兰州地区人群对六六六的暴露及健康风险评价

为研究兰州地区六六六(HCH)对人群的健康风险,应用改进的美国环境保护署(US EPA)多介质暴露模型,结合兰州地区人群状况,计算了各年龄人群通过11种暴露途径对六六六的暴露量.结果表明,兰州地区居民对环境中六六六的终身日平均暴露量为2.01×10-5 mg/(k·d)(儿童)和2.53×10-5 mg/(kg·d)(成人).暴露途径中以食物暴露为主导,其次是呼吸暴露,皮肤暴露作用很小.食物中贡献较大的为谷物和蔬菜.相应的健康风险度分别为5.40×10-9 a-1(男性)和6.30× 10-9a-1(女性).兰州地区六六六居民人体健康风险度低于可接受健康风险度标准,兰州地区六六六人群暴露水平与天津、太原、太湖地区相比存在一定的差异,女性对六六六的暴露量高于男性.兰州人群成人的六六六暴露量大于儿童,成人是六六六暴露风险最高的群体.各项参数中,谷物和蔬菜摄食量和相应的六六六残留浓度是影响暴露的重要因素.通过蒙特卡罗模拟得到各年龄段人群对HCH的日均暴露量的分布特征,各输出变量均服从对数正态分布.     

上海松江泖港地区蟹种养殖对水质的影响

为了探究河蟹蟹种养殖模式对水环境的影响,于2012年6-10月,对上海松江泖港地区蟹种池塘和水源的水质进行了监测.结果表明,在整个养殖周期中,蟹种池CODMn不断增长,水源水的变化趋势为先增后减.在多数时段,水源水亚硝酸盐质量浓度高于蟹种池,但6月26日蟹种池反而显著高于水源水(p＜0.05).在整个监测过程中,水源水硝酸盐质量浓度均显著高于蟹种养殖池(p＜0.05).养殖前期,水源水磷酸盐质量浓度高于蟹种池;养殖后期蟹种池高于水源水,但均无显著差异(p＞0.05).台风过境后,水源水氨氮质量浓度达2.21 mg/L,磷酸盐质量浓度达0.467 mg/L,表明农田化肥水和地表径流可能是导致水源水体富营养化的重要原因.     

带压开采陷落柱突水影响因素数值模拟

为研究承压水压与煤层陷落柱位置这两种因素对陷落柱突水的影响,在分析固流耦合数学模型的基础上,利用数值模拟软件FLAC3D,以双柳矿地质条件为背景,分别对3 MPa和5 MPa承压水压下开采上、下两组煤4种情况进行模拟,分析陷落柱及其周边围岩的渗流-塑性破坏耦合场、应力场和位移场的变化.结果表明:随着工作面推进至接近陷落柱,工作面前方集中应力场与柱体周边应力场发生耦合,并出现应力集中,当水压为5 MPa开采上组煤时应力集中系数最大,最容易形成突水危险区域;当上组煤工作面距离陷落柱为30 m时,陷落柱渗流场与集中应力场开始连通,在开采下组煤时这一距离比上组煤扩大15 ～ 20 m;煤层底板随工作面推进发生压缩-膨胀周期变化,引起拉伸、剪切破坏.     

模糊综合评价法的改进及其在水库水质评价中的应用

为了克服传统模糊综合评价法中权重赋值的片面性及最大隶属度原则导致评价结果不合理的弊端,提出了基于层次分析法和熵权法的主客观组合权重,并结合相乘相加算子及加权平均原则,建立了改进的模糊综合评价法.选取TP、TN、DO、NH3-N、CODMn和BOD5为评价指标,用改进的模糊综合评价法对重庆某水库2012年7-12月的水质进行了综合评价.结果表明:TN为主要的污染物;水质最差时段为8月,评价结果为2.655,水质属于Ⅱ级,略偏于Ⅲ级.评价结果与人工神经网络模型所得结果基本一致.     

