A method for removing persulfate interference in the analysis of the chemical oxygen demand in wastewater

Environmental Chemistry Letters - In recent years, sulfate radical-based advanced oxidation has received increasing attention for the treatment of water and wastewater....     

全氟辛烷磺酸(PFOS)对斑马鱼血浆和组织匀浆中卵黄蛋白原含量的影响

为了研究低剂量的全氟辛烷磺酸(perfluorooctane sulfonate,PFOS)对水生生物的内分泌干扰效应和作用机制,考察了PFOS对斑马鱼(Brachydanio rerio)血浆和组织匀浆中卵黄蛋白原(vitellogenin,VTG)含量的影响。将雄性和雌性斑马鱼分别暴露于0.1、1、10和100μg·L-1的PFOS中进行21d毒性实验,染毒结束后分别检测雄鱼和雌鱼的血浆、头尾组织匀浆液和全鱼匀浆液中的VTG含量。结果显示:(1)PFOS暴露可引起斑马鱼血浆、全鱼和头尾匀浆液中VTG含量的升高,VTG含量的排序为雌鱼(血浆>>全鱼匀浆>头尾匀浆)>>雄鱼(血浆>全鱼匀浆>>头尾匀浆);(2)PFOS暴露所引起的雄鱼血浆和头尾匀浆中VTG含量的升高与剂量呈负相关关系,暴露浓度为0.1μg·L-1时与对照组相比有显著性差异(p<0.05);(3)雌鱼血浆和头尾匀浆中VTG含量的升高与剂量呈倒U型曲线关系,暴露浓度为10μg·L-1时与对照组相比有显著性差异(p<0.05);(4)雄鱼和雌鱼的全鱼匀浆液中的VTG含量与对照组相比均无显著性差异。研究结果表明,PFOS暴露对斑马鱼的内分泌干扰作用明显,其毒性作用机制可能是类雌激素效应,血液和头尾匀浆液中VTG含量能够作为PFOS内分泌干扰效应评价的敏感生物标志物,但响应曲线可能因性别和组织部位的不同有所差异。     

PFOA对斑马鱼胚胎发育、行为和DNA损伤的毒性研究

全氟辛酸(PFOA)是一种分布广泛的环境持久性有机污染物,在野生动物与人体内普遍被检出。目前PFOA发育毒性的特点和机制尚未阐明,已有的研究显示,PFOA毒性与受试物种及性别密切相关。因此,利用不同物种进行PFOA毒性研究对阐明其毒性机制十分重要。本研究选用了斑马鱼这种理想的脊椎动物模型,考察了PFOA暴露对其胚胎发育的自主运动、心跳、行为、细胞凋亡和DNA损伤的影响。研究发现,始于6hpf的PFOA暴露会导致斑马鱼胚胎自主运动异常,心率降低,且具有一定的剂量依赖性;6～24hpf的高浓度的PFOA暴露(>414.0mg·L-1)会导致胚胎发生显著的细胞凋亡,凋亡主要出现在眼部、头部、心脏和尾部。较高浓度的PFOA暴露(165.6mg·L-1)会使仔鱼的光刺激应激行为模式发生变化。此外,PFOA暴露会致使斑马鱼发生DNA损伤,且损伤程度随PFOA浓度的升高而加重,表明PFOA具有一定的基因毒性。上述结果表明,PFOA对斑马鱼胚胎具有发育毒性,具体表现为自主运动异常,心率降低和行为反应能力变弱,同时伴随畸形、细胞凋亡和DNA损伤。     

Characterization and performance of V2O5/CeO2 for NH3-SCR of NO at low temperatures

A series of CeO₂ supported V₂O₅ catalysts with various loadings were prepared with different calcination temperatures by the incipient impregnation. The catalysts were evaluated for low temperature selective catalytic reduction (SCR) of NO with ammonia (NH₃). The effects of O₂ and SO₂ on catalytic activity were also studied. The catalysts were characterized by specific surface areas (S_BET) and X-ray diffraction (XRD) methods. The experimental results showed that NO conversion changed significantly with the different V₂O₅ loading and calcination temperature. With the V₂O₅ loading increasing from 0 to 10 wt%, NO conversion increased significantly, but decreased at higher loading. The optimum calcination temperature was 400°C. The best catalyst yielded above 80% NO conversion in the reaction temperature range of 160°C–300°C. The formation of CeVO₄ on the surface of catalysts caused the decrease of redox ability.     

Evidence for DNA-diquat interaction and cytotoxicity in in vitro rat cells

Over 98% of sprayed insecticides and 95% of herbicides reach non-target species in air, soil, and water. Numerous studies have reported that pesticide residues can cause acute and chronic toxicity. Pesticide residues can be carcinogenic, mutagenic, and immunotoxic. There are actually too few studies that bridge the disciplines of chemobioanalysis and environmental toxicology. Here, we assessed the cytotoxicity of a bipyridilium herbicide diquat in rat adrenal pheochromocytoma cells (PC12). Our results show that diquat caused the decrease in cell viability with a lethal concentration 50 (LC₅₀) of 1.4 × 10⁻⁵ mol/L. This cytotoxicity may result from diquat-induced apoptosis, characterized by nuclear fragmentation and chromatin condensation by Hoechst 33324 staining. To explore the possible mechanisms, the interaction between herbicide diquat and calf thymus DNA (ctDNA) was further investigated using fluorescence quenching. The detection of static quenching showed that diquat was linked with ctDNA by electrostatic interaction with a binding constant of 9.288 × 10⁴ L/mol. This is the first study on the interaction of DNA with herbicide diquat by fluorometric method as well as on the evaluation of cytotoxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Hoechst staining. Given the widespread use of synthetic pesticides, the data would be valuable for the risk assessment of pesticide residues.     

