沙尘暴PM2.5水溶和有机成分对巨噬细胞的损伤

用超纯水或二氯甲烷从甘肃省武威市和内蒙古包头市采集的沙尘暴细颗粒物(PM2.5)中提取水溶成分和有机成分,于体外处理大鼠肺泡巨噬细胞4h,测定细胞谷胱甘肽(GSH)和丙二醛(MDA)含量、质膜ATP酶活性、膜表层和膜脂疏水区流动性、胞质内游离钙离子(Ca2+)浓度以及细胞培养液中乳酸脱氢酶(LDH)和酸性磷酸酶(ACP)活性.结果表明,沙尘暴PM2.5水溶成分可抑制质膜Ca2+-Mg2+-ATP酶、Na+-K+-ATP酶活性,降低质膜表层和膜脂疏水区流动性,增加胞质LDH外渗,并使细胞脂质过氧化作用增强、抗氧化能力减弱,但对ACP和Ca2+浓度影响不大;有机成分除引起胞质LDH渗漏、质膜Na+-K+-ATP酶活性下降外,对其它测定指标的影响无统计学意义.说明沙尘暴PM2.5水溶和有机成分均可对肺泡巨噬细胞产生毒性,其中水溶成分的毒性作用大于有机成分.     

内蒙古是北京地区沙尘天气的主要沙尘源

本文就内蒙古西部地区生态环境恶化现状、生态环境恶化的原因、沙尘暴发生情况及对北京等地区的影响进行了分析探讨，并就如何改善内蒙古西部地区生态环境提出建议。     

Use of Surrogates to Predict the Stressor Response of Imperiled Species

Abstract: Rare or narrowly distributed species may be threatened by stressors to which they have never been exposed or for which data are very limited. In such cases the species response cannot be predicted on the basis of directly measured data, but may be inferred from the response of one or more appropriate surrogate species. Here, I propose a practical way to use the stressor response of one or more surrogate species to develop a working hypothesis or model of the stressor response of the target species. The process has 4 steps: (1) identify one or more candidate surrogate species, (2) model the relationship between the stressor and the response variable of interest for the surrogate species, (3) adapt the stressor–response relationship from the surrogate species to a model for the target species, possibly using Bayesian methods, and (4) incorporate additional data as they become available and adjust the response model of the target species appropriately. I applied the approach to an endangered fish species, the amber darter (Percina antesella), which is potentially threatened by urbanization. I used a Bayesian approach to combine data from a surrogate species (the bronze darter[Percina palmaris]) with available data for the amber darter to produce a model of expected amber darter response. Although this approach requires difficult decisions on the part of the manager, especially in the selection of surrogate species, its value lies in the fact that all assumptions are clearly stated in the form of hypotheses, which may be scrutinized and tested. It therefore provides a rational basis for instituting management policy even in the face of considerable uncertainty.     

Seasonal Flushing of Pollutant Concentrations and Loads in Urban Stormwater1

Schiff, Kenneth C. and Liesl L. Tiefenthaler, 2011. Seasonal Flushing of Pollutant Concentrations and Loads in Urban Stormwater. Journal of the American Water Resources Association (JAWRA) 47(1):136‐142. DOI: 10.1111/j.1752‐1688.2010.00497.x Abstract: Despite broad observations of first flush within storms, the scientific understanding of seasonal flushing remains incomplete. Seasonal flushing occurs when initial storms of the season have greater concentrations or loads than storms later in the season. The goal of this study was to census stormwater concentrations and loads from an arid, urban watershed to quantify seasonal flushing. Samples were collected every 15 min during the 1997‐1998 wet season from the Santa Ana River and analyzed for total suspended solids. Initial storms of the season generated event mean concentrations 3‐10 times the event mean concentration of storms later in the season. Cumulative flow‐weighted mean concentrations were calculated as the season progressed. Early season storms discharged only 6% of the annual volume, but influenced flow‐weighted mean concentrations well past the midpoint of the wet season. Mass‐based estimates also indicated a disproportionate load in the early portion of the year; over 52% of the annual load was discharged in the first 30% of the annual volume from the highly urbanized lower watershed. Other stormwater pollutants, including six trace metals (Cd, Cr, Cu, Pb, Ni, Zn), were highly correlated with total suspended solids and also exhibited a significant seasonal flush.     

