问题驱动教学法在环境法课程中的应用

在问题驱动教学法下,在自主学习中提出问题、解决问题是重点,进行学习效果评价、形成反馈信息是总结提高阶段,每一个环节都必须统筹安排、合理兼顾。环境法课程教学活动中合理采用问题驱动教学法不仅充分体现了学生为主体、老师为主导的现代教育思想,而且极大地调动了学生的积极性和创造性,也为提高学生的实践能力和创新能力营造了良好的氛围。     

河北省海域承载力多层次模糊综合评价

借鉴有关承载力的研究成果,利用多层次模糊综合评判法对河北省海域承载力进行了评价分析。结果表明:1996—2006年间河北省近海海域承载力一直处于超载状态,但承载状况总体趋于好转;人口和环境污染的加剧、环境治理能力和科技发展水平缓慢、资源供给能力不足是导致河北省海域承载力超载的主要因素。基于此提出了改善河北省海域承载状况的对策建议。     

秦皇岛沿海灾害性天气对自然环境的影响和预报

风暴潮天气是一种灾害性的自然现象。一般情况下,大于500 km的东到东北大风持续12个小时,且风速大于或等于6级,将在秦皇岛沿海形成风暴潮天气。通过分析引发风暴潮天气的动力条件,风暴潮与台风、温带气旋等天气系统相关联系,再根据天文、潮汐变化、台风、温带气旋24 h诊断预报,判断台风、温带气旋移动径,从而达到准确预报风暴潮天气之目的。分析表明:成灾风暴潮多发生在朔日和望日及其后的5天。     

Mechanistic and kinetic study on the ozonolysis of n-butyl vinyl ether, i-butyl vinyl ether and t-butyl vinyl ether

Density functional theory (DFT) and ab initio method are employed to elucidate the mechanisms for O(3)-initiated oxidation of n-butyl vinyl ether (n-BVE) and its isomers (i-BVE and t-BVE). For each BVE, the reactions proceed via O(3) cycloaddition resulting in the formation of primary ozonides (POZs) and then two self-decomposition pathways of POZs are followed. Major products are identified to be formaldehyde and butyl formates (CH(3)CH(2)CH(2)CH(2)OCHO for n-BVE, (CH(3))(2)CHCH(2)OCHO for i-BVE and (CH(3))(3)COCHO for t-BVE). The total and individual rate constants for main product channels have been calculated using the modified multichannel Rice-Ramsperger-Kassel-Marcus (RRKM) approach. At 298 K and 101 kPa, the calculated total rate constants are 2.50×10(-16), 3.41×10(-16) and 4.17×10(-16) cm(3) molecule(-1) s(-1) for n-BVE+O(3), i-BVE+O(3) and t-BVE+O(3), respectively, which are in perfect agreement with experimental results. The total rate coefficients are almost pressure independent in the range of 0.001-101 kPa but obviously positive temperature dependent over the whole study temperature range (200-400 K). Also, the favorable reaction pathways have been determined through the estimation of branching ratios. Moreover, the influence of alkoxy group structure on the reactivity of vinyl ethers was examined.     

基于层次分析法的坦塘垃圾填埋场适宜性评价

垃圾填埋场场址的适宜性评价是生活垃圾填埋场建设和运营的前提和基础。以湖南省永州市坦塘垃圾填埋场为例,在分析研究区的地质与水文地质条件的基础上,确定了填埋场适宜性的影响因素为填埋场规模、运输条件、环境条件、建场条件和地质条件,具体包括填埋场面积及容量、综合路况条件、对地表水体污染的可能性、地形平坦程度以及场地是否处在岩溶区等条件,明确了局部地区岩溶发育是制约其适宜性的主要因素。结合垃圾填埋场的建设情况和相关规范、标准,采用层次分析法对坦塘垃圾填埋场进行适宜性评价。评价结果表明,坦塘垃圾填埋场是一个适宜场地,评价结果与实际情况相符。     

Geosmin degradation by seasonal biofilm from a biological treatment facility

Introduction  

Initial geosmin degradation was closely related to water temperature and natural geosmin concentration of sampling environment. Here, for the first time, we evaluated the biodegradation of geosmin by microorganisms in biofilm from biological treatment unit of actual potable water treatment plant.     

