4-硝基酚对大鼠肝脏的毒性及氧化损伤

研究环境内分泌干扰物4-硝基酚(4-nitrophenol,PNP)对大鼠肝脏功能的毒性作用及其对核因子相关因子-2(Nrf2)通路的影响.20只SD雄性大鼠随机分成4个组,分别为对照组、1、10和100 mg·kg-1体重PNP处理组,连续皮下注射28d,检测肝脏的结构变化、氧化损伤和Nrf2及其相关基因的表达情况.结果表明,与对照组相比,100 mg·kg-1PNP处理组大鼠的血清肝功能主要指标ALT、AST、AKP活性和TBIL含量显著性升高p＜005);100 mg·kg-1组肝脏GSH-PX、CAT和SOD活性显著性降低p＜005);大鼠肝脏中Nrf2及其下游基因NQOI和HO-1 mRNA表达水平在1mg·kg-1组显著升高(p＜0.05),10、100 mg·kg-1组有升高趋势;100 mg ·kg-1组肝脏显微和超微结构都发现有不同程度的损伤.结果提示,皮下注射1 mg·kg-1 PNP引起了大鼠肝脏氧化损伤,机体可能通过提高Nrf2及其相关基因mRNA的表达水平来抵抗PNP引起的肝脏损伤;皮下注射100 mg·kg-1 PNP改变了肝脏的正常生理功能,造成肝细胞超微结构病理损伤,引起肝脏毒性.     

吡草醚原药对大鼠胚胎及胎仔发育的影响

经口染毒大鼠检测妊娠动物接触吡草醚原药后引起致畸的可能性,初步评价吡草醚原药致畸危害程度。依据《GB15670-1995农药登记毒理学试验方法》,选用的大鼠按雄、雌2:1比例同笼交配,次日清晨阴道涂片检查雌鼠,发现精子即确定为受孕第0天,设低、中、高三个剂量组(18.56、92.80、464.00 mg·(kg·d)-1)、一个阴性对照组和一个阳性对照组。在雌鼠受孕第6~15天灌胃给予受试物,连续共10天,在妊娠第19.5天,处死孕鼠检查胚胎发育情况。高剂量组和阳性对照组大鼠孕期体重增重值降低,差异有显著性(p0.05);中、高剂量组和阳性对照组大鼠吸收胎率与阴性对照组比较差异有显著性(p0.05);中、高剂量组和阳性对照组胎鼠重量与阴性对照组比较,差异有显著性(p0.01);阳性对照组胎鼠外观畸形明显,与阴性对照组比较差异有显著性(p0.01);各剂量组胎鼠外观畸形与阴性对照组比较,差异均无显著性(p0.05);中、高剂量组组和阳性对照组胎鼠骨骼及内脏畸形例数明显增多,差异有显著性(p0.01)。实验结果表明吡草醚原药中、高剂量组可明显影响雌鼠体重增长及其胚胎的发育。     

Novel synthetic approaches and TWC catalytic performance of flower-like Pt/CeO2

A novel Ultrasonic Assisted Membrane Reduction （UAMR）-hydrothermal method was used to prepare flower-like Pt/CeO2 catalysts. The texture, physical/chemical properties, and reducibility of the flower-like Pt/CeO2 catalysts were characterized by X-Ray Diffraction （XRD）, Scanning Electron Microscope （SEM）, Transmission Electron Microscope （TEM）, N2 adsorption, and hydrogen temperature programmed reduction （HE-TPR） techniques. The catalytic performance of the catalysts for treating automobile emission was studied relative to samples prepared by the conventional wetness impregnation method. The Pt/CeO2 catalysts fabricated by this novel method showed high specific surface area and metal dispersion, excellent three-way catalytic activity, and good thermal stability. The strong interaction between the Pt nanoparticles and CeO2 improved the thermal stability. The Ce4＋ ions were incorporated into the surfactant chains and the Pt nanoparticles were stabilized through an exchange reaction of the surface hydroxyl groups. The SEM results demonstrated that the Pt/CeO2 catalysts had a typical three-dimensional （3D） hierarchical porous struc- ture, which was favorable for surface reaction and enhanced the exposure degree of the Pt nanoparticles. In brief, the flower-like Pt/CeO2 catalysts prepared by UAMR-hydrothermal method exhibited a higher Pt metal dispersion, smaller particle size, better three-way catalytic activity, and improved thermal stability versus conven- tional materials.     

Warning signals confer advantage to prey in competition with predators: bumblebees steal nests from insectivorous birds

Aposematic (warning) signals of prey help predators to recognize the defended distasteful or poisonous prey that should be avoided. The evolution of aposematism in the context of predation has been in the center of modern ecology for a long time. But, the possible roles of aposematic signals in other ecological contexts have been largely ignored. Here we address the role of aposematic signals in competition between prey and predators. Bumblebees use visual and auditory aposematic signals to warn predators about their defenses. For 2 years, we observed competition for nestboxes between chemically defended insects, Bombus ardens (and possibly also Bombus ignitus), and cavity nesting birds (Parus minor and Poecile varius). Bumblebees settled in 16 and 9 % of nestboxes (in 2010 and 2011 breeding seasons, respectively) that contained bird nests at the advanced stage of nest building or at the stage of egg laying. Presence of bumblebees prevented the birds from continuing the breeding activities in the nestboxes, while insects took over the birds’ nests (a form of kleptoparasitism). Playback experiments showed that the warning buzz by bumblebees contributed to the success in ousting the birds from their nests. This demonstrates that aposematic signals may be beneficial also in the context of resource competition.     