九龙江河口区主要污染物时空变化特征

根据九龙江河口区近30年的历史监测资料和2010年2个航次的现场调查资料,分析了该海域表层海水中无机氮(DIN)、活性磷酸盐(DIP)、化学耗氧量(COD)和石油类浓度的年际变化特征和平面分布变化特征,并应用富营养状态指数(EI)对海水水质进行评价与分析.结果表明,近30年,DIN、DIP年均浓度持续上升,COD年均浓度呈“W”状小幅波动趋势,石油类年均浓度先缓慢增加再降低;DIN浓度平面分布呈由西至东递减的特征,不同年份的DIP浓度平面分布有所差别,而COD和石油类浓度平面分布呈由湾内、西海域向湾外递减的趋势;海水EI呈不断加速升高的趋势,海水水质富营养化程度急剧恶化;受九龙江径流影响,高富营养化海域主要分布在九龙江北、中、南港和南溪入海口附近.所得的主要污染物浓度年际变化特征和平面分布变化特征等将为实施入海污染物总量控制奠定坚实基础.     

梯形巷道平均风速分布特征的数值与实验研究

为实现矿井巷道内风量的准确监测,基于3D数值模型,对梯形截面巷道内平均风速的分布规律进行了数值分析,并通过实验研究对模拟结果进行对比验证,同时在不同断面尺寸及不同通风风速条件下,数值分析了梯形巷道内紊流充分发展截面上平均风速点的分布特征。结果表明:平均风速分布呈现环状连续分布,数值结果与实验结果符合良好;梯形截面上平均风速点的分布与通风风速无关,仅与巷道截面特征和参数有关;得到了梯形截面平均风速分布曲线在巷道顶部的特征方程。     

Environmental sustainability index of Shandong Province,China

Since the 1992 Rio Earth Summit, sustainable development has been embraced as an important goal. In order to measure sustainable development, many scientists and researchers have made efforts to establish measurement systems such as the Driving Force State Response (DSR) framework (Hens 1995), the Human Development Index (HDI) (Goeteyn 1996) devised by the United Nations Development Programme, the Sustainable National Income (SNI) developed by Hueting et al. (1992) and the Ecological Footprint proposed by Wackernagel and Rees (1996). The environmental sustainability index (ESI) is a composite index, which was created by the World Economic Forum, Yale and Columbia Universities, aggregating data at the national level to measure a country's performance in sustaining a healthy, livable environment. 142 countries have been measured with ESI by 2002. However, it has not yet been documented if it can be applied at a regional level. In this study, we have tried to apply ESI to measure the sustainable development of Shandong in China. 22 indicators and 43 variables were chosen, and results showed the ESI of Shandong was 49, suggesting that Shandong is still far from a position of sustainable development.     

Simulation of soil carbon changes due to land use change in urban areas in China

Land use change can have a strong impact on soil carbon dynamics and carbon stocks in urban areas. Due to rapid urbanization, large areas of land have been paved, and other areas have undergone rapid land use change. Evaluation of the impact of urbanization on carbon dynamics and carbon stock (30 cm) has become an issue of urgent concern. The soil carbon dynamics, due to rapid land use change in Tianjin Binhai New Area of China, have been simulated in this paper using the RothC model. Because this area is saline, a modified version of RothC that includes a salt rate modifier provided more accurate simulations than the original model. The conversion to urban green land was not accurately simulated by either of the models because of the undefined changes in soil and plant conditions. According to the model, changes of arable to grassland resulted in a decline in soil carbon stocks, and changes of grassland to forest and grassland to arable resulted in increased soil carbon stocks in this area. Across the whole area simulated, the total carbon stocks in 2010 had decreased due to land use change by 6.5% from the 1979 value. By 2050, a further decrease of 21.9% is expected according to the 2050 plan for land use and the continuing losses from the soils due to previous land use changes.     

草型湖泊叶绿素a浓度时空分布特征及其与氮磷浓度关系

采用2006—2010年5—10月份乌梁素海监测数据,对叶绿素a浓度的时空分布特征及其与总氮、总磷浓度相关关系进行了分析。结果表明:乌梁素海叶绿素a浓度具有明显的时空分布差异性:在时间上,呈现出明显的季节性变化,5、6、9、10月份叶绿素a浓度较高,7、8月份叶绿素a浓度偏低,秋季≈春季>夏季,最高值出现在2007年9月,均值为9.01 mg/m3,最低值出现在2010年7月,均值为1.80 mg/m3;在空间上,南北部叶绿素a浓度以7.78 mg/m3为界,呈现北部区>南部区的趋势。通过叶绿素a与总氮、总磷浓度相关性分析得出,2006年5月叶绿素a与总氮、总磷(r=0.7450、0.7596)、2008年5月叶绿素a与总磷(r=0.5421)、2010年5月叶绿素a与总氮(r=0.5089)存在较好的相关性。