西藏拉萨河流域河水主要离子化学特征及来源

为掌握拉萨河流域水化学的时空变化特征、来源以及主要控制因子,于2014年8月~2015年7月在拉萨河拉萨水文站断面定点采集水样,并对其主要的化学离子进行分析.结果表明:HCO_3~-是主要的阴离子,占离子总量的68.73%,SO_4~(2-)含量其次,Ca~(2+)是主要的阳离子,占离子总量的67.75%,其次为Mg~(2+),拉萨河流域四季的pH值介于8.31~8.90,平均值为8.59,整体偏碱性,其中夏季的pH平均值最高,主要是因为水生植物光合作用以及浮游植物生长的影响.EC值介于155.0~257.0μS·cm-1之间,平均值为210.5μS·cm-1,TDS均值为181.35 mg·L-1,高于世界河流平均值.这是因为高原构造抬升活动频繁,造成岩石机械风化加强,从而加速岩石溶解.拉萨河流域的主要离子浓度大小表现为冬季春季秋季夏季的变化规律.离子来源分析表明,HCO_3~-、Ca~(2+)和Mg~(2+)主要来源于碳酸盐岩的风化,Cl-、SO_4~(2-)、NO_3~-离子主要来源于大气和岩石风化.此外,由于降雨和冰川融水的稀释作用,河流中的主要离子浓度与河流径流量呈现负相关的关系.     

Distribution and migration of 95Zr in a tea plant/soil system

(95)Zr is a primary radionuclide in the radioactive liquid efflux from a pressurized water reactor and one of the main radionuclides released after nuclear accidents. The fission yield of (95)Zr is as high as 6.2%, however, its environmental behavior has not been well documented. An experiment was conducted to evaluate the accumulation and distribution of (95)Zr in a tea plant/soil system. (95)Zr was accumulated primarily in the trunk of tea plants after being taken up from the soil. The radioactivity concentration of (95)Zr in the trunk increased slowly with time, then it reached a dynamic equilibrium 14 days after application. The radioactivity concentration of (95)Zr in the other parts of the tea plant was very low; only slighter greater than the detection limit. The results indicated that (95)Zr was not readily translocated in the tea plant. About 98.9% of applied (95)Zr was found to concentrate in the upper 5 cm layer after being sprayed onto the soil surface. The results indicated that (95)Zr could not readily move downwards with percolating water due to strong adsorption to surface soil.     

Modeling human exposures to air pollution control (APC) residues released from landfills in England and Wales

Human exposures to air pollution control (APC) residues released from 6 landfills were modeled and assessed. Following a qualitative risk characterisation, direct and indirect exposures were quantified. Site-specific air dispersion modeling was conducted for PM(10), PCDDs/PCDFs, Pb, Cd, As and Cr(VI) concentrations at the closest residential points of exposure for 4 landfill sites accepting, in total, 75% w/w of the APC residues disposed of in 2000-2001 (UK). Inhalation risks, assessed by reference to air quality standards at residential exposure points, were assessed as insignificant. Preliminary modeling suggested that indirect exposures from PCDDs/PCDFs at the 95th percentile level for the site where APC deposition rates were highest could potentially exceed the tolerable daily soil intake (TDSI) but this warrants further study given the model limitations. These results offer an initial screen of the significance of potential risks from APC disposal, which is of value in addressing concerns about the uncertainty of potential risks to human health from bulk APC disposal at strategic locations.     

On the Nexus of SO<Subscript>2</Subscript> and CO<Subscript>2</Subscript> emissions in China: the ancillary benefits of CO<Subscript>2</Subscript> emission reductions

This paper examines the issue of ancillary benefits by linking sulfur dioxide (SO₂) emission to CO₂ emission using a panel of 29 Chinese provinces over the period 1995–2007. In the presence of non-stationarity and cointegrating properties of these two data series, this paper applies the panel cointegration techniques to examine both the long-run and short-run elasticities of SO₂ with respect to CO₂. The major findings are that: (1) there exhibits a stable long-run equilibrium relationship between the SO₂ and CO₂ emission with the long-run elasticity being 2.15; (2) there exists a short-run relationship between these two emissions with the short-run elasticity being 0.04. In addition, following an exogenous shock that causes a deviation from the long-run equilibrium, it would take approximately 15 years for SO₂ emission to revert toward the long-run equilibrium path with an average annual convergence rate of 6.5%; (3) the derived ancillary benefits that is generated from one metric ton of CO₂ emission reduction, are 11.77 Yuan (approximately US1.7) in the short run and 196.16 Yuan (US 1.7) in the short run and 196.16 Yuan (US 30) in the long run. These findings are not only crucial from the econometric modeling perspective, but also have important policy implications.     

