Sorption of lambda-cyhalothrin,cypermethrin, deltamethrin and fenvalerate to quartz,corundum, kaolinite and montmorillonite

Sorption to mineral surfaces may be important for retention and degradation of hydrophobic pesticides in subsoils and aquifers poor in organic matter. In this work the title pyrethroids have been used to investigate selective interactions with the surfaces of four minerals. Sorption of the four pyrethroids was quantified in batch experiments with initial pyrethroid concentrations of 1–100 μg/l. Sorption to centrifuge tubes used in the batch experiments accounted for 25–60% of total sorption. Net sorption was obtained from total sorption after subtracting the amounts of pyrethroids sorbed to centrifuge tubes used. All isotherms could be fitted by the Freundlich equation with n ranging between 0.9 and 1.1. Bonding affinities per unit surface area decreased in the order: corundum>quartz>montmorillonitekaolinite. A similar sequence as found for the total surface tension of the minerals. All minerals showed the same selectivity order with respect to sorption affinity of the four pyrethroids: lambda-cyhalothrin>deltamethrin>cypermethrin>fenvalerate, which shows that the most hydrophobic compound is sorbed most strongly. Stereochemical properties of the four pyrethroid formulations may also contribute to the selectivity pattern.     

A statistical comparison of naphthenic acids characterized by gas chromatography-mass spectrometry

Naphthenic acids are complex mixtures of alkyl-substituted acyclic and cycloaliphatic carboxylic acids, with the general chemical formula C_nH_2n+zO₂, where n is the carbon number and Z specifies a homologous family. These acids have a variety of commercial uses, including being used as wood preservatives. They are found in conventional and heavy oils, and in the oil sands of northeastern Alberta, Canada. Naphthenic acids are major contributors to the toxicity of tailings waters that result from the oil sands extraction process. Eight naphthenic acids preparations (four from commercial sources and four from the oil sands operations) were derivatized and analyzed by gas chromatography–mass spectrometry. The composition of each mixture was summarized as a three-dimensional plot of the abundance of specific ions (corresponding to naphthenic acids) versus carbon number (ranging from 5 to 33) and Z family (ranging from 0 to −12). The data in these plots were divided into three groups according to carbon number (group 1 contained carbon numbers 5–14, group 2 contained carbon numbers 15–21, and group 3 contained carbon numbers 22–33). A t-test, using arcsine-transformed data, was applied to compare corresponding groups in samples from various sources. Results of the statistical analyses showed differences between various commercial naphthenic acids preparations, and between naphthenic acids from different oil sands ores and tailings ponds. This statistical approach can be applied to data collected by other mass spectrometry methods.     

建筑物对空气污染物扩散影响的研究

本文简要地介绍了建筑物对空气污染物扩散的影响，回顾了风洞实验、现场观测和模型计算等几种研究方法及结果的对比情况，重点讨论了各种计算模型的性质和适用范围及使用效果，并展望了未来计算建筑物影响污染物扩散方法的发展趋势     

加速溶剂萃取-气相色谱质谱法同时测定土壤及沉积物中34种有机氯农药及18种多氯联苯类化合物

建立了加速溶剂萃取-气相色谱质谱法同时测定34种有机氯农药(OCPs)和18种多氯联苯类化合物(PCBs)的方法。当取样量为10. 0 g时,52种有机化合物的检出限为0. 03～0. 29μg/kg,以空白样品为基体进行加标回收试验,平均回收率为44. 7%～123. 0%,相对标准偏差(RSD,n=7)为1. 8%～21. 5%。该方法灵敏度高,实现了低浓度有机化合物的定量分析,分析结果准确可靠,满足土壤和沉积物中34种有机氯农药和18种多氯联苯类化合物分析的要求。     

毛细管柱气相色谱法测定水性涂料中的苯系物

用二硫化碳萃取经水稀释过的水性涂料中的苯系物,离心分离后,用毛细管气相色谱测定,用极性柱和非极性柱双柱定性,单柱定量。线性范围为0~120mg/L,相关系数大于0.9996,检出限0.005mg/kg,回收率大于90%。方法快速、准确、灵敏度高、干扰少。     

气相色谱／质量选择检测器测定死鱼水体中有机污染物

为查明有机污染物的种类,取死鱼水经GDX-501树脂富集后,用气相色谱/质量选择检测器分析。检出水中82种污染物。     

对一起矿井动力现象事故的分析探讨

本文对一起“矿井动力现象”事故,从发生这起事故的条件和可能性及其事故后的特征等多方面进行了分析论证,认为该次事故不是一起“矿井动力现象”——煤与瓦斯突出,而是一次因放炮引起的瓦斯爆炸事故。指出了发生这次事故的原因,总结了该次事故的经验及教训,同时也提出了防止这类事故的预防措施。     

负压在焦化生产过程中对煤气设备及容器损坏的探讨

在焦化生产过程中,煤气设备及容器内容易出现负压而造成设备损坏。本文对此类典型事故进行了分析。     

循环流化床锅炉对环保的价值及其立管内物料结渣问题的研究

循环流化床锅炉是减少燃煤锅炉烟气污染的一个良好选择,这表明了其在环保上的价值,对其立管内物料燃烧结渣影响问题,给出了燃烧过程的特征及各因素的影响作用,并提出了防止结渣的原则。