贫营养和痕量抗生素对质粒抗生素抗性适应度代价的影响

本文针对饮用水系统中营养和抗生素水平对质粒抗生素抗性的适应度代价进行了研究.选取了p ACYC184、RP4和PBR322这3种不同的抗性质粒,发现在不同的营养水平下,抗性质粒的适应度代价具有普遍性.而且,营养水平越低,其适应度代价表现得越明显.另外,痕量浓度的抗生素也会影响抗性质粒的适应度代价.本研究中,小于50%MIC的抗生素浓度对野生菌的损伤或抑制作用不足以抗衡抗性质粒的适应度代价,质粒难以维持.因而,推断在饮用水系统(贫营养和ng·L-1水平的抗生素)中,质粒抗生素抗性的适应度代价较大,质粒不易维持,在饮用水系统中传播和扩散的风险较小.     

嘉兴市春节期间烟花爆竹燃放对大气污染物分布特征的影响

为研究春节期间烟花爆竹的燃放对嘉兴市空气质量的影响,利用2015年春节期间嘉兴市3个监测站点的常规污染物(PM10、PM2.5、SO_2、NO_2、CO)和南湖区残联站的有机碳(OC)和元素碳(EC)数据,分析了烟花爆竹对嘉兴市不同功能区和不同空气质量条件下大气污染物的污染特征的影响.结果表明:春节烟花爆竹燃放显著影响PM10和PM2.5的浓度,残联站、清河小学和北部站在23日00∶00达最高值,PM10浓度分别为190、263和147μg·m~(-3),是非春节期间的2.2、2.8和2.1倍,PM2.5浓度分别高达156、158和78μg·m~(-3),是非春节期间的2.6、2.2和2.2倍.烟花爆竹燃放对污染气体的影响存在差异,对CO和SO_2的浓度影响较大,对NO_2和O_3的浓度影响较小.烟花爆竹燃放对嘉兴市老城区大气污染物的影响最大,其次是新城区,对工业区影响最小.污染源减排对大气污染物的影响比较大,2013—2015年嘉兴市春节期间大气污染物浓度(PM10、PM2.5、SO_2、NO_2、CO)整体要低于非春节期间,平均降幅在6.8%~46.1%之间.二次生成物O_3在春节期间的浓度均要高于非春节期间,增幅为20.1%~22.1%.不同空气质量条件下烟花爆竹的燃放对大气污染物的影响不同.     

颗粒污泥厌氧氨氧化动力学特性及微量NO2的影响

采用批试验方法,研究了颗粒污泥厌氧氨氧化动力学特性及微量NO₂的影响.用Haldane模型描述厌氧氨氧化反应动力学,得到最大氨氮反应速率6.65×10^-3 mg·(mg·h)^-1、氨氮半饱和常数87.1 mg·L^-1和抑制常数1 123 mg·L^-1,亚硝态氮半饱和常数15.39 mg·L^-1和抑制常数159.5 mg·L^-1.微量NO₂对厌氧氨氧化具有强化作用,基于Haldane模型建立了厌氧氨氧化的NO₂强化函数,估计了强化函数中的最大强化系数48.79、NO₂半饱和常数2 480 mg·m^-3、NO₂抑制常数4.22 mg·m^-3和基础速率系数0.018 2.试验中大部分的NO_x出现损失.     

中国西南乌江流域石灰土中微量金属的富集

为了解石灰土中微量金属的富集特征、机理及供给能力,本文以乌江流域9条石灰岩风化剖面为对象,运用R型聚类分析和质量平衡计算方法,研究了石灰岩风化过程中V、Co、Ni和Zn的富集问题,并获得了以下认识:(1)本区石灰土中V、Co、Ni和Zn的富集程度与其它地区的石灰土相当(甚至更高),高于上陆壳(UCC)、中国土壤(CS)和世界土壤(WS);(2)V、Co和Zn在石灰土中的富集主要与铁氧化物/氢氧化物等的吸附或共沉淀产生的淀积富集有关,而Ni的富集则主要与铝硅酸盐黏土矿物吸附和其它更易溶元素强烈迁出引起的弱残留富集有关。     

贵州主要城市PM2.5的氧化性损伤评价

对贵州省主要城市(贵阳、安顺、遵义、都匀)按季节进行PM_2.5样品的采集,应用质粒DNA评价法研究了贵州省主要城市PM_2.5氧化性损伤能力,并与PM_2.5质量浓度、微量元素含量做相关性分析。结果表明,PM_2.5全样TD₂₀值均小于其相应的水溶样TD₂₀值;四个城市PM_2.5氧化性损伤能力均表现为冬季>秋季>春、夏季;城区PM_2.5氧化性损伤能力强于背景区;研究区内PM_2.5样品的氧化性损伤能力表现为都匀市最强,安顺市最弱;PM_2.5全样和水溶样的TD₂₀值与质量浓度之间无明显相关关系;PM_2.5水溶样的TD₂₀值与相应的12种微量元素的浓度总和呈负相关关系(P<0.05);全样Al、Mn、Cd、Pb的含量与PM_2.5全样TD₂₀值呈明显负相关关系,水溶样Cd、Pb、Cu的含量与PM_2.5水溶样TD₂₀值呈明显负相关关系,表明研究区PM_2.5氧化性损伤可能与样品中水溶性元素Cd、Pb、Cu等的含量有关。     

