宁波市镇海区大气降尘矿物组成及来源解析

为探讨宁波市镇海区大气降尘矿物组成及来源,用X射线衍射法分析了镇海区6个土地功能区2019年12月至2020年11月4个季度的大气降尘样品的矿物组成和含量,并开展了矿物来源解析。结果显示,降尘中以石英、长石、碳酸盐类矿物和黏土矿物为主,年均质量分数分别为29.2%、33.3%、24.2%和7.7%,且不同功能区各季度降尘中矿物含量普遍有显著差异。来源解析表明,镇海区降尘中矿物来源主要以地面扬尘输入为主,同时周边源区输入及人类活动和工业密集区燃煤等输入对降尘矿物组成有较显著影响,除黏土矿物、碳酸盐类矿物和长石类矿物之外,其他矿物的含量还与不同季节的气温和风向有关。     

Waterfowls habitat modeling: Simulation of nest site selection for the migratory Little Tern (Sterna albifrons) in the Nakdong estuary

This paper aims to find patterns in nest site selection by Little Terns Sterna albifrons, in the Nakdong estuary in South Korea. This estuary is important waterfowl stopover and breeding habitat, located in the middle of the East Asia-Australasian Flyway. The Little Tern is a common species easily observed near the seashore but their number is gradually declining around the world. We investigated their nests and eggs on a barrier islet in the Nakdong estuary during the breeding season (May to June, 2007), and a pattern for the nest site selection was identified using genetic programming (GP). The GP generated a predictive rule-set model for the number of Little Tern nests (training: R² = 0.48 and test: 0.46). The physical features of average elevation, variation of elevation, plant coverage, and average plant height were estimated to determine the influence on nest numbers for Little Tern. A series of sensitivity analyses stressed that mean elevation and vegetation played an important role in nest distribution for Little Tern. The influence of these two variables could be maximized when elevation changed moderately within the sampled quadrats. The study results are regarded as a good example of applying GP to vertebrate distribution patterning and prediction with several important advantages compared to conventional modeling techniques, and can help establish a management or restoration strategy for the species.     

Retention capacities of several bryophytes for Hg(II) with special reference to the elevation and morphology of moss growth

Hg(II) Retention capacities of nine bryophyte species, collected from Jinfo Mountains (JFM) in Chongqing, China, had been investigated with special reference to the effect of morphology and elevation of moss growth. Results indicated that adsorption capacities of bryophytes for Hg(II) became stronger with the increase of multi-branches and leafy-shoots, as well as the elevation of moss growth, which was observed both in adsorption isotherm and adsorption kinetics experiments. Contrarily, the desorption kinetics showed a decrease tendency with the increase of multi-branches and leafy-shoots and the elevation of moss growth. The results demonstrated that bryophytes with higher multi-branches and leafy-shoots and higher growth elevation had a stronger adsorption capacity and a weaker desorption tendency, and therefore had a stronger retention capacity to Hg(II). The results disclosed the different relative sensitivity and retention capacity of mosses to pollution resulting from heavy metals, due to the differences in growth elevation and morphology. These should be considered when bryophytes were chosen as a tool for biomonitoring materials to environmental pollution, especially caused by Hg(II).     

不同类型施工降尘中重金属污染特征及健康风险评价

为了解北京市建筑施工降尘中重金属的污染特征及存在的健康风险,分别选择建筑物拆迁及主体建设两个研究区,共收集大气降尘样品25份,使用微波消解-电感耦合等离子体质谱法(ICP-MS)测试了样品中8种重金属的质量分数.结果表明:Zn、Mn、Cu、Pb、Cr、Ni、Cd在建筑物拆迁降尘中的平均含量高于建筑主体建设降尘.建筑物拆...     

城镇生活污水排放对红树林植物群落凋落物的影响

利用凋落物收集网研究城镇生活污水排放对红树林植物群落凋落物的影响。所研究的红树林群落年总凋落物量为１１９８．９１ｇｍ＾－２,其中叶片和繁殖物部分共占９０％左右。总凋落物量具有明显的季节变化模型,凋落物的高峰期落在多雨的夏季,尤其是８月份。污水排放一年期间,排污样带和对照样带之间红树林的总凋落物量以及凋落叶中的总有机碳、总氮、总磷水平没有显著的差异,污水排放没有导致红树林植物群落的凋落物量发生明显的     

