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291.
为了解重金属污染对海洋鱼类热休克蛋白(HSPs)基因表达的影响,将褐菖鲉(Sebastiscus marmoratus)分别暴露于1.6、8、40、200、500μg·L~(-1)Cd、Pb溶液中,用环介导等温扩增技术(loop-mediated isothermal amplification,LAM P)定量检测褐菖鲉肝脏HSP60、HSP70、HSP90、HSC70 mRNA表达量。结果表明:Pb仅在40μg·L-1时显著抑制HSP60、HSP90、HSC70 mRNA表达量,8μg·L~(-1)时即可显著抑制HSP70 m RNA表达量,并在40μg·L~(-1)时达到最小值;Cd对HSP60、HSP90、HSC70的诱导不明显,但能显著诱导HSP70,并在500μg·L~(-1)时达到最大值。相比之下,褐菖鲉肝HSP70基因对重金属Cd、Pb污染较为敏感,有潜力成为监测海洋重金属污染的预警分子。 相似文献
292.
Lyumeng?Ye Xuemei?WangEmail author Shaofeng?Fan Weihua?Chen Ming?Chang Shengzhen?Zhou Zhiyong?Wu Qi?Fan 《Frontiers of Environmental Science & Engineering》2016,10(6):15
Surface O3 production has a highly nonlinear relationship with its precursors. The spatial and temporal heterogeneity of O3-NO x -VOC-sensitivity regimes complicates the control-decision making. In this paper, the indicator method was used to establish the relationship between O3 sensitivity and assessment indicators. Six popular ratios indicating ozone-precursor sensitivity, HCHO/NO y , H2O2/ HNO3, O3/NO y , O3/NO z , O3/HNO3, and H2O2/NO z , were evaluated based on the distribution of NOx- and VOC-sensitive regimes. WRF-Chem was used to study a serious ozone episode in fall over the Pearl River Delta (PRD). It was found that the south-west of the PRD is characterized by a VOCsensitive regime, while its north-east is NO x -sensitive, with a sharp transition area between the two regimes. All indicators produced good representations of the elevated ozone hours in the episode on 6 November 2009, with H2O2/HNO3 being the best indicator. The threshold sensitivity levels for HCHO/NOy, H2O2/HNO3, O3/NO y , O3/NO z , O3/HNO3, and H2O2/NO z were estimated to be 0.41, 0.55, 10.2, 14.0, 19.1, and 0.38, respectively. Threshold intervals for the indicators H2O2/HNO3, O3/NO y , O3/NO z , O3/HNO3, and H2O2/NO z were able to identify more than 95% of VOC- and NO x -sensitive grids. The ozone episode on 16 November 16 2008 was used to independently verify the results, and it was found that only H2O2/HNO3 and H2O2/NO z were able to differentiate the ozone sensitivity regime well. Hence, these two ratios are suggested as the most appropriate indicators for identifying fall ozone sensitivity in the PRD. Since the species used for indicators have seasonal variation, the utility of those indicators for other seasons should be investigated in the future work. 相似文献
293.
Liu YANG Ye WU Jiaqi LI Shaojie SONG Xuan ZHENG Jiming HAO 《Frontiers of Environmental Science & Engineering》2015,9(4):675
Mass concentrations of PM10, PM2.5 and PM1 were measured near major roads in Beijing during six periods: summer and winter of 2001, winter of 2007, and periods before, during and after the 2008 Beijing Olympic Games. Since the control efforts for motor vehicles helped offset the increase of emissions from the rapid growth of vehicles, the averaged PM2.5 concentrations at roadsides during the sampling period between 2001 and 2008 fluctuated over a relatively small range. With the implementation of temporary traffic control measures during the Olympics, a clear “V” shaped curve showing the concentrations of particulate matter and other gaseous air pollutants at roadsides over time was identified. The average concentrations of PM10, PM2.5, CO and NO decreased by 31.2%, 46.3%, 32.3% and 35.4%, respectively, from June to August; this was followed by a rebound of all air pollutants in December 2008. Daily PM10 concentrations near major roads exceeded the National Ambient Air Quality Standard (Grade II) for 61.2% of the days in the non-Olympic periods, while only for 12.5% during the Olympics. The mean ratio of PM2.5/PM10 near major roads remained relatively stable at 0.55 (±0.108) on non-Olympic days. The ratio decreased to 0.48 (±0.099) during the Olympics due to a greater decline in fine particles than in coarse-mode PM. The ratios PM1/PM2.5 fluctuated over a wide range and were statistically different from each other during the sampling periods. The average ratios of PM1/PM2.5 on non-Olympic days were 0.71. 相似文献
294.
