An approach to calculating allowable watershed pollutant loads

To improve the management of discharge pollutants loads in the reservoirs’ watershed, an approach of the allowable pollutants loads calculation and its allocation, based on the water environment model, was proposed. Establishment of the approach framework was described at first. Under the guidance of this framework, two major steps were as follows: modeling and scenario analysis were involved and should be applied to support the decision of discharge loads management; Environmental Fluid Dynamic Code (EFDC) model was selected as the kernel model in this framework. In modeling step, spatial discretization for establishing cell map in model, data preprocessing, parameter calibration and uncertainty analysis (which is considered as the significantly relevant factor of the margin of safety (MOS)), were conducted. As a result of the research, the model-based approach presented as a combination of estimation and precise calculation, which contributed to scenario analysis step. Some integrated modules, such as scenario simulation, result analysis and plan optimization were implemented as cycles in the scenario analysis. Finally, allowable pollutant loads under various conditions were calculated. The Chaihe Reservoir in Liaoning Province, China was used as a case study for an application of the approach described above. Results of the Chaihe reservoir water quality simulation, show good agreement with field data and demonstrated that the approach used in the present study provide an efficient and appropriate methodology for pollutant load allocation.     

微塑料与有机污染物的相互作用研究进展

微塑料(粒径小于5 mm的塑料)作为海洋中一种新型的污染物正受到越来越多的关注。微塑料在全球多个海域均有检出,根据其来源分为原生微塑料和次生微塑料。原生微塑料由人工直接制造所得,常见于日常生活用品中;次生微塑料由大块塑料制品长期风化、磨损和光解形成。塑料自身含有多种有机添加剂,不断向环境中释放,污染海洋环境;微塑料表面还可吸附有机污染物,此吸附作用受两者的物理化学性质和环境条件影响,吸附污染物后的微塑料生物毒性增强。另外,聚合物复合光催化材料可加快有机污染物如染料的光降解反应速率,因而微塑料可能会促进有机污染物的光解。针对目前微塑料对有机物光降解的贡献、机理鲜见研究的问题,未来应加强以下3方面的研究:(1)微塑料对不同有机污染物光降解是否存在影响?(2)微塑料类型、尺寸以及反应条件对有机污染物光降解如何影响?(3)微塑料对有机污染物光降解影响的内在机制是什么?     

基于监测及Kriging方法的京津冀地区大气污染物暴露分布研究

为了实现充分利用已有环境监测站点数据进行人群精细化暴露评估的目的,同时解决某些待测人群社区周边无监测站点时数据的选择问题,以保定市作为大气高污染研究城市,基于现场监测和Kriging（克里金插值）空间分析方法,明确了在研究大气污染物人群暴露时,某一个固定监测站污染物数据的代表性问题.研究表明:对于大气中φ（SO₂）、φ（NO₂）、颗粒物及其组分,空气质量监测点位的代表性一般为5~6 km;对于φ（CO）、φ（O₃）和φ（VOCs）,它们在城市不同地区的空间分布更为均匀,空气质量监测点位的代表性范围更大.通过使用Radial Basis Functions（径向基函数,RBF）、Local Polynomial Interpolation（局部多项式插值,LPI）、Inverse Distance Weighting（反距离权重插值,IDW）、Kriging、Kernel Smoothing（内核平滑插值,KS）和Diffusion Kernel（内核扩散插值,DK）等6种空间分析方法对大气污染物浓度进行预测发现,Kriging方法对大气污染物浓度预测时可使预测值和实测值间的偏差小于10%,准确度最高.因此,在进行某城市某点位的污染物人群暴露浓度预测时,若该点位周边5 km以内有空气质量监测点位,则可用该点位的监测值代替;若5 km以内没有空气质量监测点位,则可基于最近监测点位的污染物浓度进行Kriging空间插值,从而获得该点位的污染物暴露水平.      

不同掺混比例甲醇汽油车的排放特性

采用《轻型汽车污染物排放限值及测量方法》(GB 18352.3─2005)规定的Ⅰ型试验方法,对汽油车和不同掺混比例的甲醇燃料车在原催化器和新催化器条件下的瞬态常规污染物排放特性进行了研究. 结果表明:甲醇燃料汽车CO和HC排放较汽油车低,其NO_x的排放通常高于汽油车,且随甲醇比例的提高而增加,使用针对甲醇燃料开发的新催化器后,3种常规污染物排放均明显降低;甲醇燃料汽车CO的排放多数出现在第1个195工况,HC的瞬态排放规律与CO相近,NO_x几乎在每个急加速阶段和城郊运行工况(EUDC)循环中均出现峰值.      

