辐射环境监测优化布点的特征分析方法

介绍了特征分析方法的基本原理及其MATLAB语言实现过程,并将特征分析法、传统布点法,以及BP人工神经网络法对同一地区辐射环境监测优化布点的核素含量均值作了比较,结果表明,用特征分析法优选出的采样点位,其核素含量均值对传统布点法的相对偏差均为负值,且＜10%,即便与BP法相比,也不失其优越性,表明用特征分析法监测一个地区环境辐射平均水平的优化布点是十分理想的.     

空难对湿地底栖大型无脊椎动物的影响

探讨了包头"11·21"空难对南海子底栖大型无脊椎动物的种类、数量和空间分布以及水质的重要影响.研究发现:南海子底栖大型无脊椎动物有6种,其中寡毛类有2种、摇蚊幼虫有4种;摇蚊幼虫在数量和生物量上均占绝对优势,是南海子的优势种.南海子底栖大型无脊椎动物的种类多样性指数为1.262 9,Shnnon-Wiener多样性指数为0.614 5.南海子底栖大型无脊椎动物的分布率为92%,事故发生地附近没有底栖大型无脊椎动物出现;底栖大型无脊椎动物的数量和生物量以及种类多样性指数随着与事故发生地距离的增加而增加.空难事故后南海子水体已出现严重富营养化.      

LSC0.5-0.7-AII锅炉爆炸事故的爆炸能量及危害半径计算

针对一起LSC0.5-0.7-AII锅炉爆炸事故进行了事故分析,通过分析认定了事故原因,对事故的爆炸能量及危害半径进行了较为全面的实例分析计算,并将锅炉爆炸能量折算成了TNT当量,理论计算出了锅炉爆炸死亡半径、重伤半径、不同程度的摧毁半径等相应数据.     

The impact of domestic wood burning on personal, indoor and outdoor levels of 1,3-butadiene, benzene, formaldehyde and acetaldehyde

The aim of this study was to quantify personal exposure and indoor levels of the suspected or known carcinogenic compounds 1,3-butadiene, benzene, formaldehyde and acetaldehyde in a small Swedish town where wood burning for space heating is common. Subjects (wood burners, n = 14), living in homes with daily use of wood-burning appliances were compared with referents (n = 10) living in the same residential area. Personal exposure and stationary measurements indoors and at an ambient site were performed with diffusive samplers for 24 h. In addition, 7 day measurements of 1,3-butadiene and benzene were performed inside and outside the homes. Wood burners had significantly higher median personal exposure to 1,3-butadiene (0.18 microg m(-3)) compared with referents (0.12 microg m(-3)), which was also reflected in the indoor levels. Significantly higher indoor levels of benzene were found in the wood-burning homes (3.0 microg m(-3)) compared with the reference homes (1.5 microg m(-3)). With regard to aldehydes, median levels obtained from personal and indoor measurements were similar although the four most extreme acetaldehyde levels were all found in wood burners. High correlations were found between personal and indoor levels for all substances (r(s) > 0.8). In a linear regression model, type of wood-burning appliance, burning time and number of wood replenishments were significant factors for indoor levels of 1,3-butadiene. Domestic wood burning seems to increase personal exposure to 1,3-butadiene as well as indoor levels of 1,3-butadiene and benzene and possibly also acetaldehyde. The cancer risk from these compounds at exposure to wood smoke is, however, estimated to be low in developed countries.     

广西地下水污染现状与防治对策研究

基于广西地下水基本现状,分析广西地下水污染成因及地下水污染防治中存在的不足,提出建立健全地下水污染防治法律法规;完善地下水监测站网规划,建立地下水监测信息系统;加大宣传力度,提高公众环境保护意识;从整体规划广西地下水的使用与治理;加大资金投入,重视地下水科学研究5点污染防治建议,为今后广西地下水开发利用及污染防治研究提...     

太原市冬季PM2.5水溶性组分污染特征分析

为了探讨太原市大气阴霾天气的主要污染物PM2.5中水溶性组分的污染特征,于2011年12月~2012年1月,采用美国Thermal Anderson公司的大流量PM2.5颗粒物采样器进行了PM2.5样品采集,共获得样品56个.通过采样前后滤膜的重量变化计算PM2.5的质量浓度.并采用微波提取技术,用TOC/TN分析仪研究了水溶性TOC和水溶性TN等的污染特征.研究结果表明,太原市冬季采暖期PM2.5污染严重,并且比北京、天津、广州、南京、西安的污染水平都高.对PM2.5主要影响因素风速、相对湿度、温度和昼夜变化等的分析表明,风速大小与PM2.5的浓度大小呈负相关(r=-0.4693,α=0.05),相对湿度与PM2.5浓度呈正相关(r=0.4092,α=0.05),而温度与其浓度变化关系不明显;采样期间PM2.5浓度的昼夜变化规律不明显.水溶性TOC对PM2.5贡献较高,占PM2.5总量的13.2%~57.7%;NO3-、SO42-也与水溶性TOC有重要的相关关系.     

