并联式双梯度反相离子对液相色谱法快速检测土壤中芳磺酸

通过阀切换并联式双系统,建立了一套测定土壤样品中7种芳磺酸的反相离子对液相色谱法。该方法采用2根色谱柱,一根色谱柱分析的同时,另一根色谱柱通过阀切换实现平衡,节约了38.5%的分析时间。方法使用Dikma Diamonsil C18(150 mm×4.6 mm×5μm)色谱柱,以离子对试剂(四丁基硫酸氢铵)和乙腈为流动相,检测波长为226、235、258 nm。各组分线性关系良好,线性相关系数均在0.999 9以上。随机抽取样品进行重新提取、检测,得到各组分的相对标准偏差均小于7%,且定量限最高不超过0.181 2μg/g,重复性和定量限均能满足实验要求。     

底质农残测定中固相柱净化体系的选择

使用固相柱对底质中的7种农残进行净化。结果表明,在相同淋洗条件下,使用氟罗里硅土柱比硅胶柱净化效果好。比较了不同溶剂体系、不同溶剂配比下2种萃取柱的净化效果,选择乙醚-正己烷(体积比1∶2)或丙酮-正己烷(体积比1∶4)作为净化溶剂,较小的收集体积都可满足所有目标化合物的回收率要求;相比较而言,丙酮-正己烷(体积比1∶4)作为净化溶剂,洗脱液的杂质干扰更小,净化效果更好。使用氟罗里硅土柱和丙酮-正己烷(体积比1∶4)对样品净化,方法简单,快速,净化效果好,适合大批量底质样品的前处理净化过程。     

成都PM2.5与气象条件的关系及城市空间形态的影响

2013年2月1日至3月20日、2013年7月10日至8月10日对成都市大气中细颗粒物(PM2.5)进行连续监测,同步记录气象数据。将PM2.5质量浓度与城市气象条件进行相关性分析,研究气象条件对PM2.5质量浓度的影响。2月1日至3月20日PM2.5质量浓度平均为147.38μg/m3,7月10日至8月10日平均为50.19μg/m3,大气细颗粒物污染最严重的时间出现在2月1—6日。成都市各气象条件中,PM2.5质量浓度与能见度、风速呈现显著负相关,而与其他气象要素相关性较弱,降水对PM2.5质量浓度影响也很大。改善城市通风有利于成都市大气中PM2.5的稀释和消散。通过建立3D模型并运用计算流体力学(CFD)软件模拟成都市选定的一处密集的建成区域,分析城市空间形态对通风的影响。研究发现,在假设等温的情况下,多层密集的区域对城市通风影响小,而高层对城市通风影响很大,建筑高度相近的街道与风向平行的风速大于与风向成角度的,与风向平行的街道沿线为高层的风速高于沿线为多层的,较大的开敞空间及背景风速更有利于城市通风环境。     

环境监测能力建设项目管理思路与实现

近年来,环境监测能力建设项目资金投入不断加大,项目规模增长迅速,实施任务日益繁重,项目绩效考核要求越来越高,但项目管理还处于比较粗放的状态。在分析环境监测能力建设项目管理现状和需求的基础上,提出通过转变项目管理模式、强化信息支撑手段、完善制度建设、培养管理人才等多种手段,提高项目管理的科学性和时效性,实现重点项目管理的精细化、科学化和规范化。     

大数据解析技术在大气环境监测中的应用研究

针对近年来新兴的大数据及挖掘、分析技术,对大数据解析技术在环境科学研究中的应用进行了分析和探析。以城市局部地区大气细颗粒污染物PM2.5浓度计算为例,筛选了PM2.5浓度历史数据、气象条件、交通状况、人群活动情况、网格道路状况等数据为影响特征量,分析了用神经网络法进行大数据解析和推演的原理和数学过程,是用数学、计算机、统计等方法研究解决多元、非线性复杂环境问题的一种新的探索。     

大气气溶胶酸度和酸化缓冲能力研究

为了掌握大气气溶胶与酸性降水的关系 ,分析和研究了中国北方和南方不同观测点可吸入颗粒物 (PM10 )的酸度 ,并利用微量酸碱滴定的方法测定了其酸化缓冲能力。结果表明大气气溶胶具有一定的酸度 ,同时对酸化的缓冲能力非常低 ,甚至可以促进降水的酸化 ,这种污染特征也是上述观测点发生酸性降水的重要原因之一。     

Land desertification monitoring and assessment in Yulin of Northwest China using remote sensing and geographic information systems (GIS)

