Determination of octanol-air partition coefficients and supercooled liquid vapor pressures of organochlorine pesticides

Octanol-air partition coefficients (K_OA) and supercooled liquid vapor pressures (P_L) of nine organochlorine pesticides (OCPs) including p,p′-DDE, p,p′-DDD, o,p′-DDT, o,p′-DDE, o,p′-DDD, α-HCH, β-HCH, γ-HCH, δ-HCH were determined as functions of temperature using a gas chromatographic retention time method. Among them, the K_OA of o,p′-DDE and o,p′-DDD and the P_L of o,p′-DDE, o,p′-DDD, β-HCH and δ-HCH were determined for the first time. The determined K_OA and P_L values of investigated compounds at 25°C ranged from 3.14 × 10⁷ (α-HCH) to 3.76×10⁹ (p,p′-DDD), and 8.95×10^{? 4} Pa (p,p′-DDD) to 1.08×10^{? 1} Pa (α-HCH), respectively. The K_OA and P_L data were compared with published data. The K_OA values of o,p′-DDT at 25°C were 3.23×10⁹, higher than o,p′-DDE (1.02×10⁹) and o,p′-DDD (2.01×10⁹), indicating o,p′-DDT were more preferred to partition in soil compared with the metabolites. The K_OA values were lower and P_L values were higher for o,p′-DDE and o,p′-DDD, compared with their p,p′-isomeric counterparts, leading to a potential difference in behavior and fate of these isomers. The discrepancies among chemicals are obvious, which reflected in the increasing K_OA and decreasing P_L values in order of α-HCH, γ-HCH, β-HCH, δ-HCH, o,p′-DDE, p,p′-DDE, o,p′-DDD, o,p′-DDT, p,p′-DDD. For each compound, the LogK_OA decreased linearly with reciprocal absolute temperature, while LogP_L had a significant positive correlation with the inverse absolute temperature. The present study suggested that the method of gas chromatographic retention time was appropriate to measure the K_OA and P_L of a number of OCPs.     

Atmospheric organochlorine pesticide (OCP) levels in a metropolitan city in Turkey

Air concentrations of organochlorine pesticides (OCPs) were measured at four different sites in Bursa, Turkey to determine current levels. For this purpose, about 35 samples were collected from June 2008 to June 2009 using a high volume air sampler (HVAS) equipped with particle and gas-phase units. Ten OCP compounds (alpha-, beta-, gamma-, delta-hexachlorocyclohexane, Heptachlor epoxide, Endrin, Endosulfan beta, Endrin aldehyde, p,p′-DDT and Methoxychlor) were reported within the scope of this study. The average concentrations of total (particle + gas) ∑OCPs were 550.9 ± 277.6 pg m⁻³ (coastal), 1030.7 ± 453.5 pg m⁻³ (urban/traffic), 519.7 ± 277.5 pg m⁻³ (semi-rural) and 722.8 ± 351.8 pg m⁻³ (urban/residential). The individual OCP concentrations were in line with reported concentrations. The maximum particle and gas-phase concentrations were determined for Endosulfan beta and beta-HCH for all sites, respectively. Available gas/particle partitioning models were applied in order to investigate the compatibility of the experimental data and the significant relationships were observed.     

Solid waste characteristics and their relationship to gas production in tropical landfill

Solid waste characteristics and landfill gas emission rate in tropical landfill was investigated in this study. The experiment was conducted at a pilot landfill cell in Thailand where fresh and two-year-old wastes in the cell were characterized at various depths of 1.5, 3, 4.5 and 6 m. Incoming solid wastes to the landfill were mainly composed of plastic and foam (24.05%). Other major components were food wastes (16.8%) and paper (13.3%). The determination of material components in disposed wastes has shown that the major identifiable components in the wastes were plastic and foam which are resistant to biodegradation. The density of solid waste increased along the depth of the landfill from 240 kg m⁻³ at the top to 1,260 kg m⁻³ at the bottom. Reduction of volatile solids content in waste samples along the depth of landfill suggests that biodegradation of solid waste has taken place to a greater extent at the bottom of the landfill. Gas production rates obtained from anaerobic batch experiment were in agreement with field measurements showing that the rates increased along the depth of the landfill cell. They were found in range between 0.05 and 0.89 l kg⁻¹ volatile solids day⁻¹. Average emission rate of methane through the final cover soil layer was estimated as 23.95 g⁻²day⁻¹ and 1.17 g⁻²day⁻¹ during the dry and rainy seasons, respectively.     