3种增塑剂单独和联合暴露对MCF-7细胞增殖的影响

为了探究结构差异较大、应用较为广泛的几类增塑剂雌激素活性的联合效应,选择邻苯二甲酸二丁酯(DBP)、双酚A(BPA)和壬基酚(NP)作为邻苯二甲酸酯、双酚A类和烷基酚类增塑剂的代表物进行试验.用DBP、BPA和NP单独及两两混合处理MCF-7细胞.采用MTT法检测培养24h、48 h、72 h和96h时的细胞增殖情况.采用流式细胞术检测药物培养48h后的细胞生长周期分布,并计算细胞增殖指数(PI).运用效应叠加模型(ES)判定联合效应类型.结果表明,在单独暴露试验中,DBP、BPA和NP组PI均大于1,且均能提高S期(DNA合成期)细胞比例.因此,DBP、BPA和NP均能显著促进MCF-7细胞增殖.混合暴露试验中,1)DBP和BPA在MTT试验中24h、48h、72 h和96h时的效应叠加指数(ESI)分别为1.013 9、1.023 8、0.9999、1.010 8,在流式细胞仪试验中ESI为1.014 1.因此,DBP和BPA的雌激素活性联合效应为加和作用.2)DBP和NP在MTT试验中24 h、48 h、72 h和96 h时的ESI分别为1.004 0、1.008 6、1.011 5、1.010 3,流式细胞仪试验中ESI为0.997 0.因此,DBP和NP的雌激素活性联合效应为加和作用.3)BAP和NP在MTT试验中24h、48 h、72 h和96h时的ESI分别为0.980 6、0.981 8、0.977 7、0.973 3,流式细胞仪试验的ESI为0.912 8.由此可知,BPA和NP的雌激素活性联合效应为拮抗作用.因此,可以采用MCF-7细胞增殖试验研究环境污染物雌激素活性联合效应.     

生物表面活性剂产生菌处理水体石油污染物的研究

为研究水体石油污染物的生物处理方法,通过富集培养、蓝色凝胶平板分离初筛、摇瓶复筛等方法从长期被石油污染的油泥中筛选生物表面活性剂产生菌.采用薄层层析显色法和红外光谱法鉴定该菌所产表面活性剂种类,测定表面活性剂的乳化性能、表面张力和临界胶束浓度等性能,并对菌株降解水体石油污染物的影响因素及效果进行了研究.结果表明,筛选出的生物表面活性剂高产菌株LJ2所产表面活性剂为糖脂,其乳化指数为33％,25℃下可将水的表面张力从71.14 mN/m降至27.22 mN/m,临界胶束质量浓度为5 mg/L;当表面活性剂水溶液质量浓度为100 mg/L时,其乳化指数可达50％.温度、降解时间以及NaCl质量分数对菌株LJ2处理水体石油污染效果影响很大.在34℃条件下处理5d,菌株LJ2对质量浓度为2 g/L的水体石油污染物的降解率高达99.5％.研究表明,生物表面活性剂产生菌L J2对水体石油污染物有良好的降解效果,而且该菌还对水体中较高浓度的NaCl有一定的耐受性.     

基于生命周期的轨道交通能耗与碳排放分析

轨道交通的高效低污染特征备受关注,以广佛二期地铁为研究对象,测算广佛二期地铁的能源消费量,以及CO2、CH4、N2O等温室气体(Greenhouse Gases,GHGs)排放量;再基于生命周期理论,采用量化方法对比广佛二期地铁与出租车、私人载客汽车、公交车、私人摩托车4种客运交通工具的能源利用效率、能源强度、碳排放强度;最后,分析广佛二期地铁对佛山市交通行业能耗和GHGs排放的影响.结果表明,广佛二期地铁近期能源消费量为4 562.95 t标准煤,CO2排放量为12 651.57 t,CH4排放量为0.152 t,N2O排放量为0.201 t.与燃油机动车相比,广佛二期地铁具有更高的能源利用效率,同时具有较高的节能减排潜力.研究表明,广佛二期地铁的开通不但是缓解佛山市机动车辆增长的重要方式,而且对城市交通节能减排具有重要意义.     

