Phytoavailability and geospeciation of cadmium in contaminated soil remediated by Rhodobacter sphaeroides

A microorganism was isolated from oil field injection water and identified as Rhodobacter sphaeroides. It was used for the remediation of simulated cadmium-contaminated soil. The phytoavailability of Cd was investigated through wheat seedling method to determine the efficiency of remediation. It was found that after remediation, the accumulation of Cd in wheat roots and leaves decreased by 67% and 53%, respectively. The Cd speciation in soil was determined with Tessier extraction procedure. It was found that the total Cd content in soil did not change during the experiments, but the geo-speciation of Cd changed remarkably. Among the five fractions, the concentration of exchangeable phases decreased by 27-46% and that of the phases bound to Fe-Mn oxides increased by 22-44%. The decrease of Cd accumulation in wheat showed significant positive correlation with the decrease of exchangeable phases. It could be concluded that the remediation of R. sphaeroides was carried out through the conversion of Cd to more stable forms. The decrease of sulfate concentration in supernatant indicated that the R. sphaeroides consumed sulfate.     

滇池外海北岸封闭水域控养水葫芦对水质的影响

在滇池外海北岸污染严重的0.25 km2封闭性蓝藻治理试验示范区内控养水葫芦,以削减富营养化水体内源氮(N)、磷(P)等污染物,探讨有效改善湖泊水质的生物治理措施.6月底按9.30 kg m-2投放水葫芦种苗,控养面积2.51hm2,示范区水面覆盖度为10%.结果显示:水葫芦放养后生长迅速,特别是在7-9月份,最大生长速率达37 2.7 g m-2 d-1;整个植株干物质平均N、P含量分别为23.22 g kg-1和5.03 g kg-1,每t鲜重水葫芦吸收1.63 kg N、0.35 kg P,通过水葫芦种养示范工程,直接由示范工程水域吸收带走N 1.15 t、P 0.25 t;水葫芦生长期间(7-12月),种养区较对照区水体DO、SD和p H均有下降;水葫芦根系具有较好的吸附拦截浮游藻类效果,致使种养区水体TN、TP和CODMn浓度显著高于对照区(P<0.05),并与水体Chl-a浓度显著正相关(P<0.05);水葫芦采收后并未引起二次污染,水质无恶化趋势.综上认为,规模化控养水葫芦可显著削减水体N、P等内源污染负荷,同时对浮游藻类吸附拦截效果明显,可将其滞留于特定水域,又能吸收利用藻类衰亡释放到水体的污染物,减轻外部空白水域水质恶化的压力.     

城市煤气化综合效益实例分析

本文以煤气化工程的典型实例分析为基础，通过对气源厂经济效益的分析，提出了以气化替煤量和节煤量两项指标，进行宏观经济效益、社会效益和环境效益的综合效益分析的步骤及相应的计算公式与方法。     

High performance of multi-layered alternating Ni–Fe–P and Co–P films for hydrogen evolution

Judiciously engineering the electrocatalysts is attractive and challenging to exploit materials with high electrocatalytic performance for hydrogen evolution reaction. Herein, we successfully perform the interface engineering by alternately depositing Co–P and Ni–Fe–P films on nickel foam, via facile electroless plating and de-alloying process. This work shows that there is a significant effect of de-alloying process on alloy growth. The electronic structure of layered alloys is improved by interface engineering. The multilayer strategy significantly promotes the charge transfer. Importantly, the Co–P/Ni–Fe–P/NF electrode fabricated by interface engineering exhibits excellent electrocatalytic hydrogen evolution activity with an overpotential of 43.4 mV at 10 mA cm-2 and long-term durability for 72 h in alkaline medium (1 mol L-1 KOH). The innovative strategy of this work may aid further development of commercial electrocatalysts.     

Spatial differentiation of comprehensive suitability of urban human settlements based on GIS: a case study of Liaoning Province,China

Environment, Development and Sustainability - The comprehensive suitability of regional human settlements is of great significance to the development and spatial distribution of regional human...     

