一种大批量测定沉积物微量间隙水样品中溶解态磷和铁含量的方法

利用384微孔板微量比色分析方法,建立了一种大批量分析微量溶液样品中溶解态反应磷(DRP)和溶解态铁(Ⅱ)含量的方法,确定了方法的最佳参数和条件.利用Epoch微孔板分光光度计,对溶液中磷和铁分别采用磷钼蓝和邻菲啰啉比色法进行分析,所需溶液样品体积(稀释后)为20~50μL,磷和铁的检出限分别为0.006 mg·L-1和0.010 mg·L-1,精密度控制在5%以内.在此基础上,采用高分辨间隙水扩散平衡装置(HR-Peeper,垂向分辨率2 mm)获取了太湖沉积物间隙水样品,利用本方法同步分析了微量间隙水样品中DRP和溶解态铁(Ⅱ)的含量,发现两者含量同步升高的现象.     

两种沉水植物对上覆水和间隙水中可溶性无机氮的影响

在实验室模拟研究沉水植物金鱼藻(Ceratophyllum demersum)、苦草(Vallisneria spiralis L.)对上覆水、间隙水中可溶性无机氮(dissolved inorganic nitrogen,DIN)的浓度、赋存形态及DIN扩散通量的影响.结果表明,金鱼藻和苦草对上覆水中DIN的去除效果均强于间隙水,对各形态DIN的去除差异:NO-2-N>NH+4-N>NO-3-N;金鱼藻对上覆水中DIN的去除效果明显强于苦草,但对间隙水中DIN的去除效果弱于苦草;金鱼藻和苦草减少了NH+4-N和NO-2-N的扩散通量,显著增加了NO-3-N的扩散通量,使NO-3-N取代NH+4-N成为间隙水向上覆水中扩散DIN的主要形态,但对NO-3-N和NH+4-N扩散通量的影响,金鱼藻和苦草之间差异不显著;金鱼藻和苦草增加了上覆水和间隙水中3种形态DIN含量比例的变化幅度,金鱼藻对上覆水中DIN含量比例影响强于苦草,对间隙水中DIN含量比例的影响弱于苦草.总体来讲,金鱼藻对上覆水中DIN形态影响较大,苦草对间隙水中DIN形态影响较大,两者对DIN扩散通量的影响差别不显著.     

实际污水培养好氧颗粒污泥及其特性研究

采用实际城市污水在序批式反应器(SBR)中试装置中成功培养出好氧颗粒污泥.颗粒污泥的沉降速率>21 m·h-1,显示了良好的沉降性能.颗粒污泥对化学需氧量(COD)、氮(N)、磷(P)具有同步去除的能力.在3 h的运行周期中,反应器出水COD<50 mg·L-1,氨氮(NH+4-N)<5.0 mg·L-1,总氮(TN)<15 mg·L-1,对TN和总磷(TP)的去除率达到50%.采用共聚焦激光扫描显微镜(CLSM)对好氧颗粒污泥的结构分析表明,好氧颗粒污泥的胞外多聚物(EPS)在整个颗粒污泥中均匀地分布,构成颗粒污泥的骨架.对颗粒污泥的X射线衍射(XRD)分析显示,在好氧颗粒污泥的内部存在许多无机矿物质,在颗粒污泥形成初期,废水中的无机成分可能具有"晶核"的作用.     

煤矿区地下水中溶解性有机质荧光特征Ⅱ——深部含水层分布特征

为研究霍州矿区深部含水层中溶解性有机质地层差异及其迁移转化机理,通过三维荧光光谱(3 DEEM)、TOC和硝酸盐质量浓度综合分析了溶解性有机质(DOM)的含量和分布特征.结果表明,深部含水层中溶解性有机质和硝酸盐质量浓度均较低,其中TOC(总有机碳)质量浓度小于0.6 mg/L、NO3--N质量浓度小于1.6 mg/L.太灰水和奥灰水中主要出现了Ⅱ区的色氨酸类荧光峰和Ⅳ区的溶解性微生物代谢产物荧光峰,其中色氨酸类荧光峰强度随着地下水流向而逐渐降低,溶解性微生物代谢产物荧光峰强度在李雅庄矿和辛置矿出现了一定异常.生物源指数(BIX)和腐殖化指数(HIX)表明深部含水层中DOM来源于生物或水生细菌,且具有较好的溯源一致性;荧光指数f470/520比f450/500更能说明DOM中腐殖质组分的来源,且f470/520较大(＞2.1),表明深部含水层中DOM来源于生物,且腐殖类物质芳香性较弱,含有的苯环结构较少.太灰水中TOC、色氨酸类荧光峰强度和溶解性微生物代谢产物荧光峰强度均与硝酸盐质量浓度呈负相关,且线性拟合的相关度较高;奥灰水中相关性则较差.     

