Lead Contamination of Urban Soils and Vegetation by Emissions from Secondary Lead Industries

The degree and extent of lead contamination of urban soils and vegetation in the vicinity of secondary lead industries are provided. These urban industries, a secondary smelter reprocessing lead from used batteries and scrap metal and a manufacturer of new storage batteries, were located near residential communities. Levels as high as 21,000 ppm of lead in the upper 5 cm of soil (based on air dried weight) and 3500 and 2700 ppm in willow foliage (not washed and washed, respectively, based on dry weight) were found adjacent to the secondary smelter, with the levels decreasing exponentially from the sources. The data on lead contamination of soils and vegetation at various distances and directions from the urban secondary lead industries were compared with levels of lead found in control urban and highway locations. In addition, arsenic levels in soil were examined as a tracer for the source of industrial lead emissions. High levels of lead found In both vegetation and soil in the vicinity of the urban industries reflected both historical and current emissions of lead in those areas. These studies were conducted for industrial abatement purposes; to assist medical related epidemiology studies; to define the areas of severe contamination for soil cleanup purposes; and to formulate guidelines for excessive levels of lead in soil and vegetation. Since lead in soil is persistent, concern arises with respect to pica for small children, contamination of edible vegetables grown in high-lead soil, and reentrainment of leaded particulate matter into the air.     

Field study of nitrous oxide production with in situ aeration in a closed landfill site

Nitrous oxide (N₂O) has gained considerable attention as a contributor to global warming and depilation of stratospheric ozone layer. Landfill is one of the high emitters of greenhouse gas such as methane and N₂O during the biodegradation of solid waste. Landfill aeration has been attracted increasing attention worldwide for fast, controlled and sustainable conversion of landfills into a biological stabilized condition, however landfill aeration impel N₂O emission with ammonia removal. N₂O originates from the biodegradation, or the combustion of nitrogen-containing solid waste during the microbial process of nitrification and denitrification. During these two processes, formation of N₂O as a by-product from nitrification, or as an intermediate product of denitrification. In this study, air was injected into a closed landfill site and investigated the major N₂O production factors and correlations established between them. The in-situ aeration experiment was carried out by three sets of gas collection pipes along with temperature probes were installed at three different distances of one, two and three meter away from the aeration point; named points A-C, respectively. Each set of pipes consisted of three different pipes at three different depths of 0.0, 0.75 and 1.5 m from the bottom of the cover soil. Landfill gases composition was monitored weekly and gas samples were collected for analysis of nitrous oxide concentrations. It was evaluated that temperatures within the range of 30–40°C with high oxygen content led to higher generation of nitrous oxide with high aeration rate. Lower O₂ content can infuse N₂O production during nitrification and high O₂ inhibit denitrification which would affect N₂O production. The findings provide insights concerning the production potentials of N₂O in an aerated landfill that may help to minimize with appropriate control of the operational parameters and biological reactions of N turnover.

Implications: Investigation of nitrous oxide production potential during in situ aeration in an old landfill site revealed that increased temperatures and oxygen content inside the landfill site are potential factors for nitrous oxide production. Temperatures within the range of optimum nitrification process (30–40°C) induce nitrous oxide formation with high oxygen concentration as a by-product of nitrogen turnover. Decrease of oxygen content during nitrification leads increase of nitrous oxide production, while temperatures above 40°C with moderate and/or low oxygen content inhibit nitrous oxide generation.     

微波活化中孔酸性生物质炭对亚甲基蓝的吸附行为与机理

以甘蔗渣为原料,采用微波辅助磷酸活化法制备了同时富含中孔结构和含氧酸官能团的生物质炭,以氮气吸附、红外光谱FT-IR等技术对炭样品表面物化性质进行了表征,通过静态实验法测定了生物质炭对水中亚甲基蓝的吸附特性,分析了溶液pH、初始浓度、温度对吸附的影响,研究了不同pH下蔗渣生物质炭对亚甲基蓝的吸附行为,并从热力学及动力学角度探讨了生物质炭对亚甲基蓝的吸附机理。结果表明,不同制备参数下生物质炭的得率均大于39.2%,但表面物化性质因参数变化有较大差异。在浸渍比1∶1,烘干时间10 h,活化功率900 W,活化时间22 min的条件下,制得的生物质炭的比表面积为1 021 m2/g,亚甲基蓝值超过国家一级品标准1.70倍,表面富含微中孔结构和羟基、羰基、羧基等酸性官能团,中孔约占总孔的40%。静态吸附实验表明,溶液初始浓度对吸附有较大的影响,吸附量随初始浓度的增加,pH的升高及温度的上升而增大,Freundlich方程、Redlich-Peterson方程与Temkin方程能较好地描述等温吸附行为;吸附动力学结果表明,数据符合Elovich方程,吸附行为更倾向于化学吸附;热力学研究表明,吸附吉布斯自由能(ΔG0)0,吸附标准焓变(ΔH0)70 kJ/mol,说明该吸附为自发的吸热反应,且化学反应在吸附过程中发挥了重要作用。     

A New Statistical Dynamic Analysis of Ecosystem Patterns

While phenomenological investigations of ecosystem patterns often fail to reveal underlying dynamic mechanisms, we highlight a universal principle for pattern formation in ecosystems. We consider ecosystems to be typical complex adaptive systems that seek an optimal process to obtain maximized flux under given constraints. An analysis of the optimal process reveals underlying microscopic dynamic mechanisms that induce complex patterns in ecosystems. We emulate ecosystem patterns using a Self-Organization Feature Map: an artificial neural network theoretical model by which evolution processes, structural classifications, and the fractal growth of ecosystem patterns can be simulated. The results help us analyze the formation and dynamics of ecosystem patterns, with attending implications for the classification, protection, and optimization of ecosystems.     

