宁夏地区二斑叶螨的寄主植物选择及其季节转移

采用田间系统观察和室内饲养方法,调查并发现宁夏引黄灌区和新垦区二斑叶螨（Tetranychus urticae Koch)为寄主植物88种,其中野生寄主植物59种,栽培寄主29种,垦前荒漠,半荒漠有适宜二斑叶螨生存和繁殖的寄主植物分布,用生命表方法研究了20种主要寄主植物对二斑叶螨实验种群净生殖率（R0)的营养效应,不同寄主植物随季节的变化其营养效应明显不同,对二斑叶螨在这些寄主植物间的季节转移规律研究表明,宁夏农田,以野荠菜Capsella bursa-pastoris,小旋花Calystegia hederacea,小蓟Cephalanoplos segetumji,苦苣菜Sonchus brachyotus,车前草Plantago asiatica,蚕豆Vicia foba,大豆Glycine max,玉米Zea mays等一起,构成了有利于二斑叶螨季节转移的寄主体系,分析认为,宁夏麦套玉米间作大豆的耕种模式是二斑叶螨大发生的主要原因之一。     

氯代苯及氯代酚类优先污染物好氧生物降解动力学的研究

利用测定微生物呼吸耗氧量的方法,对氯代苯及氯代酚类中的７种优先污染物,用经它们分别驯化的活性污泥对其好氧生物降解动力学进行了研究。     

The role of a steel plant in north-west Italy to the local air concentrations of PCDD/Fs

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are ubiquitous contaminants, mainly released into the environment during combustion processes (point sources), but also from other sources (traffic, uncontrolled combustion).This study aims at investigating the contribution of a steel plant in NW Italy (700 000 tons of steel year⁻¹) to the air concentrations of PCDDs/PCDFs at local level, through the analysis of measured, modelled and literature data. The study was carried out in an area of 600 km², using air quality data measured by the institutional monitoring network, data obtained from AERMOD simulations and literature data.The measured air concentrations were consistent with literature values for similar areas, and both the homologue profiles and PCA analyses showed a clear distinction between the monitoring stations and the source profiles.All the previous results were confirmed by the air dispersion model (AERMOD), that predicted PCDD/F air concentrations due to the steel plant from four to two orders of magnitude lower than those measured in the monitoring stations, highlighting the presence of other sources.This study outlines the limited influence of the source in the local PCDD/F air concentrations and at the same time the usefulness of a joint analysis of measured, literature and calculated data to correctly evaluate the role of a source to the local pollution. The study also highlights the usefulness of AERMOD as a complementary tool to define the correct placement of monitoring stations and to locate those areas expected to have the highest air concentrations deriving from a source.     

Fish consumption reduces transfer of BDE47 from dam to murine offspring

Fish and seafood are important contributions to a healthy diet, but also contain persistent organic pollutants (POPs) like polybrominated diphenylethers (PBDEs) and polychlorinated biphenyls (PCBs). Discrepancies have been found between intake and accumulated levels of POPs, where fish consumers have had similar levels of POPs to the general population. Similarly fish oil consumption has been found to reduce accumulation of POPs. This study examined the accumulation of BDE47 or PCB153 in mice fed diets with different nutritional composition, using female mice with pre-weanling pups exposed through gestation and lactation. A fish-based diet was compared to a standard casein-based rodent diet. All diets had low background levels of environmental contaminants and were spiked with BDE47 or PCB153 to levels representing a realistic (∼0.004 μmol kgbw⁻¹ d) or a high dietary exposure (∼1.3 μmol kgbw⁻¹ d). Accumulation of BDE47 or PCB153 in offspring tissues after 18 d lactation reflected the maternal exposure levels. However, the pups of dams fed a fish-based diet had consistently lower BDE47 accumulation in liver, fat and stomach than pups from casein-fed dams. Similarly the pups of dams fed a high dose of PCB153 in a fish diet also accumulated less PCB153 than pups of the dams fed a casein diet, although not significant. In conclusion, the fish based diets seemed to reduce transfer of BDE47 and PCB153 from dams to pups. The study highlights that in-depth knowledge about nutritional impact on toxicokinetics is of great interest to vulnerable consumers.     

