包头南海湿地磷形态及污染源定量识别

采用钼锑抗分光光度法和连续提取法对包头南海湿地和南海湿地沿黄河边的水体和表层沉积物中总磷（TP）及各形态磷的含量进行测定,以分析其生物可利用性及释放风险,并采用APCS-MLR受体模型结合相关性分析（CA）和主成分分析（PCA）等方法进行污染源的识别并量化.结果表明：①研究区水体和表层沉积物中磷都处于不同程度的污染水平,其中南海湿地水体中溶解性无机磷（DIP）对水体总磷（WTP）的贡献最低,表层沉积物中钙结合态磷（HCl-P）对表层沉积物总磷（STP）的贡献最大,南海湖（L区）和湿地植物区（P区）的表层沉积物具有较高的生物可利用性以及向水体释放磷的可能性,更容易发生富营养化,应引起关注.② APCS-MLR受体模型表明,研究区水体和表层沉积物中磷的主要污染来源为工业废水及生活污水（29.07%）和农药化肥（29.00%）.此外动植物残体的降解（18.49%）也对研究区具有一定贡献.     

A 'Principled' Approach to Complex Emergencies: Testing a New Aid Delivery Model in the Nuba Mountains

This paper provides an analysis of the Nuba Mountains Programme Advancing Conflict Trans-formation (NMPACT) as an example of an operational response in a complex emergency that innovatively addressed an incipient food security crisis. NMPACT is notable for having brought together an array of actors around a common principled agenda and for being the only operational programme in the Sudan to which both warring parties subscribed during the conflict. The key features of the programme are presented and the main innovative elements are reviewed, including the role of the principles of engagement and the 'political humanitarianism' of NMPACT. The paper looks at how NMPACT broke from traditional externally driven responses to food insecurity, and, drawing on lessons from Operation Lifeline Sudan, adopted an approach that focuses on capacity building, sustainable agriculture and market revitalisation, alongside conflict transformation and peace-building. The limitations of the model are also assessed, and preliminary lessons regarding its replication in other complex emergency contexts are presented.     

POTENTIAL,ACTUAL, AND EQUILIBRIUM EVAPOTRANSPIRATION IN A WHEAT FIELD 1

ABSTRACT: This paper examines the relationship between both potential (E*) and nonpotential evapotranspiration and equilibrium evapotranspiration (EQ) in an irrigated wheat field in southcentral Alberta, Canada. The control exercised by surface wetness and root reservoir moisture content in determining the value of the Priestley-Taylor constant a is explored. Also investigated is the relationship between a and the vapor flux fraction ET/(R-G) where ET is the actual evapotranspiration, R the net radiation, and G the soil heat flux. It is shown that evapotranspiration occurred at the potential rate (E*) when the available soil moisture (ASM) within the root zone was ≥3 percent. a varied from 0.84 for a dry soil to 1.49 for a saturated soil. The mean a for E* was 1.24. Surface wetness sustained evapotranspiration at the potential rate when such wetting exceeded 2mm d^?1 following a period of prolonged drawdown of soil moisture, α and ET/(R-G) were positively correlated and this correlation strengthened with increasing soil moisture for constant values of the energy partitioning factor s+γ/s where s is the slope of the saturation humidity-temperature curve and γ is the psychrometric constant. ET=EQ when ETI(R-G) lay within the range of 0.59 to 0.82 corresponding to Bowen ratio (β) values of 0.22 and 0.69, respectively.     

Local government policies toward environmentally sensitive areas in British Columbia,Canada; Washington and Oregon,USA

While there has been sustained debate on the issue of provincial and state versus local government environmental planning, maintaining privately owned natural resources in the public interest is increasingly viewed as beyond the scope of local governments alone. This paper describes and compares province- and state-level mandates and options for local governments (i.e., city, county, or district) to regulate land uses of environmentally sensitive areas (ESAs) in British Columbia in Canada and in Washington and Oregon in the United States. We define ESAs as landscape elements or places that are vital to the long-term maintenance of biological diversity, soil, water, and other natural resources, especially as they relate to human health, safety, and welfare, both on-site and in a regional context. Underlying similarities are that all three jurisdictions legally express the need for land-use planning by local governments in managing ESAs. Although all three jurisdictions exhibit similar problems in their attempt to accomplish this, ESA planning by local governments is an optional process in British Columbia and Washington but mandatory in Oregon. Furthermore, actual processes prescribed by each of the three jurisdictions are quite different. The information base upon which local regulation of privately held ESAs depends is variable, both within and between the province- and statelevel jurisdictions. Other than for some specific water-related resources, standard definitions and inventory methods for ESAs are lacking, as is coordination among local governments or among the province- and state-level governments. This study concludes that there is a need for a regional environmental information system in the Pacific Northwest based upon an integrated and scientific approach toward ESA structures and functions.     