Pesticide residues in rain water from Hisar, India

Presence of pesticide residues was studied in rain water during 2002 employing multi residue analysis method by gas liquid chromatography equipped with ECD and NPD detectors and capillary columns. The presence of pesticide residues in surface aquatic system triggered the investigation of the presence of pesticides in rain water. A total of 13 pesticides were detected in rain water samples. Among the different groups of pesticides, organochlorines were present in the range of 0.041–7.060 ppb with maximum concentration of p,p’-DDT up to 7.060 μg l⁻¹. Synthetic pyrethroids were present ranging from 0.100 to 1.000 μg l⁻¹ and organophosphates in the range of 0.050–4.000 μg l⁻¹ showing maximum contamination with cypermethrin (1.000 μg l⁻¹) and monocrotophos (4.000 μg l⁻¹) of the respective groups. Almost 80% samples showed the residues above MRL of 0.5 ppb fixed for multi residues and on the basis of single pesticide, 16–50% samples contained residues above the MRL value of 0.1 ppb.     

煤气吹脱解吸法处理含氨废水中氨氮的研究

主要采用"煤气吹脱解吸法"对焦化厂含氨废水中氨氮进行吹脱解吸的优选实验研究。实验的最佳反应条件为:T=80℃,pH=10.2,Q=5L/min(气液比为1500∶1),t=120min,C=0~25 mg/L。处理后废氨水中氨氮脱除率达到96%以上,取得了满意的效果,同时氰、酚和COD也都不同程度地被脱除。经生化处理后,氨氮含量可达到国家排放标准。     

火化场焚烧污染现状及存在问题

从环保角度入手,着重调查沈阳市全市范围内殡葬行业现有状况,重点研究了火化机焚烧尸体后产生的废气污染问题,并提出几点对策和建议。监测结果表明,烟尘、二氧化硫和氮氧化物等废气污染物的排放浓度超过国家标准要求。     

两室阳膜电解再生脱硫吸收液的影响因素研究

利用二室阳离子膜电解装置,以亚硫酸钠和亚硫酸氢钠溶液模拟钠碱烟气脱硫吸收富液,进行吸收液再生规律的研究。实验考察了流体流速和槽压对膜电解过程的影响,明确了其相关规律,确定了较佳操作参数。研究结果证明:增大槽压和流体流速有利于脱硫富液的电解再生,而且钠离子浓度越低电解再生越容易。同时,实验中注意到电解过程中溶液伴渗对电流效率和钠离子迁移率有较大的影响。     

清洁发展机制(CDM)实践及理论研究进展

清洁发展机制(CDM)是《京都议定书》(KP)中规定的发达国家与发展中国家之间的温室气体减排合作方式。随着2005年2月26日KP的生效,CDM实施活动在全球范围内开始全面展开。中国被公认为是温室气体减排潜力最大的国家,具有广阔的开展CDM合作的前景。为了能配合国内CDM的实践活动,本文在大量文献及重要文件研究基础上,总结了CDM诞生10年来的实践及理论发展情况,并分析了CDM今后的发展趋势。     

设施验收中甲基丙烯酸甲酯的采集和气相色谱测定

用活性炭吸附气体中的甲基丙烯酸甲酯有令人满意的吸附效率,用ＳＥ－５４ ０．５３ ｍｉｎ×５０ｍ色谱柱低温操作可使二硫化碳溶剂与甲基丙烯酸甲酯得到完全分离。该方法有较宽的线性范围,较高的灵敏度和精密度。     

陕—甘天然气管道工程对环境的影响及防治对策

陕—甘天然气输气管道工程地跨毛乌素沙地南缘和陇东黄土高原,生态环境十分脆弱。根据对管道沿线生态环境现状以及输气工程对沿线生态环境影响的分析和预测,工程施工期将造成沿线植被的破坏及大片沙质地表和黄土的裸露以及土体结构的改变,使管道沿线20 m范围内的土壤可蚀性指数上升2～4倍,施工区平均侵蚀模数将会由施工前的0.856万t/(km2.a)增加至3.424万t/(km2.a)。若不采取有效的预防和保护措施,必将引起管道沿线土地沙漠化的扩大和水土流失的加剧。