石墨炉原子吸收法测定空气中铋

建立了硝酸-双氧水体系消解、石墨炉原子吸收法测定空气中铋的方法。采用抗坏血酸和磷酸二氢铵作混合基体改进剂,热解涂层石墨管,塞曼扣背景。此方法对测定环境空气中铋的灵敏度、准确度都有很大的提高,方法的最低检出浓度为1.00μg/L,当采样体积为150L,铋最低检出质量浓度为0.0007mg/m3。     

Influence of fuel moisture, charge size, feeding rate and air ventilation conditions on the emissions of PM, OC, EC, parent PAHs, and their derivatives from residential wood combustion

Controlled combustion experiments were conducted to investigate the influence of fuel charge size, moisture, air ventilation and feeding rate on the emission factors (EFs) of carbonaceous particulate matter, parent polycyclic aromatic hydrocarbons (pPAHs) and their derivatives from residential wood combustion in a typical brick cooking stove. Measured EFs were found to be independent of fuel charge size, but increased with increasing fuel moisture. Pollution emissions from the normal burning under an adequate air supply condition were the lowest for most pollutants, while more pollutants were emitted when an oxygen deficient atmosphere was formed in the stove chamber during fast burning. The impacts of these factors on the size distribution of emitted particles was also studied. Modified combustion efficiency and the four investigated factors explained 68%, 72%, and 64% of total variations in EFs of PM, organic carbon, and oxygenated PAHs, respectively, but only 36%, 38% and 42% of the total variations in EFs of elemental carbon, pPAHs and nitro-PAHs, respectively.     

基于生态足迹的福州仓山区生态安全评价

以生态足迹分析方法为基础,利用生态压力指数对福州市仓山区2010年的生态安全进行初步研究和评价。结果表明,仓山区2010年的生态足迹为0.845255ghm2,生态压力指数为2.693。仓山区的人口消费需求超过了自然生态系统的承载能力,可持续发展状况不容乐观,生态环境处于不安全状态。就此提出建议。     

Machining efficiency of powder mixed near dry electrical discharge machining based on different material combinations of tool electrode and workpiece electrode

Powder mixed near dry electrical discharge machining (PMND-EDM) is a novel electrical discharge machining (EDM) process. It is proposed to further improve the machining efficiency of dry EDM. The principle of material removal in PMND-EDM is illustrated and its deionization principle is proposed. The influence of residual heat on MRR is analyzed. The concept of superfluous residual heat is proposed. The material removal rate (MRR), the main index of machining efficiency for PMND-EDM process, is researched. Single factor experiments are performed to get effect of peak current, pulse on time, pulse off time, flow rate, tool rotational speed, air pressure and powder concentration on MRR under different material combinations of tool electrode and workpiece electrode. Thermal phenomena in PMND-EDM are illustrated. Effect of each process parameter on MRR of PMND-EDM is gotten and analyzed based on the deionization principle of PMND-EDM. Differences in MRR under different material combinations are found out. Brass tool electrode and W18Cr4V workpiece gain higher MRR under most of discharge conditions, while the superiority of copper tool electrode and 45 carbon steel workpiece in MRR arise when there is improper heat dissipation. The difference is analyzed based on the deionization principle of PMND-EDM.     

Review on plant uptake of PFOS and PFOA for environmental cleanup: potential and implications

Environmental Science and Pollution Research - Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have gained increasing concern due to their persistent characteristics, wide...     

不同污染区巨菌草生物炭内源污染物分布及其生物毒性

由于生物质原料来源广泛,缺乏生物炭内源污染物及其用量限制标准,极有可能将含有高内源污染物的生物炭用于环境修复,产生潜在的环境风险.采用清洁区、中度和重度污染区的巨菌草为原料制备生物炭,考察其内源铜（Cu）和镉（Cd）全量及其酸溶态含量和持久性自由基（PFRs）分布,并研究生物炭浸出液对小麦根伸长抑制率和抗氧化酶活性的影响.结果表明,重度污染区九牛生物炭Cu和中度污染区水泉生物炭中Cd含量分别是清洁区红壤生物炭Cu和Cd的3.73倍和4.43倍,九牛生物炭中酸溶态Cu含量分别是水泉和红壤生物炭的3.32倍和2.84倍,水泉和九牛生物炭中酸溶态Cd含量分别是红壤生物炭的7.95倍和5.11倍.3种生物炭中均含有相邻氧原子以碳为中心的PFRs,表现为：红壤>九牛>水泉.3种生物炭浸出液对小麦根伸长均表现为抑制作用,但均不同程度地提高了小麦幼苗超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性,其中九牛生物炭浸出液对小麦根伸长抑制率最高,达到27.7%.本研究表明,生物炭中内源重金属及PFRs等污染物的共同作用对小麦幼苗产生了显著的生物毒性,后期的研究需关注生物炭内源污染物的潜在环境风险,避免产生二次污染等环境问题.     

