Chlorinated and brominated dibenzo-p-dioxins and dibenzofurans in surface sediment from Taihu Lake, China

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in surface sediment samples from Taihu Lake--an important water supply of the Yangtze River Delta, China--were investigated in the present study. Concentrations of PCDD/Fs ranged from 0.91 to 4.8 pg TEQ g(-1) dw (mean: 2.9 pg TEQ g(-1) dw, TEQ: Toxic Equivalent), which were all higher than the threshold effect level established by interim sediment quality guidelines in Canada (0.85 pg TEQ g(-1) dw). The levels of PBDD/Fs ranged from 0.16 to 1.6 pg TEQ g(-1) dw (mean: 0.52 pg TEQ g(-1) dw) and accounted for 5-33% (mean: 14%) of the total PCDD/Fs and PBDD/Fs TEQ. Comparatively, the abundance of sedimentary PCDD/Fs in the three regions (Meiliang Bay, Gonghu Bay, and Xukou Bay) showed a decreasing trend from the inflow region to the outflow region, while no significant difference was observed among their 2,3,7,8-PBDD/Fs levels, which suggested that the sources of PCDD/Fs and PBDD/Fs differed in this area. Principal component analysis suggested that the historical production/usage of pentachlorophenol and sodium pentachlorophenate was the dominant source of PCDD/Fs in the sediment of these regions. Although the specific sources of PBDD/Fs in the sediment of Taihu Lake were unclear, it was suspected to be due to atmospheric deposition; however, an additional study is needed to confirm this.     

A novel approach to rapid detection of acute water toxicity and its policy implications for grassroots sustainable environmental monitoring

Unknown chemicals, emerging contaminants, and the resulting reactions among them make early detection and warning of acute water toxicity extremely challenging. The conventional approach using small fish for toxicity monitoring normally requires a designated species of fish and over a week's time to complete, including dilution of the wastewater, a pre-test, and a full test. It often increases chances for error and delays emergency management. This paper reports a novel approach, based on grassroots knowledge and field and lab experience in Jilin, China. This approach uses a combination of different species of aquarium fish to achieve fast and reliable monitoring. It tests the original source water directly without going through the dilution procedure, while paying attention to the time factor. The approach does not require a pre-test and may shorten the time needed for detecting acute toxicity to a few minutes, using a new classification of aquatic toxicity levels. It is inexpensive to use and may be easily adopted by grassroots organizations. The approach is "greener" and more financially and socially sustainable than traditional approaches. The wide use of the approach has the potential to encourage policy innovations for making toxicity monitoring grassroots based and more effective in reducing acute contamination emergencies.     

扩散电化学法现场测定高湿度烟气中低浓度二氧化硫能力的 研究

根据目前定电位电解法出现的问题,对扩散电化学法测定固定污染源高湿度烟气中低浓度二氧化硫的能力展开研究。结果显示,扩散电化学法测定值与参比值保持较好的一致性,说明该方法不受固定污染源烟气浓度、湿度以及负压等因素的影响,对高湿烟气中低浓度二氧化硫具备较强测定能力,非常适合该状况下SO₂的现场测定。但是方法也受传感器制约,适用范围受到限制。     

Water chemistry in 179 randomly selected Swedish headwater streams related to forest production,clear-felling and climate

From a policy perspective, it is important to understand forestry effects on surface waters from a landscape perspective. The EU Water Framework Directive demands remedial actions if not achieving good ecological status. In Sweden, 44 % of the surface water bodies have moderate ecological status or worse. Many of these drain catchments with a mosaic of managed forests. It is important for the forestry sector and water authorities to be able to identify where, in the forested landscape, special precautions are necessary. The aim of this study was to quantify the relations between forestry parameters and headwater stream concentrations of nutrients, organic matter and acid-base chemistry. The results are put into the context of regional climate, sulphur and nitrogen deposition, as well as marine influences. Water chemistry was measured in 179 randomly selected headwater streams from two regions in southwest and central Sweden, corresponding to 10 % of the Swedish land area. Forest status was determined from satellite images and Swedish National Forest Inventory data using the probabilistic classifier method, which was used to model stream water chemistry with Bayesian model averaging. The results indicate that concentrations of e.g. nitrogen, phosphorus and organic matter are related to factors associated with forest production but that it is not forestry per se that causes the excess losses. Instead, factors simultaneously affecting forest production and stream water chemistry, such as climate, extensive soil pools and nitrogen deposition, are the most likely candidates The relationships with clear-felled and wetland areas are likely to be direct effects.     

