水体环境中氟喹诺酮类药物的污染现状及分析方法

阐述了水体环境中的氟喹诺酮类（FQs）药物的来源和污染现状,介绍了FQs在水体环境中的迁移、转化和转归途径,归纳了各种当前使用较多的FQs分析检测方法的功能特点和适用条件。指出今后在FQs分析技术的开发上,应注重提高检测容量、降低检出限和削减环境负面影响因素。     

TiO2-xNx光催化氧化苯甲酸的研究

采用悬浮态光催化反应体系,以氙灯为光源,自制纳米TiO2-xNx为催化剂,考察了苯甲酸光催化氧化过程中TiO2-xNx质量浓度、反应体系初始pH和苯甲酸初始质量浓度对苯甲酸溶液中TOC去除率的影响。实验结果表明：最佳催化剂质量浓度为0．30g／L;TiO2-xNx的等电点为pH=5．3,在酸性条件下（pH=2．0）更有利于苯甲酸在催化剂表面的吸附,以及光生电子与O2反应生成·OH的进行;随苯甲酸初始质量浓度增加,TOC去除率降低,反应速率也相应地降低。TiO2-xNx比P25型TiO2表现出更强的浓度适应能力。     

电源变压器温升试验中（绕组法）的影响因素及不确定度的评估

本文中探讨的是根据绕组法计算电源变压器绕组温升的试验方法,以及对整个试验过程中环境、仪器设备、仪表、人为因素所引起的误差等对最终试验结果的影响,并对其测量不确定度进行评估。     

烟气脱硝技术及在我国的应用

氮氧化物气体是危害最大、最难处理的大气污染物之一。随着经济的发展,有效控制燃煤造成的大气污染已经刻不容缓,特别是控制燃煤过程中的氮氧化物,烟气脱硝技术显得相当重要。本文分析了几种常用的烟气脱硝技术（选择性催化还原脱硝技术、选择性非催化还原脱硝技术、碱性溶液吸收法和等离子体活化法等）的原理、技术特点以及在我国的应用情况。     

Different reaction mechanisms of diphenylether and 4-bromodiphenylether with nitrous acid in the 355 nm laser flash photolysis of mixed aqueous solution

The microscopic reaction mechanisms of diphenylether (DPE) and 4-bromodiphenylether (4-BrDPE) with nitrous acid (HNO(2)) in the absence of O(2) have been explored by the 355nm laser flash photolysis. It was proposed that OH radical, from the photolysis of HNO(2), added to DPE forms the C(12)H(10)O-OH adduct while added to 4-BrDPE forms the 4-BrDPE-OH and 4-BrOH-DPE adducts. The first-order decay rate constants of the C(12)H(10)O-OH adduct, 4-BrDPE-OH adduct and 4-BrOH-DPE adduct were measured to be (1.86+/-0.14)x10(5)s(-1), (2.19+/-0.04)x10(5)s(-1) and (1.56+/-0.03)x10(5)s(-1), respectively. The final photolysis products of DPE and HNO(2) identified by GC/MS analysis were phenol, o-hydroxydiphenylether, p-hydroxydiphenylether and p-nitrodiphenylether, while the final photolysis product of 4-BrDPE and HNO(2) identified by LC/MS analysis was mainly the dimer.     

Enhancement of heavy metal accumulation by tissue specific co-expression of iaaM and ACC deaminase genes in plants

The aerobic riboflavin (Rf)-sensitized photodegradation of the endocrine disruptor 4,4'-isopropylidenebisphenol (bisphenol A, BPA), and of the related compounds 4,4'-isopropylidenebis(2,6-dibromophenol) and 4,4'-isopropylidenebis(2,6-dimethylphenol) has been studied in water and water-methanol mixtures through visible-light continuous photolysis, polarographic detection of oxygen uptake, stationary and time-resolved fluorescence spectroscopy, time-resolved near-IR phosphorescence detection and laser flash photolysis techniques. Bisphenols (BPs) quench excited singlet and triplet states of Rf, with rate constants close to the diffusion limit. BPs and dissolved molecular oxygen, employed in similar concentrations, competitively quench triplet excited Rf. As a consequence, superoxide radical anion and singlet molecular oxygen (O(2)((1)Delta(g))) are produced by electron- and energy-transfer processes, respectively, as demonstrated by auxiliary experiments employing selective quenchers of both oxidative species and the exclusive O(2)((1)Delta(g)) generator Rose Bengal. As a global result, the photodegradation of Rf is retarded, whereas BPs are degraded, mainly by an O(2)((1)Delta(g))-mediated mechanism, which constitutes a relatively efficient process in the case of BPA. Oxidation, dimerization and fragmentation products have been identified in the photooxidation of BPA. Results indicate that BPs in natural waters can undergo spontaneous photodegradation under environmental conditions in the presence of adequate photosensitizers.     