深化建设项目环境管理促进环境友好型社会建设

以温岭市建设项目的环境管理为例,介绍了其城市经济发展的基本情况,指出了环境管理中存在的问题,提出了环评促集聚发展、明确功能定位、强化总量控制、实行服务与指导并重等方面的对策,以此促进环境友好型社会建设。     

Evolutionary relationships among deep-sea mytilids (Bivalvia: Mytilidae) from hydrothermal vents and cold-water methane/sulfide seeps

A protein electrophoretic survey of mytilids inhabiting deep-sea hydrothermal vents and cold-water methane/sulfide seeps revealed electromorph patterns diagnostic of 10 distinct species. From hydrothermal vents located at sites on the Galápagos Rift, the Mid-Atlantic Ridge, and the Mariana Back Arc Basin, we detected four species of mytilids. Six additional species were detected from three cold-water seep sides in the Gulf of Mexico. The patchy distribution and temporal stability of seeps may provide a greater opportunity for mytilid diversification and persistence than vent sites Nei's genetic distances (D) between species were relatively large (range: 0.528 to ) both within and among habitat types. This pronounced degree of genetic differentiation suggests a relatively ancient common ancestor for the group. Phylogenetic trees were generated using distance Wagner and parsimony analyses of allozyme and morphological characters. The tree topologies obtained from both methods support: (1) the hypothesis that a seep ancestor gave rise to the deep-sea hydrothermal vent mytilids, (2) a historical progression from shallow-water to deep-water habitats, and (3) a co-evolutionary progression from external to internal localization of bacterial symbionts. Whether the seep mytilid taxa constitute paraphyletic or polyphyletic groups remains unresolved. Our phylogenetic hypotheses also provide a benchmark for the phylogeny of mytilid bacterial symbionts.     

Leaching of nitrogen in Swedish agriculture — a historical perspective

There is a need to examine long-term changes in nitrogen leaching from arable soils. The purpose of this study was to analyse variations in specific leaching rates (kg ha⁻¹ per year) and gross load (Mg per year) of N from arable land to watercourses in Sweden from a historical perspective. The start of the study was set to 1865 because information on crop distribution, yield and livestock has been compiled yearly since then. The SOIL/SOILN model was used to calculate nitrogen leaching. Calculations were done for cereals, grass and bare fallow for three different soil types in nine agricultural regions covering a range of climatic conditions. Results indicate that both specific leaching rates and gross load of nitrogen in the middle of 19th century were approximately the same as they are today for the whole of south and central Sweden. Three main explanations for this were (1) large areas of bare fallow typical for the farming practice at the time; (2) enhanced mineralisation from newly cultivated land; and (3) low yield . From 1865, i.e. the start of the calculations, N leaching rates decreased and were at their lowest around 1930. During the same period, gross load was also at its lowest despite the fact that the acreage of arable land was at its most extensive. After 1930, average leaching increased by 60% and gross load by 30%, both reaching a peak in the mid-1970s to be followed by a declining trend. The greatest increase in leaching was in regions where the increase in animal density was largest and these regions were also those where the natural conditions for leaching such as mild winters and coarse-textured soils were found. Extensive draining projects occurred during the period of investigation, in particular an intensive exploitation of lakes and wetlands. This caused a substantial drop in nitrogen retention and the probable increase in net load to the sea might thus have been more affected by this decrease in retention than the actual increase in gross load.     

Effect of group size and physiological state of a cagemate on reproduction in the parthenogenetic lizard,Cnemidophorous uniparens (Teiidae)

Summary Cnemidophorous uniparens, an all-female, parthenogenetic species of whiptail lizard (Teiidae), were housed in the laboratory under seminatural conditions in groups of four, in pairs, or as isolates. Group structure and an animal's position in the dominance hierarchy affect reproductive effort. Housed in pairs, the dominant animals exhibit a higher rate of reproduction, as measured by number of clutches and length of clutch cycle, than do their subordinate cagemates. Females housed with dihydrotestosterone-treated ovariectomized females lay more clutches than females housed with ovariectomized hormone-untreated females, those housed with intact females, or housed alone.