武汉市一次污染过程的局地流场和边界层结构的数值模拟

利用2013年11月武汉市逐日空气质量资料、地面气象观测资料、NCEP/NCAR再分析资料和L波段雷达探空资料,通过WRF模式模拟空气污染生消过程中的局地气象条件变化,探讨特殊地形条件下边界层结构变化和局地环流在污染物生消过程中的作用和影响。结果表明：（1）武汉地区当背景环流场强的时候,由地形引起的局地流场对污染物扩散的影响就弱,反之当背景环流场弱的时候, 地形对流场影响明显:夜间为山风,白天为谷风。夜间山风与偏西北气流及偏东气流在武汉及周边地区辐合,形成气流汇聚带,在武汉地区形成一个反复污染带,即由地形引起的局地流场对污染物扩散的贡献就大;（2）武汉地区发生空气污染时,地面湿度较高,边界层呈上干下湿状态,其特征为暖而干且有偏东小风,这导致污染物不断堆积和重污染过程的形成。     

蔬菜常用农药在地下水中残留风险评估

为明确蔬菜常用农药在地下水中的环境风险,运用China-Pearl和SCI-GROW模型开展地下水环境暴露评估,并根据我国成人和儿童暴露参数推导25种农药预测无效应浓度(PNEC)。研究发现,25种农药PECgw为0~18.340μg·L-1,成年人PNECgw为0.003~19.654 mg·L-1,儿童PNECgw为0.001~23.253 mg·L-1。成年人和儿童的RQgw值均小于1,表明25种农药按照登记用量使用,我国成人和各年龄阶段儿童直接饮用施用农药区域地下水的环境风险可接受。     

农药环境风险评估中常用的计算毒理学模型软件

农药的大量使用为我国带来了严重的环境和健康问题,仅依靠传统生物测试和环境监测的方法已经不能满足农药风险评估的需要。利用计算毒理学模型,可以实现农药的高通量风险评估。本文主要介绍了农药环境风险评估中常用免费的EPI Suite、QSAR Toolbox和PBT Profiler等定量结构-活性关系(Quantitative Structure-Activity Relationship,QSAR)模型软件和SCIGROW、PRZM-GW、China-PEARL和EQC等环境多介质模型软件,以期能为农药的风险评估和科学管理提供参考。     

A dynamic modelling of nutrient metabolism in a cyclic activated sludge technology (CAST) for treating low carbon source wastewater

Environmental Science and Pollution Research - A new mathematical model incorporating biopolymer kinetics and the process of the simultaneous storage and growth are established for the treatment of...     

Application of phosphate solubilizing bacteria in immobilization of Pb and Cd in soil

Environmental Science and Pollution Research - In the present study, heavy metal (HM)-tolerant phosphate solubilizing bacteria (PSB) were isolated and their performance during the remediation of Pb...     

基于GIS的太湖流域主要生态风险源危险度综合评价研究

以太湖流域主要生态风险源为评价对象,充分考虑多类型多等级风险源作用强度的差异性,构建了风险源危险度评价模型,并在此基础上依据风险源发生机率、强度及作用范围等建立了太湖流域洪涝、干旱、极端气象、土壤侵蚀及污染排放等主要生态风险源的危险度评价指标体系。在ArcGIS技术支持下,创建了太湖流域1 606个网格和24个县市的风险源危险度统计数据库,采用AHP权重法确定指标权重,运用叠加分析、空间分析等技术方法最终实现太湖流域单要素及综合生态风险源危险度的定量评价。结果表明流域内生态风险源的分布存在明显的空间分异规律。其中,高生态风险源危险区集中分布在环太湖北部一带,面积约占流域面积的1172%;较高危险区主要呈“西北 北 东北 东”半环状分布格局,所占面积约2452%,危险度较低的区域集中在流域西南部的苕溪流域一带,面积占1566%。此外,不同区域主导生态风险源组成亦不同,约599%的区域是以污染排放为主导生态风险源,主要分布在镇江 宜兴 长兴 安吉一线以东的地区;2545%的区域主导生态风险源为干旱,主要集中在镇江 宜兴 长兴 安吉一线以西;1244%的区域是以洪涝灾害为主导风险源,集中分布在湖州、宜兴等地;而以水土流失、极端气象灾害作为主导风险源地区相对较为分散,所占比例较小     

