甲醛危害性工程学评价模型的实验研究

本文主要研究在国标限量浓度上下的低浓度甲醛对果蝇的影响,同时建立其危害性工程学评价模型。实验以Oregon K野生型黑腹果蝇为实验对象,以果蝇的半数死亡天龄(LT50)作为评价标准,使其暴露在动态浓度稳定控制的染毒装置中,污染物浓度控制在0～900μg/m~3范围内。实验结果表明,果蝇的半数死亡天龄与甲醛浓度间存在明显负相关性(相关性r=-0.980,显著性P0.01)。在同等暴露浓度下,雌性果蝇对甲醛浓度耐受性较雄性果蝇弱,半数死亡天龄小于雄性果蝇。根据甲醛的剂量与果蝇寿命的关系,建立了甲醛浓度与危害性指数(HI)之间的Logistic回归模型(拟合度R~2=0.996)。     

苯危害性工程学评价模型的实验研究

本文主要研究低浓度苯对果蝇生命周期的影响,建立相应的苯危害性工程评价模型,为进一步研究室内挥发性有机化合物(VOC)的叠加危害性提供研究方法基础。采用Oregon k黑腹果蝇作为受试生物,在动态染毒装置中进行0~600μg/m3低浓度水平的苯暴露实验。结果显示:8个实验组中,相同暴露时间下,雌性果蝇死亡数均高于雄性果蝇;随着苯的浓度升高,果蝇半数死亡时间(LT50)显著缩短,果蝇半数死亡时间与苯的浓度呈现良好的剂量-反应关系(相关性r=-0.988,显著性P0.001);根据苯单独作用下的剂量-反应关系,建立了苯的危害性指数(HI)与浓度之间的Logistic回归模型(拟合度LRI=0.996)。     

甲醛和苯叠加危害性工程学评价模型的实验研究

本文主要研究低浓度水平甲醛和苯叠加对果蝇生命周期的影响,建立相应的叠加危害性工程评价模型。实验采用Oregon k黑腹果蝇作为受试生物,在动态染毒装置中进行低浓度水平的暴露实验,暴露污染物浓度范围为0~500μg/m3。当甲醛(苯)浓度水平一定时,随着苯(甲醛)的浓度升高,果蝇半数死亡时间(LT50)显著缩短;甲醛与苯在标准浓度下的叠加实验组与两者单独实验相比较,叠加组果蝇半数死亡时间(LT50)显著缩短。综合分析实验数据得出:在实验浓度范围内,甲醛与苯联合作用于果蝇时,其毒性呈现协同作用,且当两者处于较低浓度下,协同作用更为显著。另外本研究根据甲醛和苯联合作用下的剂量-反应关系,建立了混合污染物危害性指数(HI)与污染物浓度之间的二元Logistic回归模型(拟合度LRI=0.957)。     

基于果蝇的甲醛危害性评价中室内湿度的影响

甲醛被世界卫生组织列为一级致癌物,广泛存在于现代封闭式办公居住空间,对人体危害甚大。WHO以及国标根据甲醛对鼻子和喉咙的刺激阀值,建议室内甲醛的浓度值为不高于0.1mg/m3。但实际上室内空气污染是混合的,探讨混合污染时危害性的评价方法十分必要。本文采用果蝇作为受试生物,建立动态暴露浓度控制实验系统,实验研究不同湿度条件下甲醛浓度变化对果蝇生命周期的影响,并通过数据分析,探讨湿度对果蝇生命周期的影响,为建立混合空气污染评价果蝇生命周期模型积累基础数据。     

基于改进果蝇算法优化SVM的个人信用风险评估

为了提高信用风险评估的准确率,应用支持向量机(SVM)来建立信用风险评估模型。针对SVM模型性能的优劣与参数的选择密切相关,提出对传统的果蝇优化算法(FOA)进行改进,采用改进的果蝇算法优化支持向量机的参数,并将该模型的评估结果分别与网格法、遗传算法(GA)和果蝇算法(FOA)优化SVM参数的评估结果对比。实验结果表明:使用改进的果蝇算法优化后的支持向量机模型的评估准确率更高,更适合用于信用风险评估。     

