plant canopy had senesced, daytime latent heat flux and the Bowen ratio averaged 46 W m^?2 and 2.8, respectively. An hourly Penman‐Monteith (PM) model that was fitted to the surface‐flux data provided values for the surface resistance to water‐vapor diffusion that ranged from 78 s m^?1 during late August to 206 s m^?1 during mid‐October. Similarly, a Priestley‐Taylor (PT) model provided values for the PT multiplier (a) that ranged from 0.96 during late August to 0.37 during mid‐October. The PM and PT models predicted evapotranspiration totals of 560 and 480 mm, respectively, for May 28 to October 12, 1997.     

华北稳定塘氧平衡的研究

溶解氧(DO)是氧化塘内有机物降解的主要动力,本文介绍了华北稳定塘中的妤氧塘和强化塘进行污水妤氧处理所需氧的来源主要是浮游藻类光合放氧。在春季和秋季藻类产的氧可占水体溶解氧总来源的80％左右,氧的消耗是以“水呼吸”耗氧为主,“泥呼吸”耗氧为次。从氧平衡的角度阐述了各塘有机物降解与藻类产氧、生物耗氧的关系。      

湖泊 POPS污染的来源与质量平衡

对湖泊POPS污染来源的调查与研究是了解湖泊POPS污染的最初,也是最重要的一项工作,对于制定相应措施消除污染源,控制湖泊POPS污染,具有重要的现实意义。而在此基础上开展的对污染物进出湖泊途径的质量平衡估算与研究,对于从动态上把握湖泊POPS污染的现状,乃至进一步讨论POPS在湖泊的分布、对湖泊生态和周边公众环境安全的影响,十分重要。     

The impact of wood smoke on ambient PM2.5 in northern Rocky Mountain valley communities

During the winters of 2006/2007 and 2007/2008, PM_2.5 source apportionment programs were carried out within five western Montana valley communities. Filter samples were analyzed for mass and chemical composition. Information was utilized in a Chemical Mass Balance (CMB) computer model to apportion the sources of PM_2.5. Results showed that wood smoke (likely residential woodstoves) was the major source of PM_2.5 in each of the communities, contributing from 56% to 77% of the measured wintertime PM_2.5. Results of ¹⁴C analyses showed that between 44% and 76% of the measured PM_2.5 came from a new carbon (wood smoke) source, confirming the results of the CMB modeling. In summary, the CMB model results, coupled with the ¹⁴C results, support that wood smoke is the major contributor to the overall PM_2.5 mass in these rural, northern Rocky Mountain airsheds throughout the winter months.     

Determination of biocides and pesticides by on-line solid phase extraction coupled with mass spectrometry and their behaviour in wastewater and surface water

This study focused on the input of hydrophilic biocides into the aquatic environment and on the efficiency of their removal in conventional wastewater treatment by a mass flux analysis. A fully automated method consisting of on-line solid phase extraction coupled to LC-ESI-MS/MS was developed and validated for the simultaneous trace determination of different biocidal compounds (1,2-benzisothiazoline-3-one (BIT), 3-Iodo-2-propynylbutyl-carbamate (IPBC), irgarol 1051 and 2-N-octyl-4-isothiazolinone (octhilinone, OIT), carbendazim, diazinon, diuron, isoproturon, mecoprop, terbutryn and terbutylazine) and pharmaceuticals (diclofenac and sulfamethoxazole) in wastewater and surface water. In the tertiary effluent, the highest average concentrations were determined for mecoprop (1010 ng/L) which was at comparable levels as the pharmaceuticals diclofenac (690 ng/L) and sulfamethoxazole (140 ng/L) but 1-2 orders of magnitude higher than the other biocidal compounds. Average eliminations for all compounds were usually below 50%. During rain events, increased residual amounts of biocidal contaminants are discharged to receiving surface waters.     

