Adsorptive removal of antibiotics from water using magnetic ion exchange resin

The occurrence of antibiotics in the environment has recently raised serious concern regarding their potential threat to aquatic ecosystem and human health. In this study, the magnetic ion exchange(MIEX) resin was applied for removing three commonly-used antibiotics, sulfamethoxazole(SMX), tetracycline(TCN) and amoxicillin(AMX) from water.The results of batch experiments show that the maximum adsorption capacities on the MIEX resin for SMX, TCN and AMX were 789.32, 443.18 and 155.15 μg/m L at 25°C,respectively, which were 2–7 times that for the powdered activated carbon. The adsorption kinetics of antibiotics on the MIEX resin could be simulated by the pseudo-second-order model(R~2= 0.99), and the adsorption isotherm data were well described by the Langmuir model(R~2= 0.97). Solution p H exhibited a remarkable impact on the adsorption process and the absorbed concentrations of the tested antibiotics were obtained around the neutral p H.The MIEX resin could be easily regenerated by 2 mol/L Na Cl solution and maintained high adsorption removal for the tested antibiotics after regeneration. Anion exchange mechanism mainly controlled the adsorption of antibiotic and the formation of hydrogen binding between the antibiotic and resin can also result in the increase of adsorption capacity. The high adsorption capacity, fast adsorption rate and prominent reusability make the MIEX resin a potential adsorbent in the application for removing antibiotics from water.     

南京地区污水厂、自来水厂及长江中抗性基因MCR-1和NDM-1的污染特征

近年来,新型抗性基因以其易传播和耐药广等特性,展现出比传统抗性基因更严峻的健康风险,在临床卫生领域受到广泛关注,但目前对其在环境中的行为和风险研究很少.为此,考察了2种有代表性的新型抗性基因MCR-1和NDM-1的污染特征,并借助荧光定量PCR探索了长江下游（南京段）及附近污水厂和自来水厂中MCR-1和NDM-1的分布特征,进而采用RDA（冗余性分析）评价了分布特征受水质指标的影响效果.结果表明:①污水厂进水中MCR-1和NDM-1绝对丰度较高,且随处理流程呈下降趋势,总去除率分别为92.5%和92.7%,但出水中MCR-1和NDM-1绝对丰度仍分别达2.5×108和7.0×106 copies/L.②长江下游（南京段）各采样点MCR-1和NDM-1绝对丰度的范围分别为8.5×107~3.5×109和4.3×105~2.1×107 copies/L,随水流方向呈降低趋势,但在个别采样点出现异常升高的情况,主要受该区域人为污染的影响.③自来水厂处理工艺对MCR-1和NDM-1去除率分别为75.0%和70.6%,但出水中存留的MCR-1和NDM-1绝对丰度分别达1.4×107和6.3×104 copies/L,且MCR-1和NDM-1在排泥水中大量富集.④MCR-1绝对丰度与ρ（COD_Cr）、ρ（NH₃-N）、电导率呈正相关,而NDM-1绝对丰度仅和浊度存在弱相关关系,与其他水质指标无明显相关性.研究显示,污水处理工艺无法有效去除MCR-1和NDM-1,大量抗性基因通过污水厂出水排入长江,同时自来水厂以含有较高绝对丰度抗性基因的长江水作为水源水,最终自来水厂出水中残存的抗性基因可能进入人体,生态健康风险较大.      

组合压气机中尾迹与势流同频/异频干涉的叠加特性

为揭示多级压气机中上下游叶轮对中间叶片叠加气动影响特性,阐述不同叠加干涉情况下下游叶轮进气角度变化,采用数值方法模拟了一级轴流和一级离心组成的组合压气机非定常流场。详细讨论了上游动叶尾迹和下游动叶势流对中间导流叶栅段气流非定常流动的异频和同频叠加干涉特性,依据计算结果,直观地展示了静叶通道中两种干涉间相互激励和抑制作用的位置和时间,与数学公式的推导结果相互印证。研究结果表明:当上下游动叶对中间静叶段异频干涉时,干涉的激励、抑制区域的轴向位置随时间发生变化;当上下游动叶对中间静叶干涉频率相同时,干涉的相互激励、抑制区域的轴向位置不随时间发生变化,但干涉的激励、抑制区域的轴向位置受时序位置影响。另外,上游动叶尾迹与下游离心叶轮势流的不同叠加情况,决定着下游离心叶轮进口相对气流角的大小及波动幅值。      

城市道路交通噪声评价方法研究进展

在分析城市道路交通噪声现状的主要危害的基础上，较全面介绍了国内外城市道路交通噪声评价方法的最新进展。继而分析了评价方面存在的问题，并讨论了这一环境声学领域未来发展方向。     