狭长交叉山谷中污染物浓度预测分析

为更准确地预测狭长交叉山谷中大气污染物浓度,利用高斯山谷扩散模式和美国Earth Technology Incorporat-ed公司研究的中尺度空气质量扩散模型CALPUFF对某山谷工业园区所在的狭长山谷中大气污染物浓度进行了计算。计算中,CALPUFF模型考虑了山谷中地表地形的变化,融入了诊断风场模块CALMET。...     

紊动特性对污染物降解的影响研究

采用潜水泵作为紊动诱发装置,利用PIV测量了流场,研究了不同流量下紊动对污染物降解的影响规律。结果表明,紊动对污染物的降解有明显的影响,流量越大,紊动强度越大,污染物的降解率越高。对紊动强度与有无紊动水箱COD、NH4^＋-N、TN和TP降解增加量的变化曲线进行指数函数拟合,拟合结果良好,可以认为紊动对污染物降解的影响可以描述为“一级反应”理论。     

Methane emissions from a dairy feedlot during the fall and winter seasons in Northern China

Accurately determining methane emission factors of dairy herd in China is imperative because of China’s large population of dairy cattle. An inverse dispersion technique in conjunction with open-path lasers was used to quantify methane emissions from a dairy feedlot during the fall and winter seasons in 2009-2010. The methane emissions had a significant diurnal pattern during both periods with three emission peaks corresponding to the feeding schedule. A 10% greater emission rate in the fall season was obtained most likely by the higher methane emission from manure during that period. An annual methane emission rate of 109 ± 6.7 kg CH₄ yr⁻¹ characterized with a methane emission intensity of 32.3 ± 1.59 L CH₄ L⁻¹ of milk and a methane conversion factor (Y_m) of 7.3 ± 0.38% for mature cattle was obtained, indicating the high methane emission intensity and low milk productivity in Northern China.     

Bioremediation With Oxygen-Releasing Solids: A Mathematical Model

The use of oxygen releasing solids in passive wells has become of considerable interest in the bioremediation of groundwater contaminated with hydrocarbons and other biodegradable contaminants. Labor, operating, and maintenance costs of this technology are quite competitive with more conventional techniques in many instances. Because of the small rates of mass transport by transverse dispersion, however, a pin-stripe pattern of alternating contaminant and oxygen distribution is expected downgradient of a line of wells which is unacceptable if it extends beyond the point of compliance downgradient. A mathematical model is presented which permits determination of the maximum well spacing in an array of wells which will yield effective remediation within a specified distance of a plume of contaminated groundwater passing through the array. Transverse dispersion of both oxygen and the contaminant is assumed, and biodegradation is modeled by means of Monod kinetics. Longitudinal numerical dispersion is minimized by the use of a asymmetrical upwind algorithm for modeling advection. Modeling results are presented showing the dependence of model behavior on input parameters.     

垃圾渗滤液同时硝化反硝化处理中有机污染物去除效果

采用同时硝化反硝化对某垃圾填埋场渗滤液进行处理,并对有机物去除效果进行分析。实验结果表明,反应器对渗滤液中COD、氨氮、总氮和部分有机物具有较好的处理效果,COD、氨氮和总氮的平均去除率为82.34%、99.82%和65.31%。GC-MS分析总共检测出53种主要有机污染物,其中邻苯二甲酸二丁酯等29种有机物的去除率达100%,乙基苯等5种有机物的去除率高于90%,邻苯二甲酸二异辛酯等8种有机物的去除率介于60%和90%之间,此外还有4-苯基戊醇等5种有机物去除率低于60%。反应器内存在亚硝氮途径的脱氮反应形式。     

Numerical simulation of the large-scale malignant environmental pollution incident

With the development of economy, the expansion in industrial production resulted in the increase in the number of malignant environmental pollution incidents. The dispersion of toxic gaseous materials was chosen for study in detail, which took the ‘12.23’ Kaixian blowout accident in Chongqing as an example. This paper firstly reviewed the ‘12.23’ Kaixian blowout accident. Then, the physical boundary conditions including initial conditions were outlined to form an integrated mathematical problem. Thirdly, the blowout accident was simulated for a period of 5 h. In term of criteria for acute poisoning, simulation results were analyzed using the concentration slices that can serve for the decision-making. Finally, based on the analysis of simulation result, four important conclusions were put forward that can be used for the design of emergency evacuation routes.