动式吸入染毒装置对低浓度甲苯控制效果评价

本文提出了动式吸入染毒实验装置,采用微量注射泵以恒定速度发生汽化污染物的方式对染毒装置进行改进;实现污染物浓度动态控制,并对甲苯的浓度控制进行了实验测试,以验证该方法的可行性。结果发现:1)染毒柜内甲苯浓度与微量注射泵的注射速度成显著一次线性关系,并且拟合得出的排风量与实测排风量比值A=1.031,误差为3.1%;2)染毒柜内甲苯浓度平均变化范围与其小时平均值的百分比在±9%左右,由此得出该实验装置可以精确控制调节甲苯浓度。     

粉末活性炭去除水中1,4-二氯苯和1,2,4-三氯苯应急处理方法的研究

针对本地水源研究了采用粉末活性炭(PAC)吸附去除水中1,4-二氯苯和1,2,4-三氯苯的可行性、吸附行为及应对能力。结果表明,PAC能有效去除水中1,4-二氯苯和1,2,4-三氯苯,吸附行为符合Frendlich方程。PAC投加量20mg/L,1,4-二氯苯和1,2,4-三氯苯浓度均为5倍标准限值时,PAC吸附60min和10min可分别将水源水1,4-二氯苯和1,2,4-三氯苯残余浓度控制在标准限值以下,去除率分别为84.6%和93.6%。当PAC最大投加量为80mg/L,吸附时间120min时,PAC能将水源水下浓度为5.26mg/L的1,4-二氯苯和2.73mg/L的1,2,4-三氯苯去除至标准限值以下,可应对浓度分别为标准限值的17.5倍和136.5倍。     

重铬酸钾对泥鳅鳍细胞系的毒理学研究

为探究重铬酸钾的毒性机制,建立适合监测铬污染的体外检测系统,以体外培养的泥鳅Misgurnus anguillicaudatus鳍细胞系(DIMF)为试验材料,研究了重铬酸钾的毒性效应。结果表明:通过噻唑蓝(MTT)比色法测定重铬酸钾染毒后细胞的24 h半致死浓度为(25.3±1.2)μmol/L;暴露在浓度为0³0μmol/L的重铬酸钾中,细胞超氧化物歧化酶(SOD)活性随着染毒浓度的增加而增大;谷胱甘肽超氧化物酶(GSH-Px)在重铬酸钾浓度为030μmol/L的重铬酸钾中,细胞超氧化物歧化酶(SOD)活性随着染毒浓度的增加而增大;谷胱甘肽超氧化物酶(GSH-Px)在重铬酸钾浓度为0²0μmol/L时活性升高,当染毒浓度为30 mol/L时,活力开始下降;谷胱甘肽S-转移酶(GST)活性则随重铬酸钾浓度的升高而降低;微核试验显示,DIMF微核率随染毒浓度的增加呈先升高后降低的趋势,其中最大微核率为0.733%;实时定量PCR结果显示,对照组的金属硫蛋白(MT)基因表达量很低,经重铬酸钾诱导后MT基因表达量显著升高(P<0.01)。研究表明,重铬酸钾可对细胞的酶系统和遗传物质造成一定的损伤。     

重铬酸钾对泥鳅鳍细胞系的毒理学研究

为探究重铬酸钾的毒性机制,建立适合监测铬污染的体外检测系统,以体外培养的泥鳅Misgurnus anguillicaudatus鳍细胞系(DIMF)为试验材料,研究了重铬酸钾的毒性效应。结果表明:通过噻唑蓝(MTT)比色法测定重铬酸钾染毒后细胞的24 h半致死浓度为(25.3±1.2)μmol/L;暴露在浓度为0~30μmol/L的重铬酸钾中,细胞超氧化物歧化酶(SOD)活性随着染毒浓度的增加而增大;谷胱甘肽超氧化物酶(GSH-Px)在重铬酸钾浓度为0~20μmol/L时活性升高,当染毒浓度为30 mol/L时,活力开始下降;谷胱甘肽S-转移酶(GST)活性则随重铬酸钾浓度的升高而降低;微核试验显示,DIMF微核率随染毒浓度的增加呈先升高后降低的趋势,其中最大微核率为0.733%;实时定量PCR结果显示,对照组的金属硫蛋白(MT)基因表达量很低,经重铬酸钾诱导后MT基因表达量显著升高(P<0.01)。研究表明,重铬酸钾可对细胞的酶系统和遗传物质造成一定的损伤。     

