Experimental and numerical investigations of the effect of imbricated gravel structures on flow and solute transport in a highly heterogeneous alluvial-proluvial fan aquifer,SW China

Environmental Fluid Mechanics - An alluvial-proluvial fan (APF) has heterogeneous characteristics, which result in the development of imbricated gravel channel networks formed by flow erosion. In...     

微塑料污染现状及其毒性效应和机制研究进展

微塑料(microplastics,MPs)作为一种新型的环境污染物近年来逐渐引起全世界的关注,除了对生态环境的影响,微塑料对生物体的毒性效应及其潜在的健康风险也日益成为环境领域的研究热点.本文基于已有研究,阐述微塑料的污染现况,总结微塑料进入机体的分布,归纳微塑料的生物毒性作用和机制,分析微塑料毒性效应的影响因素,并展望了未来的研究方向,为进一步开展微塑料的生物毒性效应、机制研究和健康风险评估提供科学线索和参考.     

Effects of ambient temperature on regulated gaseous and particulate emissions from gasoline-, E10- and M15-fueled vehicles

• Emissions from two sedans were tested with gasoline, E10 and M15 at 30°C and -7°C. • As the temperature decreased, the PM, PN and BC emissions increased with all fuels. • Particulate emissions with E10 and M15 were more sensitive to the temperature. • The PN and BC generated during cold start-up dominated those over the WLTC. Ambient temperature has substantial impacts on vehicle emissions, but the impacts may differ between traditional and alcohol gasolines. The objective of this study was to investigate the effects of temperature on gaseous and particulate emissions with both traditional and alcohol gasoline. Regulated gaseous, particle mass (PM), particle number (PN) and black carbon (BC) emissions from typical passenger vehicles were separately quantified with gasoline, E10 (10% ethanol and 90% gasoline by volume) and M15 (15% methanol and 85% gasoline by volume) at both 30°C and -7°C. The particulate emissions with all fuels increased significantly with decreased temperature. The PM emissions with E10 were only 48.0%–50.7% of those with gasoline at 30°C but increased to 59.2%-79.4% at -7°C. The PM emissions with M15 were comparable to those with gasoline at 30°C, but at -7°C, the average PM emissions were higher than those with gasoline. The variation trend of PN emissions was similar to that of PM emissions with changes in the fuel and temperature. At 30°C, the BC emissions were lower with E10 and M15 than with gasoline in most cases, but E10 and M15 might emit more BC than gasoline at -7°C, especially M15. The results of the transient PN and BC emission rates show that particulate emissions were dominated mainly by those emitted during the cold-start moment. Overall, the particulate emissions with E10 and M15 were more easily affected by ambient temperature, and the advantages of E10 and M15 in controlling particulate emissions declined as the ambient temperature decreased.     

微生物管式膜污水处理工艺试验与应用

某油田污水处理站设计处理规模1500 m³/d,实际处理量630 m³/d,处理工艺为“微生物接触氧化+加药絮凝沉淀+二级过滤”,在运行过程中投加的混凝剂等药剂成本高,且二级过滤器使用年限过长,其处理后出水无法达到Q/SYTH 0082—2020《油田注水水质规定》中油小于5 mg/L、悬浮物含量小于3 mg/L、粒径中值小于2μm的注水水质要求。该油田污水处理站开展了“特种微生物+低能耗管式膜”污水处理技术研究,并完成现场中试试验,处理后膜出水的悬浮物含量基本稳定在1 mg/L,出水水质达标,表明此工艺处理油田污水是可行和可靠的,为该油田污水处理工艺优化提供了可靠依据。     

试论安全管理中惩罚的合理应用

介绍了惩罚的定义、类型、作用及负效应。重点阐述了在安全管理中如何科学合理地利用惩罚。     

PCB118对GT1-7细胞GnRH分泌及Kisspeptin/GPR54信号通路蛋白表达的影响

为研究多氯联苯118(polychlorinated biphenyl 118,PCB118)对GT1-7细胞的毒性作用,探讨其对促性腺激素释放激素(gonadotropin-releasing hormone,GnRH)分泌的影响及相关机制,在PCB118作用GT1-7细胞后,分析了细胞存活率、GnRH分泌水平以及Kisspeptin/GPR54信号通路中关键蛋白的表达水平。结果表明,PCB118(0.05～50 000 nmol·L-1)分别作用GT1-7细胞6、12、24和48 h后,细胞存活率随PCB118浓度的增加和作用时间的延长而显著降低。但只有在高浓度(50 000nmol·L-1)条件下,PCB118才能显著促进GT1-7细胞释放乳酸脱氢酶(lactate dehydrogenase,LDH)。PCB118作用GT1-7细胞6 h后,5、500和50 000 nmol·L-1组能显著抑制GnRH的分泌,并降低Kisspeptin/GPR54信号通路中GnRH、G蛋白偶联受体54(G-protein-coupled receptor 54,GPR54)、磷脂酶C(phospholipase C,PLC)和蛋白激酶C(protein kinase C,PKC)等关键蛋白的表达水平;作用24 h,500和50 000 nmol·L-1PCB118能显著抑制GnRH的分泌,并降低GnRH、GPR54、PLC和PKC等关键蛋白的表达水平。研究表明:PCB118对GT1-7细胞具有细胞增殖毒性作用,呈现一定的剂量和时间效应; PCB118能在一定程度上抑制GT1-7细胞GnRH的合成与分泌,并下调Kisspeptin/GPR54信号通路中GnRH、GPR54、PLC和PKC等关键蛋白的表达水平,推测Kisspeptin/GPR54信号通路可能参与介导了PCB118对GT1-7细胞GnRH分泌的抑制作用。     