The objective of this study is to develop techniques for assessing and analysing land desertification in Yulin of Northwest China, as a typical monitoring region through the use of remotely sensed data and geographic information systems (GIS). The methodology included the use of Landsat TM data from 1987, 1996 and 2006, supplemented by aerial photos in 1960, topographic maps, field work and use of other existing data. From this, land cover, the Normalised Difference Vegetation Index (NDVI), farmland, woodland and grassland maps at 1:100,000 were prepared for land desertification monitoring in the area. In the study, all data was entered into a GIS using ILWIS software to perform land desertification monitoring. The results indicate that land desertification in the area has been developing rapidly during the past 40 years. Although land desertification has to some extent been controlled in the area by planting grasses and trees, the issue of land desertification is still serious. The study also demonstrates an example of why the integration of remote sensing with GIS is critical for the monitoring of environmental changes in arid and semi-arid regions, e.g. in land desertification monitoring in the Yulin pilot area. However, land desertification monitoring using remote sensing and GIS still needs to be continued and also refined for the purpose of long-term monitoring and the management of fragile ecosystems in the area.     

Heavy metal concentration and speciation of seven representative municipal sludges from wastewater treatment plants in Northeast China

The analysis of heavy metals is very important for assessing the feasibility of the agricultural utilization for the municipal sludge. In this paper, a four-step sequential extraction method was applied to extract heavy metals (Cu, Zn, Mn, Cr, and Ni) in municipal sludges from seven individual wastewater treatment plants located in Jilin and Heilongjiang Province, China, for estimating the mobility and bioavailability of the metal ions in the agricultural application. The total concentrations of heavy metals and their chemical fractions after the sequential extraction were determined. Principal component analysis (PCA) was applied to analyze the relations of heavy metals fractions in the municipal sludges. Experimental results indicated that the total concentrations of Cu, Zn, Cr, and Ni in all sludge samples were below the threshold values set out by the Chinese legislation (GB18918-2002). Specially, Zn had a high bioavailability and mobility, Cu and Cr had potential bioavailability, while Mn mainly existed in the residual fraction of municipal sludge. On the other hand, Ni had different mobility in different municipal sludge. PCA results were confirmed by the environmental behavior of heavy metals.     

Spatial and seasonal distribution of nitrogen in marsh soils of a typical floodplain wetland in Northeast China

Horizontal and profile distributions of nitrogen in marsh soils in different seasons were studied in a typical site within the Erbaifangzi wetland in Northeast China. Results showed that there was higher spatial heterogeneity for nitrate nitrogen (NO₃^--_{3}^{-}-N) and ammonium nitrogen (NH₄⁺_{4}^{+}–N), as well as available nitrogen (AN), in surface soils in July compared to that in September. Relative to July, the mean nitrogen contents in surface soils were slightly higher in September; however, in November, soils contained significantly lower NO₃^--_{3}^{-}-N and NH₄⁺_{4}^{+}–N, higher AN, organic nitrogen (Org-N), and total nitrogen (TN). Except for mineral nitrogen, no significant differences were observed between Org-N and TN contents in September and November. Nitrogen contents generally declined exponentially with depth along soil profiles in three sampling dates (July, September, and November), except for a significant accumulation peak of NO₃^--_{3}^{-}-N at the 20–30 cm depth in September. However, NH₄⁺_{4}^{+}–N contents showed a vertical alternation of “increasing and decreasing” in both July and September, while nearly kept constant with depth in November. The depth ranking of nitrogen showed the shallowest distribution for AN, followed by Org-N and TN, while deeper distributions for NO₃^--_{3}^{-}-N and NH₄⁺_{4}^{+}–N. TN, Org-N, and AN were significantly correlated with soil organic matter and total phosphorus. Soil pH values were significantly correlated with TN and AN contents in surface soils. Clay contents showed significant correlations with nitrogen contents except for NO₃^--_{3}^{-}-N in surface soils and NH₄⁺_{4}^{+}–N in profile soils. However, soil moisture was not significantly correlated with nitrogen contents among all soil samples.     

Determination of hydrazine hydrate based on electrochemiluminescence of Ru(bpy) 3 2+

Considering of the basic properties and also the two nitrogen atoms in the structure, hydrazine hydrate was employed to be an amine additive candidate, to build a Ru(bpy) ₃ ²⁺ /hydrazine electrochemiluminescence (ECL) system, and ECL of Ru(bpy) ₃ ²⁺ has been employed for the determination of hydrazine hydrate in the paper. The result demonstrated that the logarithmic ECL increasing (ΔECL?=?ECL_{after addition of hydrazine}???ECL_{before addition of hydrazine}) versus the logarithmic concentration of hydrazine hydrate is linear over a concentration range of 1.0?×?10^?9 to 1.0?×?10^?5?mol/L, on both glassy carbon and Pt electrodes in a pH 9 phosphate buffer. The hydrazine hydrate detection limit was down to 1.0?×?10^?9?mol/L, comparatively lower than other detection methods. To check its applicability, the proposed method was applied to the determination of hydrazine hydrate added into a tap water sample with good reproducibility and stability. All these provide a possibility to develop a novel ECL detection method for hydrazine in water.