用树叶、树皮含硫量监测包头市大气SO2污染的探讨

植物与周围环境不断进行着气体交换,当外界大气环境发生变化时,就会对植物产生影响,这种影响会在植物体有关部位以各种形式反映出来.研究表明,植物中含硫量与大气SO2浓度呈现出密切相关性,因此,可以通过植物含硫量来反映大气SO2的污染状况.     

空气气氛下木材表观热解动力学

研究了空气气氛下马尾松和楠木的树叶、树皮和树干试样的热解过程,发现每种试样的热解均包含两步主要的失重过程,在600℃时总失重均达90%以上.利用积分方法建立了适用于所有试样的两阶段一级动力学模型,实验失重曲线较好地符合模型计算出的失重曲线.     

Atmospheric pollution in an urban environment by tree bark biomonitoring - part II: Sr, Nd and Pb isotopic tracing

The harmful effect of manmade particles on natural processes and human health is documented by a large number of studies showing a positive correlation between particulate matter (PM) concentration and health effects. Diminution of this health risk necessitates among others the precise knowledge of the particle sources, their physical and chemical properties and their dissemination in the environment. Pb isotope ratios have been successfully used during the past decades as tracers of anthropogenic Pb disseminated in the biosphere. Here we show that tree bark biomonitoring with lead (Pb), strontium (Sr) and neodymium (Nd) isotope ratios as tracers allow a thorough analysis of the impacts of industrial and other anthropogenic emissions on the urban environment. This is the first comprehensive multi-isotope tracer study of atmospheric pollution in an urban environment allowing to identify and to integrate the different plume paths of emissions in a digital map system. This innovative approach might become an important tool for environmental management and policy-making processes dealing especially with risks and surveillance of air quality in the urban environment.     

Characteristics of Anaerobic Fermentation with Different Parts of Corn Stalks at Low Concentrations

In order to obtain the characteristics of anaerobic fermentation with different parts of corn stalks at low concentrations, air-dried corn stalks stem bark (SB), stem pith (SP), leaves (L), and corn stalks (CS) were, respectively, mixed with cow dung to perform fermentation at the temperature of 35 ^oC and carbon-to-nitrogen ratio (C/N) of 25. Mixed with cow dung compost, the fermentation broths were adjusted to a neutral pH value. Along with the enhancing of the total solid (TS) content of SB, SP, L, and CS fermentation broths, both of the daily biogas yields and methane contents increased under the same fermentation condition, except for Sample TS 6% of L. The optimal TS content of SB, SP, L, and CS broth is 8%, 5%, 10%, and 8%, separately. In 35 days, the highest methane yield of SB, SP, L, and CS broth was 125.0 mL/(volatile solid) VS g, 115.3 mL/VS g, 109.7 mL/VS g, and 80.0 mL/VS g, respectively, and the potential of methane transformation production of broth ranks as: SB> L> SP> CS. Daily methane producing rate of SB, SP, and L broth are faster than that of CS. It is necessary to separate the corn stalks into different parts to ferment because the optimal fermentation concentrations for the different parts are different. Additionally, the Gompertz equation was also adopted to simulate the anaerobic digestion process of different materials. The Gompertz equation fitting parameters show that the biodegradation (from easy to difficult) was: L < SP < SB < CS.     

Acidity and conductivity of Pinus massoniana bark as indicators to atmospheric acid deposition in Guangdong, China

Introduction The ever-increasing development of human activities has given significant rise to atmospheric pollutants which have negative impacts on natural ecosystems, as for example the severe decrease of the forests (Soikkeli, 1981; Hirano and Hijii, 1…     

Bark salicylates and condensed tannins reduce vole browsing amongst cultivated dark-leaved willows (<Emphasis Type="Italic">Salix myrsinifolia</Emphasis>)

