碳基表面吸附铅的机理

建立了表征飞灰的碳基表面模型,应用量子化学密度泛函理论B3PW91方法,研究了碳基表面对铅的吸附机理。计算得到了单质铅和氯原子在碳基表面的吸附构型和吸附能,并得出Cl相比铅更易于吸附在碳基表面。为研究Cl对碳基吸附铅的影响机理,计算得到了单质铅在含氯碳基表面的吸附构型和吸附能。结果显示,Cl能够显著增强邻近活性位的吸附活性,从而显著增强铅在碳基表面的吸附效果。最后讨论了温度对含氯碳基表面吸附铅的影响。     

Knowledge transfer initiative between molecular biologists and environmental researchers and regulators

A Natural Environment Research Council (NERC) funded Knowledge Transfer (KT) workshop was held in the United Kingdom (UK) to identify the needs and opportunities in the application of molecular biology and ‘omics’ techniques to environmental monitoring and risk assessment. Attendees highlighted a lack of effective communication between end-users and researchers as well as difficulties with data interpretation as reasons behind the slow uptake of molecular biology and omics techniques. A number of promising areas in which new techniques could be implemented at a practical level in the very near future were identified, thereby raising the profile of these recent technologies and providing vital proof of concept work. Molecular taxonomy, bacterial source tracking and pre-screening of chemicals for potential toxicities were all viewed as areas in which omics and molecular techniques could have immediate value, with the aim of reducing cost, increasing efficiency and providing more comprehensive data of improved quality.     

基于功能基因表达的高氯酸盐与硝酸盐氮修复

为更好地研究环境中高氯酸盐离子(ClO-4)与硝酸盐氮(NO-3-N)混合污染的共同降解。选用pcrA、cld基因表征参与高氯酸盐降解的细菌,NirS基因表征反硝化细菌,16S rRNA基因表征整个细菌群落的活性。通过对高浓度硝酸盐氮与高氯酸盐混合污染降解体系内不同时间点不同种基因的表达分析,实时定量的反应复杂环境中混合污染物生物降解机理。结果表明,在外源添加足够的醋酸盐作为电子供体条件下,NO-3-N与ClO-4质量浓度比为5∶1时,硝酸盐氮的存在不会完全抑制ClO-4的降解,当NO-3-N降解完全时,可以加快ClO-4的降解过程。在有硝酸盐氮存在的混合降解体系内,pcrA和cld基因与ClO-4的浓度变化之间的相关性不是很高,证明该功能基因对复杂环境中特定生物群落的表征有一定局限性。     

鞍山市空气颗粒物中酞酸酯的季节变化与功能区差异

采用气相色谱-质谱仪(GC-MS)对辽宁省鞍山市空气颗粒物中15种酞酸酯夏季和冬季的浓度进行了分析测定,研究了酞酸酯污染水平的季节变化,不同功能区酞酸酯浓度的差异,以及DBP和DEHP在夏冬两季中的污染特点,将鞍山市夏冬两季酞酸酯的浓度与国内外部分城市进行了比较,分析了产生上述结果的原因,基本说明了鞍山市空气颗粒物中酞酸酯的污染状况。     

盐龙湖水源生态净化系统FG和MBFG演替特征及水质响应性评价

为探究水源生态净化系统水质净化及浮游植物控制效能,并评价FG(functional group,FG)和MBFG(morphology-based functional group,MBFG)两种功能群对水源生态净化系统内部环境以及水质响应的有效性,于2018年夏季对盐龙湖生态净化系统各单元出水水质和浮游植物功能群进行监测分析.结果表明,盐龙湖生态净化系统能够有效净化水质,进水总磷、总氮、溶解氧和浊度的平均值分别为0.20 mg·L^-1、 1.91 mg·L^-1、 2.88 mg·L^-1和60.23 NTU,经系统处理后分别为0. 09 mg·L^-1、 0.95 mg·L^-1、 6.26 mg·L^-1和39.53 NTU.同时,系统内部水质的空间分布具有异质性,其中溶解氧(DO)、酸碱度(pH)和浊度的空间差异显著(P<0.001).盐龙湖生态净化系统在出水处于轻度富营养状态下仍能够有效控制浮游植物密度(4.42×10⁵～4.3...     

三氯生及其降解中间产物对活性污泥中微生物群落变化和硝化反硝化功能基因的影响

三氯生（TCS）对活性污泥中氮循环和微生物群落的长期影响尚不清楚.在长期运行185 d的序批式反应器（SBR）进水中添加100 g·L^-1的TCS,探讨了TCS在活性污泥中的转化特性及其对活性污泥的生长、硝化反硝化性能及关键氮代谢功能基因和微生物群落结构的影响.添加TCS的反应器中硝酸盐浓度为3.80～9.11 mg·L^-1,略低于不添加TCS的空白组(6.66～9.72 mg·L^-1),说明其硝化作用被减弱.随着驯化时间的延长,硝化作用逐渐恢复. TCS在活性污泥迁移转化过程中总共检测出12种代谢中间产物,推导出4种迁移转化路径.添加TCS后,对TCS有潜在降解效能的细菌的相对丰度明显增加,如：Flavobacteriales和Myxococcales目,分别为2.95%～9.07%（第0～185 d）和2.01%～4.53%（第0～90 d）.与硝化作用有关的菌属,如：Nitrosovibrio、Nitrosomonas（氨氧化菌,AOB）和Nitrospira（亚硝酸盐氧化菌,NOB）的相对丰度急剧减少,分别为0....     