Potential toxicity of amphenicol antibiotic: binding of chloramphenicol to human serum albumin

Antibiotics are widely used in daily life but their abuse has posed a potential threat to human health. To evaluate the toxicity of chloramphenicol (CAP) at the protein level, the interaction between CAP and human serum albumin (HSA) was investigated by fluorescence, Ultraviolet–visible (UV–Vis) absorption, Fourier transform infrared (FT-IR) spectroscopy and molecular docking methods. Fluorescence data revealed that the fluorescence quenching of HSA by CAP was the result of the formation of CAP–HSA complex, and the binding constant was determined to be 3.196?×?10⁴ L mol^?1 at 310 K. The thermodynamic determination indicated that the interaction was driven by enthalpy change and entropy change together, where the multiple hydrogen bonds (CAP and the residues Arg 222 and His 242 of HSA) and van der Waals forces were the dominant binding force. The site marker competition revealed that CAP bound into sub-domain IIA of HSA. The binding of CAP induced the drastic reduction in α-helix conformation and the significant enhancement in β-sheet conformation of HSA. Molecular docking study further confirmed the binding mode obtained by experimental study. This work provides a new quantitative evaluation method for antibiotics to cause the protein damage.     

高效脱硫菌的筛选及其性能研究

从高硫污染的活性污泥中富集培养,分离纯化得到一株可以降解噻吩的菌株s_4,并对该菌株的形态特征进行观察。应用Design—Expert8．0．5b软件进行响应面优化实验,研究了反应时间、噻吩浓度、微生物浓度3个因素的组合对菌株s_4脱硫效果的影响,并拟合得到多元二次回归方程,得出最佳实验条件。拟合结果表明,当反应时间27．46h,噻吩浓度为1．04％,微生物浓度4．04％时,预测噻吩降解率为14．8％,通过验证得最佳条件下的降解率为14．3％,与预测值相符。     

Kinetics study of fermentative hydrogen production from liquid swine manure supplemented with glucose under controlled pH

Kinetics of H₂ production from liquid swine manure supplemented with glucose by mixed anaerobic cultures was investigated using batch experiments under four different pH conditions (4.4, 5.0, 5.6, and uncontrolled). The temperature for the experiments was controlled at 37 ± 1°C and the length of experiments varied between 50 and 120 hours, depending upon the time needed for completion of each individual experiment. The modified Gompertz model was evaluated for its suitability for describing the H₂ production potential, H₂ production rate, and substrate consumption rate for all the experiments. The results showed that the Gompertz model could adequately fit the experimental results. The effect of pH was significant on all kinetic parameters for H₂ production including yield, production rate and lag time, and the substrate utilization rate. The optimal pH was found to be 5.0, at which a maximum H₂ production rate (0.64 L H₂/h) was obtained, and deviation from the optimal pH could result in substantial reductions in H₂ production rate (0.32 L H₂/h for pH 4.0 and 0.43 L H₂/h for pH 5.6). The results also showed that if pH was not controlled for the batch fermentation process, the substrate utilization efficiency could steeply decrease from 98.8% to 33.7%.     

A Model for Pulse Jet Fabric Filters

ABSTRACT

A new model for pulse jet fabric filtration is proposed. In contrast to the earlier model of Ravin and Humphries,¹ which was formulated on the steady state assumption, the present study is aimed at developing a predictive capability for both transient and steady state operations, taking into account the compression effect of filter cakes. The model's relative simplicity allows frequent updating of the model parameter values, thus improving the accuracy of predictions. As a result, the model is particularly useful in developing control algorithms and designing controllers of pulse jet fabric filtration systems.