南极菲尔德斯半岛岛弧火山岩中的辉石

菲尔德斯半岛岛弧火山岩中的辉石有贫钙和富钙两类,前者由古铜辉石、紫苏辉石和易变辉石组成,后者包括透辉石、顽透辉石、次透辉石及普通辉石,以普通辉石为主。辉石的化学成分及其变化与寄主玄武岩浆的演化有密切联系。其端元组分呈有规律变化,基质中辉石微晶,Fs明显高于斑晶,Wo低于斑晶。其稀土元素含量与寄主岩的稀土总量呈正相关,轻稀土亏损,重稀土较富集,Eu具较小的负异常,δEu约为0.6。热力学计算表明结晶时的平衡温度为1053—1150℃,平衡压力为0.25—1.03GPa,氧逸度为10~(-6.3)—10~(-8.9)atm,斑晶晶出深度多数在10—25km,岩浆房可能位于下部地壳。     

长春市热岛效应的时空演变研究

以长春市为例,借助1988年9月25日,1995年9月29日和2000年9月18日三个时相的TM/ETM+遥感影像,研究长春市近12年热岛效应的时空演化规律。研究发现:长春市热岛效应明显且多年稳定存在,热岛中心主要分布在宽城区南部、二道区北部伊通河两岸和绿园区西南部;绿园区西南部和宽城区西北部强热岛区面积呈逐年增加态势,二道区北部伊通河两岸热状况有所改善;从1998年到1995年和从1995年到2000年,热岛面积分别增加约9.32 km2和14.93km2,增长速度加快。     

A multi-hazard history of Antigua*

Antigua experiences earthquakes, droughts and hurricanes. To isolate for study each of these as they occur, would be to over simplify the inter-relationships between the aftereffects of one and the occurrence and the effects of the next. Moreover, there will be conditions arising from factors outside the natural disaster spectrum which bear upon, and are themselves affected by, all of these phenomena. This interplay of events and conditions is readily illustrated in the case of island countries, which have a natural and clearly defined containment. Such interrelationships suggest a complex human-ecological system which must be recognized if environmental balance and compatability are to be maintained - particularly in respect of hazards. This documentary analysis of the colonial era in Antigua, has to conclude for the time being with questions concerning the environmental effectiveness of imported systems of administration which, with no knowledge of comparable natural hazards, assumed sectoral separation.     

崇明岛生态保护与生态补偿分析

以崇明岛为研究对象,通过与上海整体水平的比较,分析了岛域的社会经济状况和生态环境特点,并采用生态足迹模型分析了崇明岛的生态承载力及其对上海城市发展的生态支持作用。在此基础上,从内部机制和外部机制两个方面提出了对崇明岛生态保护进行生态补偿的对策措施。     

Impact of the earthquake and tsunami of December 26, 2004, on the groundwater regime at Neill Island (south Andaman)

The aquifer and groundwater regime has been affected by the earthquake and tsunami of December 26, 2004, particularly on the islands and coastal regions of India. The groundwater regime on many islands of Andaman and Nicobar islands, which is the only source of fresh water on the islands, has been found to be deteriorated. Detailed hydrogeological studies have been carried out at one of the tiny islands of Andaman, namely Neill Island, and results have been compared with prior observations. It has been found that the shell limestone aquifer at a few places has developed cracks due to the earthquake and these openings have allowed quick movement of seawater into the aquifer resulting into deterioration of groundwater quality. In the places where the aquifer is at sea level, the tsunami waves have caused seawater ingress. Most parts of the island which have hard mudstone as a base and where the aquifer lies much above sea level, did not show any change in groundwater regime.     

Sustainable development as a policy guide: an application to affordable housing in island communities

This article uses sustainability as a lens through which to examine affordable housing policies in geographically-isolated island communities, with the intent of assessing the utility of using sustainable development as a guide to policy decision-making. Focusing on the case of Key West, Florida, the article points to the conflicts that must be reconciled to achieve true sustainability. The study applies criteria to identify policy solutions for the provision and retention of affordable housing in island communities, and at the same time provides an application of the sustainable development concept as a policy guide. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue.     