Unraveling the size distributions of surface properties for purple soil and yellow soil

Soils contain diverse colloidal particles whose properties are pertinent to ecological and human health, whereas few investigations systematically analyze the surface properties of these particles. The objective of this study was to elucidate the surface properties of particles within targeted size ranges (i.e. > 10, 1–10, 0.5–1, 0.2–0.5 and < 0.2 μm) for a purple soil (Entisol) and a yellow soil (Ultisol) using the combined determination method. The mineralogy of corresponding particle-size fractions was determined by X-ray diffraction. We found that up to 80% of the specific surface area and 85% of the surface charge of the entire soil came from colloidal-sized particles (< 1 μm), and almost half of the specific surface area and surface charge came from the smallest particles (< 0.2 μm). Vermiculite, illite, montmorillonite and mica dominated in the colloidal-sized particles, of which the smallest particles had the highest proportion of vermiculite and montmorillonite. For a given size fraction, the purple soil had a larger specific surface area, stronger electrostatic field, and higher surface charge than the yellow soil due to differences in mineralogy. Likewise, the differences in surface properties among the various particle-size fractions can also be ascribed to mineralogy. Our results indicated that soil surface properties were essentially determined by the colloidal-sized particles, and the < 0.2 μm nanoparticles made the largest contribution to soil properties. The composition of clay minerals within the diverse particle-size fractions could fully explain the size distributions of surface properties.     

Flux characteristics of total dissolved iron and its species during extreme rainfall event in the midstream of the Heilongjiang River

The occurrence of extreme rainfall events and associated flooding has been enhanced due to climate changes, and is thought to influence the flux of total dissolved iron(TDI) in rivers considerably. Since TDI is a controlling factor in primary productivity in marine ecosystems, alteration of riverine TDI input to the ocean may lead to climate change via its effect on biological productivity. During an extreme rainfall event that arose in northeastern China in 2013, water samples were collected in the midstream of the Heilongjiang River to analyze the concentration and species of TDI as well as other basic parameters. The speciation of TDI was surveyed by filtration and ultrafiltration methods.Compared with data monitored from 2007 to 2012, the concentration of TDI increased significantly during this event, with an average concentration of 1.11 mg/L, and the estimated TDI flux reached 1.2 × 105 tons, equaling the average annual TDI flux level.Species analysis revealed that low-molecular-weight complexed iron was the dominant species, and the impulse of TDI flux could probably be attributed to the hydrological connection to riparian wetlands and iron-rich terrestrial runoff. Moreover, dissolved organic matter played a key role in the flux, species and bioavailability of TDI. In addition,there is a possibility that the rising TDI flux could further influence the transport and cycling of nutrients and related ecological processes in the river, estuary coupled with the coastal ecosystems, which merits closer attention in the future.     

复合污染体系中溶解性有机质对雌二醇降解的影响

针对天然水体常见的重金属-有机污染物复合污染问题,探讨水体中普遍存在的溶解性有机质(DOM)对有机污染物降解的影响.采集黄河花园口断面水样,模拟天然水体中DOM质量浓度变化,研究了17β-雌二醇(E2)单一污染体系和Cu(Ⅱ)-E2复合污染体系中DOM对E2降解的影响,用环境扫描电镜、傅里叶变换红外光谱和X射线光电子能谱等手段分析了Cu(Ⅱ)-E2复合污染体系中DOM与Cu(Ⅱ)的作用机理.结果表明:在E2单一污染体系中,DOM明显促进E2降解,E2降解速率常数由0.062 d-1提高到0.430 d-1;在Cu(Ⅱ)-E2复合污染体系中,DOM与Cu(Ⅱ)络合,改变了Cu(Ⅱ)的沉淀形态,降低了Cu(Ⅱ)对微生物的抑制作用,因此,E2降解速率常数由0.006d-1提高到0.030 d-1.     