煤矸石烧结砖厂废气凝结物的研究

采集煤矸石烧结砖厂隧道窑废气热交换器内壁的凝结物,利用XRF、XRD、IR、DTA-TG、SEM、EDS、ICP-MS和AFS等方法进行了研究。结果表明:凝结物主要为水合硫酸亚铁和水合硫酸铁,S含量为119.2 mg/g,且Se、As、Pb等微量元素在凝结物中富集。与煤矸石原料相比,凝结物中Se的富集程度最高,含量达到了0.637 mg/g,相对富集因子为467.52;S、Tl、Mo、As、Pb的相对富集因子从57.05依次减小到6.18,F及亲硫元素Sb、Cd、Zn、Ni、Cu、Co富集程度较低;Sr、Th、Be、Ba、U、V、Cr的相对富集因子小于0.5,显示在烧结砖制备过程中的挥发性很低。     

BSSF滚筒法钢渣处理技术发展现况研究

介绍了BSSF滚筒法渣处理技术的原理和发展现状,通过对主体设备的不断优化完善及工艺系统的再次开发,对钢渣黏度适应性增强,钢渣处理率从30%提高到85%,系统运行稳定,为钢渣资源化利用提供了良好的条件,符合当今社会对环保及固废资源循环利用的需求。     

水解池取代初沉池用于污泥减量和改善出水水质实验研究

利用水解池取代初沉池,实现初沉池功能的同时达到污泥减量并改善出水水质,以满足后续脱氮除磷对碳源的要求。实验结果表明:在进水水质不稳定的情况下,水解池对SS平均去除率为81.8%,高于初沉池60.8%的平均去除率,水解池可以更加有效地截留SS。水解池实现高SS去除率的同时,能够实现污泥减量,水解池的污泥水解率为50.60%。在实验规模条件下,与初沉池相比,污泥减量92.31 kg/d,并且水解池出水VFA浓度较初沉池出水提高30.89 mg/L,SCOD/COD比值提高19.9%,水解池可提高出水水质。     

An arsenic-contaminated field trial to assess the uptake and translocation of arsenic by genotypes of rice

Compared to other cereals, rice has particular strong As accumulation. Therefore, it is very important to understand As uptake and translocation among different genotypes. A field study in Chenzhou city, Hunan province of China, was employed to evaluate the effect of arsenic-contaminated soil on uptake and distribution in 34 genotypes of rice (including unpolished rice, husk, shoot, and root). The soil As concentrations ranged from 52.49 to 83.86 mg kg^?1, with mean As concentration 64.44 mg kg^?1. The mean As concentrations in rice plant tissues were different among the 34 rice genotypes. The highest As concentrations were accumulated in rice root (196.27–385.98 mg kg^?1 dry weight), while the lowest was in unpolished rice (0.31–0.52 mg kg^?1 dry weight). The distribution of As in rice tissue and paddy soil are as follows root ? soil > shoot > husk > unpolished rice. The ranges of concentrations of inorganic As in all of unpolished rice were from 0.26 to 0.52 mg kg^?1 dry weight. In particular, the percentage of inorganic As in the total As was more than 67 %, indicating that the inorganic As was the predominant species in unpolished rice. The daily dietary intakes of inorganic As in unpolished rice ranged from 0.10 to 0.21 mg for an adult, and from 0.075 to 0.15 mg for a child. Comparison with tolerable daily intakes established by FAO/WHO, inorganic As in most of unpolished rice samples exceeded the recommended intake values. The 34 genotypes of rice were classified into four clusters using a criteria value of rescaled distance between 5 and 10. Among the 34 genotypes, the genotypes II you 416 (II416) with the lowest enrichment of As and the lowest daily dietary intakes of inorganic As could be selected as the main cultivar in As-contaminated field.     

北京官厅水库特征污染物筛查及其健康风险评价

水源水中存在数以万计的污染物,需要根据不同水源污染特征筛查相应的特征污染物,并确定其对人体产生的健康风险。针对官厅水库及其出入库河流的表层水样,采用气相色谱质谱方法,对77种有机污染物进行了目标筛查和定量分析;采用非目标筛查的方法,对1 655种有机污染物进行了定性筛查。定量分析检出43种挥发性有机物(VOCs),浓度为nd～8.17 μg·L^-1;8种羰基化合物,浓度为nd～5.04 μg·L^-1;7种嗅味物质,浓度为nd～1 421.58 ng·L^-1。在检出的58种污染物中,有国家生活饮用水卫生标准(GB5749-2006)的共有23种,有国家地表水环境质量标准(GB3838-2002)的22种,浓度均未超过相关标准。对所检出的污染物进行了危害识别,发现5种嗅味物质浓度均超过了其嗅阈值。对其中有基础毒性数据的17种污染物进行了致癌风险评价,对37种污染物进行了非致癌风险评价。研究表明,17种污染物致癌风险处于10^-6～10^-5水平,而37种污染物的非致癌风险处于10^-2水平,均低于国际认同的风险控制阈值。定性筛查出80种具有潜在健康风险的有机污染物,作为进一步深入研究的目标污染物。据此,2012年调查中官厅水库水中的有机微污染对人体健康的风险总体上处于较低水平。其中,苯系物在官厅水库中普遍存在,六氯丁二烯和巴豆醛是主要的风险特征污染物,2-异丙基-3-甲氧基吡嗪(IPMP)、2-异丁基-3-甲氧基吡嗪(IBMP)和2,4,6-三氯茴香醚(TCA)是主要的致嗅特征污染物。