农业区水库水体重金属分布特征及来源解析

以鲁南某典型农业区15个水库为研究对象,利用SC-ICP-MS对水库水体中的Cd、Cr、Cu、Zn和As的质量浓度进行测定,并运用主成分分析方法对水体中的重金属来源进行了分析.结果表明:5种重金属(Cd、Cr、Cu、Zn、As)全部被检出,但Cd的检出率较低(仅为26.7％),5种重金属元素质量浓度均未有超标现象,低于...     

承德黑山钒钛磁铁矿矿集区土壤重金属空间结构特征与生态风险评价

矿区土壤重金属来源、空间分布特征对矿山周围的生态环境脆弱区土壤环境保护、修复以及生态风险评价具有重要意义。本文以承德市隆化县韩麻营镇黑山钒钛磁铁矿所在小流域为研究区,利用地累积指数法、内梅罗污染指数法验证矿区周围土壤重金属污染程度,利用潜在生态危害指数法对土壤重金属的生态环境风险做了全面评价,利用变异函数、相关性分析、金属元素主成分和聚类分析等方法明确了研究区重金属来源及空间分布特征。研究结果表明:研究区土壤中重金属元素Mn、Ti、V、Zn、Co、Cu、Mo、Cd和SOM的平均含量均高于河北省背景值;重金属元素As、Cr、Ni、Sb、Pb的平均含量均略低于河北省背景值;土壤重金属元素的空间分布十分均匀。研究区大量土壤重金属元素为轻度污染,少量为中度污染,只在极少量的局部地区土壤重金属元素Ti、Cu、Co、Hg、Cr显示出重污染特性。研究区整体处于较清洁水平,并且研究区土壤重金属元素高值点主要分布在矿区周围和人类活动区域,钒钛磁铁矿矿区及其伴生矿物和人类生产活动对重金属元素含量分布有较大影响。     

湖南省三十六湾矿区耕地重金属健康风险评价及生态修复对策

三十六湾矿区是全国第三批“山水林田湖草”生态保护修复工程耕地复垦重点修复试点区。本文基于污染指数法、地积累指数、富集系数和USEPA健康风险评价模型,探究三十六湾矿区土壤重金属的污染特征、农作物重金属累积状况及其对人体健康的危害,提出土壤修复建议,以期为矿区土壤重金属污染防治和管控提供科学依据。结果表明,土壤重金属综合污染指数为中—重度,其风险等级为：Cd>Pb>As>Zn>Hg>Cu>Cr>Ni;农作物Cd全部超标,白菜和萝卜Pb、Cr超标,水稻、白菜和萝卜As超标,白菜Hg超标。农作物对重金属的富集能力为：水稻>白菜>萝卜。食用农产品的非致癌风险Cr>As>Cd>Pb>Hg,成人与儿童的非致癌危害指数分别为1.04和2.11,致癌风险指数分别为1.62×10^-5和3.34×10^-4,显示成人和儿童均有非致癌风险,儿童有致癌风险,且儿童各种风险都大于成人。建议采取工程措施与物理化学法结合、重金属稳定剂-抗逆性植物联合、植物修复、土壤调理-轮作休耕等技术开展区域耕地...     

高度城镇化地区景观生态风险时空特征及驱动力——以苏州市为例

探明快速城镇化进程中景观生态风险（landscape ecological risk, LER）的时空特征及驱动力,可为高度城镇化地区LER的有效识别与管控提供参考。结合1995—2020年的Landsat TM/ETM卫星影像、数字高程模型（DEM）和美国航空航天局（NASA）数据集等多源数据,利用LER评价模型、时空地理加权回归（geographically and temporally weighted regression, GTWR）模型,探究最佳尺度下苏州LER的时空分异特征及驱动力。1）苏州市景观格局的尺度依赖性显著,最佳粒度和最佳幅度分别为550 m和1 250 m。2）1995—2020年苏州市LER总体趋好,呈“平缓—加剧—恢复”阶段性特征;低风险区占比始终居高且空间格局分布稳定,中、高风险区占比则持续增长且聚集性均显著。3）苏州市LER受社会经济因素影响最大,自然因素空间作用最稳定,其余因子空间作用差异性显著。研究结果可在最佳尺度和高度城镇化层面为深化LER理论体系提供支撑,为同类型城市及城镇化后发地区的生态风险管控提供科学参考。     

