Spatial distribution of dissolved Pb, Hg, Cd, Cu and As in the Bohai Sea

Characteristics of the spatial distribution of selected dissolved heavy metals were analyzed during large scale surveys from August 12 to 25,2003 in the Bohai Sea.Dissolved Pb was the only element with average concentrations higher than the grade-one sea water quality standard of China.The spatial distribution of dissolved Pb in surface water was similar to those of Cd,Cu and As,where the isopleths generally indicated decreasing values from the bays to the central areas.Only for Hg did the high concentrations not only appear in Liaodong Bay,Bohai Bay and Laizhou Bay,but also in the Central Area,viz.not only in inshore but also in offshore areas. Vertical distributions of dissolved Pb,Cd,Cu and As were largely uniform,while that of dissolved Hg increased with depth.We infer that the input of pollutants from land was the main influencing factor for the detected distribution patterns of dissolved heavy metals, followed by the dynamics of sea water,release from bottom sediments and biochemical processes.Comparing with historical data, average concentrations of dissolved heavy metals appear to decline in recent years.     

Statistical optimization of adsorption processes for removal of 2,4-dichlorophenol by activated carbon derived from oil palm empty fruit bunches

The adsorption capacity of activated carbon produced from oil palm empty fruit bunches through removal of 2,4-dichlorophenol from aqueous solution was carried out in the laboratory. The activated carbon was produced by thermal activation of activation time with 30 min at 800℃. The adsorption process conditions were determined with the statistical optimization followed by central composite design. A developed polynomial model for operating conditions of adsorption process indicated that the optimum conditions for maximum adsorption of phenolic compound were： agitation rate of 100 r/min, contact time of 8 h, initial adsorbate concentration of 250 mg/L and pH 4. Adsorption isotherms were conducted to evaluate biosorption process. Langmuir isotherm was more favorable （R^2=0.93） for removal of 2,4-dichlorophenol by the activated carbon rather than Freundlich isotherm （R^2=0.88）.     

采空区亚自燃状态及其向自燃转化研究

针对高危自燃采空区遗留煤发生自燃问题,提出采空区亚自燃状态的概念.开采推进过程中的采空区自燃,都可理解为是从亚自燃状态向自燃状态转化的结果,且其转化过程时间很短,小于最短自然发火期.在不同条件下的自燃过程满足叠加组合原理,采空区亚自燃状态向自燃转化过程是两种以上过程的叠加.转化受亚自燃状态程度(稳定温度)、工作面推进度、漏风供氧、煤堆积状态及防灭火措施(注氮)等因素影响.亚自燃状态理论能够解释生产实践中一旦某一不利因素出现,能在短时间内导致自燃发生的现象(自燃突发性).亚自燃状态概念的提出,将有助于从理论上正确认识实际采空区自燃状态的演变过程,实现早期预防采空区自燃的发生.     

地下含水层中污染物生物降解的机制和数值模拟

对地下含水层污染物生物降解的数学模型建模原则作了补充,对一维均匀介质定常流下生物降解过程进行了模拟研究。对模型适用性的验证结果表明：模型的模拟结果与已发表的模拟结果和已有的实测结果较为一致。对细菌生物降解机制模拟试验结果表明：降解过程是高度非线性相互作用过程,除个别参数有明显趋向作用外,多数过程相应参数的影响后果由特定条件决定。而模型正是能预报这些作用的详细过程。     

Identification and ecotoxicity assessment of intermediates generated during the degradation of clofibric acid by advanced oxidation processes

The aim of this study was to identify the intermediates in clofibric acid degradation under various advanced oxidation processes, namely ultraviolet (UV), UV/H₂O₂, vacuum ultraviolet (VUV), VUV/H₂O₂, and solar/TiO₂ processes, as well as to assess the toxicity of these intermediates. Eleven intermediates have been detected by gas chromatography-mass spectrometer, most of which were reported for the first time to our best knowledge. Combining the evolution of the dissolved organic carbon, Cl^- and specific ultraviolet absorption at 254 nm, it could be deduced that cleavage of aromatic ring followed by dechlorination was the mechanism in solar/TiO₂ process, while dechlorination happened first and accumulation of aromatic intermediates occurred in the other processes. Different transformation pathways were proposed for UV-, VUV-assisted and solar/TiO₂ processes, respectively. The acute toxicity was evaluated by means of Photobacterium phosphoreum T₃ spp. bioassay. It was believed that aromatic intermediates increased the toxicity and the ring-opening pathway in solar/TiO₂ process could relieve the toxicity.     