苏州市独墅湖高教区PM_(2.5)对大鼠呼吸系统急性损伤的研究

目的研究大气细颗粒物对大鼠呼吸系统急性损伤特征和可能的损伤机制。方法将24只Wistar雄性大鼠随机分为4组,即对照组、PM_(2.5)低、中、高剂量组(2.5 mg/kg、5.0 mg/kg和10.0 mg/kg)。以从苏州市独墅湖高教区某校区采集的PM_(2.5)配制不同浓度的PM_(2.5)悬液,急性染毒大鼠,采用气管滴注法连续染毒3 d。最后一次染毒结束24 h后处死实验动物,固定左肺组织并收集右肺的支气管肺泡灌洗液(BALF)。观察肺组织的病理学改变;检测BALF中乳酸脱氢酶(LDH),酸性磷酸酶(ACP),碱性磷酸酶(AKP),促炎因子TNF-α、IL-8,抗炎因子IL-4、IL-10水平;以流式细胞仪检测肺细胞线粒体膜电位(MMP),钙离子浓度(Ca~(2+)),活性氧(ROS)含量变化。结果肺组织病理学结果表明,PM_(2.5)会引起肺部炎症反应,肺间质增宽,肺泡腔内分泌物增多,且随着染毒剂量的增加,病变程度有加重的趋势;大鼠肺泡灌洗液中酶、细胞因子基本没有变化,仅5.0 mg/kg和10.0 mg/kg PM_(2.5)染毒后大鼠肺泡灌洗液中碱性磷酸酶(AKP)含量显著低于对照组;PM_(2.5)染毒组钙离子浓度增高、线粒体膜电位降低,5.0 mg/kg PM_(2.5)染毒组活性氧含量升高。结论采自苏州市独墅湖高教区的PM_(2.5)急性染毒可引起机体肺实质损伤,诱导氧化损伤,导致急性炎症性病变。     

Biological denitrification in a fluidized bed with sand as carrier material

A mathematical model for biological fluidized bed denitrification was tested in a 400 l h⁻¹ expanded bed. Nitrate proved to inhibit the nitrite-reductase activity. Competitive inhibition showed a better correspondence between theory and experiment than uncompetitive inhibition. The efficiency of the fluidized bed for denitrification purposes was much higher than in the case of conventional mixed liquor processes. Both theory and experiments showed a substantial accumulation of the intermediary product nitrite, a potential health hazard. Nitrite-N maxima in the column were determined analytically and amounted to about 20% of the influent nitrate-N concentration.     

No-effect concentrations in algal growth inhibition tests

We propose three simple models for effects of chemical compounds on the growth of batch cultures of algae that allow the estimation of the no-effect concentration. The growth model assumes that the costs for growth is proportional to the concentration that exceeds the no-effect level. The hazard model assumes that the hazard rate is proportional to the concentration that exceeds the no-effect level. The adaptation model is similar to the hazard model, but the effects only occur at the start. The no-effect concentrations of the three models turn out to be very similar.     

Benthic fluxes of cadmium, lead, copper and nitrogen species in the northern Adriatic Sea in front of the River Po outflow, Italy

Trace heavy metal (Cd, Pb and Cu) and nitrogen species (N-NO3, N-NO2 and N-NH4) fluxes between sediment and water were examined for approximately 4 days, in a coastal marine station located in the northern Adriatic Sea in front of the River Po outflow. An in situ benthic chamber, equipped with electronic devices for monitoring and adjustment of oxygen and pH and with a temperature detector, was used. The benthic chamber experiment enabled study of the temporal trend of metals and nutrients when oxygen concentration varied in a controlled environment. Although particular care was devoted to chamber deposition and parameter control, sediment resuspension occurred at the beginning of the experiment and O2 fluctuations were observed during the course of the experiment. Pb concentration was affected by both resuspension and oxic conditions in bottom water, which prevented determination of any reasonable Pb flux value. Cd and Cu, not influenced by oxygen fluctuations, reached an equilibrium phase in a short period with initial positive fluxes from sediment of 0.68 (S.D. = 0.07) and 6.9 (S.D. = 5.6) pmol cm(-2) h(-1), respectively. With regard to nitrogen species, the highest positive flux was that of N-NH4 (10.5, S.D. = 2.4, nmol cm(-2) h(-1)) whose concentration increased in the chamber, while nitrate concentration (initial flux of -5.7, S.D. = 1.5, nmol cm(-2) h(-1)) immediately decreased after the beginning of the experiment. Nitrite concentration was almost constant throughout the experiment and its flux was generally low (initial flux 0.1, S.D. = 0.9, nmol cm(-2) h(-1)).     

