河流沉积物中微生物DNA的提取方法比较研究

提取河流沉积物中DNA是研究河流沉积物微生物多样性的难点之一,实验开发了一种酚与SDS的DNA提取方法,与OMEGA和BioDee 2种DNA提取试剂盒方法进行了比较,并通过DNA纯度、PCR扩增结合16S rDNA克隆文库检验对几种方法进行了评价.结果表明,OMEGA DNA提取试剂盒法方法简单,提取的DNA纯度较高...     

钙镁离子及重碳酸盐对零价铁还原对氯硝基苯的影响

通过间歇式实验,考察了地下水中常见硬度离子Ca2＋、Mg2＋及HCO3-的独立作用和联合作用对零价铁还原对氯硝基苯的影响。实验结果表明,Ca2＋、Mg2＋对零价铁还原对氯硝基苯反应的促进作用不明显。HCO3-浓度为0～100mg/L时可显著提高零价铁还原对氯硝基苯的速率,反应2 h后对氯硝基苯转化率由44.1%升至84...     

Residual congener pattern of dioxins in human breast milk in southern Vietnam

This study evaluated residual congener patterns of dioxin/furan (=PCDD/DF) related to tactical herbicides aerially sprayed over the regions of southern Vietnam through Operation Ranch Hand. The study focused on Cam Chinh (CC) commune, Quang Tri province (an area sprayed with tactical herbicides), and the Cam Phuc (CP) commune, Ha Tinh province (a non-sprayed area). Breast milk samples for analysis were collected in September 2002 and July 2003 from lactating primiparous and multiparous mothers born after the war (<31 years old). We found the levels of each congener in the CC commune were higher than in the CP commune, and determined specificity in the PCDD/DF congener pattern in CC commune samples by cluster analysis. The congener pattern is characterized by higher (the hexa-, the hepta-, and the octa-) chlorinated PCDD/DFs; this appears to be the same profile as that presented by pentachlorophenol (PCP), rather than 2,4,5-trichlorophenoxy acid (2,4,5-T) contaminated with 2,3,7,8-TCDD. A GC/MS study in the 1970s detected the chlorophenols 2,4-di and 2,4,6-trichlorophenol in some Agent Orange samples, which contained, like PCP, a wide variety of PCDD/DF congeners. In this context, it may be expected that certain tactical herbicides contaminated with various chlorophenol impurities, have a unique congener pattern when compared with pure 2,4,5-T formulations.     

Development of an analytical strategy based on liquid chromatography-high resolution mass spectrometry for measuring perfluorinated compounds in human breast milk: application to the generation of preliminary data regarding perinatal exposure in France

Perfluorinated compounds (PFCs) are man-made chemicals for which endocrine disrupting properties and related possible side effects on human health have been reported, particularly in the case of an exposure during the early stages of development, (notably the perinatal period). Existing analytical methods dedicated to PFCs monitoring in food and/or human fluids are currently based on liquid chromatography coupled to tandem mass spectrometry, and were recently demonstrated to present some limitations in terms of sensitivity and/or specificity. An alternative strategy dedicated to the analysis of fourteen PFCs in human breast milk was proposed, based on an effective sample preparation followed by a liquid chromatography coupled to high resolution mass spectrometry measurement (LC-HRMS). This methodology confirmed the high interest for HRMS after negative ionization for such halogenated substances, and finally permitted to reach detection limits around the pg mL(-1) range with an outstanding signal specificity compared to LC-MS/MS. The proposed method was applied to a first set of 30 breast milk samples from French women. The main PFCs detected in all these samples were PFOS and PFOA with respective median values of 74 (range from 24 to 171) and 57 (range from 18 to 102) pg mL(-1), respectively. These exposure data appeared in the same range as other reported values for European countries.     

A follow up of the decrease of non exchangeable organically bound tritium levels in the surroundings of a nuclear research center

In the past decades limited amounts of tritium were handled on the CEA site of Bruyères le Châtel with authorised atmospheric releases. A small fraction of the tritium released entered into environmental samples under three forms: (i) as part of free water (TFWT - Tissue Free Water Tritium), or associated with organic matter in two ways; either (ii) bound to the oxygen and nitrogen atoms of the material as exchangeable organically bound tritium (E-OBT), or (iii) bound to carbon atoms as non exchangeable organically bound tritium (NE-OBT). The first two components provide only a picture of atmospheric tritium concentrations at the sampling time as they are in equilibrium with atmospheric moisture and soil humidity. Unlike these exchangeable forms, however, NE-OBT is tightly bound to the organic matter and provides an integrated record of atmospheric tritium during the growing phase of the vegetation. We mapped NE-OBT in tree leaf samples in an area of about 25 × 30 km² around the centre of the CEA site and compared the results with those obtained during a previous sampling exercise in 1989. At this time, the activity levels were almost ten times higher than those observed presently in a similar area almost 20 years later which is consistent with the decrease of atmospheric releases issued from the centre. As the activity levels are now close to environmental background specific attention was also paid to the analytical procedure to ensure reliable low level NE-OBT detection.     

