苏州河氨化菌分布及生理生化研究

对苏州河氨化菌进行了生态调查,并对其进行了生理生化分析。研究结果表明,苏州河水体中氨化菌数量普遍较高,上游至下游氨化菌数量逐步增多。氨化菌数量与水体中总氮和氨氮呈正比,与硝酸盐成反比。     

Formation and Emission of N2O and CH4 from Compost Heaps of Organic Household Waster

Composting can be a source of N₂O andCH₄ production. In this investigation, differentcompost heaps of organic household waste weremonitored with the focus on potential formation ofCH₄ and N₂O in the heaps and emission ofthese gases from the heaps. The studied compost heapshad different compost ages, turning intervals andcompost sizes. The analysed compost gases containedbetween 1–3421 L of N₂O-N L^-1 and 0–470 mL of CH₄ L^-1. The emission rates ofN₂O and CH₄ from the compost heaps werebetween 1–1464 mg N₂O m^-2 day^-1 and0–119 000 mg CH₄ m^-2 day^-1. These verylarge differences in compost gas composition andemission indicate the importance of compostmanagement. The results also give an understanding ofwhere in the composting process an increasing emissionof N₂O and CH₄ can occur.     

华南玄武岩红土化过程中微量元素地球化学

广东、海南的玄武岩．在强烈的红土化过程中．元素在红土剖面中发生迁移和残留、贫化和富集。根据红土化过程中元素的地球化学性状，将元素划分为活泼元素和不活泼元素两大类。并首次采用了元素它集因子这个概念来探讨红土化过程中微量元素的地球化学行为。最后讨论了红土化过程小金的表生富集作用。     

多溴代二苯醚化合物的研究进展

多溴代二苯醚(PBDEs)作为防火阻燃剂，在世界范围内被广泛应用，它是一种环境内分泌干扰物，类似于甲状腺素T3、T4。现有的研究认为，PBDEs具有生物累积性。并影响甲状腺，神经和免疫等系统。该文主要对现有的PBDEs研究进展进行了总结，并着重介绍了PBDEs的毒性，以及对人类和生物体的暴露水平及其相关的分析方法。     

模拟酸露对植物影响的实验

模拟酸露对植物影响的实验结果表明，用酸露处理后，蚕豆的生理指标发生一定的变化，尤以ｐＨ１３．０时的变化较明显，显示了模拟酸露对植物的伤害作用。     

Driving while impaired by alcohol: An analysis of drink-drivers involved in UK collisions

Objective: Drink-driving represents a critical issue on international organizations’ agendas as one of the key behavioral risk factors in road traffic safety, alongside speed and nonuse of motorcycle helmets, seat belts, and child restraints. Changing road user behaviors regarding these 5 factors is a critical component in reducing road traffic injuries and casualties. The objective of this study is the identification of drivers who are more likely to contribute to crashes in the UK while impaired by alcohol to design targeted drink drive compliance campaigns.

Method: To profile drivers with the factor “impaired by alcohol” assigned in collisions, an extensive data set is used, including all reported injury collisions between 2011 and 2015 in the UK (police records), merged with the Experian Mosaic Database. A multilevel mixed-effects logistic regression is conducted, utilizing the hierarchical nature of the data (drivers within Mosaic types).

Results: Using multilevel mixed-effects logistic regression analysis, the finding is that some driver profiles are more likely to contribute to crashes and are assigned the contributory factor “impaired by alcohol.” Drink-related crashes are more common in some circumstances or for some crash-involved driver groups than others. For instance, alcohol-related crashes are more likely to occur on single carriageways and among males and 25- to 35-year-olds. Drink-drive-related crashes are found to be strongly associated with dark lighting conditions and, more specifically, with late night hours (the interval between 3:00 a.m. and 4:00 a.m. accounts for a third of the drink-drive-related collisions). Using the Experian Mosaic Database which divides the UK population into 66 types based on demographic, lifestyle, and behavior characteristics, the finding is that, among crash-involved drivers, some Mosaic types are significantly more likely (e.g., pocket pensions, dependent greys, streetwise singles) and others are significantly less likely (e.g., crowded kaleidoscope, cultural comfort, penthouse chic) to contribute to a drink-related crash.

Conclusions: The outcome is a more nuanced understanding of drivers contributing to drink-related crashes in the UK. The study concludes by discussing the implications for governments and other interested bodies for better targeting and delivery of public education campaigns and interventions.     

含氧非烃在土壤剖面上迁移行为的土柱淋滤模拟研究

为了揭示土壤剖面中含氧非烃污染物的迁移特征,以及TOC和淋滤水量等因素对迁移作用的影响,选择了部分典型的含氧非烃开展了纵向迁移的土柱淋滤实验,对原土及添加污染物的土柱淋滤实验后样品中含氧非烃的含量及组成进行了对比分析.结果表明,土柱淋滤实验后,土柱表层添加的含氧非烃主要残留在土柱表层0~5 cm范围内,但相比所添加的化合物的量均有不同程度的降低,土柱深部(>10 cm)土壤中含氧非烃含量仍然很低,甚至低于原土中的,在TOC较高的土柱中,这种现象尤为突出.说明土柱淋滤实验过程中,不同剖面含氧非烃均存在向下迁移的现象,且以水溶方式迁移为主.不同含氧非烃单体含量均有随深度增加而降低的趋势,表明其在土壤剖面淋滤过程中均具有一定的迁移性,但不同性质的含氧非烃单体在表层土中残留量及组成差别较大,说明不同化合物迁移能力存在差别,其中,胆甾醇、β-谷甾醇、正构十六烷酸和邻苯二甲酸二丁酯迁移性较强.土壤TOC和淋滤水量对含氧非烃在土壤剖面的迁移作用都有不同程度的影响,淋滤水量相同时,TOC含量越高,土壤中有机质越丰富,越容易富集含氧非烃;TOC相同时,淋滤水量越大,含氧非烃迁移量越大,迁移的深度越大,尤其在TOC含量较低时更明显.     

