三氯乙醛前驱物的筛选及其生成影响因素探讨

选取苹果酸、酒石酸、柠檬酸、色氨酸、组氨酸、酪氨酸代表自然界中低分子量的有机酸和氨基酸,实验室模拟氯化,GC/MS确证了氯化产物中的三氯乙醛,GC-ECD定量测定了氯化产物中三氯乙醛的浓度,筛选了生成三氯乙醛主要前驱物,并进一步探讨了各种因素对三氯乙醛形成的影响。     

Recent socio-economic changes in relation to environmental quality of the Pearl River delta

Due to the favorable weather, abundant water resources and fertile soil, the area has been known as the homeland for crops and fish. However, being one of the most developed regions in China, the environmental quality of the Pearl River delta has deteriorated due to recent socio-economic changes during the past two decades. The drivers are industrialization and economic growth, population growth and agricultural development; and the pressures are water pollution which include nutrients and suspended solids, pesticides, other persistent toxic substances (PAHs and PCBs) and oil. These have imposed various impacts such as eutrophication, formation of red tides and biomagnification of organic contaminants through food chains. In response to these, regulatory measures have been established by the Environmental Protection Bureau of Guangdong Province, joining forces with environmental protection authorities in all urban cities and most counties, in addition to the Hong Kong Environmental Protection Department, to control pollution in order to prevent further environmental deterioration and economic loss. The present paper is an attempt by following the DPSIR approach promoted by the OECD in the early 1990s and further developed by IGBP LOICZ to review the environmental quality of Pearl River with emphasis on water quality and the impact of rapid socio-economic changes.     

Effect of NOM characteristics on brominated organics formation by ozonation

In this study, organic fractions, namely, humic acid, fulvic acid, hydrophobic base and neutral, and hydrophilic acid, base, and -neutral, were extracted from source water. First, the characteristics of the organic fractions, such as carboxylic acidity, phenolic acidity, ultraviolet absorbance, and aromatic content, were analyzed. Further, a systematic study was carried out to the by-products obtained when organic fractions, to which various amounts of bromide had been added, were oxidized with ozone. Samples after ozonation were analyzed for several brominated organics. The results indicate that the characteristics of the aquatic organic matter, including carboxylic/phenolic acidity, aromatic/aliphatic content, and ultraviolet absorbance, appear to affect the formation of halogenated organics. In general, hydrophobic organics having higher phenolic acidity, aromatic content, and ultraviolet absorbance have higher ozone consumption and produce higher concentrations of brominated organics than hydrophilic organics. It was also found that humic acid demonstrated the highest bromoform (CHBr(3)), dibromoacetic acid (DBAA), and 2,4-dibromophenol (2,4-DBP) formation, whereas hydrophilic neutral produced less CHBr(3) and 2,4-DBP than the rest of the organic fractions but produced the highest amount of dibromoacetone (DBAC) and dibromoacetonitrile (DBAN).     

安徽省农业自然灾害及其防治对策

本文阐述了安徽省历年来农业主要自然灾害的灾情及特点,并分析了产生这些灾害的主要成因;同时提出了防治灾害的对策。     

四川盆地农业自然环境质量综合评价研究

本文用一种综合定量的方法,评价了四川盆地130个县的农业自然环境质量,获得了比传统的定性描述更直观、确切的结果。分析显示,四川盆地农业自然环境的自然潜力质量、生态质量和综合质量均属“一般”质量等级,并非通常所言“农业自然条件优越”:生态质量和自然潜力质量因盆地地形引起的各种质量因子的变化,有明显的区域差别。文中各种参评因子的量化及评价模型,可为农业自然环境质量评价研究提供参考。     

农业生态与土壤环境中硼元素的关系

论述了硼元素的地球化学特征及其分布状况，与硼元素有关的主要作物分类，作物产量和质量与硼元素的关系，影响硼元素有效态和作物吸收硼元素的因素，硼肥的种类和施用方法与效果。     

浅论农村生态环境的主要问题及其保护对策

农村环境质量不能得到改善，全国环境质量 难以改善。但长期来由于经济发展的压力和各咎人为破坏，工农业污染和自然损毁退化等，使农村生态环境问题十分突出，已成为区域可持续发展的严重制约因素，。许多贫困地区难以走上小康之路，生态环境经是重要原因之一。该文在概述了我国农村生态环境主要问题的基础上，着重报导致其恶化的主观原因，并提出了一些具体的对策措施。     

Community richness and stability in agricultural landscapes: The importance of surrounding habitats

In this paper, the role played by habitat diversity in the landscape on species richness and on the stability of farmland bird communities was investigated. Species richness was estimated on 374 samples monitored in farmland by the French breeding bird survey during the 2001–2005 period. A capture–recapture approach was used to estimate species richness accounting for the variation in detection probability among species of the 100 most common species detected in farmland. Landscape structure and composition were measured both in farmland and in adjacent habitats. The independent effect of each variable on community richness and stability was further assessed using hierarchical variance partitioning and taking spatial autocorrelation into account. A strong matrix effect was detected: non-cropped land deeply influenced richness and stability of bird assemblages.     

Integrating agricultural and forestry GHG mitigation response into general economy frameworks: Developing a family of response functions

An econometrically estimated family ofresponse functions is developed forcharacterizing potential responses togreenhouse gas mitigation policies by theagriculture and forestry sectors in theU.S. The response functions are estimatedbased on results of anagricultural/forestry sector model. Theyprovide estimates of sequestration andemission reductions in forestry andagriculture along with levels of sectoralproduction, prices, welfare, andenvironmental attributes given a carbonprice, levels of demand for agriculturalgoods, and the energy price. Sixalternative mitigation policiesrepresenting types of greenhouse gasoffsets allowed are considered. Resultsindicate that the largest quantity ofgreenhouse gas offset consistently appearswith the mitigation policy that pays forall opportunities. Restricting carbonpayments (emission tax or sequestrationsubsidy) only to aff/deforestation or onlyto agricultural sequestration substantiallyreduces potential mitigation. Highercarbon prices lead to more sequestration,less emissions, reduced consumer and totalwelfare, improved environmental indicatorsand increased producer welfare.     

缓冲带在农业非点源污染防治中的应用

论述了缓冲带防治非点源污染的机理和效果，分析了影响缓冲带功能的各个因素。缓冲带能有效地控制土壤与土壤养分的流失，其建设与管理在整个生态环境建设中具有重要地位，目前国内外的研究主要集中于缓冲带对径流中营养物质氮和磷的吸收上，对较大区域环境水质影响的研究不曾多见。为达到防治非点源污染的更好效果，应对缓冲带的设计及各种缓冲带合理配置与布局作更深入的研究，并要与水土保持措施相结合。