BOD微生物传感检测仪中高效微生物膜的研究

为了制备高效微生物膜,从污水中筛选菌种（QT2061）,经BIOLOG鉴定为枯草芽孢杆菌。并以聚乙烯醇为包埋剂制作BOD生物传感器微生物膜,通过对国家标准样品及几种典型水样的检测,结果表明,该微生物传感器的响应时间为8 min,可连续稳定测试10 d以上;对国家标准溶液的测试结果准确度较高,相对误差≤5%;对实验中几种水样均有响应,测试结果与5日法的测试结果有良好的相关性（相对偏差≤5%）。     

PBDE and PCB contamination of eels from the Gironde estuary: from glass eels to silver eels

Since the 1980s, the eel population has been decreasing dangerously. Persistent Organic Pollutants (POPs) such as Polychlorinated Biphenyls (PCBs) are one of the suspected causes of this decline. A preliminary study of PCB contamination carried out on different fish from the Gironde estuary (southwest of France, Europe) has shown a relatively high level of contamination of eel muscles. In order to characterize the contamination level of PCBs and PBDEs (PolyBrominated Diphenyl-Ethers) in eels from this estuary more than 240 eels were collected during the years 2004-2005 in the Gironde estuarine system, from glass eels to silver eels. Individual European eels were grouped according to length and localization sites. The results have shown a low contamination level of glass eels: respectively 28 ± 11 ng g⁻¹ dw for PCBs and 5 ± 3 ng g⁻¹ dw for PBDEs. The contamination level in eels (expressed in ng g⁻¹ dw) increases from glass eels to silver eels up to 3399 ng g⁻¹ dw of PCBs for the most contaminated silver eel. Such levels of PCBs similar to those observed in Northern Europe, could raise sanitary problems connected with the World Health Organization (WHO) recommendations. These results are worrying for the local people who regularly eat eels caught in the Gironde estuary.     

Differential global profiling as a new analytical strategy for revealing micropollutant treatment by-products: application to ethinylestradiol and chlorination water treatment

The detection and structural elucidation of micropollutants treatment by-products are major issues to estimate efficiencies of the processes employed for drinking water production versus endocrine disruptive compounds contamination. This issue was mainly investigated at the laboratory scale and in high concentration conditions. However, potential by-products generated after chlorination can be influenced by the dilution factor employed in real conditions. The present study proposes a new methodology borrowed to the metabolomic science, using liquid chromatography coupled to high-resolution mass spectrometry, in order to reveal potential chlorination by-products of ethinylestradiol in spiked real water samples at the part-per-billion level (5 μg L⁻¹). Conventional targeted measurements first demonstrated that chlorination with sodium hypochlorite (0.8 mg L⁻¹) led to removals of ethinylestradiol over 97%. Then, the developed differential global profiling approach permitted to reveal eight chlorination by-products of EE2, six of them being described for the first time. Among these eight halogenated compounds, five have been structurally identified, demonstrating the potential capabilities of this new methodology applied to environmental samples.     

PCDD/Fs and dioxin-like PCBs in sediment and biota from the Mondego estuary (Portugal)

The concentrations of 17 polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in sediment and key species as an initial investigation on PCDD/Fs and dl-PCBs contamination in the Mondego estuary (Portugal). The results demonstrated that the values of the total PCDD/Fs (∑PCDD/Fs) concentrations were considerably lower than those of the sum of dl-PCBs (∑dl-PCBs) in all the studied samples. Regarding the contribution of individual congeners, OCDD was the predominant PCDD/F and the mono-ortho PCB 118 and PCB 105 were the dominant PCBs in the majority of the samples. Our results suggest that PCDD/Fs and PCBs behave quite differently along the aquatic food web: ∑PCDD/Fs concentrations were lower in higher trophic-level organisms with fish presenting a distinct PCDD/Fs congeners profile; on the contrary, the higher ∑dl-PCBs values were found in upper-level biota, although not exclusively, and quite similar dl-PCBs congener profiles were observed in nearly all the studied species.