海南岛北部海湾沉积物重金属来源、分布主控因素及生态风险评价

基于海南岛北部海口湾、铺前湾、东寨港和木兰湾海域159站位表层沉积物地球化学测试分析,查明沉积物中重金属元素As、Cd、Cr、Cu、Hg、Pb和Zn分布特征.运用数理统计方法研究重金属来源并明确其分布主控因素,建立主控因素与重金属含量间定性或半定量关系.评价各重金属元素及其总体污染状况和潜在生态风险.结果表明,研究区海域沉积物重金属中As、Cd、Cr、Cu、Hg、Pb和Zn含量平均值分别为8.40、0.06、32.50、8.32、0.02、18.77和35.87μg·g-1.Cr、Cu、Hg、Pb和Zn含量高值区主要分布于近岸河流入海口及港湾内部,As由南向北其含量逐渐增加,Cd主要聚集于海口湾内.沉积物中Cu、Zn、Hg、Pb、Cr和Cd主要来自陆源输入,包括人为污染和母岩风化产物运移两方面因素,As或有海外物质来源.沉积物中Cu、Zn、Hg、Pb和Cr含量分布主控因素为沉积物粒度,即沉积物粒度越细,其所吸附并积累重金属含量越高;As高含量主要受控于自然地质背景;Cd含量分布则反映了城市发展进程对地区污染差异性影响.所调查159站位表层沉积物中As、Cr分别有3站位和6站位属Ⅱ类海洋沉积物,污染程度中等,其余各站位及重金属元素含量均为Ⅰ类沉积物,污染程度低,单因子污染影响程度依次为AsCrPbZnCuCdHg.沉积物重金属总体为低程度污染,总体潜在生态风险低,研究区海域底质生态环境优良.各重金属元素潜在生态危害程度低,生态危害影响依次为AsHgCdPbCuCrZn,As是最主要的生态风险因子.     

河道护岸工程生命周期碳排放评价探讨

全球变暖已成为人类亟待解决的问题,而解决该问题的关键在于减少全球CO2、CH4和N2O等温室气体的排放。基于生命周期评价方法,将河道护岸工程生命周期全过程划分为材料生产、材料运输、施工建设、维护管理、拆毁处置(或回收)5个单元,进行了河道护岸工程生命周期碳排放来源分析,提出了适合于河道护岸工程的生命周期碳排放评价方法框架。利用此框架,文章对崇明岛典型河道护岸类型——钢筋砼桩板护岸进行了生命周期碳排放计算,得到1功能单位钢筋砼桩板护岸工程的生命周期碳排放为447.05 t。其中,原材料生产单元、材料运输单元和施工单元的碳排放分别为330.33,13.62,103.1 t。目前,崇明岛已有此种护岸工程长度约为2 983 km,得到其总碳排放为133.4万t,占上海2005年碳排放总量的2.30%。     

上海市崇明岛农田土壤中多环芳烃分布和生态风险评价

为研究崇明岛农田土壤中PAHs浓度分布和生态风险,于2008年采集崇明岛农田表层土壤33个.使用加速溶剂萃取仪（ASE300）进行萃取,经净化后,使用气相色谱-质谱联用仪（GC-MS）测定.结果表明,在采集的土壤样品中,PAHs的含量范围为24.92～1 014.61 ng·g-1（干重）,均值为192.83 ng·g-1（干重）.16种美国EPA优控的多环芳烃,只有茚并（1,2,3-cd）芘（IcdP）和二苯并（a,h）蒽（DahA）未全部检出.PAHs主要以2～4环为主,其中2环和3环多环芳烃所占比例为42.6%;4环多环芳烃的比例为42.2%;5～6环多环芳烃的比例为15.7%.使用浓度比值法判定,主要来源为石油源以及煤和木材的燃烧;崇明岛生活燃烧和汽车等尾气排放可能是农田土壤中PAHs的重要来源之一.生态效应区间法评价显示,崇明岛农田土壤中PAHs生态风险较小.