采用自行设计的反应器,通过调节培养液的配比对载体进行挂膜,得到蛋白质和多糖含量比分别为7:1、5:1和10:1的3种生物膜作为吸附剂,用其对Cu2+进行吸附试验,同时对吸附机理进行探讨.结果表明,培养8d后,生物膜可挂膜成熟,在C/N=12时,生物膜上的菌落数较C/N=4和C/N=37条件下多.PN/PS值越小,生物膜对铜的吸附量越高,EPS3对Cu2+的吸附量分别高出EPS1 7.37 %, EPS2 7.62%.在生物膜吸附Cu2+后,溶液中Ca2+、Mg2+、K+含量明显升高,表明离子交换对生物膜吸附Cu2+起主要作用,且Cu2+更易与Ca2+和Mg2+产生离子交换作用.当KNO3浓度在0.1~0.6mol/L之间,随着离子强度的增加,生物膜吸附Cu2+的量迅速减少,当KNO3浓度大于0.6mol/L时,生物膜对Cu2+吸附量的变化趋于平缓,说明生物膜对Cu2+的吸附同时包括离子交换吸附和化学吸附. 相似文献
295.
296.
297.
Qing YE Donghui LI Jun ZHAO Jiansheng ZHAO Tianfang KANG Shuiyuan CHENG 《Frontiers of Environmental Science & Engineering》2011,5(4):497-504
Au-supported 13X-type zeolite (Au/13X) was synthesized using a common deposition–precipitation (DP) method with a solution of sodium carbonate as a precipitate agent. Further testing was conducted to test for catalytic oxidation of CO. A study was conducted on the effects of different preparation conditions (i.e., chloroauric acid concentration, solution temperature, pH of solution, and calcinations temperature) on Au/13X for CO oxidation. In respect to the catalytic activity, the relationship between different the preparation conditions and gold particles in 13X zeolite was analyzed using X-ray diffraction, TEM and XPS. The activity of Au/13X catalysts in CO oxidation was dependent on the chloroauric acid concentration. From XRD results, a higher chloroauric acid concentration induced larger gold nanoparticles, which resulted in lower catalytic activity. Results revealed that higher temperatures induced higher Au loading, homogeneous deposit, and smaller gold clusters on the support of 13X, resulting in higher CO activity. Furthermore, a pH of 5 or 6 generated greater amounts of Au loading and smaller Au particles on 13X than at a pH of 8 or 9. This may be a result of an effective exchange between A u ( O H ) 2 C l 2 - and Au(OH)3Cl- on specific surface sites of zeolite under the pH’s 5 and 6. The sample calcined at 300°C showed the highest activity, which may be due to the sample’s calcined at 200°C inability to decompose completely to metallic gold while the sample calcined at 400°C had larger particles of gold deposited on the support. It can be concluded from this study that Au/13X prepared from a gold solution with an initial chloroauric acid solution concentration of 1.5 × 10-3 mol·L-1 gold solution pH of 6, solution temperature of around 90°C, and a calcination temperature of 300°C provides optimum catalytic activity for CO oxidation. 相似文献
298.
The concentrations of four essential (Ca, Mg, Zn, and Cu) and two nonessential elements (Pb and Cd) in feathers and kidneys, livers, gut walls, and muscles of eight carcasses of migratory red-crowned cranes (Grus japonensis) from Zhalong Wetland, northeastern China, were examined. The concentrations of Cd in the feathers were between 0.4 mg kg?1 dry weight (dw) and 3.1 mg kg?1 dw, in the livers between 0.4 and 4.4 mg kg?1 dw, the maximum of which exceeded a level considered to be environmental exposure risk (i.e., 3 mg kg?1 dw in the liver or kidney). High Pb levels (0.4–3.2 mg kg?1 dw, with an average of 1.8 mg kg?1) were also detected in livers, which exceeded a level considered toxicosis in birds (1.7 mg kg?1 dw). Pb and Cd had the highest scores in principal component analysis. Relatively high Pb and Cd concentrations in the migratory cranes were thought to be associated with their habitat and prey. 相似文献
299.
300.
Xun Wang Haixin Yao Ming Hung Wong Zhihong Ye 《Environmental geochemistry and health》2013,35(6):779-788
Temporal variations and correlations between radial oxygen loss (ROL), iron (Fe) plaque formation, cadmium (Cd) and arsenic (As) accumulation were investigated in two rice cultivars at four different growth stages based upon soil pot and deoxygenated solution experiments. The results showed that there were significant differences in ROL (1.1–16 μmol O2 plant?1 h?1), Fe plaque formation (4,097–36,056 mg kg?1), Cd and As in root tissues (Cd 77–162 mg kg?1; As 49–199 mg kg?1) and Fe plaque (Cd 0.4–24 mg kg?1; As 185–1,396 mg kg?1) between these growth stages. ROL and Fe plaque increased dramatically from tillering to ear emergence stages and then were much reduced at the grain-filling stage. Furthermore, significantly positive correlations were detected between ROL and concentrations of Fe, Cd and As in Fe plaque. Our study indicates that increased Fe plaque forms on rice roots at the ear emergence stage due to the increased ROL. This stage could therefore be an important period to limit the transfer and distribution of Cd and As in rice plants when growing in soils contaminated with these toxic elements. 相似文献