新疆准东煤田降尘重金属污染及健康风险评价

为研究准东煤田大气降尘重金属的污染状况及潜在健康风险,选取52个覆盖全区的样点采集大气降尘,并测试分析样品中Zn、Cu、Cr、Pb、Hg和As共6种重金属元素含量.结合地累积指数(I_geo)进行污染研究,使用EPA人体暴露风险评价.结果表明,研究区大气降尘重金属浓度具有明显差异,Zn > Cr > Cu > As > Pb > Hg.Hg、Cu和As的变异系数为381.91%、99.94%和97.82%,受人类活动影响较大; 6种重金属间的相关性较复杂,Zn-Cu-Cr较Hg-As-Pb的相关性更强.地累积指数评价表明,重金属Zn、Cr的污染较严重,Zn处于极强度污染,Hg可视为无污染,Cu、Pb、As处于轻度-中度污染.研究区致癌风险暴露量与非致癌风险暴露量差异不大.非致癌风险商均小于1, HQ_Cr > HQ_As > HQ_Zn > HQ_Pb > HQ_Cu > HQ_Hg,总非致癌风险指数0.258,研究区6种重金属健康风险较小.致癌风险CR_As > CR_Cr > CR_Pb,Pb无致癌风险.其中As的致癌风险值占总致癌风险(TCR)的93.85%,是最主要的致癌因子.TCR均值为1.95E-05,处于人体可耐受的致癌风险范围.     

中国房屋市政工程安全事故分布规律及致灾因子耦合性分析——基于2012-2018年中国31省市4096条数据

选取2012-2018年中国31个省市自治区的4096条房屋市政工程安全事故的统计数据,基于时间、空间和事故类型3个维度,对安全事故分布规律及其原因进行了系统研究。结果表明:在时间维度上,2012-2015年逐年下降,2015-2018年逐年上升,2015年为谷底;每年的2月为事故谷值,8月为峰值,6月明显降低。这与国家对安全生产工作的重视、相关管理文件连续颁布、全国建筑总产值逐年大幅度增长、工程露天施工、中国传统节日及安全检查月等都密切相关。在空间维度上,主要集中在秦岭淮河以南地区,华东地区是安全风险的高危区域,且江苏省连续6年为高频发事故地区,排在中国的首位,浙江省连续3年为高频发事故地区。这与以上两省庞大的建筑业总产值有直接关系,但由于浙江省在工程安全管理方面的投入远大于江苏省,其安全事故发生概率也远低于江苏省。在事故类型维度上,高处坠落是发生最多的事故类型,通过对三因素耦合性风险和两因素耦合性风险分析均发现,"人"是高处坠落事故发生的最根本原因,设备的不安全状态和环境的复杂性增加了高处坠落事故发生的概率。     

建筑工地大气降尘与总悬浮颗粒物相关性研究

通过统计大量实测数据,对北京市建筑工地施工扬尘大气污染指标DF与TSP的相关性进行了研究.结果表明,建筑施工扬尘所产生的DF与TSP有较好的线性关系,建筑工地边界处DF与TSP的关系可以用c_TSP＝11.6×c_DF表示.监测点与污染源的距离对相关系数影响较大,相关系数与距离成正比例;施工阶段对相关系数影响较小.     

Test Method for Retractable Type Fall Arresters Designed for Horizontal Use

Retractable type fall arresters are designed to protect against falls from a height of people who need freedom of vertical movement. The practice of fall protection shows that the devices are also used to protect people who work on flat roofs. This application creates quite different operating conditions for the devices. In some situations those conditions can be dangerous for users. The article presents a theoretical analysis of phenomena occurring during a fall arrest with retractable type fall arresters arranged horizontally. The analysis was verified with laboratory tests. The article presents a proposal for the construction of a test stand and a test method for estimating retractable type fall arresters intended for horizontal use.     

Locking of Retractable Type Fall Arresters—Test Method and Stand

Retractable type fall arresters are very effective personal equipment protecting against falls from a height. These devices are used under different atmospheric conditions and in the presence of various types of industrial pollution. For this reason appropriate locking after conditioning simulating extreme conditions of a worksite is one of the essential characteristics of retractable type fall arresters. This article presents the requirements for locking of the devices. A previously used locking test method and its disadvantages are discussed. The article suggests an improved test method and test equipment. Measurement of the test mass acceleration is the most important improvement introduced into the test method. The article shows laboratory tests used to verify the method, which turned out to be a valuable source of information concerning the performance of retractable type fall arresters.