两级Fenton-厌氧滤池-曝气生物滤池深度处理垃圾渗滤液

浙江某生活垃圾填埋场采用两级Fenton-厌氧滤池-曝气生物滤池工艺对其渗滤液进行深度处理。工艺最终出水ρ(COD)<70 mg/L,去除率达96.1%;ρ(TN)<40 mg/L,去除率达95.9%;ρ(NH3-N)<10 mg/L,工艺出水达GB 16889—2008《生活垃圾填埋场污染控制标准》中一般地区表2排放标准。     

Tools for an enhanced solvent properties screening in the early stages of pharmaceutical process development

The objective of this research was the implementation of tools for the evaluation of solvents trough property screening in the early stages of process development. An important feature of the tools is that the implementation of indexes, scores, or weights is avoided. Information already available from the literature was stored in a database in order to turn raw data into decision making information. As a result, a solvent radar chart, a solvent representation table, and a solvent telescopying tool were developed in an ASP.NET application. The synthesis of Propranolol was used as study case in order to explore the selection of solvents in the early stages of process development. The replacement of diethyl ether was possible in the extraction step, while solvent choices were detected for potential telescoping for extraction and crystallisation steps. Solubility was found as a critical parameter in telescoping analysis. The methodology proposed enhanced the view towards a more holistic perspective and a more robust solvent screening process. As a consequence, the next steps into solvent evaluation and process development can be reduced.     

青岛大气气溶胶中微量元素溶解度及影响因素

利用2012年12月在青岛采集的31个总悬浮颗粒物（TSP）样品,分析其中11种微量元素的总浓度和溶解态浓度,讨论了沙尘负载、气溶胶来源、酸过程及天气条件对微量元素溶解度的影响.结果表明,Fe和Al的溶解度<5%,Pb、Ba、Bi的为10%左右,Cu、V、Cd、Mn的为20%~30%,Zn和As的约为40%.随着沙尘负载量的增加,气溶胶中微量元素溶解度呈规律性递减.气团后向轨迹聚类分析和正矩阵因子分析（PMF）结果显示,受人为源影响的气溶胶中微量元素溶解度明显高于受沙尘源影响的,受二次生成源和海洋源影响的的气溶胶中微量元素溶解度明显高于受土壤源影响的.大气酸过程是造成这些差异的主要原因.相关性分析表明,SO₄^2-、NO₃^-和有机酸等酸组分均对微量元素溶解度有一定影响.霾天时气溶胶中微量元素溶解度明显低于雾天的,其原因为酸组分在较高的相对湿度下更能促进微量元素溶解度的提高.     

Assigning results of the Tool for Sustainability Impact Assessment (ToSIA) to products of a forest-wood-chain

A Tool for Sustainability Impact Assessment (ToSIA) has been developed for assessing sustainability impacts of forest-wood-chains (FWCs). Sustainability is determined by analysing environmental, economic, and social sustainability indicators for all the production processes along the FWC. Results of the tool can be analysed at an aggregated level for complete FWCs, but for some applications it is useful to assign the indicator results to products of the chain.This paper presents a procedure in ToSIA to assign sustainability impacts to multiple output products of FWC. The procedure was tested and demonstrated with an example FWC from Scandinavia that included furniture and bio-energy production. Two different allocation criteria, carbon-based and economic value-based, were applied with different options for assigning the impacts on the sub-products of the chain. Three indicators representing the three pillars of the sustainability were chosen to demonstrate the procedure: production costs (economic), employment (social) and transport intensity (environmental).The results indicated that the allocation criteria greatly affect the indicator results assigned to the different products of FWCs. The selection of the allocation criterion depends on the question approached and on the availability of the needed process related data. The data availability is assured for the carbon-based allocation within ToSIA, as following the carbon flows within the chain is mandatory for any ToSIA application. Economic values of products, on the other hand, are more closely linked to the aims of the production processes of the value chains and are thereby meaningful allocation criteria in many cases. The allocation procedure of ToSIA was proved to be flexible allowing different criteria and still consistent in allocation of the various sustainability impacts of the FWCs.     

Influence of Small Dams on Downstream Channel Characteristics in Pennsylvania and Maryland: Implications for the Long‐Term Geomorphic Effects of Dam Removal1

Abstract: We evaluate the effects of small dams (11 of 15 sites less than 4 m high) on downstream channels at 15 sites in Maryland and Pennsylvania by using a reach upstream of the reservoir at each site to represent the downstream reach before dam construction. A semi‐quantitative geomorphic characterization demonstrates that upstream reaches occupy similar geomorphic settings as downstream reaches. Survey data indicate that dams have had no measurable influence on the water surface slope, width, and the percentages of exposed bedrock or boulders on the streambed. The median grain diameter (D₅₀) is increased slightly by dam construction, but D₅₀ remains within the pebble size class. The percentage of sand and silt and clay on the bed averages about 35% before dam construction, but typically decreases to around 20% after dam construction. The presence of the dam has therefore only influenced the fraction of finer‐grained sediment on the bed, and has not caused other measurable changes in fluvial morphology. The absence of measurable geomorphic change from dam impacts is explicable given the extent of geologic control at these study sites. We speculate that potential changes that could have been induced by dam construction have been resisted by inerodible bedrock, relatively immobile boulders, well‐vegetated and cohesive banks, and low rates of bed material supply and transport. If the dams of our study are removed, we argue that long‐term changes (those that remain after a period of transient adjustment) will be limited to increases in the percentage of sand and silt and clay on the bed. Thus, dam removal in streams similar to those of our study area should not result in significant long‐term geomorphic changes.