潮汐循环影响下上覆水环境因子和氮营养盐的变化及其相关关系

潮汐循环对水体理化特征的短期影响是潮汐河口各种理化参数变化的一个重要原因。通过崇明东旺沙堤外低潮滩和东海农场低潮滩采样及环境因子分析，发现崇明东滩各环境因子之间（除浊度外）相关性较好，均呈宽 “U”型变化；东海农场各环境因子之间相关性较差，变化不一致，且盐度、电导率变化与崇明东滩变化相反；受潮汐循环影响，崇明东滩涨潮初期各形态氮有明显释放过程，而东海农场的近底层水体在涨潮初期NH4+ N急剧下降，NOX- N缓慢下降；无论是在崇明东滩还是在东海农场，营养盐浓度受环境因子的共同影响，整个潮汐循环过程中总无机氮（TIN）与盐度呈显著线性负相关，这与整个长江口近岸水体的营养盐负荷相一致，长江上游淡水带来的高负荷营养盐流经河口进入海洋。     

企业环境行为:环境政策研究的微观视角

企业环境行为是是企业面对来自政府、公众、市场等方面的压力．而采取的宏观战略和制度变革、内部具体生产的调整等措施和手段．是环境政策效果的具体体现。政府、公众和市场压力在不同阶段发挥着不同的作用。在工业绿色化的初级阶段以政府压力为主。随着公众和企业更多地参与到环保行动中来．来自市场及社区的压力逐渐成为企业环境行为的主导驱动力量。我国正处于工业化加速阶段．环境问题突出．必须积极开展对企业环境行为的研究，探求环境压力与企业环境行为转变的内在关系．找到促进企业改善环境行为和表现的最优方式，为我国环境政策的制定提供决策支持。     

Environment as the Stage for Economic Actors

The relative importance of economics and environment in debate may soon be reversed due to the influence of three fac- tors. Firstly, in the global economy it is hard to hide the unwanted products of economic processes. Secondly, huge advances in sci- ence will reduce the imperfect knowledge of markets, making some monitoring and analyzing tools show the design of sensible and equitable livelihood in communities, which is more important than the motivation of maximising profits for some individuals or firms. Thirdly, China, as the last major player on the planet to take on economic growth, comes from traditions fundamentally differ- ent from those economies that have experienced the Industrial Revolution previously. Its challenges with sustainability and en- vironmental conservation predate Western economics by millennia, and it is implementing policies domestically and starting to work on the world stage that acknowledges that the surroundings are the host for any economic and socio-political system.     

Water-saving Technologies,Solar Green House and Ecological Rehabilitation in Minqin Oasis of Gansu Province,China

Land degradation and desertification have become severe environmental problems in arid areas due to excessive use of water resources. It is urgent to reduce agricultural water use for ecological rehabilitation, which may result in a decrease in agricultural production and farmer＇s welfare. This paper focused on the impacts of some main measures including extensions of watersaving irrigation, expanding solar green house and increasing off-farm employment, which are generally recognized to be important to alleviate water shortage and poverty. A bioconomic model is applied taking Minqin Oasis in Gansu Province as a case study site. Simulation results showed that the effect of expanding solar greenhouse was more positive than other ones so it drew more attention. On the view of the different effects between each irrigation zone, mixed policy patterns suitable for them are suggested. In Baqu, expanding solar greenhouse should be the most important, auxiliary with encouraging pipe irrigation. Inversely, with regard to Quanshan, the major attention should be paid to subsidy for pipe irrigation and it would be better to supply the off-farm employment opportunities to the households in Huqu, where the expanding of solar greenhouse should also be summoned. Finally, it should be noted that farmer＇s income would only resume to 90% of the current level in the short run by putting more effort into local policies. Thus, the ecological compensation is needed to ensure farmer＇s welfare.     

Impact of Cloud on Net Ecosystem CO2 Exchange of Alpine Meadow in Tibetan Plateau

Meteorological elements and CO2 fluxes over alpine meadow ecosystem were observed continuously from 2004 to 2005in Damxung Alpine Meadow Flux Station,China Flux Network.Based on the eddy covariance CO2 fluxes and meteorological data obtained,the relationships among the CO2 fluxes,the cloud amount,and the meteorological factors in alpine meadow ecosystem were explored and analyzed.Some conclusions can be drawn from the discussion with previous researches as following:(1)the cloud amount can affect the net ecosystem CO2 exchange(NEE)of alpine meadow on Tibetan Plateau;(2)the soil temperature sensitive to the cloud amount,is a major environmental controlling factor for NEE,and closely relates to the maximum of NEE.In the morning period with large cloud amount,the NEE reaches its maximum when the clearness index ranges from 0.5 to 0.7; yet in the afternoon it comes to the maximum with the index from 0.2 to 0.35.The span of soil temperature covers from 12 to 15℃ as the NEE at its highest;(3)the scatterplots between NEE and photosynthetic available radiation(PAR)was a significant inverse triangle in the clear day,two different kinds of concave curves in the cloudy day,and strongly convergent rectangular hyperbola in the overcast day.These differences were controlled by the changes of light radiation and soil temperature.