北京奥运会期间奥运村站空气质量的观测与研究

为了跟踪研究北京2008年奥运会期间奥运村大气污染物浓度的变化,2008年6月1日─9月30日,利用符合国际标准的在线观测仪器,对奥运村站大气中主要污染物进行加强观测. 结果表明:奥运会期间奥运村站大气中φ(NO₂),φ(SO₂),ρ(PM_2.5)和ρ(PM₁₀₎分别比奥运会前(7月1日─8月7日)下降了11.2%,46.7%,57.0%和50.0%;比残奥会后时段(9月20─30日)分别下降了41.7%,31.8%,21.6%和28.6%;与2007年同期相比,奥运会时段的φ(NO₂),φ(O₃),ρ(PM_2.5)和ρ(PM₁₀₎分别下降了38.8%,37.2%,42.1%和68.0%;残奥会时段分别下降了17.8%,27.5%,44.0%和64.1%. 除对污染源严格的控制措施取得了良好的效果外,有利的天气过程也是奥运会期间北京空气质量全面达标的重要原因.      

稳健变异函数在土壤污染物来源识别中的应用：以某重金属污染场地为例

空间特异值可以提供污染源的位置信息.以Genton稳健估计量为基础的变异函数为研究工具,对某重金属冶炼场地土壤中Cu、Zn、Pb、Cd、As、Se和Hg含量进行了空间特异值分析,并根据空间特异值的地理位置及土地利用方式等信息指示污染源.结果表明,7种元素变异函数曲线的理论模型符合球状模型,7种元素都具有较小的块金方差,Cu、Zn和Pb只为0.000.与Matheron估计量相比,该研究得到的变异函数具有更小的块金效应,说明Genton估计量能够消除或减弱特异值对变异函数的影响.7种元素的空间特异值多集中在个别小范围内,以簇状形式存在,与该区域冶炼高炉及尾渣堆放处的位置具有很好的相关性,说明冶炼行为及其相关过程是该区重金属的重要来源.     

微生物处理技术在有机污染物降解中的应用

微生物处理有机污染物是一种费用低,效果好,无二次污染且操作简单的处理方法。综述了国内外几种微生物处理有机污染物技术的研究进展。     

电化学法处理苯酚模拟废水的研究

电化学法处理废水中有机污染物,具有效率高、操作简便、与环境兼容等优点,是一种很有潜力的高级氧化技术。实验是以废旧一号干电池中的碳棒作电极,用烧杯作电解池,在室温下,通过改变支持电解质（Na2SO4）浓度、负载电压、pH值和苯酚初始浓度等影响因素,对苯酚模拟废水进行电化学处理,利用高效液相色谱仪对其处理效果进行了分析研究,结果表明：支持电解质（Na2SO4）浓度为20.0g/L、负载电压为5.5V、pH值为8.0是处理苯酚模拟废水的最佳条件。最后对苯酚的降解机理进行了初步探讨。     

武汉月湖和莲花湖表层沉积物中持久性有机物的污染状况

采用气－质联用技术分析了武汉汉阳月湖和莲花湖的4个表层沉积物样品中的有机污染物,探讨了两湖沉积物受持久性有机物污染的程度。月湖中共检测出124种有机物,其中属环境优先控制污染物和美国EPA筛选的内分泌干扰物19种;莲花湖中共检测出186种有机物,环境优先控制污染物和美国EPA筛选的内分泌干扰物34种。主要污染物包括：酞酸酯、酯类、酚类、杂环和苯及其衍生物等。污染物浓度顺序为L1＞L2＞Y2＞Y1,莲花湖中有机物浓度明显高于月湖。两湖邻苯二甲酸酯的含量最高,占了污染物总量的96%~98%,邻苯二甲酸乙基己基酯（平均值 17 59903 ng/g 干重）和邻苯二甲酸二丁酯（平均值 2 515.76 ng/g 干重）是两湖沉积物中的主要酞酸酯类污染物。     

Estimating the volatilization of ammonia from synthetic nitrogenous fertilizers used in China

Although it has long been recognized that significant amounts of nitrogen, typically in the form of ammonia (NH(3)) applied as fertilizer, are lost to the atmosphere, accurate estimates are lacking for many locations. In this study, a detailed, bottom-up method for estimating NH(3) emissions from synthetic fertilizers in China was used. The total amount emitted in 2005 in China was estimated to be 3.55 Tg NH(3)-N, with an uncertainty of ± 50%. This estimate was considerably lower than previously published values. Emissions from urea and ammonium bicarbonate accounted for 64.3% and 26.5%, respectively, of the 2005 total. The NH(3) emission inventory incorporated 2448 county-level data points, categorized on a monthly basis, and was developed with more accurate activity levels and emission factors than had been used in previous assessments. There was considerable variability in the emissions within a province. The NH(3) emissions generally peaked in the spring and summer, accounting for 30.1% and 48.8%, respectively, of total emissions in 2005. The peaks correlated with crop planting and fertilization schedules. The NH(3) regional distribution pattern showed strong correspondence with planting techniques and local arable land areas. The regions with the highest atmospheric losses are located in eastern China, especially the North China Plain and the Taihu region.