Determination of VOCs in groundwater at an industrial contamination site using a homemade low-density polyethylene passive diffusion sampler

A home-made inexpensive passive diffusion bag （PDB） sampler, prepared by filling deionized water in low-density polyethylene （LDPE） tubes, was evaluated for volatile organic compounds （VOC） sampling in groundwater at industrial contamination sites. Impacts of environmentally relevant conditions on the sampling equilibration time and partitioning of VOCs between the sampler and the water sample were investigated. Sample salinity, agitation and temperature can influence the equilibration time, but generally sampling equilibration was obtained in 14 days under real field sampling of VOCs in groundwater. Both laboratory study and field testing in a contaminated site showed that the VOC concentrations in the developed sampler were equal to those in the water samples at equitibrium. Coupled with a purge and trap concentrator-gas chromatograph-mass spectrometer （P＆T-GC-MS）, the developed PDB sampler provided a low-cost sampling device for routine monitoring of VOCs in groundwater in wells, with LODs in the range of 2.9-10 μg/L. The proposed PDB was applied to determine VOCs in groundwater at an industrial contamination site, and the present results agreed well with those determined using conventional pump-and-sample monitoring. All the studied 13 VOCs were tested in the four wells in the industrial contamination sites, with their concentrations in the range of 12-73660 μg/L. In addition, while benzene and toluene were heavily contaminated up to a maximum concentration of 74000 μg/L and 6000 μg/L, respectively, 1,2,3-trichlorobenzene and bromobenzene had relatively low contamination levels （below 25 μg/L）.     

遥感与GIS辅助下的非点源模型空间参数提取

非点源模型的应用面临着数据收集和管理困难等难题，本文以SWAT模型在芦溪小流域的应用为例，阐述了遥感与GIS技术在非点源研究中的应用，主要包括利用TM影像提取土地利用信息，利用GIS进行插值，划分子流域和信息提取。研究表明，遥感与GIS能够在相当程度上解决非点源模型应用中的数据收集、分析和管理困难。遥感能经济快速获取空间信息。GIS在空间数据综合分析、空间数据的插值中发挥着重要作用。建议在今后的研究工作中加强研究空间数据对非点源模型模拟结果的误差传递。     

全球变暖对上海和广州人群死亡数的可能影响

研究表明，最高气温达到３４℃以上的“热日”死亡数显著增加，“热日多出死亡数”占夏季总死亡数的百分率，上海为４．２％，广州为３．８％。广州人对热压力的适应性比上海人强。如果上海和广州未来温升不到１℃，冬夏死亡效变化不大；如温升几度，夏季死亡数上升，超过冬季死亡数的下降，全年死亡率增高。     

旋流板塔钠强化石灰石湿式烟气脱硫研究

向石灰石脱硫浆液中添加硫酸钠可提高脱硫率。以旋流板塔为吸收器,测定了钠强化石灰石湿式烟气脱硫过程的脱硫率、pH值等随脱硫反应时间的变化情况,对不同pH值范围内的石灰石溶解速率等进行了分析。在与工业操作温度相近的条件下,测定了不同塔板数时的脱硫率和塔压降,计算了平均单板效率。结果表明,增加塔板数,脱硫率提高,而平均单板效率减小,实验条件下,塔板数由1增加到4,液气比为4L／m^3时脱硫率由25．5％提高到48．6％,而平均单板效率则由25．5％下降到15．3％。得出了平均单板效率与塔板数之间的关系式。     

大骨节病病情下降与环境因素的定位研究

１９８７年４月－１９８９年９月对内蒙三个大骨节病村进行了随诊观察，结果表明，大骨节病病情逐年下降，人体硒营养水平相应提高，病情与硒营养水平之间呈显负相关，每日由外源性食物中摄取的硒与病情呈显负相关，而由当地产粮，菜中摄取的硒与情呈显正相关。由肉蛋类食物中摄取与病情呈显负相关，生态环境中的硒基本无变化，增加外源性高硒食物输入病区和改变病区食物构成是控制硒反应性疾病的主要途径。     

