全氟辛烷磺酸盐(PFOS)及替代品对两栖类蝌蚪的急性毒性

PFOS及其4种替代品对两栖动物非洲爪蟾和黑斑蛙蝌蚪的急性毒性结果为:用调聚法合成的织物三防整理剂对非洲爪蟾蝌蚪和黑斑蛙蝌蚪的96h-LC50分别为8和21mg·L-1,而PFOS对两种蝌蚪的96h-LC50分别为92和81mg·L-1。此实验结果说明织物三防整理剂的急性毒性高于PFOS。用电解氟化法合成的C4、C6织物三防整理剂和50%的全氟丁基有机铵盐阳离子表面活性剂浓度在100mg·L-1时,对两种蝌蚪都没有毒性。这说明,从急性毒性的角度,C4、C6织物三防整理剂和表面活性剂可作为PFOS的替代品使用,但是织物三防整理剂的急性毒性比PFOS大,作为替代品使用应慎重考虑。另外,PFOS和织物三防整理剂对黑斑蛙蝌蚪的急性毒性与对非洲爪蟾蝌蚪的急性毒性存在差异。出于保护我国本土两栖动物的目的,使用黑斑蛙开展毒性评价比使用非洲爪蟾更有现实意义。     

斋家冲尾矿库排水斜槽加固实践

通过对斋家冲尾矿库排水斜槽结构强度演算及危险分析,采用埋设加固方法进行安全整改实践,达到了预期要求和效果。     

雾霾期北京大气中多环芳烃污染特征及暴露风险评估

雾霾对我国尤其是华北平原地区造成了极大的困扰,其发生常以颗粒物浓度急剧增长为特征,给人群健康带来了极大的风险。为进一步阐释雾霾的形成过程及其健康效应,在冬季雾霾期对北京城区大气颗粒态及气态中18种多环芳烃(PAHs)进行了连续测定,同步监测颗粒物、痕量气体污染物以及气象参数的变化,并对PAHs的浓度、组成、气粒分配等大气行为以及其与气象因素的作用机制进行了探讨。北京城区大气气相和颗粒物相中ΣPAHs浓度分别为585 ng·m~(-3)和705 ng·m~(-3)。雾霾发生时,PM_(2.5)浓度升高了3.6倍,PAHs浓度升高了2.6倍,18种PAHs同系物的浓度均随PM_(2.5)的浓度线性增加,其线性相关性受PAHs来源以及氧化活性的影响;夜间较重质量数的PAHs相对比例增加,主要受日间交通源以及夜间燃烧源贡献强度影响。受颗粒物组成以及湿度的影响,雾霾天气下PAHs颗粒相分配率降低。进一步评估了北京城区人群的PAHs吸入健康效应,冬季雾霾频繁发生下其对人群癌症风险为6.2×10~(-5)。     

环境浓度下壬基酚对秀丽隐杆线虫时间依赖性的毒性兴奋效应

为研究暴露时间对壬基酚生态毒理学效应的影响,选取秀丽隐杆线虫(Caenorhabditis elegans)作为受试生物,采用急性(24 h和72 h)、慢性(10 d) 3个不同时间点,进行壬基酚环境浓度下(0、0.0001、0.001、0.01、0.1、0.2 mg·L~(-1))的暴露实验,以秀丽隐杆线虫的生理指标(体长、运动行为)、生化指标(氧化应激、细胞凋亡、脂褐素)为终点进行评估。结果表明:急性暴露24 h后,活性氧自由基(ROS)在0.01 mg·L~(-1)时即出现了明显的下降,其他生理生化指标无统计学意义上的明显变化。72 h暴露条件下,体长随壬基酚浓度的增加呈现倒U型趋势,在0.0001 mg·L-1时表现出最大刺激效应,比对照组高出26.4%(P0.01);头部摆动频率和身体弯曲频率在2个较高浓度(0.1和0.2 mg·L~(-1))时表现出明显的刺激效应;细胞凋亡水平在0.0001 mg·L~(-1)时显著性下降,呈现负剂量-效应关系(P0.05),在0.2 mg·L~(-1)时表现出最大刺激效应,比对照组降低了45.5%; ROS及脂褐素在壬基酚暴露浓度范围内呈正相关性增加。慢性暴露条件下,脂褐素在0.001 mg·L~(-1)时表现出最大效应,和对照组相比下降了65.4%,并且随着壬基酚浓度的增加呈现U型趋势;其他生理生化指标随着壬基酚浓度的增加表现出明显的负面效应。研究揭示了环境浓度水平的壬基酚对秀丽隐杆线虫的生态毒理效应是时间依赖性的,急性暴露以引起刺激作用为主,表现为毒性兴奋效应,而长期暴露后壬基酚对生理生化指标的负面效应更为明显。上述结果为进行壬基酚的毒性评价及更好地理解其毒性作用机理提供基础数据。     