多重环境因子对氟胺磺隆在土壤中降解的影响

氟胺磺隆作为普遍使用的一种磺酰脲类除草剂,已经对土壤和作物造成了危害,其环境行为受很多物理化学或生物因素的影响.为探明不同环境因素对氟胺磺隆在土壤中降解程度的影响,通过实验室内模拟培养的方法,研究了土壤微生物、不同土壤类型、水溶性有机物（dissolved organic matter,DOM）、温度、土壤含水量等因素对氟胺磺隆在土壤中降解的影响.结果表明,各种环境因子：温度、湿度、土壤微生物和土壤类型等均在不同程度上影响了氟胺磺隆的土壤降解速率.土壤微生物量、土壤有机质和DOM的增加均有利于氟胺磺隆在土壤中的降解,并且土壤pH的降低,也会促进氟胺磺隆在土壤中的降解.其中,土壤微生物是影响氟胺磺隆土壤降解的主要因素.该研究结果将为一些生物和物理化学因子调节氟胺磺隆在土壤中消散提供初步数据.     

淹水条件下三峡库区典型消落带土壤释放DOM的光谱特征:紫外-可见吸收光谱

消落带土壤在淹水发生时释放溶解性有机质(DOM),是上覆水体DOM的重要来源.但同时对淹水释放DOM进行定量定性分析的报道并不多见.本文以三峡库区典型消落带为研究对象,通过模拟实验,利用紫外-可见吸收光谱,研究了厌氧淹水和正常淹水条件下,淹水土壤释放DOM的光谱特征.结果表明,消落带4个区域土壤淹水均呈"快速释放-下降-动态平衡"释放规律;释放速率和通量计算表明,DOM释放呈现出"源-汇动态交换"特征.对比两种淹水处理,尽管溶解性有机碳(DOC)和有色溶解性有机质(CDOM)无显著差异,但厌氧淹水DOM芳香性(SUVA280)高于正常淹水,而光谱斜率比值(SR)对不同淹水条件不敏感.同时,厌氧淹水时,DOC和CDOM的相关性也明显高于正常淹水.另外,各区域土壤淹水释放DOM存在差异,以忠县石宝寨土壤释放强度最高,尽管土壤有机质含量是影响各区域土壤淹水释放DOM差异的重要原因之一,但其他地化因素仍需考虑.因此,仅仅关注DOC浓度变化并不足以完全描述DOM的释放特征.     

闽江口短叶茳芏+芦苇沼泽湿地大、小潮日土壤间隙水溶解性CH4与CO2浓度日动态

研究河口感潮沼泽湿地土壤间隙水溶解性CO_2和CH_4浓度日动态对于揭示河口湿地碳循环过程具有重要作用.于2010年的4月4~5日和9月2~3日(小潮日)和4月14~15日和9月9~10日(大潮日),对闽江河口鳝鱼滩中部中高潮滩过渡区分布的短叶茳芏(Cyperus malaccensis)+芦苇(Phragmites australis)沼泽湿地的土壤间隙水溶解性CO_2和CH_4浓度进行24 h连续监测,并同步测定了原位土壤温度、电导率及NH+4-N等参数.结果表明:14月与9月大、小潮日土壤间隙水溶解性CH_4浓度日变化范围分别介于88.20~190.74、53.42~141.24、16.27~81.89和44.90~88.53μmol·L~(-1),其中4月大、小潮日土壤间隙水溶解性CH_4浓度均呈现昼低夜高特征(P0.05),而9月大、小潮日呈现相反的日变化趋势(P0.05);29月大、小潮日土壤间隙水溶解性CO_2浓度日变化范围分别介于19.33~40.1μmol·L~(-1)和9.69~29.96μmol·L~(-1),均呈现昼低夜高特征(P0.01);3涨潮期间土壤间隙水溶解性CO_2浓度均要低于涨潮前与落潮后,而涨潮期间土壤间隙水溶解性CH_4浓度高于涨潮前和落潮后.