南京地区典型霾天气个例特征的比较分析

利用2011年南京大学城市大气环境观测站气象因子及污染物浓度资料、58238站点气象探空资料及NCEP再分析资料、CALIPSO卫星资料,比较分析了南京地区4类典型霾天气(烟花爆竹、沙尘、秸秆燃烧及不利气象条件污染)的污染特征.结果表明:烟花爆竹个例污染物排放集中,以细颗粒物为主,除夕和初五的PM2.5小时浓度分别达到0.46 mg·m-3和0.34 mg·m-3,受逆温层影响,能见度持续降低,最低达到1.16 km;受北方沙尘暴南下影响,沙尘个例以粗颗粒为主要污染物,PM10小时最高浓度为0.78 mg·m-3,PM2.5/PM10平均值为0.39,粒子形状不规则,体积偏退比为0.17;秸秆燃烧个例为重霾污染,能见度最低值为0.97 km,后向散射系数为0.0039 km-1獉sr-1,PM10和PM2.5最高小时浓度达到0.80 mg·m-3和0.49 mg·m-3,颗粒物主要来自南京东南地区秸秆的集中燃烧;不利气象条件导致的污染过程在冬季比较常见,下沉气流活跃,出现双层逆温,近地面静小风造成污染物积累,PM2.5与能见度的相关系数达到0.86,细颗粒物为主要污染物.可见,南京市霾天气可分为两类,分别是由不利气象条件导致的累积性污染和由高强度排放源造成的暴发性污染,具有不同的气象和污染特征.     

加速并行遗传算法及其在暴雨强度公式参数优化中的应用

针对标准遗传算法中存在早熟收敛、后期收敛速度慢以及解精度低的问题,结合正交试验设计和元胞自动机模型,提出了一种改进的遗传算法--加速并行遗传算法(APGA).APGA利用正交试验设计确定较好的初始种群,利用元胞自动机模型固有的并行计算能力设计并行遗传算法,借助元胞信息的动态性和多元性实现正交加速过程.该方法不仅能加快遗传算法的收敛速度,而且能提高遗传算法的搜索效率和解的精度,适用于求解复杂的非线性优化问题.APGA用于暴雨强度公式参数的优化实例结果表明,该算法是有效和可行的.     

A SYSTEMS STUDY OF STORM RUNOFF PROBLEMS IN A NEW TOWN1

A system study was conducted on the use of a large number of small reservoirs dispersed throughout an urban community as a means of storm water pollution control. The study was based on an area within the “new city” of Columbia, Maryland. Water collected and stored in the reservoirs is treated for release or use in meeting sub-potable and potable water demands in the community. Design and performance criteria were developed for such a system. A simulation model and a computerized evaluation technique were used to select the optimal locations and system configurations. The results of this study indicated that such a system would be less expensive than a conventional engineering approach to storm water pollution control. Further, the benefits derived from use of the storm water as a water supply can offset a portion of the cost of pollution control. Several secondary benefits also result from this concept including erosion and sediment control, storm flow dampening, and recreational facilities. A program is now underway to demonstrate this concept in Columbia, Maryland.     

PRELIMINARY OBSERVATIONS ON WATER QUALITY OF STORM RUNOFF FROM FOUR SELECTED RESIDENTIAL ROOFS1

ABSTRACT: Storm runoff from four characteristic types of residential roofs and incident rainwater were monitored for 47 storm events over a six-month period at Nacogdoches, Texas, to study water quality conditions for 20 element and four chemical variables. The total element concentration in storm runoff from each roof type was greater than that of rainwater in the open. Differences in element concentrations in storm runoff among the four roof types were statistically significant (α≤ 0.05) with the differences for the wood shingle roof being the greatest and that for terra cotta clay roof being the least. The median concentrations of four element variables exceeded the Texas surface water quality standards, while 12 variables exceeded the standards at least one time in all samples collected. Zinc concentrations violated the Standard ranging from 85.7 percent of the samples for the wood shingle roof to 66.0 percent for the composite shingle, the greatest exceedances of all 24 variables studied. Storm characteristics and gutter maintenance level had some effects on these water quality conditions. The study suggested that roof types can be important to water pollution management programs. More detailed studies on roof water quality in major municipalities are required.     

A MODELING APPROACH FOR STORM WATER QUANTITY AND QUALITY CONTROL VIA DETENTION BASINS1

ABSTRACT: Storm water detention basins have historically been employed for quantity (i.e., flooding) control only. However, recently it has been suggested that these basins may also provide a practical means of storm water quality control. This paper presents the formulation of a mathematical modeling approach which may be used by professionals to simultaneously design detention basins for the dual purpose of storm water quantity and quality control. Model simulations demonstrate that for a given basin, pollutant removal increases as storm frequency increases. The importance of particle size distribution and settling velocity for net pollutant removal is illustrated, The design procedure is demonstrated, and pollutant loading diagrams for estimating pollutant removal as a function of storm size are developed.     

AN OVERVIEW OF POROUS PAVEMENT RESEARCH1

ABSTRACT: This paper discusses the economics, advantages, potential applications, and status and future research needs of porous pavements. Porous pavements are an available storm water management technique which can be used on parking lots and low volume roadways in order to reduce both storm water runoff volume and pollution. In addition, ground water recharge is enhanced. Also, cost reductions result due to elimination of curbs, drains, and small sized storm sewers. Porous asphalt pavements consist of a relatively thin course of open graded asphalt mix over a deep base of large size crushed stones. Water can be stored in the crushed stone base until it can percolate into the subbase or drain laterally. Other porous pavement types include concrete lattice blocks and a porous concrete mix.