Multivariate imputation in cross-sectional analysis of health effects associated with air pollution

We demonstrate a recently developed spatial interpolation methodology in a study of the chronic effects of air pollution on respiratory morbidity. Our study uses data from the Ontario Health Study, a large survey of households in Ontario conducted for the province by Statistics Canada. The interpolation procedure imputes unobserved vectors of air pollution concentrations for individual Public Health Units, from those observed at a few fixed air pollution monitoring sites. We use logistic regression methods to assess the significance of air pollution levels based on the imputed values after modelling the relationship between binary health responses and assorted covariates such as measures of life style. Our findings prove negative; no significant relationship between chronic respiratory morbidity and air pollution is found. The imputation methodology is seen to be promising and might well be used in other such analyses.     

有机物料对土壤中水溶性氟环境效应的影响

土壤是固、液、气三相共存体,氟在土-水-植物、动物界面的转化可通过土壤水溶性氟含量表征。试验选用典型贵州黄壤和石灰土,运用有机质进行土壤污染修复的机理,通过向模拟高氟污染土壤中添加有机物料泥炭和风化煤,采用两因素最优设计,研究两种有机物料对土壤中水溶性氟含量的影响。结果表明,泥炭和风化煤都能降低土壤中水溶性氟含量,且泥炭的处理效果更好,最佳添加量是1.258g·kg-1。同时表明,黄壤和石灰土环境下氟形态转化的化学机理不同,运用有机质修复氟污染黄壤添加适量就可达到理想效果,而氟污染石灰土还存在其它更直接有效的方法改变氟在石灰土环境下的形态及其活性。     

Information transfer during recruitment in the ant<Emphasis Type="Italic"> Lasius niger</Emphasis> L. (Hymenoptera: Formicidae)

In this paper, we used the food-correlated search behavior observed in foraging ants returning to a previously rewarding site to study information transfer during recruitment in the ant Lasius niger. We hypothesized that, if information about the characteristics of the food is conveyed during recruitment, food-correlated search tactics should also be observed in recruited workers. Our results show that the characteristics of the trajectories of recruited workers are comparable to those of scout ants returning to a site or prior food find and depend more on the type (prey/sugar) than on the quality (sugar concentration) of the food discovered by the scouts. Independent of sugar concentration, workers recruited to a source of sugar search with a greater sinuosity than workers recruited to a prey. Experimental manipulation of the recruitment signals (chemical trail and contact between ants) shows that the trail pheromone laid down by recruiting ants does not play a role in the modification of trajectory sinuosity. This change appears to be most likely triggered by a direct perception of the residue of sugar smeared on the body of the recruiting workers coming back to the nest.Communicated by J. Heinze     

Development of the typical driving cycle for buses in Hanoi,Vietnam

This paper develops a typical driving cycle for buses in Hanoi that does not require the deconstruction of the natural driving patterns. Real velocity–time data were collected along 15 routes in the inner city. The raw velocity–time series were preprocessed to remove errors, and smooth and denoise the data. These data, then, were tested for stationary behavior before being used in the construction of the driving cycle based on Markov chain theory. The 14 representative parameters of the driving cycle, including vehicle-specific power, which were extracted from 33 driving cycle parameters using the hierarchical agglomerative clustering method, were used to integrate the features of realistic driving patterns into the typical driving cycle. The conformity of the developed driving cycle with the real-world driving data was evaluated by the speed–acceleration frequency distribution (SAFD). A typical driving cycle for buses in Hanoi with a SAFD of 13.2% was developed. This is the first driving cycle developed for buses in Vietnam.

Implications: A typical driving cycle was developed for the first time for buses in Hanoi. With the deviation in speed-acceleration frequency distribution (SAFD) reaching to 13.2%, the developed driving cycle reflects well the overall real-world driving data in the city. This driving cycle, therefore, can be applied for the development of the country-specific emission factors and emission inventories for buses which are a very good tool as well as useful information for integrated air quality management in Hanoi.     

Photocatalytic degradation of 5-nitro-1,2,4-triazol-3-one NTO in aqueous suspension of TiO2. Comparison with Fenton oxidation

5-nitro-1,2,4-triazol-3-one (NTO) is a powerful insensitive explosive, present in industrial waste waters. A remediation method based on photochemical decomposition and Fenton oxidation of NTO has been evaluated by monitoring the mineralization of 14C-labelled NTO. The TiO2-catalyzed photodegradation (lambda > 290 nm, TiO2 0.4 g/l, NTO 150 mg/l)) leads to the complete mineralization of NTO in 3 hours. This degradation involves a simultaneous denitrification and ring scission of NTO leading to nitrites, nitrates and carbon dioxide. No significant photo-degradation of NTO was detected in the absence of the catalyst. Long term irradiation over one week, leads to a complete degradation of concentrated NTO (5 g/l), suggesting that this method could be useful to clean-up NTO wastes. Fenton oxidation offers an efficient cost-effective method for NTO remediation. This reaction is faster that the TiO2 catalyzed photolysis and find application on the mineralization of high concentrations of NTO (15 g/l). Fenton oxidation provokes ring cleavage and subsequent elimination of the two carbon atoms of NTO as CO2. During this reaction, the nitro group is completely transformed into nitrates.     

