北京南口风口对中心城区空气质量的差异化影响与关联性分析

南口地区位于北京城区西北强风通过带,这里空气干燥,极易扬沙起尘,是对北京中心城区空气质量影响最大的上风口。特别是处于南口地区核心位置的马池口西部,不仅是各大沟口风带的交汇区,还是各种污染源群落的聚集区,这一区域的风口扬尘和污染排放成为北京城区空气颗粒物污染的重要来源。由于气候条件、地理环境以及下垫面等因素的不同,本地风口颗粒物污染与高原高空沙尘在输送方式、污染物成分和季节变化等方面有显著的不同。北京颗粒物污染浓度与西北风口冬春季节的大风天气具有显著的相关性,说明本地风口扬尘和污染排放对北京空气质量具有重要影响,亟需采取措施进行规划治理。     

福州内河沉积物中三氯生和甲基三氯生的含量、来源及其生态风险

对福州市20个内河表层沉积物样品中的三氯生(TCS)和甲基三氯生(MTCS)的含量进行了测定,并对其生态风险进行了评估.研究结果表明,沉积物中TCS和MTCS的含量范围分别为11.8~120.4μg·kg-1和未检出(n.d.)~41.7μg·kg-1,平均含量分别为50.1μg·kg-1和7.8μg·kg-1.沉积物中TCS总量和总有机碳(TOC)含量呈显著正相关关系(r=0.590,p0.05),而MTCS和TOC之间无相关关系.用风险熵(RQ)对TCS和MTCS的生态风险进行了评估,发现有14个沉积物样品中TCS的RQ值和11个沉积物样品中MTCS的RQ值大于1,呈高风险;其他样品中TCS和MTCS(3个未检出样品除外)的RQ值介于0.1~1之间,均呈中等风险.     

精神病类药物在城市污水中的分布与净化

精神病类药物直接作用于中枢神经系统,破坏神经内分泌信号,其在环境中的积累将给生态系统和人类健康带来巨大的潜在风险,城市污水是其最重要的环境排放源.本文介绍了精神病类药物的分类、使用情况及生物毒性,总结了环境水样中精神病类药物分析检测方法,综述了世界各地城市污水中精神病类药物分布情况,比较了不同类型污水处理技术对精神病药物的去除效率,为促进我国城市污水中精神病类药物排放控制提供了基础资料和科学依据.     

火灾标准燃烧室相似模型试验箱设计及有效性研究

运用相似理论对火灾探测标准燃烧室建立1/10的相似模型试验箱,确定火灾试验所涉及的主要相似准则关系,并通过FDS数值模拟对其相似有效性进行分析.通过模拟试验,讨论火灾探测中关心的3m环及羽流中心线上烟气参数的变化及其相似性.模拟试验数据表明,在火灾研究误差范围内,该模型试验箱在烟气温升及运动特性上可以对原型标准燃烧室进行较好的模拟.     

Effects of six selected antibiotics on plant growth and soil microbial and enzymatic activities

The potential impact of six antibiotics (chlortetracycline, tetracycline and tylosin; sulfamethoxazole, sulfamethazine and trimethoprim) on plant growth and soil quality was studied by using seed germination test on filter paper and plant growth test in soil, soil respiration and phosphatase activity tests. The phytotoxic effects varied between the antibiotics and between plant species (sweet oat, rice and cucumber). Rice was most sensitive to sulfamethoxazole with the EC10 value of 0.1 mg/L. The antibiotics tested inhibited soil phosphatase activity during the 22 days' incubation. Significant effects on soil respiration were found for the two sulfonamides (sulfamethoxazole and sulfamethazine) and trimethoprim, whereas little effects were observed for the two tetracyclines and tylosin. The effective concentrations (EC10 values) for soil respiration in the first 2 days were 7 mg/kg for sulfamethoxazole, 13 mg/kg for sulfamethazine and 20 mg/kg for trimethoprim. Antibiotic residues in manure and soils may affect soil microbial and enzyme activities.     

垃圾焚烧飞灰热处理过程中Zn的挥发机理研究

试验在650~1350℃条件下探讨了温度和时间对飞灰中Zn的挥发率的影响,采用XAFs对飞灰及二次飞灰中Zn的赋存形态进行分析,运用吉布斯自由能理论推导了Zn的氯化反应途径,并开展了验证试验.结果表明：温度是影响Zn挥发的主要因素,其挥发趋势随温度先增加而后降低,在1000℃时挥发率达到最高,而时间对其挥发效果影响较小;Zn主要以氯化物形态挥发,从假设反应途径的吉布斯自由能理论计算及验证试验得出,热处理过程中Zn的氯化反应分两步进行,首先飞灰中氯化物与SiO₂反应生成Cl₂,而后与ZnO反应生成ZnCl₂,而小部分Cl₂可能与水蒸气反应形成HCl,再与ZnO反应生成ZnCl₂.     

Distribution of polychlorinated biphenyls in effluent from a large municipal wastewater treatment plant: Potential for bioremediation?

This study involved an evaluation of the potential for bioremediation of polychlorinated biphenyls(PCBs) in the effluent from a large municipal wastewater treatment plant. It was focused on the presence of PCBs in two types of effluents: the continuous effluent present during dry weather conditions and the intermittently present effluent that was present during wet weather due to incoming stormwater. The annual discharge of PCBs for both types of effluent was calculated based on a five-year dataset(2011–2015). In addition, the toxicity and bioremediation potential of the PCBs in the effluent were also assessed. It was found that the continuous effluent was responsible for the majority of the discharged PCB into the receiving river(1821 g for five years), while the intermittent effluent contributed 260 g over the five years.The average number of chlorine per biphenyl for the detected PCB congeners showed a 19%difference between the two types of effluent, which indicated a potential for organohalide respiration of PCBs during the continuous treatment. This was further supported by a high level of tri-, tetra-and penta-chlorinated congeners accounting for 75% of the anaerobically respired PCBs. Potential for aerobic degradation and thus biomineralization of PCBs was identified for both effluents. Furthermore, toxicity of 12 dioxin-like PCBs showed that normal operation of the wastewater reduced the toxicity throughout the wastewater treatment plant.