Neurotoxicological evaluation of microcystin-LR exposure at environmental relevant concentrations on nematode Caenorhabditis elegans

Previous studies have not examined the adverse effects of microcystin-LR (MC-LR) at environmental relevant concentrations on the development and functions of nervous system. The neurotoxic effects of MC-LR exposure on neurotransmitter systems were investigated in Caenorhabditis elegans. After exposing L1 larvae to 0.1, 1, 10, and 100 μg?l^?1 of MC-LR for 8 and 24 h, the adverse effects on GABAergic, cholinergic, serotonergic, dopaminergic, and glutamatergic neurons were examined. The expression levels of genes required for development and functions of GABAergic neurons were further investigated. Body bend frequency and head thrash frequency decreased significantly after MC-LR exposure for 8 h at concentrations more than 1 μg?l^?1 and after MC-LR exposure for 24 h at concentrations more than 0.1 μg?l^?1. Loss of GABAergic neurons increased significantly in a dose-dependent manner after MC-LR exposure at concentrations more than 0.1 μg?l^?1. In contrast, no obvious neuronal losses or morphologic changes were observed in cholinergic, serotonergic, dopaminergic, and glutamatergic neurons in MC-LR-exposed nematodes. Quantitative real-time PCR assay further showed that expression levels of unc-30, unc-46, unc-47, and exp-1 genes required for development and function of GABAergic neurons decreased significantly in nematodes exposed to MC-LR at concentrations more than 0.1 or 1 μg?l^?1. MC-LR at environmental relevant concentrations caused neurobehavioral defects, which may be largely due to the neuronal loss and the alterations of expression level of genes required for GABAergic neurotransmitter system in C. elegans.     

进水碳负荷浓度对垂直潜流式人工湿地中植物根系微生物动态的影响

植物的不同生长发育阶段是影响根系微生物功能多样性的原因之一。植物的生长改变了微生物的群落结构。在低有机负荷或高有机负荷下,植物幼苗与成苗根系的微生物整体活性均差异明显,一般成苗期具有较高AWCD值。有植物湿地中微生物Simpson和Mcintosh多样性指数在植物成苗期均明显高于幼苗期(P0.05),但Shannon指数变化不明显(P0.05)。无植物湿地中微生物Simpson和Mcintosh指数受季节影响差异显著(P0.05)。主成分和聚类分析结果表明,不同生长发育阶段其微生物种类存在差异,而且不同进水条件下有植物湿地和无植物湿地各自有相似的微生物群体结构。     

河北省重点镇城镇化水平探析

城镇化是社会发展的结果,也是衡量区域经济社会发展水平的重要标志.以河北省50个省级重点镇为研究对象,利用模糊数学综合评价法测算出不同区域的城镇化水平.在总结重点镇的城镇化速度慢、地区差异性大等特点的基础上,提出了城镇化建设的具体优化措施,以期为合理发展城镇经济、正确选择发展道路提供参考.     

含镉废水处理现状及其生物处理技术的进展

在概述物理、化学及生物吸附法处理含镉废水现状的基础上,系统阐述生物强化技术处理重金属废水的研究进展.与普通生物吸附法相比,生物强化技术能提高生物的处理效率,加强生物的稳定性好,增强生物的抗毒性,所以在含镉等重金属废水处理方面具有很大的发展潜力.     

冲击载荷下螺栓预紧力对应力波影响分析

目的 研究拉伸冲击载荷作用下螺栓预紧力对应力波的影响.方法 针对螺栓弹性变形、塑性变形和冲击破坏3种情形,对螺栓未施加预紧力及施加不同预紧力下的连接结构进行冲击数值模拟,对比分析连接结构的测点应变及螺栓响应,并与霍普金森拉伸实验结果进行对比.结果 螺栓达到断裂或塑性变形时,预紧力对测点应变及螺栓最大应力影响较小;螺栓弹...     