Identifying human-induced influence on microbial community: A comparative study in the effluent-receiving areas in Hangzhou Bay

Microbial compositions showed high differences in two study areas. COD was the key anthropogenic indicator in the coastal wastewater disposal area. Distinctive microbes capable of degrading toxic pollutants were screened. Microbial communities in effluent-receiving areas followed “niche theory”. Microbial community structure is affected by both natural processes and human activities. In coastal area, anthropegenetic activity can usually lead to the discharge of the effluent from wastewater treatment plant (WWTP) to sea, and thus the water quality chronically turns worse and marine ecosystem becomes unhealthy. Microorganisms play key roles in pollutants degradation and ecological restoration; however, there are few studies about how the WWTP effluent disposal influences coastal microbial communities. In this study, sediment samples were collected from two WWTP effluent-receiving areas (abbreviated as JX and SY) in Hangzhou Bay. First, based on the high-throughput sequencing of 16S rRNA gene, microbial community structure was analyzed. Secondly, several statistical analyses were conducted to reveal the microbial community characteristics in response to the effluent disposal. Using PCoA, the significant difference of in microbial community structure was determined between JX and SY; using RDA, water COD and temperature, and sediment available phosphate and ammonia nitrogen were identified as the key environmental factors for the community difference; using LDA effect size analysis, the most distinctive microbes were found and their correlations with environmental factors were investigated; and according to detrended beta-nearest-taxon-index, the sediment microbial communities were found to follow “niche theory”. An interesting and important finding was that in SY that received more and toxic COD, many distinctive microbes were related to the groups that were capable of degrading toxic organic pollutants. This study provides a clear illustration of eco-environmental deterioration under the long-term human pressure from the view of microbial ecology.     

利用垃圾焚烧发电技术与环境污染防控措施

大连利用生活垃圾焚烧发电,在消除污染的同时发展新能源,促进循环经济发展,具有较好的社会、环境和经济效益。简要介绍垃圾焚烧原理、工艺流程和技术特点,二恶英类污染物预防控制措施,以及焚烧灰渣无害化处理处置措施等,与国内同行交流、借鉴。     

Changes in Soil Properties After Establishment of Artemisia halodendron and Caragana microphylla on Shifting Sand Dunes in Semiarid Horqin Sandy Land, Northern China

In the semiarid Horqin sandy land of northern China, establishment of artificial sand-fixing shrubs on desertified sandy lands is an effective measure to control desertification and improve the regional environment. Caragana microphylla Lam. and Artemisia halodendron Turcz. ex Bess. are two of the dominant native shrub species, which are adapted well to windy and sandy environments, and thus, are widely used in revegetation programs to control desertification in Horqin region. To assess the effects of artificially planting these two shrub species on restoration of desertified sandy land, soil properties and plant colonization were measured 6 years after planting shrubs on shifting sand dunes. Soil samples were taken from two depths (0–5 cm and 5–20 cm) under the shrub canopy, in the mid-row location (alley) between shrub belts, and from nonvegetated shifting sand dune (as a control). Soil fine fractions, soil water holding capacity, soil organic C and total N have significantly increased, and pH and bulk density have declined at the 0–5-cm topsoil in both C. microphylla and A. halodendron. At the 5–20 cm subsurface soil, changes in soil properties are not significant, with exception of bulk density and organic C concentration under the canopy of A. halodendron and total N concentration under the canopy of C. microphylla. Soil amelioration processes are initiated under the shrub canopies, as higher C and N concentrations were found under the canopies compared with alleys. At the same time, the establishment of shrubs facilitates the colonization and development of herbaceous species. A. halodendron proved to have better effects in fixing the sand surface, improving soil properties, and restoring plant species in comparison to C. microphylla.     

更新观念转换机制

近两年来．海淀区地震办公室在区政府的领导下，在中国地震局的大力支持和北京市地震局的具体指导下．更新观念．转变理念，开阔视野，借助区域优势．转换机制．在新的形势下重新确定工作思路。调整工作定位．加强管理．积极探索，努力实践，在夯实基础上下功夫．防震撼灾各项工作的局面逐渐打开，呈现良好发展势头：2004年建立了海淀区青少年防灾减灾科普教育基地，