Application of chemometric methods to the investigation of main microcontaminant sources of endocrine disruptors in coastal and harbour waters and sediments

Identification, resolution and distribution of main microcontaminant sources of endocrine disruptors in Spanish harbours, coastal waters and sediments are investigated using chemometric methods. We investigated eighteen different endocrine disruptor chemical compounds, including non-ionic surfactants, their degradation products and linear alkylbenzene sulfonates, found in a total number of 74 samples (35 water samples and 39 sediment samples) over a period of 16 months from March 1999 to July 2000, and in 32 different geographical sites along the Spanish Mediterranean Coast (e.g. Barcelona, Tarragona, Almeria Harbour, Malaga and the Bay of Cadiz). Main environmental contamination sources of these endocrine disruptor compounds were investigated and interpreted according to their chemical composition and according to their resolved geographical distribution profiles.An erratum to this article can be found at     

Analytical methods for determination of free metal ion concentration, labile species fraction and metal complexation capacity of environmental waters: A review

Different experimental approaches have been suggested in the last few decades to determine metal species in complex matrices of unknown composition as environmental waters. The methods are mainly focused on the determination of single species or groups of species.The more recent developments in trace elements speciation are reviewed focusing on methods for labile and free metal determination.Electrochemical procedures with low detection limit as anodic stripping voltammetry (ASV) and the competing ligand exchange with adsorption cathodic stripping voltammetry (CLE-AdCSV) have been widely employed in metal distribution studies in natural waters. Other electrochemical methods such as stripping chronopotentiometry and AGNES seem to be promising to evaluate the free metal concentration at the low levels of environmental samples. Separation techniques based on ion exchange (IE) and complexing resins (CR), and micro separation methods as the Donnan membrane technique (DMT), diffusive gradients in thin-film gels (DGT) and the permeation liquid membrane (PLM), are among the non-electrochemical methods largely used in this field and reviewed in the text. Under appropriate conditions such techniques make possible the evaluation of free metal ion concentration.     

Distribution of Impurities During Low-Temperature Directed Crystallization of Water Solutions

Trends in the distribution of impurities at low-temperature directed crystallization of water solutions of various concentrations are described and the mechanism of their incorporation in the solid phase is explained. The data on the distribution coefficients of the impurities between the solid and liquid phases are presented. It is shown that the behavior of the impurities in the process of directed crystallization is the same and does not depend on the nature of the macrocomponent. The unique case of CsI is explained due to the negative values of hydration of iodide and cesium ions. It is recommended to use the observed trends for the purification of water or analytical pre-concentration of impurities.The coefficients of enrichment of the impurities after low-temperature directed crystallization of aqueous solutions with different composition and total concentration of the dissolved salts are estimated and their dependencies on the composition and concentration of the aqueous solution are shown.     

Determination of Some Metal Ions in Aquatic Environs by Atomic Absorption Spectrometry after Concentration with Modified Silica

The uptake behavior of porous silica modified with N‐propylsalicylaldimine (IE11) for Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) metal ions were studied. The Log k_d values were found to be within the range 2.19–5.16 depending on pH and time of stirring. IE11 was used in the separation and preconcentration of Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) from some natural water samples. The data were compared with those obtained by the solvent extraction method (APDC/MIBK). The method was found to be accurate and precise and not subject to random error.     

Rapid separation of humic acid in fresh waters by coprecipitation and flotation

After removal of suspended matter in 1 liter of water by flotation with a cationic surfactant, humic acid at theg/l level is separated from fulvic acid by coprecipitation with milligram quantities of iron(III) hydroxide at pH 7 followed by flotation with anionic surfactants. The iron(III) hydroxide is dissolved in 2M hydrochloric acid, and the acid-insoluble humic acid is filtered off on an ultrafilter and then dissolved in 10 ml of 0.1M potassium hydroxide solution for measurements of absorption spectra, molecular weight distribution and complexing ability. The time required for the separation is ca. 1 h.     