A new approach to determine relieving temperature and thermodynamic behavior of trapped single and multi-phase fluid exposed to fire

Process safety plays a key role in modern industries. This is more significant specifically in off-shore oil and gas platforms where releasing hydrocarbons could cause irreversible damages to both environment and personnel. An important instrument device which can provide safety for process equipment in oil and gas fields is safety relief valve. Correct sizing procedure of such devices depends strongly on physical properties of fluid and relieving condition. The present study revolved around applying thermodynamic concepts and modeling to throw some light on the behavior of trapped fluid exposed to fire in order to evaluate precise temperature and fluid properties at relieving condition. Peng–Robinson equation of state together with a three phase flash has been utilized to handle the calculation. Effect of different design parameters has been evaluated for three distinct categories of fluids namely natural gas, gas-condensate mixture, and gas-oil mixtures. These parameters encompass of operating temperature, operating pressure, Difference of Operating and Design Pressure, gas and oil specific gravities, gas-oil ratio, and water cut. The study depicted that American Petroleum Institute practice number 521 which suggests an ideal gas assumption fails to provide reliable predictions as it significantly overestimate the relieving temperature. Moreover, black oil correlations were also used for the relief temperature estimation of gas-oil-water mixtures. Comparison with HYSYS results as a prominent engineering software proved that black oil models are reliable tools to predict relief temperature.     

Loss prevention in turnaround maintenance projects by selecting contractors based on safety criteria using the analytic hierarchy process (AHP)

Turnaround maintenance (TAM) is a usual plant shutdown that is done by process industries to perform asset inspections, repairs, and overhauls. TAM engineering projects are needed on a periodic basis to optimize a plant's performance. Process industrial plants usually don't have enough in-house manpower to carry out needed TAM jobs; it is not uncommon for a process industrial plant to outsource its TAM manpower supply to external contractors. This will create a peculiar management challenge regarding how to assure orientation of safety practices for the newly hired labor. Although accidents during process plant shutdowns may have severe consequences, the safety management systems in place for many companies only cover normal operations and few explicitly address TAM projects. Usually, contractors are evaluated from a safety perspective after handling the project by monitoring safety indicators such as number of injuries, incidents, etc. This paper emphasizes safety attributes to be included in selecting contractors at the bidding stage to assure loss prevention and better safety orientation during TAM implementation. The paper starts with reviewing TAM literature and defining main needed safety attributes to prequalify contractors. It develops an analytic hierarchy process (AHP) model that is applied to rank TAM contractors' selection. A case study is presented for a petrochemical plant in Saudi Arabia to demonstrate the AHP model.     

Dynamic-risk-informed safety barrier management: An application to cost-effective barrier optimization based on data from multiple sources

An integrated approach for performance assessment and management of safety barriers in a systemic manner is needed concerning the prevention and mitigation of major accidents in chemical process industries. Particularly, the effects of safety barriers on system risk reduction should be assessed in a dynamic manner to support the decision-making on safety barrier establishments and improvements. A simulation approach, named Simulink-based Safety Barrier Modeling (SSBM), is proposed in this paper to conduct dynamic risk assessment of chemical facilities with the consideration of the degradation of safety barriers. The main functional features of the SSBM include i) the basic model structures of SSBM can be determined based on bow-tie diagrams, ii) multiple data (periodic proof test data, continuous condition-monitoring data, and accident precursor data) may be combined to update barrier failure probabilities and initiating event probabilities, iii) SSBM is able to handle uncertainty propagation in probabilistic risk assessment by using Monte Carlo simulations, and iv) cost-effectiveness analysis (CEA) and optimization algorithms are integrated to support the decision-making on safety barrier establishments and improvements. An illustrative case study is demonstrated to show the procedures of applying the SSBM on dynamic risk-informed safety barrier management and validate the feasibility of implementing the SSBM for cost-effective safety barrier optimization.