Summary. Vole feeding amongst herbal willows that have a high concentration of salicylates in their bark and leaves, and may therefore be cultivated for use as raw material for herbal medicine was tested in the field and in laboratory conditions. Eight clones of dark-leaved willow (Salix myrsinifolia Salisb.) were cultivated for two years with six different methods combining three fertilisation levels (none, low and high), black plastic mulch applied for suppressing weed competition and unmulched control. Samples for the laboratory feeding trial were taken from the unfertilised plants during willow winter dormancy and twigs were fed to 16 voles as a multi-choice experiment. The bark area removed was calculated from image analysis of the material left by the voles. The diameter and the bark thickness of the twigs were measured. Concentrations of salicin, salicortin, HCH-salicortin, picein, triandrin, triandrin derivative, gallocatechin, (+)-catechin, luteolin-7-glucoside, hyperin, total condensed tannins and total nitrogen were measured from the twigs fed to voles in the laboratory. Browsing by a natural population of voles amongst winter-dormant willows was measured in the field. In the laboratory, voles browsed on 80% of the twigs and in the field voles browsed on 33% of the twigs. Vole feeding followed similar patterns in the field and in the laboratory experiment; feeding was clearly higher amongst the plants grown in unmulched control compared to those in plastic mulch. The same clones, 1, 2 and 6 were preferred in both experiments. Voles preferred thin twigs to thick ones. Feeding correlated negatively with concentrations of salicylates and tannins. As vole feeding seems to be highly affected by willow cultivation method and plant genotype, careful selection of cultivated clones and cultivation methods can enhance the reliability of herbal willow cultivation.     

57Fe Mssbauer spectroscopic study on the barks of several three species grown in Lanzhou,China

Using ⁵⁷Fe Mssbauer effect, the chemical states of iron components were investigated for the barks of Platycladus orientalis, Cedrus deodara and Platanus acerifolia sampled from Lanzhou City, China. All bark samples showed two overlapping doublets with large and small quadruple splitting. Only Platycladus orientalis's barks exhibited one sextet. Based on Mssbauer parameters, they were attributed to paramagnetic ferrous, paramagnetic ferric and magnetic iron, respectively. For the sampling site which is about 6 kilometers from Lanzhou Steel Factory, the ratio of ferrous to ferric was higher in the sample of Platanus acerifolia's barks, whereas the barks of Platycladus orientalis and Cedrus deodara gave similar values of this ratio. Platycladus orientalis was the most effective in accumulating iron complexes in barks among the three trees. Platanus acerifolia's barks sampled at Lanzhou Steel Factory's area exhibited higher absolute intensities of iron components and lower ration of ferrous to ferric, indicating that industrial air pollution is a contributing factor in accumulating iron compounds in the tree barks of this region.     

柑橘皮中果胶提取条件的研究

利用酸性水解乙醇沉淀法提取果胶,分别测定了不同的浸泡时间、酸碱度及水解温度对果胶产率的影响.结果表明:浸泡时间与水解时间过长或过短,酸碱度及水解温度过高或过低,果胶的产率均不高,只有浸泡时间在2h左右、水解时间在2～2.5h、pH在2～3之间、水解温度在80～95℃时果胶的得率最大.     

树皮填料补充碳源人工湿地脱氮初步试验研究

人工湿地可应用于城市污水厂出水深度处理和农业污染治理,但反硝化碳源不足问题制约了其脱氮能力.本试验利用树皮作为垂直流人工湿地强化反硝化脱氮填料,分析了水力负荷、硝酸盐负荷以及pH对人工湿地脱氮效果的影响.结果表明,人工湿地可以达到预期的反硝化水平,反硝化速率随水力负荷、硝酸盐负荷的增加而增大,去除率随两者的增加而减小,...     

我国苏南地区香樟树皮赋存的二英类污染特征及来源

为分析长江下游经济高速发展区的POPs污染特征,于2012年8月在苏南地区典型城市10个采样点采集香樟树皮,应用高分辨气相色谱-高分辨质谱(HRGC-HRMS)联用技术对二英(PCDD/Fs)浓度水平进行监测,同时采用主成分分析(PCA)法探讨其可能来源. 结果表明:苏南地区香樟树皮中二英的毒性当量(I-TEQ)浓度(以干质量计,下同)为5.6～12.2 pg/g,平均值为7.2 pg/g;4～8氯代二英同族体质量分数(以干质量计)范围为418～938 pg/g,平均值为635 pg/g. 由于二英在大气中的长距离迁移潜力较强,在研究的苏南地区区域尺度上,其含量在城市中心区和对照区之间的差异性并不明显;苏南地区香樟树皮二英质量分数及毒性当量浓度均高于国外报道的背景区及典型城市中树皮的水平. 对比典型二英排放源及树皮中二英特征谱图,可推断苏南地区香樟树皮中二英可能主要来源于危险(医疗)废物焚烧、机动车尾气排放和工业燃烧源.