Comparison of pollution diffusion between river mouth inflow (RMI) and beach uniform inflow (BUI) in sudden water accident

Recently high‐frequency sudden pollution originated from an explosion of industrial plants, transportation accidents and oil spills was often continuously diffused into downstream water. In this paper, the features of pollution diffusion including the boundary shape, concentration gradients and covered area from the two typical sudden water accidents of river mouth inflow (RMI) and beach uniform inflow (BUI) were investigated and compared by utilizing computational fluid dynamic (CFD) model and lab‐scale experiments. It was found that a circular boundary shape was formed when diffusion velocity was slower than threshold velocity of 0.0016 m/s, however, a long strip of boundary was replaced at the speed of more than 0.0016 m/s from RMI, using CFD simulation under lab‐scale. The coincidence degree of diffusion over time in terms of covered area and boundary shape between CFD simulation and the lab‐scale experiment was reached to 97.6–99.6% both in RMI and BUI. The result indicated that CFD was applied to simulate the pollution diffusion from the two patterns of sudden water accidents under full‐scale. Results showed that a sharp peak was capable of appearing in mainstream and there was a ring current appearing in side wing from RMI. However, the mainstream with a gentle peak and the side wing with symmetrical diffusion were arising in BUI. In addition, a high concentration gradients and a clear concentration contours were both exhibited in RMI and BUI. The results may assist in offering emergency response to control sudden pollution diffusion, further supporting the scope of pollution hazard assessment and ecological remediation to recover pollution region.     

Différentes déclinaisons de l'aléa liquéfaction: de la cartographie préventive au projet

As part of its Public Service, Applied Research, and Client Service activities, BRGM's Thematic Centre for Natural Geological Risks (NGR) has recently undertaken studies in order to characterize "liquefaction hazard". The paper considers definitions and presents several approaches to liquefaction hazard assessment, demonstrated by several examples. The first approach is a naturalistic one: Hazard assessment is considered in a structured manner by undertaking: – a regional inventory of historic events – mapping of formations susceptible to liquefaction in homogeneous risk areas subject to seimic activity – preventive mapping of the phenomena at local scale The second approach is a semi-deterministic one: It allows to produce a seismic microzonation, considering parametric calculations and charts (Seed's reverse method). This approach can be used also to recommend soil improvements when liquefaction hazard does exist. The third approach is a deterministic approach: It takes into account a 3D geotechnical model of the analysed area, as well as specific charts to produce a liquefaction hazard assessment of soils and an advanced seismic microzonation. This method was used in Guadeloupe and Martinique districts (French Lesser Antilles) ad for the design of a new TGV railway track in the south of France. The proposed methodology relies on the French Association for Earthquake Engineering recommendations and brings some innovative aspects: combined naturalistic and geotechnical analyses for liquefaction hazard assessment, combined chart use and 3D geotechnical modelling for liquefaction hazard microzonation. Apart from the complete analysis of the liquefaction hazard not always being useful, it also demands major resources, and is consequently sometimes broken down into several less-detailed stages. The various examples considered thus form a continuum and are simply variations of a same definition of the liquefaction hazard: where: X, Y and Z=coordinates t=time Δu=interstitial over-pressure σ'_vo=initial effective stress I_L=Iwasaki's liquefaction index     