Management and valuation of an environmentally sensitive area: Norfolk Broadland,England, case study

Wetlands, like any other environmentally sensitive resource, require very careful evaluation. While it is accepted that all wetlands may be equally valuable in terms of maintaining global life-support systems, individual areas may be ranked according to their uniqueness or the irreplaceability of the resource should the wetland be developed. The various techniques available for evaluating the wetland resource in the development versus conservation conflict situation are critically assessed. Indirect appraisal via the opportunity cost method can generate valuable data which have contributed to the mitigation of such conflict situations.The Broadland, in Norfolk, England, recently designated an environmentally sensitive area (ESA), provides a case study example of wetland management. The search for an acceptable flood alleviation strategy for the ESA is examined in detail. The economic and environmental asset structure of the study area is examined at two levels. A basic screening system is applied to each of the identified flood protection planning units to enable the rank ordering of the units. A more detailed appraisal is then made of the value of selected units so that the cost-effectiveness of any planned expenditure on flood protection works can be assessed. Specific management issues and their likely effect on the environment, in terms of land use for example, are also addressed. The 1986 Agriculture Act marks a potential watershed in British conservation policy. The ESA policy encompasses a dual management strategy that attempts to stimulate compatible agricultural and conservation practices and activities. Other countries that still retain significant unspoiled wetland resources may find that preemptive regulatory government intervention in favor of conservation would help to avoid the worst aspects of the British experience.     

凤冈富硒富锌茶园土壤中的锌及其形态分析

采用Tessier连续化学浸提技术,对凤冈茶园土壤进行了可交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态、残渣态锌的提取,应用火焰原子吸收光谱法(FAAS)对茶园土壤总锌和各结合态锌进行了测定,并讨论了土壤全锌含量及各形态锌含量与土壤pH的关系。测定结果表明,在测试的39件土壤样品中,土壤pH值在3.92～5.16之间,平均pH值为4.66,属酸性土壤。全锌的最高含量为245.7mg/kg,最低含量为31.1mg/kg,平均含量为116.0mg/kg,超过了我国茶园土壤锌的平均含量100mg/kg。在采样的四个茶园中,总的来说土壤锌结合态的分布规律为:残渣态(铁锰氧化物结合态(有机结合态(可交换态(包括水溶态)(碳酸盐结合态。     

沉积物内源与外源重金属形态与酶活性的相关性

文章以表层沉积物为研究对象,采用改进的Tessier连续萃取法,研究了表层沉积物中重金属(内源体系:Fe、Mn、Cu、Zn和Pb;外源体系:掺杂Cu、Zn和Pb后的Fe、Mn、Cu、Zn和Pb)形态和酶(蛋白酶、脱氢酶、磷酸酶、蔗糖酶)活性在一定时间(45d)内的转化趋势,探讨了沉积物中重金属形态与酶活性的相关性。结果表明,在外源体系中,Cu、Zn和Pb的掺杂对Fe和Mn的形态转化影响较小,而Cu、Zn和Pb显著地由残渣态向相对不稳定形态转化,转化幅度均大于20%。外源重金属掺杂初期(前5d),重金属对沉积物中的酶有一定的活化作用,但经过一段时间后以抑制作用为主。相关性分析表明,当掺杂外源重金属后,沉积物中酶的活性与重金属形态的相关性减弱,与内源体系中重金属和酶的活性关系存在明显差异。     

环境监测结果不确定度评定中灵敏系数的求解

本文介绍了重量法、容量滴定法、工作曲线法、气量法以及仪器直读式等方法,测定环境参数时,对其监测结果进行不确定度评定中,为计算标准不确定度所需的灵敏系数的求算公式.     

5种有机磷农药标准物质高效液相制备技术的研究

采用高效液相色谱(HPLC)法,对5种有机磷农药(OPPs)同时进行分离、制备,对其紫外检测波长、流动相比例进行了优化,对方法的精密度和最小检出限进行了考查.结果表明,以甲醇:水(70:30,V/V)作为流动相、波长为210 nm、流速为1.0 mL/min等梯度洗脱条件下,HPLC完全可以分离5种OPPs化工产品(氧...     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land.A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi.The loamy soil was mixed with 0%,20%,40%,60% and 80%(by weight)of digested sewage sludge(SS)and composted sludge (SC).The additions of the both sludges caused a significant raise in all fractions,resulting in that exchangeable(EXCH)and organic matter(OM) became predominance for Zn and organic bound Cu occupied the largest portion.There was more available amount for Zn and Cu in SS treatments than SC treatments.During the pot experiment,the concentration of Zn in EXCH,carbonate(CAR)and OM and Cu in EXCH and OM fractions decreased in all treatments,so their bioavailability reduced.Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi.The two sludges increased tissue contents of Zn and Cu especially in the SS treatments.Zn in pakchoi was not only in relationship toΔEXCH andΔCAR forms but also inΔOM forms in the sludge-soil mixtures.Tissue content of Cu in pakchoi grown on SC-soils could not be predicted byΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time,which might indicate that sludges represented stronger impacts on the plant in long-term land application.