Copper and cadmium effects on growth and extracellular exudation of the marine toxic dinoflagellate Alexandrium catenella: 3D-fluorescence spectroscopy approach

In this study, metal contamination experiments were conducted to investigate the effects of copper and cadmium on the growth of the marine toxic dinoflagellate Alexandrium catenella and on the production of dissolved organic matter (Dissolved Organic Carbon: DOC; Fluorescent Dissolved Organic Matter: FDOM). This species was exposed to increasing concentrations of Cu²⁺ (9.93 × 10⁻¹⁰–1.00 × 10⁻⁷ M) or Cd²⁺ (1.30 × 10⁻⁸–4.38 × 10⁻⁷ M), to simulate polluted environments. The drastic effects were observed at pCu²⁺ = 7.96 (Cu²⁺: 1.08 × 10⁻⁸ M) and pCd²⁺ = 7.28 (Cd²⁺: 5.19 × 10⁻⁸ M), where cyst formation occurred. Lower levels of Cu²⁺ (pCu²⁺ > 9.00) and Cd²⁺ (pCd²⁺ > 7.28) had no effect on growth. However, when levels of Cu²⁺ and Cd²⁺ were beyond 10⁻⁷ M, the growth was totally inhibited. The DOC released per cell (DOC/Cell) was different depending on the exposure time and the metal contamination, with higher DOC/Cell values in response to Cu²⁺ and Cd²⁺, comparatively to the control. Samples were also analyzed by 3D-fluorescence spectroscopy, using the Parallel Factor Analysis (PARAFAC) algorithm to characterize the FDOM. The PARAFAC analytical treatment revealed four components (C1, C2, C3 and C4) that could be associated with two contributions: one, related to the biological activity; the other, linked to the decomposition of organic matter. The C1 component combined a tryptophan peak and a characteristic humic substances response, and the C2 component was considered as a tryptophan protein fluorophore. The C3 and C4 components were associated to marine organic matter production.     

Measurement of pyrene in the gills of exposed fish using synchronous fluorescence spectroscopy

A synchronous fluorescence spectroscopy (SFS) method was developed for determination of pyrene in the gills of exposed fish. The wavelength differences (Δλ) of 50 nm was maintained between excitation and emission wavelengths and it was found to be suitable for the effective determination of pyrene in fish gills; the peak were observed at λ_ex 334.5 nm. Linear relationships between SFS intensity and the concentration of pyrene in n-hexane solution were established. It was demonstrated that the SFS method was effective, simple, and less expensive, providing an attractive alternative for the rapid analysis of pyrene in fish gills.     

The Use of the Isotopic Composition of Individual Compounds for Correlating Spilled Oils and Refined Products in the Environment with Suspected Sources

Correlation of crude oils, or refined products, in the environment with suspected sources is typically undertaken through the use of GC and GCMS and in certain cases bulk carbon isotope compositions. However, with crude condensates, or refined products in particular, the absence, or low concentration, of biomarkers precludes their successful use for making unique correlations. An alternative and, sometimes, complimentary technique for correlation of such products is evolving through the use of combined gas chromatography-isotope ratio mass spectrometry (GCIRMS). This approach permits determination of the carbon and hydrogen isotopic composition of individual compounds in the crude oil or refined product to produce isotopic fingerprints for use in correlation studies. In this paper, it is proposed to review applications of GCIRMS to the correlation of various spilled products with their suspected sources in different environments. Whilst not proposing that this technique will replace GC or GCMS; it is proposed that GCIRMS is a very powerful tool to be used in conjunction with GC and GCMS to make such correlations. Although isotopic fractionation has been observed in some of the lighter components such as benzene and toluene, higher carbon numbered compounds, say above C 10 , do not appear to undergo any significant isotopic fractionation as a result of weathering. Furthermore with refined products, isotopic fractionation of the lighter components has the potential to demonstrate the onset of natural attenuation of refined products in the environment.     