Review on recent progress in on-line monitoring technology for atmospheric pollution source emissions in China

Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China, and its components, which include ultrafine particles (UFPs), volatile organic compounds (VOCs), and other reactive gases, such as NH₃ and NO_x, are the most harmful to human health. China has released various regulations and standards to address pollution from mobile and stationary sources. Thus, it is urgent to develop online monitoring technology for atmospheric pollution source emissions. This study provides an overview of the main progress in mobile and stationary source monitoring technology in China and describes the comprehensive application of some typical instruments in vital areas in recent years. These instruments have been applied to monitor emissions from motor vehicles, ships, airports, the chemical industry, and electric power generation. Not only has the level of atmospheric environment monitoring technology and equipment been improving, but relevant regulations and standards have also been constantly updated. Meanwhile, the developed instruments can provide scientific assistance for the successful implementation of regulations. According to the potential problem areas in atmospheric pollution in China, some research hotspots and future trends of atmospheric online monitoring technology are summarized. Furthermore, more advanced atmospheric online monitoring technology will contribute to a comprehensive understanding of atmospheric pollution and improve environmental monitoring capacity.     

双酚类化合物的毒理学效应及微生物降解机制的研究进展

双酚类化合物作为重要的有机化工原料,广泛应用于各行各业。然而双酚类化合物是一类内分泌干扰物,毒性评价结果表明其与许多疾病发病率的升高密切相关。伴随双酚类化合物的大量使用,诸多环境样品中都检测出双酚类化合物。由于双酚类化合物的结构稳定,很难在自然界中被完全降解,会不断累积,对生态安全和人体健康产生危害,亟待有效修复。有机污染物的物理化学修复方法易对环境造成二次污染,微生物降解因其获取容易、无二次污染等特点成为双酚类化合物修复的有效途径。本文总结概述了几种典型双酚类化合物的毒性评价及微生物降解机制。     

A critical review on the application of biochar in environmental pollution remediation: Role of persistent free radicals (PFRs)

Biochar as an emerging carbonaceous material has exhibited a great potential in environmental application for its perfect adsorption ability. However, there are abundant persistent free radicals (PFRs) in biochar, so the direct and indirect PFRs-mediated removal of organic and inorganic contaminants by biochar was widely reported. In order to comprehend deeply the formation of PFRs in biochar and their interactions with contaminants, this paper reviews the formation mechanisms of PFRs in biochar and the PFRs-mediated environmental applications of biochar in recent years. Finally, future challenges in this field are also proposed. This review provides a more comprehensive understanding on the emerging applications of biochar from the viewpoint of the catalytic role of PFRs.     

Occurrence, profiles, and ecotoxicity of poly- and perfluoroalkyl substances and their alternatives in global apex predators: A critical review

Certain poly- and perfluoroalkyl substances (PFASs) exhibit significant bioaccumulation/biomagnification behaviors in ecosystems. PFASs, such as perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS) and related precursors, have elicited attention from both public and national regulatory agencies, which has resulted in worldwide restrictions on their production and use. Apex predators occupy the top trophic positions in ecosystems and are most affected by the biomagnification behavior of PFASs. Meanwhile, the long lifespans of apex predators also lead to the high body burden of PFASs. The high body burden of PFASs might be linked to adverse health effects and even pose a potential threat to their reproduction. As seen in previous reviews of PFASs, knowledge is lacking between the current stage of the PFAS body burden and related effects in apex predators. This review summarized PFAS occurrence in global apex predators, including information on the geographic distribution, levels, profiles, and tissue distribution, and discussed the trophic transfer and ecotoxicity of PFASs. In the case where legacy PFASs were restricted under international convention, the occurrence of novel PFASs, such as 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) and perfluoroethylcyclohexane sulfonate (PFECHS), in apex predators arose as an emerging issue. Future studies should develop an effective analytical method and focus on the toxicity and trophic transfer behavior of novel PFASs.