一种基于QFD的地铁施工风险评估方法

地铁施工过程中一旦发生事故,会带来严重的经济损失和人员伤亡,而对地铁项目的风险评估和有针对性的预防措施能有效提高施工过程中的抗风险能力。文章以质量功能展开(QFD)为分析工具进行地铁风险评估,通过构建二阶质量屋模型来表达分析对象之间的影响关系,并采用相对具有区域规律性的事故类型的相对风险权重作为输入以及以非归一化处理的方式解决了输入点改变带来的不同作业活动下事故类型的权重求和问题,以获得作业活动和风险因素的相对风险权重。最后将理论应用于钻眼爆破开挖作业下的事故类型与风险因素风险分析,计算结果与实际分析相符。     

Space–time clustering of seismic events and hazard assessment in the Zabrze-Bielszowice coal mine,Poland

The results of the statistical analysis of seismic activity recorded in the “Zabrze-Bielszowice” coal mine in Poland are presented in this article. The monitoring was conducted by a small network consisting of four triaxial geophones deployed in vertical holes in the roof. For over 1000 seismic events recorded during the two month's experiment, the location of sources was realized. The seismic sources were mostly located ahead of the active face of the longwall. Since the first day of the monitoring, cluster analysis was sequentially performed for increasing number of sources. At the end of the experiment, 31 clusters were identified. They consisted of different numbers of events and were separated in space. About 40% of the events were not included in the clusters. For each large cluster, hazard analysis was separately performed. The hazard function evaluated for the largest cluster was compared with hypocenters of high energy tremors (E>1000 J) recorded by the geophones in that area. For some cases, recorded tremors occurred after an abrupt decrease of hazard function, but only one of them was located in the vicinity of the appropriate cluster. We concluded that for the analyzed cluster, a correlation between evaluated hazard function and time occurrences of the high energy tremors existed. Except for one case, there is no space correlation between analyzed clusters and high energy tremors.     

火灾烟气毒性评价新的"RRC"动态模型及工程应用

就火灾中的死亡人数而言，最主要的威胁来自于火灾中的烟气。目前已经有很多种模型来描述火灾中的烟气毒性危害，如CO随机模型、FED、FEC和N气体模型。所有这些模型都不能反应真实火灾中烟气浓度的时空变化。根据真实火灾中的烟气危害度，选取人员的呼吸率、人员在火灾中的逃生路径、特定建筑中的烟气浓度场分布等三个对于人员致死具有决定性的因素，初步建立一个新的“RRC”动态模型来描述火灾中的烟气毒性危害，并通过算例展示了模型的工程应用。     

Numerical modeling of passive scalar dispersion in an urban canopy layer

A turbulent dispersion model describing the dispersion of a passive scalar from a localized source released in a built-up environment (urban area) is presented. The proposed model simulates both the flow field in the urban complex using the ensemble-averaged, three-dimensional Navier-Stokes equations with a standard k-ε turbulence closure model and the turbulent diffusion using transport equations for the mean concentration and concentration variance of the scalar. Two models for the scalar dissipation rate, required to close the transport equation for concentration variance, are investigated. Results of a detailed comparison of the flow and turbulent dispersion between a comprehensive water channel experiment and the model predictions are presented. The water channel experiment is unique in the sense that it includes data obtained from the dispersion of both continuous and nearly instantaneous releases of a tracer from a point source located within a regular array of building-like obstacles, and this data include measurements of both the mean concentration and concentration variance.     

Prevalence of skin lesions and exposure to arsenic in drinking water in Iran

Prevalence of skin lesions was investigated among 752 participants in eight villages in Kurdistan province in Iran with emphasis on total lifetime intake of arsenic from drinking water (TLIA). The participants were selected from eight villages with different exposure levels using a cluster-sampling technique. TLIA was calculated for each individual taking into account the type of water supply and their mean annual arsenic concentration. The study showed that 49 persons (6.5%) were suffering from hyperkeratosis and 20 persons (2.7%) from hyperpigmentation. The correlation between hyperkeratosis and hyperpigmentation was significant (R=0.325, p<0.01). Using the logistic regression model it was found that the relationship between TLIA and hyperkeratosis (OR=1.14, 95% CI=1.039-1.249), and hyperpigmentation (OR=1.254, 95% CI=1.112-1.416) was also significant. In conclusion, TLIA can be applied as a reliable indicator for the assessment of exposure.