玉米根际微生物氮磷转化的功能基因组学分析

化肥减量增效是保障农业生态环境安全的重要基础.微生物是调控土壤氮磷循环的关键驱动力,研究根际微生物氮磷转化功能可以为进一步提高土壤氮磷利用率提供微生物学调控途径.基于3种典型农田土壤（黑土、潮土和红壤）的田间微区试验,利用宏基因组测序技术研究玉米根际微生物在土壤氮磷转化过程中功能基因的差异及调控因子.结果表明,根际微生物功能多样性受土壤类型影响,黑土和潮土的根际微生物功能多样性主要受含水量和养分含量的影响,红壤受全磷（TP）和速效磷（AP）影响.在土壤氮转化方面,编码氮转化过程通路中相关酶的基因丰度以脲酶基因（ureC）和葡萄糖脱氢酶基因（gdh）丰度最高,分别为7.25×10^-5~12.88×10^-5和4.47×10^-5~7.49×10^-5.同化性硝酸盐还原的功能基因在红壤中总丰度要高于黑土和潮土,其它过程相关酶的功能基因总丰度以潮土最高.编码氮代谢过程相关酶的功能基因丰度主要受土壤细菌丰富度、全钾（TK）和TP含量的驱动.在土壤磷转化方面,催化有机磷矿化的碱性磷酸酶基因（phoD）数目为1093个,酸性磷酸酶基因（PHO）数目为42个.phoD丰度高出PHO丰度2个数量级,此外,同种土壤类型下施肥对phoD和PHO丰度没有显著影响.随机森林分析表明phoD和PHO丰度均受土壤水分、有机质（OM）和全氮（TN）显著影响,但AP含量对PHO丰度影响最大.从功能基因组水平研究了玉米根际微生物的氮磷转化特征,为利用微生物功能提高农田生态系统氮磷利用率提供了科学依据.     

找准定位 科学布局 抓住关键 确保环境监测改革取得扎实成效

环境监测是生态文明建设和环境保护的重要基础。目前,环境监测改革已经进入关键阶段。研究在梳理环境监测基本定位的基础上,分析了各项改革的系统性、协同性,提出要理顺各级监测事权与支出责任,化解地方干预,优化环境监测发展的总体布局,加强环境质量监测和执法监测,建设独立、公正、权威、高效的生态环境监测体系,确保改革取得扎实成效。     

植被类型对黄土高原露采矿山复垦土壤碳循环功能基因的影响

植被恢复可有效地改善矿区生态环境,提升生态服务功能,促进生态系统固碳增汇.但目前矿区植被恢复影响土壤碳循环相关功能基因的机制尚缺乏深入研究.为此,采集黄土高原黑岱沟露天矿排土场复垦区草地(GL)、灌丛(BL)、针叶林(CF)、阔叶林(BF)和针阔混交林(MF)共25个表层土壤样品,利用实时荧光定量PCR技术测定土壤碳循环功能基因绝对丰度,探究不同植被类型对土壤碳循环相关功能基因的影响及内在机制.结果表明：(1)不同植被类型对矿区复垦土壤化学性质和碳循环相关功能基因丰度影响差异显著(P<0.05),GL和BL对土壤有机碳、全氮和硝态氮的积累显著优于CF(P<0.05);(2)所有碳固定基因中rbcL、acsA和mct的丰度最高,BF土壤中碳循环相关功能基因丰度高于其它类型,与BF土壤中的铵态氮和BG酶活性较高及易氧化有机碳和脲酶活性较低密切相关.碳降解和甲烷代谢功能基因丰度与铵态氮和BG酶活性呈显著的正相关,与有机碳、全氮、易氧化有机碳、硝态氮和脲酶活性呈显著的负相关(P<0.05);(3)不同植被可直接影响土壤BG酶活性或影响土壤硝态氮含量从而间接作用于BG酶活性,从...     

Cytotoxicity and autophagy induction by graphene quantum dots with different functional groups

Graphene quantum dots(GQDs) possess great potential in various applications due to their superior physicochemical properties and wide array of available surface modifications.However, the toxicity of GQDs has not been systematically assessed, thus hindered their further development; especially, the risk of surface modifications of GQDs is largely unknown. In this study, we employed a lung carcinoma A549 cells as the model to investigate the cytotoxicity and autophagy induction of three types GQDs, including cGQDs(COOH-GQDs), hGQDs(OH-GQDs), and aGQDs(NH_2-GQDs). The results showed hGQDs was the most toxic, as significant cell death was induced at the concentration of 100 μg/mL,determining by WST-1 assay as well as Annexin-V-FITC/PI apoptosis analysis, whereas cGQDs and aGQDs were non-cytotoxic within the measured concentration. Autophagy detection was performed by TEM examination, LC3 fluorescence tracking, and Westernblot. Both aGQDs and hGQDs induced cellular autophagy to various degrees except for cGQDs. Further analysis on autophagy pathways indicated all GQDs significantly activated p-p38 MAPK; p-ERK1/2 was inhibited by aGQDs and hGQDs but activated by c GQDs. p-JNK was inhibited by aGQDs and c GQDs, while activated by hGQDs. Simultaneously, Akt was activated by hGQDs but inhibited by aGQDs. Inhibition of autophagy by 3-MA significantly increased the cytotoxicity of GQDs, suggesting that autophagy played a protective role against the toxicity of GQDs. In conclusion, c GQDs showed excellent biocompatibility and may be considered for biological applications. Autophagy induction may be included in the health risk assessment of GQDs as it reflects the stress status which may eventually lead to diseases.