基于工作过程的高职“教学做一体化”课程探究

“教学做一体化”课程有利于理论教学与实践教学相结合,有利于高职学校长期健康的发展。“教学做一体化”教学模式是基于实际工作过程导向,以工作中典型项目任务引领,激发学生兴趣,以满足培养高等技能型人才的迫切需要。一体化课程的构建应通过项目设立、建立小组、实施、反馈等环节完成。     

Accumulation levels and characteristics of some pesticides in human adipose tissue samples from Southeast China

This paper presents a comprehensive study of pesticide levels and bio-accumulation characteristics in human adipose tissues among residents of Southeast China. A large number of adipose samples (n = 633) were selected for 58 pesticides and were analyzed by high sensitive Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS). The results showed that POPs pesticides were frequently detected, including 2,4′-DDD, 2,4′-DDE, 2,4′-DDT, 4,4′-DDD, 4,4′-DDE, 4,4′-DDT, α-HCH, β-HCH, γ-HCH, δ-HCH, hexachlorobenzene (HCB), and mirex. Other detected pesticide species were dicofol, methamidophos and chlordimeform, which have rarely been reported. Comparing to different countries, the concentrations of total DDT and HCH in these three Chinese southeastern sites were in the middle range, whereas the HCB and mirex were in the lower end. A significant correlation was observed between region as well as age and POPs pesticide levels. Some pesticide residue levels were also found significantly correlated to occupation. However, there was no significant correlation between gender and pesticides. Meanwhile, it is interesting to find that mortality of malignant tumors tends to associate with the pesticides levels in human adipose tissue. More importantly, the measured data presented in this study provide realistic information which is useful for assessing human exposure to pesticides in the general population of Southeast China.     

Nano-TiO2 enhances the toxicity of copper in natural water to Daphnia magna

The acute toxicity of engineered nanoparticles (NPs) in aquatic environments at high concentrations has been well-established. This study demonstrates that, at a concentration generally considered to be safe in the environment, nano-TiO₂ remarkably enhanced the toxicity of copper to Daphnia magna by increasing the copper bioaccumulation. Specifically, at 2 mg L⁻¹ nano-TiO₂, the (LC₅₀) of Cu²⁺ concentration observed to kill half the population, decreased from 111 μg L⁻¹ to 42 μg L⁻¹. Correspondingly, the level of metallothionein decreased from 135 μg g⁻¹ wet weight to 99 μg g⁻¹ wet weight at a Cu²⁺ level of 100 μg L⁻¹. The copper was found to be adsorbed onto the nano-TiO₂, and ingested and accumulated in the animals, thereby causing toxic injury. The nano-TiO₂ may compete for free copper ions with sulfhydryl groups, causing the inhibition of the detoxification by metallothioneins.     

Carbonaceous aerosol characteristics in outdoor and indoor environments of Nanchang, China, during summer 2009

A study of carbonaceous aerosol was initiated in Nanchang, a city in eastern China, for the first time. Daily and diurnal (daytime and nighttime) PM2.5 (particulate matter with aerodynamic diameter < or =2.5 microm) samples were collected at an outdoor site and in three different indoor environments (common office, special printing and copying office, and student dormitory) in a campus of Nanchang University during summer 2009 (5-20 June). Daily PM10 (particulate matter with aerodynamic diameter < or =10 microm) samples were collected only at the outdoor site, whereas PM2.5 samples were collected at both indoor and outdoor sites. Loaded PM2.5 and PM10 samples were analyzed for organic and elemental carbon (OC, EC) by thermal/optical reflectance following the Interagency Monitoring of Protected Visual Environments-Advanced (IMPROVE-A) protocol. Ambient mass concentrations of PM10 and PM2.5 in Nanchang were compared with the air quality standards in China and the United States, and revealed high air pollution levels in Nanchang. PM2.5 accounted for about 70% of PM10, but the ratio of OC and EC in PM2.5 to that in PM10 was higher than 80%, which indicated that OC and EC were mainly distributed in the fine particles. The variations of carbonaceous aerosol between daytime and nighttime indicated that OC was released and formed more rapidly in daytime than in nighttime. OC/EC ratios were used to quantify secondary organic carbon (SOC). The differences in SOC and SOC/OC between daytime and nighttime were useful in interpreting the secondary formation mechanism. The results of (1) OC and EC contributions to PM2.5 at indoor sites and the outdoor site; (2) indoor-outdoor correlation of OC and EC; (3) OC-EC correlation; and (4) relative contributions of indoor and outdoor sources to indoor carbonaceous aerosol indicated that OC indoor sources existed in indoor sites, with the highest OC emissions in I2 (the special printing and copying office), and that indoor EC originated from outdoor sources. The distributions of eight carbon fractions in emissions from the printer and copier showed obviously high OC1 (>20%) and OC2 (approximately 30%), and obviously low EC1-OP (a pyrolyzed carbon fraction) (<10%), when compared with other sources.