Antimony (Sb) – pollution and removal techniques – critical assessment of technologies

In view of increasing emissions of antimony (Sb) into the environment due to industrialization and consequent carcinogenicity, it is essential to remove this metal from the ecosystem. Antimony and arsenic (As) are analogs. Although numerous studies examined arsenic removal, few reports are available on Sb removal. In this review, various Sb removal techniques are described to understand how this process occurs and what research gaps are needed to improve efficiency. At present, surface adsorption technique is the most widely used for Sb removal. Biological treatment namely phytoremediation is also a promising method and more investigations are required in this regard. The selection of a suitable technique for a given area depends on the conditions including economic, environmental, and social conditions.     

固定化SRB吸附乳酸钠的动力学及再生动力学研究

用聚乙烯醇包埋硫酸盐还原菌(SRB),探讨固定化SRB小球的动力学规律及再生动力学控制机理,同时利用膜扩散控制模型与粒内扩散控制模型,描述固定化SRB小球循环吸附乳酸钠的动力学过程,计算出不同条件下的膜扩散系数D/δ和粒内扩散系数D的值.通过对固定化SRB小球吸附乳酸钠的动力学和再生动力学研究,为固定化SRB小球的营养源吸附与再生工艺参数的确定提供理论依据.     

氧化镁湿法烟气脱硫回收工艺的技术经济可行性初步分析

介绍了回收结晶硫酸镁的氧化镁湿法烟气脱硫工艺的基本工艺流程,在抛弃法脱硫系统上所作的工业试验证明了吸收液循环提浓MgSO4的可行性.参照工业硫酸镁生产工艺对130t/h燃煤锅炉烟气脱硫作了回收工艺的投资效益分析和整体工艺的经济性评价,结果表明回收工业硫酸镁具有良好的经济效益.     

Regional distribution of organochlorinated pesticides in pine needles and its indication for socioeconomic development

The regional distribution of 10 potentially harmful organochlorinated pesticides (OCPs) was investigated in pine needles from 18 sites in six Chinese regions. The OCPs concentrations in six regions were as follows: sigmaHCH (sigmaHCH=alpha-+beta-+gamma-+delta-HCH), 4.7-51.5 ng/g; sigmaDDT (p,p'-DDT+p,p'-DDE+p,p'-DDD), 0.9-30.9 ng/g; hexachlorobenzene (HCB), 1.1-5.3 ng/g; sigmachlordane (cis-chlordane+trans-chlordane), no detected-4.3 ng/g, on dry weight basis. Samples from southeast Chinese area contained the highest concentrations of sigmaHCH, sigmaDDT and sigmachlordane, while the contamination levels of most OCPs in southwest Chinese area were the lowest. The ratios of alpha/gamma-HCH (ranged from 1.7 to 5) were observed to be noticeable increase from north to south China, and the ratio of 1.7 revealed the presence of the recent use of lindane in north Chinese area. The significant decrease of the sum concentrations of alpha-+gamma-HCH from mid-1980s to the present and the strong correlation between alpha-, beta-, gamma-, delta-HCH (r=0.87-0.98, n=18, p<0.05) indicated the main usage of the technical HCH in history in China. The p,p'-DDE/p,p'-DDT ratios of <1 revealed the new input of p,p'-DDT in south, southeast and southwest Chinese areas, which could be partly contributed to the new use of impure dicofol. Economic development will leave its mark in the environment, however, its impact on the input and distribution of OCPs on a regional scale is unknown. We attempted to use the socioeconomic index (gross domestic product (GDP) per capita) to explain the distribution and input of OCPs and found that HCB and sigmaDDT seemed to be linked to the economic development, while no relationship of HCH was observed. DDE% of sigmaDDT also showed a negative correlation with the GDP per capita.     

Multiplex approach for screening genetic markers of microbial indicators.

Genetic markers are expected to provide better specificity in epidemiological studies and potentially serve as better indicators of waterborne pathogens. Methods used to assess genetic markers of emerging microbial indicators include pulsed field gel electrophoresis, polymerase chain reaction (PCR), and microarrays. This paper outlines a high-throughput approach to screen for such genetic markers using a set of theoretical and experimental screening tools. The theoretical screening involves evaluating genes related to the ribosomal RNA and specific functions from emerging indicator groups, followed by experimental validation with appropriate sampling schemes and high-throughput and economical screening methods, such as microarrays, real time PCR, and on-chip PCR. Analysis of a wide range of samples covering temporal variability in location, host, and waterborne disease outbreaks is essential. The proposed approach is expected to shorten the time and cost associated with searching for new genetic markers of emerging indicators by at least 10-fold.