西安市城市主干道路面径流初期冲刷效应

以西安市城市主干道南二环太白路高架桥为路面径流采样区域,采用人工等时间间隔采样方法,在桥梁排水立管对2010年9—11月的3场径流事件进行全程采样,测试径流过程SS、COD、溶解性COD、NH3-N、Pb、溶解性Pb、Zn和溶解性Zn的浓度变化,研究路面径流的初期冲刷效应及其影响因素。结果表明,西安市城市主干道路面径流污染严重,降雨数小时后的末期径流仍具有较高的污染水平;径流过程污染物浓度变化规律与其赋存形态有关,SS、COD、Pb等以颗粒态为主的污染物的浓度随雨强变化剧烈波动,NH3-N、溶解态COD、溶解态Zn等以溶解态为主的污染物浓度变化受雨强影响较小,随径流过程呈逐渐减小趋势;路面径流初期冲刷现象并非普遍存在,与污染物的赋存状态和场次降雨特征密切相关,溶解态污染物易于出现初期冲刷现象,颗粒态污染物是否出现初期冲刷与场次降雨特征有关;测试的3场径流事件初期30%的径流携带的SS、COD、溶解性COD、NH3-N、Pb、Zn和溶解性Zn的负荷占场次径流总负荷的比例分别为21.8%～50.0%、25.5%～49.3%、36.3%～52.6%、52.6%～66.7%、26.8%～45.0%、27.2%～63.4%和36.2%～62.6%,表明仅对初期径流进行治理无法实现对西安市路面径流污染的有效控制。     

西安市及周边地区MODIS气溶胶光学厚度与PM10浓度关系模型研究

西安是空气污染监控和防治有代表性的西部大型城市。研究了西安市及周边地区上空气溶胶光学厚度与PM10浓度的关系模型。利用2011—2012年MODIS卫星气溶胶光学厚度（AOD）遥感产品，通过数据匹配，利用地面气象观测站点的能见度数据和相对湿度数据对AOD产品进行垂直标高订正和湿度订正，2项订正显著提高了AOD和地面PM10浓度的相关性，相关系数从0．36提高到0．65，按季节分类统计和订正春至冬四季的相关系数分别为0．57、0．71、0．62和0．87，夏季和冬季的订正更为有效，可用性更高，这可能由于受到不同季节气溶胶来源和特征的影响。为研究中国西部大型城市，特别是西安市空气环境监测和区域联防联控提供了一种有效方法。     

基于人工蜂群算法与BP神经网络的水质评价模型

针对BP网络水质评价模型的不足,引入人工蜂群(ABC)算法,将求解BP神经网络各层权值、阀值的过程转化为蜜蜂寻找最佳蜜源的过程,提出了一种新的结合人工蜂群算法的BP网络水质评价方法(ABC-BP)。并以2000—2006年渭河监测断面的10组实测数据作为测试样本对其水质进行了评价,实验结果表明该方法得到的水质评价结果准确,并具有很强的稳定性和鲁棒性。     

基于宜居视角的居住城市化水平测度——以大连市为例

从宜居的视角出发,结合大连市发展现状建立居住城市化水平测度指标体系,利用模糊层次分析法（AHP）确定指标权重,计算居住城市化水平测度综合指数。通过整理样本社区测度综合指数的数据,建立指标数据库,利用地理信息系统软件MapInfo 10进行格网赋值,构建基于空间插值法的居住城市化水平测度模型,绘制大连居住城市化水平测度专题图,直观展现大连市居住城市化水平发展的时空变化特征。结果表明,1995—2010年大连市居住城市化发展呈现出由整体发展水平低、内部差异小到发展速度提高、地域发展不均衡,再到发展速度减慢,日趋平衡,最后实现发展速度再次提高、均衡发展、差异减小的阶段特征。     