微量元素对白腐真菌的生长影响和抑制酵母菌效果的研究

采用振荡培养方式研究了微量元素对白腐真菌生长以及在非灭菌环境下对液体培养基抑制酵母菌的影响,结果表明,在灭菌环境培养方式下投加含有铁元素的微量元素液体培养基培养的菌丝球大小和数量均优于不含铁但含有其它微量元素液体培养基,而不含铁的液体培养基又优于不投加任何微量元素液体培养基;如果采用灭菌环境培养后在非灭菌环境降解染料方式,则不含微量元素和含其它微量元素但不含铁的液体培养基培养的白腐真菌在非灭菌环境对染料的脱色效果与灭菌环境得到的结果基本相当,而铁浓度为3.5 mg/L液体培养基培养的白腐真菌的脱色效果不如灭菌环境得到的结果,并且镜检发现铁浓度为3.5 mg/L液体培养基中感染的酵母菌的量要多于不含铁元素液体培养基和不投加任何微量元素培养体系.微量元素铁在抑制酵母菌生长方面具有很重要的作用,同时铁元素又是白腐真菌生长所必需的,只要在不影响白腐真菌生长的前提下,合理调控培养基中的铁浓度,就有可能达到抑制酵母菌的目的.     

Geochemical index of trace metals in the surficial sediments from the western continental shelf of India, Arabian Sea

The present study focuses on the determination and abundance of trace metals (viz. Cu, Ni, Zn, Cr, Co, Cd, Mn and Fe) in the surficial sediments of west coast of Arabian Sea along the Indian subcontinent. Sediment samples were collected from three transects along the western continental shelf of Arabian Sea. The enrichment of Fe and Mn in coastal oxic-sediments indicates the precipitation of these redox sensitive elements as Fe- and Mn-hydroxides and oxides, whereas the low Fe and Mn concentrations in the oxygen deficient sediments of deeper stations reflects the dissolution of their hydroxides and oxides. Concentrations of fairly redox insensitive trace metals like Cu, Ni, Zn, Cr and Cd (with the exceptions of Cr) showed higher values at nearshore sediments, then it decreased towards seaward and again showed a slight increase at oxygen minimum stations in all the three transects. This geochemical variability in their distributional characteristics is mainly associated with the extent to which the precipitation or dissolution of Fe- and Mn-oxides/hydroxides occur since the scavenging or releasing effects of Fe- and Mn-oxides/hydroxides act as significant ‘sinks’ or ‘sources’ of heavy metals. The change in wind pattern, coastal upwelling and increased productivity are also the reported factors which influence the biogeochemical cycling of trace metals in the surface sediments of west coast of India. Enrichment factor generally showed a high gradient accumulation from nearshore to shelf.     

Enhancing Diatom Growth by Using Zeolites to Change Seawater Composition (4 pp)

- Aims and Scope. The purpose of this study was to test whether two zeolites produced synthetically (products of zeolitic nature, PZN) could influence either the yield of a diatom culture or the chemical changes in the cultures. For this purpose, Phaeodactylum tricornutum was used as test organism in a culture medium of natural seawater enriched with N and P having negligible amounts of ammonia. Methods The PZN ZEBEN-06 and ZESTEC-56 were used in parallel experiments. The composition of trace metals and organic compounds with chelate activity in the culture media, were determined by anodic or cathodic stripping voltammetry. The impact of leaching silicon on the algal yield was evaluated by comparing the growth in the presence or absence of PZN, in seawater enriched or not-enriched with silicon. Results and Conclusions Both PZN significantly promoted the algal yield even in the absence of added silicon, a limiting nutrient for diatom growth. The PZN acted as a silicon buffer while providing a source of silicon required for growth. In addition, PZN released into the seawater small but significant amounts of the limiting micro-nutrient manganese (its concentration doubled during the experiments), while simultaneously removing relatively high quantities of zinc from the seawater. The presence of PZN inhibited the releasing of chelated compounds. These changes (sorption/desorption) caused by the PZN in the concentrations in the solutions used as culture media of P. tricornutum were probably responsible for the differences in both the diatom and exudation observed in the tested cultures.     

韩城燎原矿11#煤中微量元素的分布规律和赋存状态

通过对韩城燎原矿的11^#煤不同深度的煤样中的微量元素P、U、Ge和Ga进行分析,发现为11^#煤低磷煤;煤中U和Ga的含量均低于地壳中的平均含量,只有Ge含量略高于地壳中的平均含量。计算了这些微量元素与三态硫、灰分和挥发分的相关关系。结果表明Ga在煤中主要以无机态存在。P在煤中可能大部分以有机态存在,小部分以无机态存在。U与Ge在煤中可能主要以有机态存在,以无机态存在的可能性较小。