工业废水中有机污染物指标TOC、CODCr、BOD5相关性研究

研究了工业废水中有机污染物指标TOC、CODCr、BOD5三者之间的相关性。用耶拿Muhiwin N／C 3100型总有机碳测定仪测定TOC,用经典方法测定CODCr、BOD5。通过TOC线性回归计算发现TOC与CODCr、BOD5有很好的相关性。因此对于生产稳定的企业可通过测定TOC推算出CODCr、BOD5值。从而可将TOC作为有机污染物排放控制指标。     

Mapping eucalypt forest susceptible to dieback associated with bell miners (Manorina melanophys) using laser scanning, SPOT 5 and ancillary topographical data

Mapping the location and extent of forest at risk from damaging agents or processes assists forest managers in prioritizing their planning and operational mitigation activities. In Australia, Bell Miner Associated Dieback (BMAD) refers to a form of canopy decline observed in eucalypt crowns occupied by colonies of bell miners (Manorina melanophrys). High densities of bell miners are associated with decreased avian abundance and diversity and an increase in psyllid abundance on crown foliage. BMAD has recently been nominated as a key threatening process in New South Wales (NSW). Consequently, a modelling system for predicting bell miner distribution in coastal eucalypt forests of NSW has been developed. The presence or absence of bell miners was recorded in 130 plots located within a 12,800 ha catchment study area containing a range of eucalypt forest types. The modelling system was produced by integrating a machine learning software suite (WEKA), and the statistical software R within the geographic resources analysis support system (GRASS) geographical information system (GIS). The variable modelled was the binary variable: presence or absence of bell minors. Six modelling techniques (Logistic regression; generalised additive models; two tree-based ensemble classification algorithms, random forest and Adaboost and Neural Networks) were integrated with airborne laser scanning; SPOT 5 and topographic derived variables. Model evaluation and parameter selection were measured by three threshold dependent measures (sensitivity, specificity and kappa) and the threshold independent Receiver Operator Curve (ROC) analysis. The final presence and absence maps were obtained through maximisation of the kappa statistic and applied at a resolution of 10 m across the entire catchment study area. For this data set, the most accurate algorithm for predicting the distribution of bell miner colonies was random forest (kappa = 0.84; ROC area under curve = 0.97). Variables most commonly selected in the six models were the laser scanning metrics; coefficient of variation, skewness, and the 10th and 90th percentiles derived from the shape of the height frequency distribution which, in turn, is directly influenced by vertical structure of the forest. An image textural statistic based on the shortwave infrared (SWIR) band of SPOT 5 was also commonly selected by the models. The SWIR band is sensitive to vegetation and soil moisture content. These models predicted that forest stands with a sparse eucalypt canopy over a moist, dense understorey were susceptible to being colonised by bell miners and hence BMAD.     

太原市采暖季PM2.5中元素特征及重金属健康风险评价

通过采集太原市采暖季环境空气PM2.5样品,经等离子体发射光谱仪对19种元素进行测定,运用富集因子和主因子法揭示其来源,并对重金属的潜在生态风险、人体暴露和健康风险进行评价.结果表明,元素Si、Ca、Al、Na、Mg、K、Fe为PM2.5的主要元素;土壤风沙尘、煤烟尘、机动车车尾气、工业粉尘和建筑尘是元素的主要排放源,贡献率分别为43.46%、15.69%、13.41%、9.89%和9.03%.重金属潜在生态风险指数为1 953.82,具有极强的潜在生态危害程度;环境空气重金属暴露途径以手口摄食暴露为主,呼吸吸入暴露最小,皮肤接触暴露居中,儿童重金属暴露风险高于成人;PM2.5中重金属存在非致癌风险,不具有致癌风险,儿童非致癌风险值为2.94,是成人的1.39倍.     

ZSM-5沸石分子筛吸附-脱附VOCs的性能研究

以不同Si/Al比的ZSM-5分子筛为吸附剂,考察了硅铝比对其疏水性和吸附性能的影响.结果表明,随着Si/Al比的增加,其微孔孔体积和微孔表面积变大,当Si/Al100时,ZSM-5分子筛均具有良好的疏水性和对甲苯的选择性吸附能力,但脱附温度随之升高.同时,以4类VOCs(醇类、酯类、烃类、酮类)为吸附质,研究了ZSM-5分子筛吸附-脱附不同VOCs的性能.发现ZSM-5分子筛由于具有丰富的微孔结构更适合吸附小分子VOCs,对于同类VOCs分子,随着碳数的增加,分子大小和极性均增大,其与分子筛的作用力越强,热脱附温度越高,但VOCs在ZSM-5分子筛表面300℃左右就能脱附完全.     