季节性Kendall检验分析湘江长沙段水质变化趋势

季节性Kendall检验是一种广泛应用于河流水质变化趋势分析的非参数检验。以湘江长沙段三汊矶断面2001—2011年水质监测结果为样本,运用季节性Kendall检验分析湘江长沙段水质变化趋势及影响因素,结果表明:氨氮浓度呈显著上升趋势,总磷浓度呈高度显著上升趋势,总镉、总砷浓度呈高度显著下降趋势,湘江长沙段水质主要受城市生活、工业和农业面源污染物排放的影响,河水流量对水质的影响相对较小。     

黄岛电厂温排水对大型底栖生物群落的影响

以黄岛电厂温排水邻近海域为研究对象,2010年9月调查了电厂温排水对该海域大型底栖生物群落结构的影响。在9个站点共采集到大型底栖生物76种,平均生物量5．79 g/m2,平均密度830 m-2。利用Bray-Curtis相似性聚类对各样本大型底栖生物分析得出,调查区域可划分为4个群落。各样点Shannon-Wiener多样性指数在2．42～4．25之间,平均指数为3．67,其中靠近温排水区域站位的生物多样性呈现下降的趋势。丰度生物量比较（Abundance/biomass comparison, ABC）曲线分析结果显示,靠近排水口处的大型底栖生物群落受到一定程度的干扰。冗余分析（ RDA）结果表明,水温是影响底栖生物群落变化的最主要因子,对调查区域大型底栖生物群落变化的解释量达到60．5％,影响范围为排水口附近温升在3℃以上的区域。     

滇池浮游藻类群落构成调查

对滇池浮游藻类群落组成和空间分布开展了2次调查,鉴定出藻类8门66属159种及变种,绿藻种类最多,蓝藻次之。5、12月滇池全湖平均藻类密度分别为1.398×108、2.180×108个/升,蓝藻门微囊藻属为优势藻类。5月的调查中滇池外海藻类生物量呈北高南低的格局,而12月则呈现南部和中部高,北部低。外海的藻类生物量明显高于草海,草海藻类群落构成与外海明显不同,主要表现为绿藻门藻类所占比例较高。12月滇池外海及全湖藻类生物量都显著高于5月。与上一次(2006—2007年)滇池浮游藻类的系统调查相比,滇池(主要是外海)浮游藻类在物种数量、常见藻类、优势藻类及生物量水平方面与之接近。     

北京城区冬季道路灰尘粒度特征分析

对2013年1月于北京城区采集的40组道路灰尘样品用激光粒度仪进行粒度测定。结果表明:北京城区冬季道路灰尘频率曲线呈单峰态或双峰态分布,单峰型峰值粒径为112~237μm,双峰型第一峰值粒径为189~286μm,第二峰值粒径为42~57μm。道路灰尘平均粒径为183μm,分选性差,呈极不对称的极正偏宽峰态到窄峰态,属砂土。道路灰尘是局地灰尘和区域灰尘的混合物,且主要为跃移或短时悬浮颗粒物,对大气悬浮颗粒污染物的贡献量不大。研究4种不同道路类型灰尘发现,平均粒径从大到小顺序为快速路支路次干路主干路,分选系数与偏度为快速路主干路次干路支路,峰度无较大区别,细颗粒含量主干路次干路(支路、快速路)。主干路灰尘污染贡献率更高,对大气环境和人体健康的危害潜力不容忽视。     

Development of a multi-criteria index ranking system for urban runoff best management practices (BMPs) selection

Low impact development best management practices (LID-BMPs) are considered to be cost-effective measures for mitigating the water quantity and quality impact of urban runoff. Currently, there are many types of LID-BMPs, and each type has its own intrinsic technical and/or economical characteristics and limitations for implementation. The selection of the most appropriate BMP type(s) for a specific installation site is therefore a very important planning step. In the present study, a multi-criteria selection index system (MCIS) for LID-BMP planning was developed. The selection indexes include 12 first-level indices and 26 second-level indices which reflect the specific installation site characteristics pertaining to site suitability, runoff control performance, and economics of implementation. A mechanism for ranking the BMPs was devised. First, each individual second-level index was assigned a numeric value that was based on site characteristics and information on LID-BMPs. The quantified indices were normalized and then integrated to obtain the score for each of the first-level index. The final evaluation scores of each LID-BMP were then calculated based on the scores for the first-level indices. Finally, the appropriate BMP types for a specific installation site were determined according to the rank of the final evaluation scores. In order to facilitate the application of the MCIS BMP ranking system, the computational process has been coded into a software program, BMPSELEC. A case study demonstrating the MCIS methodology, using an LID-BMP implementation planning at a college campus in Foshan, Guangdong Province, is presented.     

渤海湾入海溶解无机氮总量控制研究

基于渤海湾近岸海域的实际调查结果,采取生态物理耦合模型,对渤海湾的主要污染物-溶解无机氮(DIN)的基准环境容量和极小剩余海洋环境容量进行了计算。结果表明,渤海湾DIN的极小剩余海洋环境容量在Ⅰ类和Ⅱ类水质标准下均为负值,渤海湾的DIN已经超标。结合实际的海水功能区水质管理目标,应重点控制非点源的排放,加强上游携带入境污染物的处理,从总量上控制DIN入海污染通量,改善渤海湾水质。