Concentrations of sulphur and heavy metals in needles and rooting soils of Masson pine (Pinus massoniana L.) trees growing along an urban–rural gradient in Guangzhou, China

Current (C) and previous year (C + 1) needles and soils (organic horizon, 0-10 cm and 10-20 cm mineral depth) of Masson pine (Pinus massoniana L.) trees were sampled at four forested sites (Huang Pu industrial district, HP; South China Botanical Garden, BG; Mao Feng Mt., MF; and Nan Kun Mt., NK) in Guangzhou along a urban-rural gradient and analyzed for sulfur (S) and heavy metals (Cu, Zn, Ni, Cd, Cr and Pb) concentrations. Needle concentrations of all the elements were significantly higher at industrial HP than at other three sites, except for Cu and Pb which were highest at the traffic site (BG). The C + 1 needles generally had higher Cu, Cd, Pb, Zn, Cr than the C needles while the opposite was for Ni and S. Total and available Cd, Pb, Zn in soils peaked at the urban sites (HP and BG) and decreased at suburban MF and rural NK. Heavy metals were generally higher in the organic soils than in the mineral soils at all sites. Zinc and Pb at all sites, and Cd, S and Cu at the urban sites (HP and BG) in soils or pine needles were above or near their respective natural background levels, implying that threats resulted from these toxic elements occurred on local particularly urban forests, but did not for Cr and Ni due to their presence below their background values. Our results demonstrated that elements concentrations in needles and soils had reflected the variability of pollutants and the environmental quality change along the urban-rural transect, and were efficient as biomonitors to assess the influence of anthropogenic activities along the urbanization course on forest health.     

采油废水厌氧处理系统的微生物群落特征

为了深入认识石油烃的厌氧降解过程,利用分子生物学技术分析了大庆油田采油废水处理系统厌氧池和进水中的微生物群落特征。基于DGGE和克隆文库的分析结果均表明,厌氧生物膜中存在的古菌源自于采油废水。厌氧生物膜和采油废水中的古菌主要是产甲烷菌,包括嗜甲基的Methanomethylovorans thermophila和利用氢和甲酸的Methanolinea tarda。值得注意的是,氢营养型的M.tarda在厌氧生物膜中得到了富集。进水和厌氧生物膜中的细菌群落结构明显不同。进水中的主要细菌类群为Epsilonproteobacteria,而生物膜中的主要类群为Nitrospira和Deltaproteobacteria。在厌氧生物膜中发现许多与产甲烷古菌(尤其是氢营养型产甲烷菌)协同降解石油烃类物质的细菌相关克隆:其中一个克隆与Syntrophus具有较高的同源性,该类菌是产甲烷菌介导的厌氧烃降解微生物区系中的关键细菌;许多Deltaproteobacteria克隆属于group TA类群,该类群细菌主要参与芳香族化合物产甲烷菌介导的厌氧降解过程。这些结果表明,在大庆油田采油废水厌氧处理系统中已经建立起由产甲烷菌所介导的厌氧石油烃降解的微生物区系。     

The release of lindane from contaminated building materials

The release of the organochlorine pesticide lindane (γ-hexachlorocyclohexane) from several types of contaminated building materials was studied to assess inhalation hazard and decontamination requirements in response to accidental and/or intentional spills. The materials included glass, polypropylene carpet, latex-painted drywall, ceramic tiles, vinyl floor tiles, and gypsum ceiling tiles. For each surface concentration, an equilibrium concentration was determined in the vapour phase of the surrounding air. Vapor concentrations depended upon initial surface concentration, temperature, and type of building material. A time-weighted average (TWA) concentration in the air was used to quantify the health risk associated with the inhalation of lindane vapors. Transformation products of lindane, namely α-hexachlorocyclohexane and pentachlorocyclohexene, were detected in the vapour phase at both temperatures and for all of the test materials. Their formation was greater on glass and ceramic tiles, compared to other building materials. An empiric Sips isotherm model was employed to approximate experimental results and to estimate the release of lindane and its transformation products. This helped determine the extent of decontamination required to reduce the surface concentrations of lindane to the levels corresponding to vapor concentrations below TWA.     

反馈环断裂下的安全知识积累与扩散仿真研究

为了研究个体死亡引发反馈环断裂对安全知识积累和扩散的影响，采用元胞自动机方法，构建了多层次、多状态、多行为的安全知识积累和扩散演化模型。然后运用交替变量控制法进行仿真实验，获取605组数据，并对所得数据进行层次回归分析。研究结果表明:个体死亡会阻碍安全知识积累且会加剧个体间知识差异，同时事故率的增加会提高知识积累机会和个体死亡机会，产生复杂的双向对冲效应；替代者知识水平能够对安全知识积累和扩散产生较大的正向影响，并能削弱个体死亡的负向影响；事故见证者的增加也能够产生一定的正向影响。据此提出“数量型死亡悖论”，并指出促进安全知识积累和扩散的重点方向。     

What adverse health effects will environmental heavy metal co-exposure bring us: based on a biological monitoring study of sanitation workers

Environmental Science and Pollution Research - To investigate the relationship between health effect profile and co-exposure to heavy metal, 254 sanitation workers from Guangzhou, China, were...     