QUAL2K模型的生化需氧量指标研究

QUAL2K模型是由美国环境保护署研制开发的一维河流水质模型,被广泛应用于北美、欧洲、亚洲等地的流域污染物总量控制和水质管理。由于国内与美国的水质评价指标不同,导致该模型在国内无法直接进行水质模拟与评价,如美国采用的生化水质指标是CBODu、CBODs和CBODf,而国内采用的是BOD5、CODCr和CODMn。为了促进该模型在国内的推广及应用,从有机物的生物氧化过程、生化需氧量的定义及其检测方法出发,对BOD5与CBODu两者之间的关系进行研究,推导出BOD5与CBODu的转换公式。     

我国环境空气质量标准发展及现状

环境空气质量标准是控制大气污染的重要手段,新修订的环境空气质量标准进一步提高了我国环境空气管理能力,完善了大气环境保护标准.通过对比新修订和现行环境空气质量标准的变更情况,突出了《环境空气质量标准》（GB 3095-2012）在功能分区、污染物浓度限值、数据有效性规定等方面的优越性.研究指出,新增设的PM2.5年均、日均浓度限值和臭氧8h浓度限值,是我国环境空气质量标准与国际标准接轨的重大突破.发达国家和国际代表组织已经开始有增加苯、重金属等污染物的趋势,我国也已经将这些评价指标列入参考浓度限值之列,同时通过这次环境空气质量标准的修订,我国环境空气质量标准在主要污染物控制上,一级标准已经接近或者达到了国际先进水平,但是二级标准与一级标准相差很大,因此二级标准随着我国经济社会和生态环境的发展将有非常大的严格修订空间.针对目前世界各国、国际组织或者地区已经基本取消了环境空气质量标准执行分级标准,中国继续执行分级标准,逐渐缩小差距或者在技术水平达到的情况下取消环境空气质量标准的分级制度,成为下一步努力的目标.     

长三角地区秸秆焚烧PM2.5排放量估算与分析研究

根据长三角地区的实际情况,对该地区两省一市的秸秆焚烧PM2.5排放量状况进行估算.通过长三角地区2002年-2012年主要农作物产量、草谷比、焚烧比例和PM2.5排放因子,估算了该地区内秸秆焚烧量,同时对由秸秆焚烧引起的PM2.5排放量进行了估算,并进行了分析.结果表明：长三角地区2002年-2012年秸秆焚烧量最高的为农业发达的江苏省,高峰都集中在每年的10月份前后,由秸秆焚烧引起的PM2.5排放量呈逐年上升趋势,2012年达到55 218.96 t,其中江苏省每年的PM2.5排放量占到该地区的75％以上,2012年占到80％.研究结果将为制定该地区污染控制政策,改善区域环境空气质量提供科学理论依据.     

Social capital and food security in post-conflict rural Lira District,northern Uganda

While a strong relationship has been established between social capital and food security in the research literature, it is uncertain whether this holds in post-conflict situations. This study examines associations between social capital and food security in post-conflict Lira District, northern Uganda. Since factors affecting food security are complex, we explored the roles of households' characteristics in food security outcomes. Data were collected from March to July 2011 through face-to-face interviews with 221 heads of household in rural Lira. Using multinomial logistic regression, a strong positive association was identified between social capital and household food security. The study also found significant associations of food security with sex, education of household head, amount of cultivated land, and farm and home possessions. The results of this analysis can aid the design of food security programmes that empower poor people while targeting the most vulnerable groups, thereby promoting sustainable development in post-conflict communities.     

基于系统基模的甘肃白银“5·22”越野马拉松事件分析*

为系统研究越野马拉松产业快速发展背后的安全问题,以甘肃白银“5·22”越野马拉松事件为例,采用系统基模工具,构建“5·22”越野马拉松事件系统中企业方、政府方和个体方3方主体行为模式的因果循环回路,并进行系统致因分析。研究结果表明:“5·22”越野马拉松事件是运营企业、政府职能部门、参赛者和志愿者行为逻辑偏差造成共同回应机制失衡的结果,基于此提出同类事件中主体因素的长期杠杆解,为企业安全文化建设、制定相匹配的安全保障制度和完善的个体组织参与机制,指出要解决安全问题必须降低杠杆解的时滞效应,实现杠杆解之间的正反馈机制。     

Z-scheme V2O5-Ag2O/g-C3N4异质结制备及其可见光催化性能

采用原位生长法制备V₂O₅,并将其与Ag₂O/g-C₃N₄水热复合制备V₂O₅-Ag₂O/g-C₃N₄复合光催化剂.利用XRD、FT-IR、SEM和UV-Vis DRS等方法对样品的形貌结构及光学性质进行表征.结果表明,V₂O₅成功掺杂在Ag₂O/g-C₃N₄上,与Ag₂O/g-C₃N₄相比,复合材料对可见光的吸收范围增大;在可见光照射180min后,V₂O₅掺杂量为15%的复合材料对亚甲基蓝(MB)的降解率达到99.10%.经过3次循环降解后,复合材料对MB的降解率保持85%以上,表明其具有良好的稳定性.通过掩蔽实验推测,空穴(h⁺)是光催化体系中主要的活性物质,其光催化性能增强的机理是Ag₂O与g-C₃N₄复合界面形成p-n异质结,并与V₂O₅之间的复合过程符合Z-scheme可见光驱动机制,有效阻碍了光生电子-空穴对的复合,促进活性物质的产生.