冷轧乳化废水的电凝聚处理

针对冷轧高浓度含油乳化废水,使用电絮凝工艺进行了研究,探讨了pH值、电流密度、反应时间、NaCl投加量和板间距等因素对电絮凝的影响,试验比较了电絮凝与其他化学方法对高浓度乳化液的处理效果,得到了令人满意的结果。     

污水处理厂恶臭污染物的工程治理

介绍了某纺织公司水质净化中心厂区恶臭污染物的治理方案。恶臭气体主要是H2S,质量浓度达6．0mg/m^3。将臭气引至除臭塔,塔内设嚣填料。挣化后的气体达到了GB1455-93中的二级标准0．06mg／m^3。     

Comparative analysis of impact of human occupancy on indoor microbiomes

• Exposure to indoor microbiomes is a public health concern in educational facilities. • Indoor microbiomes were characterized in two multifunctional university buildings. • Human occupancy had significant impact on the composition of indoor microbiomes. • The skin microbiota of occupants represented important sources of indoor microbiomes. Educational facilities serve as community hubs and consequently hotspots for exposure to pathogenic microorganisms. Therefore, it is of critical importance to understand processes shaping the indoor microbiomes in educational facilities to protect public health by reducing potential exposure risks of students and the broader community. In this study, the indoor surface bacterial microbiomes were characterized in two multifunctional university buildings with contrasting levels of human occupancy, of which one was recently constructed with minimal human occupancy while the other had been in full operation for six years. Higher levels of human occupancy in the older building were shown to result in greater microbial abundance in the indoor environment and greater proportion of the indoor surface bacterial microbiomes contributed from human-associated microbiota, particularly the skin microbiota. It was further revealed that human-associated microbiota had greater influence on the indoor surface bacterial microbiomes in areas of high occupancy than areas of low occupancy. Consistent with minimal impact from human occupancy in a new construction, the indoor microbiomes in the new building exhibited significantly lower influence from human-associated microbiota than in the older building, with microbial taxa originating from soil and plants representing the dominant constituents of the indoor surface bacterial microbiomes. In contrast, microbial taxa in the older building with extensive human occupancy were represented by constituents of the human microbiota, likely from occupants. These findings provide insights into processes shaping the indoor microbiomes which will aid the development of effective strategies to control microbial exposure risks of occupants in educational facilities.     

Acute associations between air pollution on premature rupture of membranes in Hefei,China

Numerous studies had focused on the association between air pollution and health outcomes in recent years. However, little evidence is available on associations between air pollutants and premature rupture of membranes (PROM). Therefore, we performed time-series analysis to evaluate the association between PROM and air pollution. The daily average concentrations of PM_2.5, SO₂ and NO₂ were 54.58 μg/m³, 13.06 μg/m³ and 46.09 μg/m³, respectively, and daily maximum 8-h average O₃ concentration was 95.67 μg/m³. The strongest effects of SO₂, NO₂ and O₃ were found in lag4, lag06 and lag09, and an increase of 10 μg/m³ in SO₂, NO₂ and O₃ was corresponding to increase in incidence of PROM of 8.74% (95% CI 2.12–15.79%), 3.09% (95% CI 0.64–5.59%) and 1.68% (95% CI 0.28–3.09%), respectively. There were no significant effects of PM_2.5 on PROM. Season-specific analyses found that the effects of PM_2.5, SO₂ and O₃ on PROM were more obvious in cold season, but the statistically significant effect of NO₂ was observed in warm season. We also found the modifying effects by maternal age on PROM, and we found that the effects of SO₂ and NO₂ on PROM were higher among younger mothers (<?35 years) than advanced age mothers (≥?35 years); however,?≥?35 years group were more vulnerable to O₃ than?<?35 years group. This study indicates that air pollution exposure is an important risk factor for PROM and we wish this study could provide evidence to local government to take rigid approaches to control emissions of air pollutants.

     

Effects of glucose dehydrogenase gene knock-out in Acetobacter sp. On the metabolism of carbon sources and the synthesis of 3-hydroxypropionic acid北大核心CSCD

3-Hydroxypropionic acid (3-HP) is an emerging platform chemical with a high added-value. Resting cells of Acetobacter sp. can efficiently catalyze 1,3-propanediol (1,3-PDO) to 3-HP. Glucose is oxidized by the membrane-bound dehydrogenase, resulting in an acidic environment that inhibits cell growth and reduces the biomass. We deleted the gdh gene for glucose dehydrogenase (GDH), and investigated the effects on cell growth, carbon metabolism, and 3-HP production. The gdh gene knocked-out showed a 1.72-fold increase in biomass in the mixed medium containing glucose and glycerol. A carbon flux analysis showed that glucose was converted to gluconic acid by GDH, followed by an oxidation to 2-ketogluconic acid. In addition, a small percentage of the gluconic acid was degraded via the pentose phosphate pathway. Glycerol was phosphorylated and entered the central pathway (gluconeogenesis). Results indicate that the deletion of gdh can effectively promote higher cell densities and improve the catalytic performance for the production of 3-HP, and thus provide a theoretical reference for improving the carbon source utilization and the catalytic performance of acetic acid bacteria. © 2018 Science Press. All rights reserved.