国家重点生态功能区转移支付的政策演进、激励约束与效果分析

国家重点生态功能区转移支付是我国乃至全球最大的政府生态补偿项目。本文系统梳理了其形成过程、体制安排以及历年的政策变化,对政策演进、政策力度、激励约束与政策效果进行分析。研究发现,历次的政策调整从政策目标上增强了"生态文明建设""生态环境保护"导向,丰富了监测与考核的指标体系,并引入资金使用的绩效考核,有利于加强对资金用途和使用效率的监督和引导。但作为均衡性转移支付,该项资金的分配方法与生态环境保护的关联性较弱,资金在改善生态环境质量上的效果有赖于更强的激励约束机制。建议加大激励资金数量和考核制度的作用,动态完善监测和考核指标体系,并对政策效果开展全面和严谨的评估。     

履约对我国典型城市和偏远背景地区气态单质汞浓度和源区的影响研究

为了解我国城市和背景地区最新的气态单质汞（gaseous elemental mercury,GEM）水平,比较《关于汞的水俣公约》履约前后这些地区GEM来源和迁移规律的差异,本研究选择了1个城市监测站（淀山湖站）和1个背景监测站（哀牢山站）,于2021年分别进行了为期1个月的GEM监测,同时使用潜在源贡献因子计算分析两地GEM的来源,并与履约前的结果进行比对。位于长三角地区的淀山湖站GEM浓度降幅大于位于我国西南的哀牢山站GEM浓度降幅,表明针对我国工业排放源超低排放的改造,获得了显著的履约成效。相对履约前,两地GEM的可能源区和传输形式没有显著改变,人为源排放仍然是影响两地GEM浓度的主要因素。本研究结果表明随着履约工作的逐步推进,我国城市和背景地区的GEM仍有下降的可能,长期在这些站点开展大气汞监测,可以为汞履约成效评估提供有效的数据支撑。     

聚乙烯醇-海藻酸钠固定铜绿微囊藻对磷的吸附

利用聚乙烯醇与海藻酸钠固定包埋铜绿微囊藻,通过正交实验获得聚乙烯醇溶液浓度、海藻酸钠溶液浓度及铜绿微囊藻液量去除磷的最佳配比,研究溶液起始pH值、反应时间、磷初始浓度对固定化小球吸附磷的影响。结果表明,固定化小球的最佳制备条件为聚乙烯醇质量分数6%,海藻酸钠质量分数0.5%及铜绿微囊藻浓度2×107个/mL;固定化小球吸附磷的最适起始pH值为6～8,吸附达到平衡的时间为9～12 d,初始磷浓度为1.00 mg/L时去除率最高,达到79.19%。     

爆破工程安全监理探讨

爆破工程实施安全监理有利于规范参与各方的建设行为,最大限度地避免不当建设行为发生;有利于促使爆破设计和施工计划更趋标准化、程序化. 结合爆破工程自身特点,对实施爆破安全监理的策略做了一些探讨.     

Nitrification performance of high rate nitrifying trickling filters at low ammonia concentrations: does the aspect ratio matter?

Environmental Science and Pollution Research - Nitrifying trickling filters (NTFs) are often introduced to pre-treat waters before chlorination process, to reduce the ammonia-driven chlorine...     

Practitioner and scientist perceptions of successful amphibian conservation

Conservation requires successful outcomes. However, success is perceived in many different ways depending on the desired outcome. Through a questionnaire survey, we examined perceptions of success among 355 scientists and practitioners working on amphibian conservation from over 150 organizations in more than 50 countries. We also sought to identify how different types of conservation actions and respondent experience and background influenced perceptions. Respondents identified 4 types of success: species and habitat improvements (84% of respondents); effective program management (36%); outreach initiatives such as education and public engagement (25%); and the application of science‐based conservation (15%). The most significant factor influencing overall perceived success was reducing threats. Capacity building was rated least important. Perceptions were influenced by experience, professional affiliation, involvement in conservation practice, and country of residence. More experienced practitioners associated success with improvements to species and habitats and less so with education and engagement initiatives. Although science‐based conservation was rated as important, this factor declined in importance as the number of programs a respondent participated in increased, particularly among those from less economically developed countries. The ultimate measure of conservation success—population recovery—may be difficult to measure in many amphibians; difficult to relate to the conservation actions intended to drive it; and difficult to achieve within conventional funding time frames. The relaunched Amphibian Conservation Action Plan provides a framework for capturing lower level processes and outcomes, identifying gaps, and measuring progress.