探究夏热冬冷地区办公建筑面积对单位建筑面积能耗(EUI)的影响

以上海地区的气象参数作为夏热冬冷气候区的典型代表,提出\"H/S——建筑形状系数\"并作为建筑形状分类指标,对办公建筑分类建模,采用能耗模拟软件e QUEST进行能耗估算,并用SPSS软件做逐步线性回归分析,探究建筑总面积、建筑形态与单位建筑面积年能耗(EUI)之间的数学关系。研究表明:1单位建筑面积能耗(EUI)随建筑总面积的增加而减少。2总面积越小的单体建筑,面积变化对能耗影响越大。3越\"瘦高\"的建筑,建筑能耗越大。     

基于景观生态风险评价的景观格局优化——以北京市浅山区为例

随着城市扩张蔓延、自然环境变化,处于城市中的深山区与山前平原过渡地带的浅山区易受到多源因素综合作用。判断浅山区景观生态风险,进行景观格局优化,能够有效实现浅山与城市区域的生态安全稳定。在总结国内外相关研究的基础上,以北京市浅山区生态环境为出发点,利用景观生态学方法、景观格局指数法、空间主成分分析法和地理信息系统（GIS）技术,从景观格局、自然要素、人类社会要素3个方面对景观生态风险进行综合评价。基于评价结果,采用最小累积阻力（MCR）模型构建生态廊道与生态节点,优化浅山区域景观格局。结果表明：浅山区景观生态风险不均衡,其变化与土地利用变化趋势基本吻合。共识别了10个生态源地,构建了10条生态廊道、14个生态节点,组成点、线、面交织的多层次生态网络。优化了浅山区域景观格局,将有效改善研究区的生态安全水平,对于北京浅山生态优先的发展战略、推动城市形成可持续的健康发展方式具有重要意义。     

Regional assessment of ambient volatile organic compounds from biopharmaceutical R&D complex

Biopharmaceutical R&D complexes are major emission sources of volatile organic compounds (VOCs), which may pose potential health risks for staff on site and residents nearby. In this paper health risk assessments were performed for the VOCs in the ambient air of a typical biopharmaceutical R&D complex in China. Results showed halogenated and alkyl compounds were dominant components among 24 major VOCs from 9 selected sampling sites, inside or around the complex. The principal component analysis (PCA) indicated VOCs were generated predominantly from the biopharmaceutical research activities (factor 1 (F1), 71.6%) and traffic vehicles (factor 2 (F2), 15.4%), which were confirmed by contour maps of five selected VOCs (benzene, toluene, chlorobenzene, methylene chloride and n-hexane) simulated by Golden Software Surfer. The cumulative cancer risks for the staff on site and residents nearby were investigated and results showed the risk value were 1.01E−5 and 2.03E−5, respectively, higher than the threshold value of 1.0E−6. These results indicated that elevated VOCs from biopharmaceutical R&D complex are potential risks to the public health. Furthermore, the human health risk assessment revealed that 1,2-dichloroethane, methylene chloride, carbon tetrachloride and benzene were the dominant risk contributors for staff on site, while methyl chloride, carbon tetrachloride, 1,2-dichloroethane and tetrahydrofuran for residents nearby. As a conclusion, this work suggests that proper control strategy should be taken for VOCs releasing to minimize the public health risks, especially for the halogenated compounds.     

The accuracy of preliminary cost estimates in Public Works Department (PWD) of Peninsular Malaysia

This paper presents the accuracy of preliminary cost estimates prepared by Public Works Department (PWD), which is the largest public construction management in Malaysia. It attempts to understand the Quantity Surveyors' (QS) estimation accuracy in relation to public projects. This study analyses 83 projects of estimates and tender bids. The analysis includes three (3) estimating targets i.e. lowest bid, accepted bid and mean of the bids. To broaden the study, 344 QS involved in the procurement answered the questionnaires. Linear multiple regression analysis on project characteristics shows that project size, number of bidders, location and type of schools affect the bias. Contract period affects the consistency. The use of mean of the bids is the best-fit target to explain the bias in terms of adjusted R². The accuracy may improve if sufficient design information is available, proper cost planning and improving the application of historical cost data. As an alternative, the phenomenon of overestimation is resulted from government directive instruction, which could challenge the rational of accurate estimate.