镍网负载纳米TiO2光催化反应器对酸性品红脱色效果实验研究

采用负载纳米TiO2的三维镍网装配了光催化反应器,就其对酸性品红溶液进行脱色效果进行了实验研究。考察了反应器的3种装配条件、品红初始浓度、pH值、H2O2投加量、紫外光剂量等因素对酸性品红脱色效果的影响。结果表明：UV灯＋镍网＋TiO2模式组合的反应器脱色效果最好;在相同的处理时间内酸性品红溶液的脱色率随起始浓度的增大而减小;将酸性品红溶液pH值调至5时脱色效果最明显,70 min的脱色率可高达94.8%。脱色效果还可以通过溶液中添加H2O2和控制紫外线剂量来调节。当溶液中H2O2投加量为0.5 g/L时,处理70 min后的脱色率可高达98.3%;到达反应界面紫外光剂量越多则能够获得越高的酸性品红脱色率。     

衡山PM_（2.5）中痕量金属元素的分析

建立了微波消解-电感耦合等离子体质谱法同时测定PM2.5中12种痕量金属元素的方法。对不同消解体系进行了讨论,确定采用HNO3＋H2O2消解体系。方法检出限在0.01～6.4 ng/m3之间,精密度为0.5%～8.9%,加标回收率在69.2%～92.6%之间。应用该方法测定了衡山PM2.5中痕量金属元素的含量,讨论了痕量元素的浓度分布特征,对各元素进行了相关性分析,并应用富集因子法对来源进行了分析。     

Modeling urban films using a dynamic multimedia fugacity model

A thin film coats impervious urban surfaces that can act as a source or sink of organic pollutants to the greater environment. We review recent developments in the understanding of film and film-associated pollutant behavior and incorporate them into an unsteady-state version of the fugacity based Multimedia Urban Model (MUM), focusing on detailed considerations of surface film dynamics. The model is used to explore the conditions under which these atmospherically-derived films act as a temporary source of chemicals to the air and/or storm water. Assuming film growth of 2.1 nm d⁻¹ (Wu et al., 2008a), PCB congeners 28 and 180 reach air-film equilibrium within hours and days, respectively. The model results suggest that the film acts as a temporary sink of chemicals from air during dry and cool weather, as a source to air in warmer weather, and as a source to storm water and soil during rain events. Using the downtown area of the City of Toronto Canada, as a case study, the model estimates that nearly 1 g d⁻¹ of ∑₅PCBs are transferred from air to film to storm water.     

Use of a food web model to evaluate the factors responsible for high PCB fish concentrations in Lake Ellasjøen, a high Arctic Lake

Background, aim, and scope

Lake Ellasjøen, located in the Norwegian high arctic, contains the highest concentrations of polychlorinated biphenyls (PCBs) ever recorded in fish and sediment from high arctic lakes, and concentrations are more than 10 times greater than in nearby Lake Øyangen. These elevated concentrations in Ellasjøen have been previously attributed, in part, to contaminant loadings from seabirds that use Ellasjøen, but not Øyangen, as a resting area. However, other factors, such as food web structure, organism growth rate, weight, lipid content, lake morphology, and nutrient inputs from the seabird guano, also differ between the two systems. The aim of this study is to evaluate the relative influence of these factors as explanatory variables for the higher PCB fish concentrations in Ellasjøen compared with Øyangen, using both a food web model and empirical data.

Methods

The model is based on previously developed models but parameterized for Lakes Ellasjøen and Øyangen using measured data wherever possible. The model was applied to five representative PCB congeners (PCB 105, 118, 138, 153, and 180) using measured sediment and water concentrations as input data and evaluated with previously collected food web data.

Results

Modeled concentrations are within a factor of two of measured concentrations in 60% and 40% of the cases in Lakes Ellasjøen and Øyangen, respectively, and within a factor of 10 in 100% of the cases in both lakes. In many cases, this is comparable to the variability associated with the data as well as the efficacy of the predictions of other food web model applications.

