明代关中渭河流域水涝灾害研究

通过对历史资料的搜集、整理和分析,对明代(1368～1644年)关中渭河流域水涝灾害的时空特征、等级序列及产生原因进行了分析研究.结果表明,该地区水涝灾害多发于夏秋季节,发生频率从早期到晚期呈明显增加趋势,且存在相对高发期;水涝灾害主要发生在关中渭河流域的中下游地区,且主要分布在渭河的干流或支流沿岸;该地区水涝灾害以中度水灾居多,约占56.14%,重度和轻度水灾次之,特大灾很少发生.较集中的大雨和暴雨是明代关中渭河流域水涝灾害发生的的主要因素,森林植被的破坏和河渠的淤浅使该地区水量承载能力减小,增大了成灾的可能性.     

黄姜皂素废酸液在均相离子膜中渗析规律的研究

为了研究皂素水解废液在离子交换膜中的渗析规律,实验考察了废液中电导率、含盐量、氢离子浓度、硫酸盐浓度、Ca离子浓度、Mg离子浓度和有机物浓度随渗析时间的关系。研究结果表明:渗析时间进行100 h后,处理效果达到稳定状态;废液与渗析液的电导率几乎相等;含盐量、H+浓度、SO2-4浓度的分离效率分别为71%、62%、78%;Ca去除效果优于Mg去除效果;大部分有机物无法通过离子交换膜。     

IKK inhibition prevents PM2.5-exacerbated cardiac injury in mice with type 2 diabetes

Epidemiological studies have found that individuals with diabetes mellitus(DM) display an increased susceptibility for adverse cardiovascular outcomes when exposed to air pollution.This study was conducted to explore the potential mechanism linking ambient fine particles(PM2.5) and heart injury in a Type 2 DM(T2DM) animal model. The KKay mouse, an animal model of T2DM, was exposed to concentrated ambient PM2.5 or filtered air for 8 weeks via a versatile aerosol exposure and concentrator system. Simultaneously, an inhibitor of IκB kinase-2(IKK-a)(IMD-0354), which is a blocker of nuclear factor κB(NF-κB)nuclear translocation, was administrated by intracerebroventricular injection(ICV) to regulate the NF-êB pathway. The results showed that ambient PM2.5 induced the increase of, NF-êB, cyclooxygenase-2(COX-2) and mitogen activated protein kinase(MAPK) expression in cardiac tissue, and that IMD-0354 could alleviate the inflammatory injury. The results suggested that the NF-êB pathway plays an important role in mediating the PM2.5-induced cardiovascular injury in the T2DM model. Inhibiting NFκB may be a therapeutic option in air-pollution-exacerbated cardiovascular injury in diabetes mellitus.     

Serious BTEX pollution in rural area of the North China Plain during winter season

Atmospheric BTEX compounds(benzene, toluene, ethylbenzene and xylenes) in a rural site of the North China Plain(NCP) were preliminarily investigated in winter, and the outdoor concentrations(25.8–236.0 μg/m3) were found to be much higher than those reported in urban regions. The pollution of BTEX inside a farmer's house was even more serious, with combined concentrations of 254.5–1552.9 μg/m3. Based on the ratio of benzene to toluene(1.17 ± 0.34) measured, the serious BTEX pollution in the rural site was mainly ascribed to domestic coal combustion for heating during the winter season. With the enhancement of farmers' incomes in recent years, coal consumption by farmers in the NCP is rapidly increasing to keep their houses warm, and hence the serious air pollution in rural areas of the NCP during winter, including BTEX, should be paid great attention.     

Synergistic effect of ozonation and ionizing radiation for PVA decomposition

Ozonation and ionizing radiation are both advanced oxidation processes (AOPs) without chemical addition and secondary pollution. Also, the two processes'' efficiency is determined by different pH conditions, which creates more possibilities for their combination. Importantly, the combined process of ozonation and ionizing radiation could be suitable for treating wastewaters with extreme pH values, i.e., textile wastewater. To find synergistic effects, the combined process of ozonation and ionizing radiation mineralization was investigated for degradation of polyvinyl alcohol (PVA) at different pH levels. A synergistic effect was found at initial pH in the range 3.0–9.4. When the initial pH was 3.0, the combined process of ozonation and ionizing radiation gave a PVA mineralization degree of 17%. This was 2.7 times the sum achieved by the two individual processes, and factors of 2.1 and 1.7 were achieved at initial pH of 7.0 and 9.4, respectively. The combined process of ozonation and ionizing radiation was demonstrated to be a feasible strategy for treatment of PVA-containing wastewater.     

Analysis of trace dicyandiamide in stream water using solid phase extraction and liquid chromatography UV spectrometry

An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction. The extraction procedure (including loading, washing, and eluting) used a flow rate of 1.0 mL/min, and dicyandiamide was eluted with 20 mL of a methanol/acetonitrile mixture (V/V = 2:3), followed by pre-concentration using nitrogen evaporation and analysis with high performance liquid chromatography–ultraviolet spectroscopy (HPLC–UV). Sample extraction was carried out using a Waters Sep-Pak AC-2 Cartridge (with activated carbon). Separation was achieved on a ZIC^®-Hydrophilic Interaction Liquid Chromatography (ZIC-HILIC) (50 mm × 2.1 mm, 3.5 μm) chromatography column and quantification was accomplished based on UV absorbance. A reliable linear relationship was obtained for the calibration curve using standard solutions (R² > 0.999). Recoveries for dicyandiamide ranged from 84.6% to 96.8%, and the relative standard deviations (RSDs, n = 3) were below 6.1% with a detection limit of 5.0 ng/mL for stream water samples.