长期不同水分调控对污染场地土壤溶解性有机质含量及其结构特征的影响

为了考察不同水分调控下污染场地中土壤有机质和溶解性有机质（DOM）的演变过程,以2种冶炼厂重金属污染土壤为研究对象,通过恒温恒湿培养实验观察不同水分调控下土壤有机质和DOM的含量变化,并采用紫外-可见光谱和荧光光谱分析了土壤DOM的光谱特征.结果表明,水分调控180 d后,2种重金属污染土壤中有机质和DOM含量呈不同程度降低趋势,且随着水分含量增加,其降幅明显增加,最大降幅分别为33.28%和89.35%.水分调控过程中,土壤DOM中类蛋白物质最易发生降解,导致类富里酸和类腐殖酸的占比相应提高;随着水分含量增加,土壤DOM的芳香性提高,腐殖化程度升高,分子聚合度和分子量增大,最终导致DOM稳定性增强,上述结果有助于揭示水分诱导过程中DOM的变化对污染场地中重金属环境行为的影响.     

畜禽养殖废水的三维荧光特征

对某畜禽养殖废水连续采样,利用荧光光谱法研究畜禽养殖废水的三维荧光特性.结果表明:该废水的三维荧光光谱有两个荧光峰,分别为270 nm/297 nm和315 nm/410 nm,两峰的强度之比为3.45～4.94;该畜禽养殖废水由蛋白质、腐酸、尿液及阴离子表面活性剂组成;各峰的峰位置及峰强度比值都可作为判断废水是否为该...     

Fluorescence fingerprints to monitor total trihalomethanes and N-nitrosodimethylamine formation potentials in water

Water samples from 56 lakes of Missouri, USA, were analysed for their fluorescence excitation/emission matrix (EEM) spectroscopy and the formation potentials of total trihalomethanes (TTHM) and N-nitrosodimethylamine (NDMA). Comparing the excitation/emission matrix fingerprints with trihalomethanes formation revealed that water with higher fluorescence intensity generally exhibited higher trihalomethanes formation potential. Moreover, waters with fluorescence centre at excitation: 290–310 nm/emission: 330–350 nm were related to high N-nitrosodimethylamine and trihalomethanes formation potentials. The results suggest that excitation/emission matrix fingerprints could be used as surrogate parameters for monitoring trihalomethanes and N-nitrosodimethylamine formation potentials.     

曙红荧光猝灭法测定水中ClO 2

在pH值为5.0的HAc-NaAc缓冲溶液中,曙红在540 nm处产生一个荧光峰,并能被ClO2氧化导致其荧光发生猝灭.通过试验确定了ClO2使曙红褪色的最佳条件,ClO2在0.042 mg/L～0.916 mg/L范围内与曙红荧光猝灭强度呈线性关系,据此建立了水中ClO2的荧光分析方法,方法检出限为0.01 mg/L.     

火山岩中主要造岩矿物的X射线定量

本文是近年来我们用x射线多相定量方法测定火山岩中主要造岩矿物相对含量的工作小结。     

Identification of abnormal chromosomal complement in formalin-fixed,paraffin-embedded placental tissue

The objective of this project was to assess the efficacy of fluorescence in situ hybridization (FISH) with chromosome-specific DNA probes to identify chromosome number in formalin-fixed, paraffin-embedded placental specimens. Using this approach, 75 per cent of the karyotypes in 20 formalin-fixed placental samples (comprising aneuploids, triploids, and normals) were correctly identified. As this technology improves, the ability to obtain information regarding chromosomal abnormalities in formalin-fixed, paraffin-embedded placental tissue should improve as well. This technology can potentially provide important cytogenetic information even when fresh tissue is not available for standard karyotypic analysis.     

Rapid detection of aneuploidy in uncultured chorionic villus cells using fluorescence in situ hybridization

Rapid detection of aneuploidy using chromosome-specific repetitive DNA probes and the potential diagnostic accuracy of fluorescence in situ hybridization (FISH) on interphase cells of chorionic villus samples (CVS) are presented. Analyses demonstrated the ability to correctly identify aneuploidy using FISH in uncultured CVS. Our preliminary investigation suggests that this technique offers a significant clinical potential to circumvent problems of culture, time, and cost in cytogenetic analysis.