无锡市大气中类二噁英多氯联苯污染水平

为了了解无锡市大气中类二噁英多氯联苯(Dioxin-like PCBs,DL-PCBs)水平,利用大流量空气采样器在无锡市分别采集了6个气相和6个颗粒相大气样品,气相色谱-质谱(GC-NCI-MS)测定样品中12种类二噁英多氯联苯。结果显示,大气样品中∑_(12)DL-PCBs的总浓度(气相+颗粒相)为1157～2 747 fg/m³,平均浓度为1759 fg/m3,平均浓度为1759 fg/m³。其中,气相的浓度为11 124～2 721 fg/m3。其中,气相的浓度为11 124～2 721 fg/m³,平均值为1 701fg/m3,平均值为1 701fg/m³;颗粒相的浓度为26～143 fg/m3;颗粒相的浓度为26～143 fg/m³,平均值为58fg/m3,平均值为58fg/m³。气相中∑_(12)DL-PCB含量占总量的97%,而颗粒相仅占3%。DL-PCBs的总毒性当量(气相+颗粒相)为2.16～4.47fg TEQ/m3。气相中∑_(12)DL-PCB含量占总量的97%,而颗粒相仅占3%。DL-PCBs的总毒性当量(气相+颗粒相)为2.16～4.47fg TEQ/m³,平均值为3.53fg TEQ/m3,平均值为3.53fg TEQ/m³。DL-PCBs单体中PCB-118的浓度最高,平均占总浓度的54%,其次是PCB-105和PCB-77,PCB+81在所有样品中均未检出。在所有DL-PCBs中,毒性当量浓度的主要贡献者为PCB-126,其平均贡献率为95%,其次为PCB-169,平均贡献率为3%。     

Distribution characteristics of dissolved organic carbon in annular wetland soil-water solutions through soil profiles in the Sanjiang Plain, Northeast China

Overwhelming evidence reveals that concentrations of dissolved organic carbon （DOC） have increased in streams which brings negative environmental impacts. DOC in stream flow is mainly originated from soil-water solutions of watershed. Wetlands prove to be the most sensitive areas as an important DOC reserve between terrestrial and fluvial biogeosystems. This reported study was focused on the distribution characteristics and the controlling factors of DOC in soil-water solutions of annular wetland, i.e., a dishing wetland and a forest wetland together, in the Sanjiang Plain, Northeast China. The results indicate that DOC concentrations in soilwater solutions decreased and then increased with increasing soil depth in the annular wetland. In the upper soil layers of 0-10 cm and 10-20 cm, DOC concentrations in soil-water solutions linearly increased from edge to center of the annular wetland （R^2 = 0.3122 and R^2 = 0.443）. The distribution variations were intimately linked to DOC production and utilization and DOC transport processes in annular wetland soil-water solutions. The concentrations of total organic carbon （TOC）, total carbon （TC） and Fe（II）, DOC mobility and continuous vertical and lateral flow affectext the distribution variations of DOC in soil-water solutions. The correlation coefficients between DOC concentrations and TOC, TC and Fe（II） were 0.974, 0.813 and 0.753 respectively. These distribution characteristics suggested a systematic response of the distribution variations of DOC in annular wetland soil-water solutions to the geometry of closed depressions on a scale of small catchments. However, the DOC in soil pore water of the annular wetland may be the potential source of DOC to stream flow on watershed scale. These observations also implied the fragmentation of wetland landscape could bring the spatial-temporal variations of DOC distribution and exports, which would bring negative environmental impacts in watersheds of the Sanjiang Plain.     

Kinetics of carbon dioxide absorption into mixed aqueous solutions of MDEA and MEA using a laminar jet apparatus and a numerically solved 2D absorption rate/kinetics model

New comprehensive numerically solved 1D and 2D absorption rate/kinetics models have been developed, for the first time, to interpret the experimental kinetic data obtained with a laminar jet apparatus for the absorption of carbon dioxide (CO₂) in CO₂ loaded mixed solutions of mixed amine system of methyldiethanolamine (MDEA) and monoethanolamine (MEA). Three MDEA/MEA weight ratios ranging from 27/03 to 23/07, over a concentration range of 2.316–1.996 kmol/m³ for MDEA and of 0.490–1.147 kmol/m³ for MEA were studied. The models take into account the coupling between chemical equilibrium, mass transfer, and the chemical kinetics of all possible chemical reactions involved in the CO₂ reaction with MDEA/MEA solvent. The partial differential equations of the 1D model were solved by two numerical techniques; the finite difference method (FDM) based on in-house coded Barakat–Clark scheme and the finite element method (FEM) based on COMSOL software. The FEM comprehensive model was then used to solve the set of partial differential equations in the 2D cylindrical coordinate system setting. Both FDM and FEM produced very accurate results for both the 1D and 2D models, which were much better than our previously published simplified model. The reaction rate constant obtained for MEA blended into MDEA at 298–333 K was k_MEA = 5.127 × 10⁸ exp(−3373.8/T). In addition, the 2D model, for the first time, has provided the concentration profiles of all the species in both the radial and axial directions of the laminar jet, thereby enabling an understanding of the correct sequence in which the reaction steps involved in the reactive absorption of CO₂ in aqueous mixed amines occur.