Changes in plasma thyroid hormones and cortisol levels in crucian carp (Carassius auratus) exposed to the extracted microcystins

The endocrine response of crucian carp injected intraperitoneally with extracted microcystins (MC) was investigated in this study. Fish were injected intraperitoneally either with 0.75% NaCl (control) and Microcystis extract corresponding to 150 and 600 microg microcystins per kg body weight. The plasma levels of triiodothyronine (T(3)), thyroxine (T(4)), free triiodothyronine (FT(3)), free thyroxine (FT(4)), and cortisol were determined at 0, 1, 3, 12, 24, and 48h post-administration of MC-containing extract. Treated fish displayed abnormal behaviors, such as a startle response and disoriented swimming, as well as changes in ventilation rates. Plasma cortisol concentrations of fish in both dose groups significantly increased after administration of extracted MC and remained high throughout the experiment, which suggested that MC elicited a stress response in treated fish. The profiles of cortisol changes in treated fish appeared to be dose dependent, indicating that fish in the high dose group experienced greater MC-induced disturbance. Mortality occurred after 12h in the high dose group. Plasma levels of T(4), T(3), FT(4), and FT(3) did not vary significantly between the control fish. In contrast to this, fish exposed to MC-containing extract showed significant declines in T(3), FT(4), and FT(3) levels in a dose-dependent manner throughout the experiment. Plasma T(4) levels, however, did not vary significantly in the low dose group, whereas they decreased significantly at 48h post injection in the high dose group. This study demonstrates that administration of microcystins-containing extract causes a stress response and reduces the plasma levels of thyroid hormones in crucian carp. These results illustrate that microcystins exerted potent effects on the endocrine system of crucian carp, through activating their hypothalamus-pituitary- interrenal axis and disturbing thyroid function.     

Seasonal effect on N2O formation in nitrification in constructed wetlands

Constructed wetlands are considered to be important sources of nitrous oxide (N(2)O). In order to investigate the contribution of nitrification in N(2)O formation, some environmental factors, plant species and ammonia-oxidizing bacteria (AOB) in active layers have been compared. Vegetation cells indicated remarkable effect of seasons and different plant species on N(2)O emission and AOB amount. Nitrous oxide data showed large temporal and spatial fluctuations ranging 0-52.8 mg N(2)O m(-2)d(-1). Higher AOB amount and N(2)O flux rate were observed in the Zizania latifolia cell, reflecting high potential of global warming. Roles of plants as ecosystem engineers are summarized with rhizosphere oxygen release and organic matter transportation to affect nitrogen transformation. The Phragmites australis cell contributed to keeping high T-N removal performance and lower N(2)O emission. The distribution of AOB also supported this result. Statistical analysis showed several environmental parameters affecting the strength of observed greenhouse gases emission, such as water temperature, water level, TOC, plant species and plant cover.     

Sorption of polar and nonpolar organic contaminants by oil-contaminated soil

Sorption of nonpolar (phenanthrene and butylate) and polar (atrazine and diuron) organic chemicals to oil-contaminated soil was examined to investigate oil effects on sorption of organic chemicals and to derive oil–water distribution coefficients (K_oil). The resulting oil-contaminated soil–water distribution coefficients (K_d) for phenanthrene demonstrated sorption-enhancing effects at both lower and higher oil concentrations (C_oil) but sorption-reducing (competitive) effects at intermediate C_oil (approximately 1 g kg⁻¹). Rationalization of the different dominant effects was attempted in terms of the relative aliphatic carbon content which determines the accessibility of the aromatic cores to phenanthrene. Little or no competitive effect occurred for butylate because its sorption was dominated by partitioning. For atrazine and diuron, the changes in K_d at C_oil above approximately 1 g kg⁻¹ were negligible, indicating that the presently investigated oil has little or no effect on the two tested compounds even though the polarity of the oil is much less than soil organic matter (SOM). Therefore, specific interactions with the active groups (aromatic and polar domains) are dominantly responsible for the sorption of polar sorbates, and thus their sorption is controlled by available sorption sites. This study showed that the oil has the potential to be a dominant sorptive phase for nonpolar pollutants when compared to SOM, but hardly so for polar compounds. The results may aid in a better understanding of the role of the aliphatic and aromatic domains in sorption of nonpolar and polar organic pollutants.