Discussion

We next used the model to quantify the relative importance of five major differences between Ellasjøen and Øyangen by replacing variables representing each of these factors in the Ellasjøen model with those from Øyangen, in separate simulations. The model predicts that the elevated PCB concentrations in Ellasjøen water and sediment account for 49%–58% of differences in modeled fish PCB concentrations between lakes. These elevated sediment and, to a lesser extent, water concentrations in Ellasjøen are due to PCB loadings from seabird guano. However, sediment–water fugacity ratios of PCBs are consistently greater in Ellasjøen compared with Øyangen, which suggests that internal lake processes also contribute to differences in sediment and water concentrations. We hypothesize that the nutrients associated with guano influence sediment–water fugacity ratios of PCBs by increasing the stock of pelagic algae. As both these algae and the guano settle, their organic carbon content is degraded faster than PCBs, which causes an extra magnification step in Ellasjøen before these detrital particles are consumed by benthic organisms, which are in turn consumed by fish. The model predicts that the remaining ～50% of the differences in PCB concentrations observed between the fish of these lakes are due to other subtle differences in their food web structures.

Conclusions

In conclusion, based on the results of a food web model, we found that the most dominant factors influencing the higher PCB fish concentrations in Lake Ellasjøen compared with Øyangen are the higher sediment and water concentrations in Ellasjøen, caused by seabird guano. Together, sediment and water are predicted to account for 49%–58% of differences in fish concentrations between lakes. Although seabird guano provides a source of nutrients to the lake, in addition to contaminants, empirical data and indirect model results suggest that nutrients are not leading to decreased bioaccumulation, in contrast to what has been observed in temperate, pelagic food webs.

Recommendations and perspectives

The results of this study emphasize the importance of considering even small differences in food web structure when comparing bioaccumulation in two lakes; although the food web structures of Ellasjøen and Øyangen differ only slightly, the model predicts that these differences account for most of the remaining ～50% of the differences in PCB fish concentrations between the two lakes. This study further demonstrates the utility of food web models as we were able to predict and tease apart the influence of various factors responsible for the elevated concentrations in the fish from Lake Ellasjøen, which would have been difficult using the field data alone.     

碱激发胶凝材料及其固化Pb^2＋的试验研究

对碱激胶凝材料（碱-偏高岭土、碱-矿渣和碱-粉煤灰）与水-水泥体系固化Ph^2＋进行了试验研究，其中水-水泥体系为对比样。结果表明：对于相同稠度的碱激发胶凝材料，即使Pb^2＋含量达到2．4％，除了碱-粉煤灰的抗压强度略低外，其他都达到30MPa以上，满足填埋或做建筑基材的使用要求；与水泥相比，碱激发胶凝材料能显著降低重金属离子（Ph^2＋）浸出浓度，其规律性与其NH4交换容量大小的规律性一致，与其固化体的抗压强度的大小没有相关性。     

Development and use of site-specific chemical and biological criteria for assessing New Bedford Harbor pilot dredging project

Numerical site-specific chemical and biological criteria were established to assess the impact of a pilot dredging project on water quality at the New Bedford Harbor, Massachusetts, USA, Superfund site. Because most existing chemical concentrations in the water column and indigenous biota exceeded federal and state water quality limits, the derivation of site-specific criteria was required. Prior to any operational phases of the project (i.e., dike construction, dredging), criteria values were developed from background concentrations of PCBs and metals in water and biota, as well as for the toxic effects of water quality on the biota. During each operational phase of the project, water samples were collected, analyzed within 16 h, and the data supplied to a management committee in order to assess the environmental impact of the previous days' operation. The ambient unfiltered water concentration of PCBs and metals were the only chemical or biological criteria exceeded. Modification of the next days' operations resulted in a return of these concentrations to background levels. The combined use of site-specific criteria and a real-time decision making management process allowed for successful completion of this project with a minimal effect on water quality.