合肥市近19年来土地利用格局的时空变化分析

利用Landsat TM、ETM 、CBERS—2资源卫星数据,采用基于知识型光谱特性的增强与人机交互解译相结合的方法,提取了合肥市1987年、2000年和2006年土地利用类型的专题信息。利用GIS空间分析技术和数理统计方法,分析了合肥市近19年来的土地利用变化特征。结果表明:①在整个阶段—耕地减少了23.38%,建设用地增加了61.26%;城镇用地新增速度最快,且新增速率远大于转移速率,属高速扩张型;②区内最"敏感"的类型是交通用地,其新增速率在两个阶段分别达到1.64和1.62,远高于其它的类型;④从城市扩展的方向上看,合肥城市的发展主要以西南部、南部和东部为主,西南部最为明显;城市已经形成以老城区为核心,向东、北、西南三翼伸展,形成"南进—东拓—西缓—北抑"的空间发展布局。     

紫外技术应用于油田含聚采出水快速降粘的研究

聚丙烯酰胺(HPAM)在提高油田采收率的同时,也为采出水的处理提出了新的挑战.采用UV254 nm处理,将其应用于油田含聚合物污水的快速降粘.研究结果表明:UV254 nm应用于聚丙烯酰胺配水时,在30 min的处理过程中,粘度由57.2 mPa·S迅速降低为2.12 mPa·S;实际含聚污水的粘度在30 min处理过程中由2.902 mPa·S降低为1.096 mPa·S.UV254 nm处理同样可以控制实际含聚污水中的悬浮物和含油量,使其在30 min的处理过程中由42.73 mg/L和38.96 mg/L分别降为20.91 mg/L和23.54 mg/L.UV254 nm在油田含聚污水处理上对粘度、含油量和悬浮物实现了较好的控制,且可以缩短处理时间,减小构筑物体积,因此可以作为传统沉降工艺的替代工艺应用于油田含聚污水的处理.     

聚合酶链式反应(PCR)用于检测环境水体指示菌的研究

对聚合酶链式反应（ｐｏｌｙｍｅｒａｓｅ ｃｈａｉｎ ｒｅａｃｔｉｏｎ，ＰＣＲ）快速检测水体指示菌－大肠菌群（ｔｏｔａｌ ｃｏｌｉｆｏｒｍ）和大肠杆菌（Ｅｓｃｈｅｒｉｃｈｉａ ｃｏｌｉ）进行了研究。采用的两对引物分别扩增了ＬａｃＺ基因的约２６０ｂｐ和ＵｄｉＡ基因的约１５０ｂｐＤＮＡ片段。引物Ⅰ和引物Ⅱ最低能分别扩增１０＾－６μｇ或１０＾－８μｇ基因组ＤＮＡ。整个检测工作在采集水样后５－６ｈ内完成。与     

废旧锌锰电池回收处理工艺的探讨

由于电池耗费量日益增加,废旧电池导致的环境污染问题倍受关注。通过对废旧电池的调研和处理技术的对比研究,提出了“焙烧—电解”回收处理废旧锌锰电池的工艺技术。在600℃、隔绝空气焙烧3h的试验条件下,“焙烧—电解”工艺不仅可回收大量的二氧化锰、锌、氯化锌、炭棒、铜帽、铁皮、蜡等资源,而且废气、废水、废渣经处理后完全达标排放。阐述了具体的“焙烧—电解”工艺。     

Concentrations and distribution of novel brominated flame retardants in the atmosphere and soil of Ny-Ålesund and London Island, Svalbard, Arctic

Novel brominated flame retardants (NBFRs) were investigated in Arctic air and soil samples collected from Ny-Ålesund and London Island, Svalbard, during Chinese scientific research expeditions to the Arctic during 2014–2015. The concentrations of Σ₉NBFRs in the Arctic air and soil were 4.9–8.7 pg/m³ (average 6.8 pg/m³) and 101–201 pg/g dw (average 150 pg/g dw), respectively. The atmospheric concentration of hexabromobenzene (HBB) was significantly correlated with that of pentabromotoluene (PBT) and pentabromobenzene (PBBz), suggesting similar source and environmental fate in the Arctic air. No significant spatial difference was observed among the different sampling sites, both for air and soil samples, indicating that the effects of the scientific research stations on the occurrence of NBFRs in the Arctic were minor. The fugacities from soil to air of pentabromoethylbenzene (PBEB), 2,3-dibromopropyl 2,4,6-tribromophenyl ether (DPTE), and decabromodiphenylethane 1,2-bis (pentabromophenyl) ethane (DBDPE) were lower than the equilibrium value, indicating a nonequilibrium state of these compounds between air and soil, the dominant impact of deposition and the net transport from air to soil. The correlation analysis between the measured and predicted soil-atmosphere coefficients based on the absorption model showed that the impact of the soil organic matter on the distribution of NBFRs in the Arctic region was minor. To the best of our knowledge, this work is one of the limited reports on atmospheric NBFRs in the Arctic and the first study to investigate the occurrence and fate of NBFRs in the Arctic soil.