美欧环境内分泌干扰物研究框架

欧美于20世纪90年代开始系统研究环境内分泌干扰物（EDs)，为此成立了专门的工作机构负责EDs研究的规划与协调工作。研究框架包括确认EDs对人类和生态效应的方法，剂量一效应关系模型以及检测环境暴露水平等。研究对环境威胁最大受试物的主要毒理学终点有致癌性，生殖发育毒性，神经毒性和免疫毒性，目前危险评价的新进展是应用定量结构活性关系（QSAR）模型预测化学物的安全性。     

Degradation kinetics and mechanism of trace nitrobenzene by granular activated carbon enhanced microwave/hydrogen peroxide system

The kinetics of the degradation of trace nitrobenzene (NB) by a granular activated carbon (GAC) enhanced microwave (MW)/hydrogen peroxide (H₂O₂) system was studied. Effects of pH, NB initial concentration and tert-butyl alcohol on the removal efficiency were examined. It was found that the reaction rate fits well to first-order reaction kinetics in the MW/GAC/H₂O₂ process. Moreover, GAC greatly enhanced the degradation rate of NB in water. Under a given condition (MW power 300 W, H₂O₂ dosage 10 mg/L, pH 6.85 and temperature (60±5)℃), the degradation rate of NB was 0.05214 min^-1 when 4 g/L GAC was added. In general, alkaline pH was better for NB degradation; however, the optimum pH was 8.0 in the tested pH value range of 4.0-12.0. At H₂O₂ dosage of 10 mg/L and GAC dosage of 4 g/L, the removal of NB was decreased with increasing initial concentrations of NB, indicating that a low initial concentration was beneficial for the degradation of NB. These results indicated that the MW/GAC/H₂O₂ process was effective for trace NB degradation in water. Gas chromatography-mass spectrometry analysis indicated that a hydroxyl radical addition reaction and dehydrogenation reaction enhanced NB degradation.     

污泥电子传递体系(ETS)活性测定中萃取剂的选择

比较了丙酮、乙醇、正丁醇、磷酸三丁酯、乙酸乙酯、甲苯和三氯甲烷等7种萃取剂检测活性污泥电子传递体系(ETS)活性的特性.结果表明,这7种萃取剂制作标准曲线的性能相近;在实际污泥样品检测中,37℃下丙酮的萃取时间仅需10min,待测样品量相同时,其萃取速度约是其它萃取剂的4～22倍,37℃下丙酮萃取污泥样品中三苯基甲脂(TF)的能力大于其它萃取剂在37℃或90℃下的萃取能力,同时以丙酮作萃取剂测定的污泥电子传递体系活性也最大,说明丙酮是污泥电子传递体系活性测定中萃取剂的最佳选择.     

基于低碳视角的天津市能源结构系统动力学分析

全球气候变化和温室气体的大量排放已成为国际社会广泛关注的问题,能源结构调整是应对这一问题行之有效的手段。通过对天津市能源结构进行研究,从低碳角度出发,以改善天津以煤为主的能源供给结构、提高能源利用效率、缓解能源供应压力、减少环境污染和生态破坏为目的,应用系统动力学对天津市能源结构的未来发展情况进行模拟,通过对非低碳模式、低碳模式和强化低碳模式3种模拟方案下能源消耗情况和温室气体排放的比较,找出适合天津市能源结构调整的最佳模式。     

壳聚糖乙酸酯冠醚对金属离子的吸附性能研究

利用壳聚糖Ｃ２位上活泼氨基与苯甲醛进行反应,制得了Ｓｃｈｉｆｆ碱苯甲醛壳聚糖（简称ＣＴＢ）,再将合成的二苯并１６－冠－５氯代乙酸酯冠醚接枝到ＣＴＢ上,得到壳聚糖－苯并１６－冠－５乙酸酯冠醚（简称ＴＣＢＣ）,使其在酸性条件下脱去苯甲醛,制得壳聚糖－二苯并１６－冠－５－乙酸酯冠醚（简称ＣＴＣＥ）。经元素分析、红外光谱分析表征了其结构。并研究了ＣＴＢＣ和ＣＴＣＥ对Ｐｂ＾２＋、Ｃｕ＾２＋、Ｃｒ＾３＋、Ｎｉ