Bottom-up approach for the reaction of xenobiotics and their metabolites with model substances for natural organic matter by electrochemistry-mass spectrometry (EC-MS)

Risk assessment of xenobiotics requires a comprehensive understanding of their transformation in the environment. As most of the transformation processes usually involve a redox reaction or a hydrolysis as the first steps of the transformation, we applied an approach that uses an electrochemical cell to investigate model “redox” reactions in aqueous solutions for environmental processes. We investigated the degradation of a variety of xenobiotics from polar to nonpolar and analyzed their degradation products by on-line coupling of electrochemistry with mass spectrometry (EC-MS). Furthermore, we evaluated possible binding reactions with regard to the generation of non-extractable residues with some model substances (catechol, phthalic acid, γ-l-Glutamyl-l-cysteinyl-glycine (GSH) and l-histidine) deduced from a natural organic matter (NOM) structure model and identified possible binding-sites.Whereas typically investigations in soil/water-systems have been applied, we used to our knowledge for the first time a bottom-up approach, starting from the chemicals of interest and different model substances for natural organic matter to evaluate chemical binding mechanisms (or processes) in the EC-MS under redox conditions. Under oxidative conditions, bindings of the xenobiotics with catechol, GSH and histidine were found, but no reactions with the model compound phthalic acid were observed. In general, no chemical binding has yet been found under reductive conditions. In some cases (i.e. benzo[a]anthracene) the oxidation product only underwent a binding reaction, whereas the xenobiotic itself did not undergo any reactions.EC-MS is a promising fast and simple screening method to investigate the environmental behavior of xenobiotics and to evaluate the potential risks of newly synthesized substances.     

氨法脱硫洗涤液pH的计算模型

应用酸碱质子理论,根据质子平衡方程建立了氨法脱硫洗涤液相关离子浓度与pH的相关性模型,并对其影响因素进行了讨论。研究表明:脱硫洗涤液理论计算pH与实测的pH基本吻合。结合实验验证了影响洗涤液pH的硫元素存在形态与脱硫洗涤液pH之间的相图关系,并提出模型修正方法。模型可作为氨法脱硫洗涤液pH的合理计算方法。     

重庆主城区春季典型天气的大气颗粒物浓度变化分析

选取重庆大气超级站2010年春季典型天气时段的颗粒物实时监测数据,将β射线法和震荡天平法(TEOM法)的PM10监测值进行了比对,分析了PM10、PM2.5和PM1质量浓度百分比例关系及10μm以下颗粒物数浓度随粒径大小的分布规律。结果表明,β射线法与TEOM法的PM10监测结果基本一致,β射线法比TEOM法监测值平均偏低5.4%;PM2.5、PM1和PM0.5的数浓度均占PM10数浓度的98%以上;PM0.25数浓度占PM10数浓度的平均比例为34.9%,占PM1数浓度的平均比例为35.1%;TEOM法监测的PM2.5占PM10日均质量浓度平均比例为51.2%;β射线法监测的PM2.5占PM10日均质量浓度平均比例为56.9%,PM1占PM10平均比例为30.9%。     

基于碳平衡的区域生态补偿量化研究——以长株潭绿心昭山示范区为例

在区域碳平衡的基础上,通过建立生态补偿中观尺度模型,对长株潭及其生态“绿心区”昭山示范区做生态补偿量化研究,并就生态补偿体制的建立和实现形式等进行了讨论。结果表明：长株潭城市群总体属于生态赤字区,其中长沙、株洲、湘潭3地均为生态赤字区,昭山示范区为生态盈余区;2008年长沙、株洲、湘潭3地应支付生态补偿资金分别为：4067、7934、7430万元,长株潭 “绿心区”昭山示范区应获得生态补偿资金1229万元,结余1 8202万元生态补偿资金;建议由长株潭生态补偿管理部门统一支配,用于统筹长株潭及其“绿心区”的生态保护与建设。研究以长株潭绿心昭山示范区为例,以生态固碳与区域碳排放为切入点构建生态补偿模型,力求为解决低碳社会建设过程中出现的区域间矛盾提供参考     

Nitrogen critical loads using biodiversity-related critical limits

Critical loads are widely used in the effects-based assessment of emission reduction policies. While the impacts of acidification have diminished, there is increasing concern regarding the effects of nitrogen deposition on terrestrial ecosystems. In this context much attention has been focussed on empirical critical loads as well as simulations with linked geochemistry-vegetation models. Surprisingly little attention has been paid to adapt the widely used simple mass balance approach. This approach has the well-established benefit of easy regional applicability, while incorporating specified critical chemical criteria to protect specified receptors. As plant occurrence/biodiversity is related to both the nutrient and acidity status of an ecosystem, a single abiotic factor (chemical criterion) is not sufficient. Rather than an upper limit for deposition (i.e., critical load), linked nutrient nitrogen and acidity chemical criteria for plant occurrence result in an ‘optimal’ nitrogen and sulphur deposition envelope.