水产养殖尾水-农田退水联合净化工艺设计

水产养殖尾水和农田退水是农业面源污染的主要来源之一。本研究基于466 666.7 m²现代农业地块,设计了一套水产养殖尾水和农田退水联合净化工艺,主要包括生态净化沟渠模块、农田净化模块以及景观湿地林模块。其中,生态净化沟渠旨在充分利用小型河道排水系统控制N、P等污染物浓度,包括生态集水预处理沟、悬浮生态床沟、生态输水廊道及调节稳定生态沟。结合水产养殖尾水和农田退水水质特点,设计出水水质目标为化学需氧量(COD)≤40 mg·L⁻¹、总氮(TN)≤3 mg·L⁻¹、总磷(TP)≤0.5 mg·L⁻¹。经一年跟踪监测,出水水质达到设计目标,此外,除TN指标,COD和TP均有8个月能够满足《地表水环境质量标准》(GB 3838-2002)III类水质要求。工程实施后,地块在保留原有生产功能的基础上兼具了水质净化及景观风貌功能。本工艺设计理念及工程实践可为其他农村地区农业面源污染控制,尤其是养殖尾水-农田退水联合净化提供借鉴。     

“FPSO+CTV+普通油轮”外输作业模式风险分析

“浮式生产系统(FPSO)+原油转驳船(CTV)+普通油轮”外输作业新模式存在双重的碰撞和泄漏风险,为克服现有研究仅将事故视为单个事件的有序发生或潜在因素的层级叠加等问题,提出一种基于功能共振事故模型(FRAM)的CTV卸油模式风险分析方法。首先,基于FRAM的一般性能条件,识别导致CTV卸油事故发生的人员、技术和组织因素;其次,评价功能性能变化,用以确定关键作业环节和事故演化过程;然后,制定性能波动的防控屏障来预防事故发生。研究结果表明:CTV卸油作业存在25类风险因素和2个关键作业环节,且操作人员的综合素质、CTV的靠泊技术、CTV与FPSO间的沟通效果等是诱导事故发生的关键因素。     

滨海滩涂土地利用变化对土壤生物可利用磷的影响

为探明滨海滩涂土地利用变化对土壤生物可利用磷（BAP）的影响,分析了滩涂由原生盐沼湿地转变为农田过程中土壤总磷（TP）、无机磷（IP）、有机磷（OP）及部分BAP （速效磷（Olsen-P）、M3提取态有效磷（M3-P）、水溶性磷（WSP）及松散结合磷（Lo-P））含量、分布的变化.结果表明,滩涂由原生盐沼湿地转变为农田后,土壤TP、IP和OP含量均显著升高（分别升高19%、12%、55%）,IP/TP显著降低,OP/TP、OP/IP显著升高,OP累积速率明显高于TP和IP.转变为农田后,滩涂土壤BAP含量和赋存比例均显著升高,Olsen-P、M3-P、WSP和Lo-P含量分别提高282%、379%、275%、192%,赋存比例则分别提高205%、267%、217%、142%,BAP提高幅度远高于TP、IP和OP;各BAP与TP、IP、有机碳（TOC）均呈显著正相关,而与盐度（EC）呈显著负相关.研究结果显示,滨海滩涂由原生盐沼湿地转变为农田的土地利用变化将极大提高土壤生物可利用磷水平,其环境影响值得关注.     

硫化汞纳米颗粒的微生物摄入及其在汞甲基化中的作用

甲基汞因其独特的食物链富集特性和毒性使汞成为重要的全球污染物.厌氧环境中微生物介导的汞甲基化是甲基汞生成最主要的来源,厌氧环境中不同汞地球化学形态控制着甲基汞的生成过程.硫化汞纳米颗粒是在实际厌氧环境中新近发现的重要颗粒汞形态,对其环境行为还缺乏基本认识.本文基于硫化汞纳米颗粒的环境行为,重点围绕其与微生物的相互作用,讨论并总结了硫化汞纳米颗粒的生成、硫化汞纳米颗粒的微生物摄入、溶解以及硫化汞纳米颗粒对微生物汞甲基化的影响,并进一步对硫化汞纳米颗粒与微生物相互作用的未来研究重点进行了展望.