陶瓷炉窑烟气污染物排放特性及治理技术现状

随着《陶瓷工业污染物排放标准》(GB 25464-2010)的颁布实施,对陶瓷炉窑烟气污染开展深度治理已成为必然。在上述背景下,文章以文献资料调研和现场监测为主,开展中国陶瓷行业烟气污染物排放特性和治理技术现状研究。重点关注陶瓷炉窑烟气颗粒物、SO2、NOx、氟化物、氯化物、重金属等污染物的产生和排放特性。研究表明各污染物的排放浓度受燃料种类、窑炉类型、工艺水平的影响较大,现阶段中国陶瓷炉窑烟气中各主要污染物排放浓度均较高,普遍超过最新陶瓷排放标准要求,因此为了达标排放必须开展有效治理。在此基础上对比分析国内外陶瓷烟气治理技术现状和发展趋势,提出多污染物联合控制是我国陶瓷行业烟气治理技术发展趋势。     

固相萃取—气相色谱法测定海水中的666、DDT

采用固相萃取技术富集海水中的666、DDT,并使用气相色谱进行测定。主要包括不同填料(C8、C18、C18-N)、SPE柱规格(500 mg/3 mL、500 mg/6 mL)、洗脱试剂、上样流速、水样pH和洗脱试剂体积6个因素对666、DDT富集效率的影响。最终确定最优条件为:采用500 mg/6 mL C18SPE小柱,调节海水pH=6,上样流速4~5mL/min,10 mL二氯甲烷洗脱。优化后的固相萃取-气相色谱方法测定海水中666、DDT加标10 ng/L回收率为75.7%~110.4%,精密度为1.16%~4.00%,方法检出限为0.19~1.20 ng/L。     

黄原酸化废弃污泥吸附Cu2+研究

将污水处理厂废弃污泥在碱性环境中用CS2处理,制备黄原酸酯类重金属吸附剂,探究一种有效的废弃污泥资源化途径.用傅里叶转换红外光谱(fourier transform infrared spectroscopy,FTIR)对污泥进行了表征,并通过批量实验研究了污泥对Cu2+的吸附性能以及pH和初始Cu2+浓度的影响.结果表明,黄原酸化成功引入了含硫基团,使黄原酸化污泥的吸附量相对于原始废弃污泥提高了20.6%~46.9%.当Cu2+初始浓度为25 mg·L-1时,黄原酸化污泥对Cu2+的去除率可达96.7%.吸附动力学遵循准二级动力学模型(Pseudo-second-order equation),平衡时间为3 h,吸附速率同时受膜扩散和颗粒内扩散两过程控制;吸附过程符合Langmuir等温模型和Freundlich等温模型,25℃下,由Langmuir模型得到的最大吸附量达142.92 mg·g-1(pH=5),且吸附容量随pH(1~5)及初始Cu2+浓度升高而升高.黄原酸化废弃污泥可作为高效重金属离子吸附剂,实现废弃资源的回收利用.     

A comparison between superfine magnesium hydroxide powders and commercial dry powders on fire suppression effectiveness

The effectiveness of superfine magnesium hydroxide powders and commercial dry powder in fire suppression were compared in a laboratory-scale, immovable fire suppression apparatus. The investigation focused on their suppression effectiveness under various pressures. It likewise studied the relationship between the powders’ surface structures and their effectiveness on fire suppression. The microcosmic structure of the powders was observed by scanning electron microscope (SEM), while the Thermal Gravity Analysis (TGA) technique was used to analyze the thermal behavior of the superfine magnesium hydroxide powders. By analyzing the results, it could be concluded that the pressure, the particle size, and the microcosmic structure of the powders’ surface mainly decide the capability of the powders to extinguish the fire. Comparing this with commercial dry powders, superfine magnesium hydroxide powders extinguished the fire in less than 10 s.     

银负载对活性炭纤维汞吸附性能的影响

银氨溶液浸渍活性炭纤维制得载银量14.07%的载银活性炭纤维.以筒状吸附体吸附气态Hg0的方式研究活性炭纤维银载前后的汞吸附性能,结果表明,载银后活性炭纤维汞吸附性能明显提高.实验还发现:随吸附温度升高,活性炭纤维的汞吸附效率随先增加后降低,而载银活性炭纤维的汞吸附效率随吸附温度升高而一直降低;延长停留时间和添加H2O(g)对两者汞吸附均有利.采用片状吸附体对2种吸附剂的汞饱和吸附量进行了测定,实验得出:70℃下活性炭纤维汞饱和吸附量为29.4 mg/g,载银活性炭纤维汞饱和吸附量为192.3 mg/g,即活性炭纤维载银后汞饱和吸附量提高到原来的6.54倍.扫描电镜分析发现:活性炭纤维上物理吸附汞占绝大多数,化学吸附汞很少;负载银后汞只吸附在活性炭纤维的含银活性点上,银粒子与汞结合生成银汞齐后形状趋于规则,且主要分布于活性炭纤维微晶的晶棱交界处.