宁波市甬江水系污染现状及其防治对策

本文记述了甬江水系,包括流入其内的奉化江、姚江和甬江及其河口区的自然条件,污染源,污染物及其水体污染现状。在此基础上提出防治对策。     

Electron microscopy of submicron particles in natural waters — Specimen preparation by centrifugation

Particles ranging from ca. 0.1 to 1.0m in 5 ml of pond water are collected on a 10–20 nm carbon film on a gold or copper specimen grid, placed on a special holder in a 7-ml centrifuge tube, by centrifugation at 10000 r. p. m. for 18 min. The specimens thus prepared are reproducible and preserve the morphology of the particles satisfactorily. The proposed technique is more suitable than filtration, direct drying and spray drying techniques for morphological studies and elemental analysis of individual particles with scanning, transmission and analytical electron microscopes.     

Determination of labile Cu(2+) in fresh waters by chemiluminescence: interference by iron and other cations

Analysis of labile Cu²⁺ in fresh waters using the Cu²⁺-catalysed oxidation of 1,10-phenanthroline by superoxide anion radical has been investigated. It was found that certain metal ions, notably Fe³⁺, Fe²⁺ and Pb²⁺ enhance the chemiluminescence (CL) intensity of this reaction by up to an order of magnitude when present in the μM concentration range. This enhancement is considered to arise through coordination of the metal ion to 1,10-phenanthroline, which prevents free rotation of the benzene rings in the excited state intermediate thought to be responsible for light emission. This introduces a potential interference when analyzing fresh waters, which usually contain Fe³⁺ concentrations of this magnitude. However, the enhancement effect saturates at about 4 μM Fe³⁺, so that reliable results can be obtained if the water sample is supplemented with Fe³⁺ to reach this level. Application of the enhanced technique to a river water, and a reservoir to which CuSO₄ had been added to control algal growth, are described. In both cases, only a small fraction of total dissolved Cu²⁺ is labile with respect to the chemiluminesence method.     

酸性媒染紫-示波计时电位法测定天然水和饮用水中铝

报道酸性媒染紫（ＳＶＲＳ）－示波计时电位法测定天然水及饮用水中铝。在０．８５ｍｏｌ／Ｌ　ＮＨ３·Ｈ２Ｏ－ＮＨ４Ｃｌ－５×１０－５ｍｏｌ／Ｌ ＳＶＢＳ（ｐＨ８．８）底液中,Ａｌ－ＳＶＲＳ络合物在－１．０５Ｖ电位处产生灵敏切口,切口深度与铝浓度成正比,可用于定量分析。线性范围为１×１０－７～６×１０－６ｍｏｌ／Ｌ． ＲＳＤ为５．５％ （ｎ＝１０,２×１０－７ｍｏｌ／Ｌ）,检测限为５×１０－８ｍｏｌ／Ｌ。本法特点为：在碱性条件下,无需加热,无需通氮除氧,无需预富集,大大减少了分析时间。仪器简单,方法灵敏准确,特别适用于天然水和饮料中Ａｌ的分析。对实际水样进行了分析,与ＩＣＰ／ＡＥＳ法所测结果基本一致。     

自然水体中生物膜的主要化学组分与水体中相关化学物质的关系

自然水体中大多数微生物是以附着状态而不是以游离状态存在的 [1] .微生物附着在固体表面形成生物膜 ,存在于河流、湖泊及湿地环境中的岩石、表层沉积物和悬浮颗粒物表面 ,由不同种类的微生物组成 [2 ] .从环境微生物学角度来看 ,生物膜被定义为一种活跃地生长发育着的单一或混合的微生物群体 ,其不可逆地附着到一种活跃的或非活跃的表面 [3] ,并由微生物群体组成 [4 ] .从环境化学角度来看 ,生物膜是由金属氧化物、有机质及少量矿物质组成的 .金属氧化物和有机质在影响重金属于固相吸附的相对作用已有报道 [5～ 10 ] .生物膜在自然水体中是…