Effects of road dust on the growth characteristics of Sophora japonica L. seedlings

Road dust is one of the most common pollutants and causes a series of negative effects on plant physiology. Dust's impacts on plants can be regarded as a combination of load,composition and grain size impacts on plants; however, there is a lack of integrated dust effect studies involving these three aspects. In our study, Sophora japonica seedlings were artificially dusted with road dust collected from the road surface of Beijing so that we could study the impacts of this dust on nitrogen/carbon allocation, biomass allocation and photosynthetic pigments from the three aspects of composition, load and grain size. The results showed that the growth characteristics of S. japonica seedlings were mostly influenced by dust composition and load. Leaf N, root–shoot ratio and chlorophyll a/b were significantly affected by dust composition and load; leaf C/N, shoot biomass, total chlorophyll and carotenoid were significantly affected by dust load; stem N and stem C/N were significantly affected by dust composition; while the dust grain size alone did not affect any of the growth characteristics. Road dust did influence the growth characteristics more extensively than loam. Therefore, a higher dust load could increase the differences between road dust and loam treatments. The elements in dust are well correlated to the shoot N, shoot C/N, and root–shoot ratio of S. japonica seedlings. This knowledge could benefit the management of urban green spaces.     

Methylated and thiolated arsenic species for environmental and health research——A review on synthesis and characterization

Hundreds of millions of people around the world are exposed to elevated concentrations of inorganic and organic arsenic compounds, increasing the risk of a wide range of health effects. Studies of the environmental fate and human health effects of arsenic require authentic arsenic compounds. We summarize here the synthesis and characterization of more than a dozen methylated and thiolated arsenic compounds that are not commercially available. We discuss the methods of synthesis for the following14 trivalent(Ⅲ) and pentavalent() arsenic compounds: monomethylarsonous acid(MMA~Ⅲ), dicysteinylmethyldithioarsenite(MMA~Ⅲ(Cys)_2), monomethylarsonic acid(MMA~Ⅴ),monomethylmonothioarsonic acid(MMMTAⅤ) or monothio-MMA~Ⅴ, monomethyldithioarsonic acid(MMDTA~Ⅴ) or dithio-MMA~Ⅴ, monomethyltrithioarsonate(MMTTA~Ⅴ) or trithio-MMA~Ⅴ,dimethylarsinous acid(DMA~Ⅲ), dimethylarsino-glutathione(DMA~Ⅲ(SG)), dimethylarsinic acid(DMA~Ⅴ), dimethylmonothioarsinic acid(DMMTA~Ⅴ) or monothio-DMAⅤ, dimethyldithioarsinic acid(DMDTA~Ⅴ) or dithio-DMA~Ⅴ, trimethylarsine oxide(TMAO~Ⅴ), arsenobetaine(AsB), and an arsenicin-A model compound. We have reviewed and compared the available methods,synthesized the arsenic compounds in our laboratories, and provided characterization information. On the basis of reaction yield, ease of synthesis and purification of product, safety considerations, and our experience, we recommend a method for the synthesis of each of these arsenic compounds.     

化学分散剂对海洋溢油与颗粒物之间相互作用的影响

海洋溢油事故频繁发生,向溢油上施加分散剂是常用的应急处理方法之一。溢油会和海洋中的悬浮颗粒物SPM（suspended particle material）相互作用形成油-悬浮物的聚集体OSAs（oil-SPM aggregations）,还可以与海洋中的颗粒物、浮游生物、细菌、生物碎屑等构成海洋油雪MOS（marine oil snow）。施加分散剂会影响这两种聚集体的生成,继而影响到溢油的迁移和归宿。本文介绍了化学分散剂的使用原则和现状,在介绍OSAs和MOS的形成机理的基础上,分析了施加分散剂对溢油与颗粒物之间相互作用的影响,并对OSAs和MOS的环境归宿进行了探讨。     

丹江口水库水体氮的时空分布及入库通量

为解析丹江口水库水体氮的时空分布特征及主要污染来源,以丹江口库区及主要入库河流为研究对象,分析了水体氮的空间分布、季节及年际变化;利用回归分析,解析了氮污染驱动因素;并估算了入库河流氮通量及对库区氮污染负荷的贡献率. 结果表明:研究区水体ρ(TN)、ρ(NH₄+-N)分别在0.07~16.73和0.01~10.65 mg/L之间,年均值分别为2.34和0.71 mg/L,空间分布呈入库河流高于库区的趋势;季节特征表现为春季、冬季>秋季>夏季. 2005—2014年库区水体ρ(TN)整体呈先升后降的趋势,其中取水口陶岔断面ρ(TN)上升较快,2012年较2007年增加了1.5倍,2013年开始ρ(TN)有所下降,但仍然维持在较高水平. 近10年来库区水体ρ(NH₄+-N)始终维持在较低水平. 神定河、犟河、泗河、剑河等环库支流河口氮污染最严重,城镇化是造成流域水体氮污染的主要驱动力. 汉江TN入库量贡献最大,占63.0%,其中境外来水TN入库量占总量的59.2%,为达到丹江口水库生态环境保护要求的Ⅲ类水质(GB 3838—2002《地表水环境质量标准》)目标,汉江TN需削减量为16 715.0 t/a. 境内河流中,环库河流的TN入库量最大,其中泗河、老灌河、神定河、金钱河、犟河和天河等TN入库量较大,TN需削减量分别为 2 286.7、2 197.7、1 493.6、1 106.9、979.1和728.9 t/a.      

Drivers for OSH interventions in small and medium-sized enterprises

The debate concerning occupational safety and health (OSH) interventions has recently focused on the need of improving the evaluation of interventions, and in particular on the need for providing information about why the intervention worked or not, under what circumstances and in which context. Key concepts in the analysis of the context are the drivers, i.e., those factors enabling, fostering or facilitating OSH interventions. However, the concept of driver for an OSH intervention is both confused and contested. Although the term is widely used, there is little consensus on how drivers should be understood, how important they are in different contexts and how they can facilitate interventions. This exploratory study based on interviews with the owner-managers and the safety officers of small and medium-sized enterprises (SMEs) gives an overview of the most characteristic drivers for OSH interventions. The results will be used to make an initial evaluation of SMEs' needs, and will help orient interventions and future research.