Occurrence of aromatic amines and N-nitrosamines in the different steps of a drinking water treatment plant

The occurrence of 24 amines within a full scale drinking water treatment plant that used chlorinated agents as disinfectants was evaluated for the first time in this research. Prior to any treatment (raw water), aniline, 3-chloroaniline, 3,4-dichloroaniline and N-nitrosodimethylamine were detected at low levels (up to 18 ng/L) but their concentration increased ∼10 times after chloramination while 9 new amines were produced (4 aromatic amines and 5 N-nitrosamines). Within subsequent treatments, there were no significant changes in the amine levels, although the concentrations of 2-nitroaniline, N-nitrosodimethylamine and N-nitrosodiethylamine increased slightly within the distribution system. Eleven of the 24 amines studied were undetected either in the raw and in the treatment plant samples analysed. There is an important difference in the behaviour of the aromatic amines and N-nitrosamines with respect to water temperature and rainfall events. Amine concentrations were higher in winter due to low water temperatures, this effect being more noticeable for N-nitrosamines. Aromatic amines were detected at their highest concentrations (especially 3,4-dichloroaniline and 2-nitroaniline) in treated water after rainfall events. These results may be explained by the increase in the levels of amine precursors (pesticides and their degradation products) in raw water since the rainfall facilitated the transport of these compounds from soil which was previously contaminated as a result of intensive agricultural practices.     

毛细管气相色谱法测定聚丙烯酰胺中残留丙烯酰胺

本文建立了毛细管气相色谱法测定水处理剂聚丙烯酰胺中残留丙烯酰胺的方法。丙烯酰胺经甲醇-水从样品中提取,经KB—WAX（30．0m×250μm×0．25μm）毛细管气相色谱分离,FID检测器测定含量,在0—80mg／L浓度范围内相对标准偏差为4．;5％-6．0％,加标回收率在92％-108％之间.     

Study on the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chloro-phenoxyacetic sodium (MCPA sodium) in natural agriculture-soils of Fuzhou, China using capillary electrophoresis

A new method of analyzing trace 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2-methy-4-chloro-lphenoxyacetic sodium (MCPA sodium) in soils by capillary electrophoresis (CE) has been developed in this study. The optimum analytical conditions including chemical component and concentration of buffer solution, pH, separation voltage and sample injection time were studied in detail. Under the optimum conditions, 2,4-D and MCPA sodium in soils can be speedy separated and determined within 20 min with detection limits of 0.15 µg/g (2,4-D) and 0.25 µg/g (MCPA sodium) , a RSD (n = 6) < 5% and a recovery > 89%.With the help of analytical method developed in this study, the degradations of 2,4-D and MCPA sodium in natural agriculture-soils of Fuzhou were studied. The experimental results indicated that the degradations of 2,4-D and MCPA sodium follow first-order kinetics with degradation constants of 0.1509 day^-1 (2,4-D) and 0.2722 day^-1 (MCPA sodium) respectively. The degradation half-life were calculated to be 4.6 days (2,4-D) and 2.6 days (MCPA sodium) at 27 °C, implied that 2,4-D and MCPA sodium can be speedy degraded in natural agriculture-soils of Fuzhou, China.     

Occurrence of nine nitrosamines and secondary amines in source water and drinking water: Potential of secondary amines as nitrosamine precursors

Due to their high carcinogenicity, the control of nitrosamines, a group of disinfection by-products (DBPs), is an important issue for drinking water supplies. In this study, a method using ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry was improved for simultaneously analyzing nine nitrosamines in source water and finished water samples of twelve drinking water treatment plants (DWTPs) in China. The method detection limits of the nine target analytes were 0.2-0.9 ng/L for the source water samples and 0.1-0.7 ng/L for the finished water samples. Of the nine nitrosamines, six (N-nitrosodimethylamine (NDMA), nitrosodiethylamine (NDEA), N-nitrosomorpholine (NMor), N-nitrosodi-n-butylamine (NDBA), N-nitrosomethylethylamine (NMEA), and N-nitrosodiphenylamine (NDPhA)) were detected. The total nitrosamine concentrations in source water and finished water samples were no detection-42.4 ng/L and no detection-26.3 ng/L, respectively, and NDMA (no detection-13.9 ng/L and no detection-20.5 ng/L, respectively) and NDEA (no detection-16.3 ng/L and no detection-14.0 ng/L, respectively) were the most abundant. Meanwhile, the occurrence of nine secondary amines corresponding to the nine nitrosamines was also investigated. All of them except for di-n-propylamine were detected in some source water and finished water samples, and dimethylamine (no detection-3.9 μg/L and no detection-4.0 μg/L, respectively) and diethylamine (no detection-2.4 μg/L and no detection-1.8 μg/L, respectively) were the most abundant ones. Controlled experiments involving chloramination of four secondary amines confirmed that dimethylamine, diethylamine, morpholine and di-n-butylamine in water can form the corresponding nitrosamines, with diethylamine and morpholine showing significantly higher yields than dimethylamine which has already been identified as a precursor of NDMA. This study proved that diethylamine, morpholine and di-n-butylamine detected in raw water would be one of the important the precursors of NDEA, NMOR and NDBA, respectively, in drinking water.     

高效毛细管电泳在高效减水剂合成过程控制中的应用

利用高效毛细管电泳快速测定氨基磺酸系高效减水剂合成过程中对氨基苯磺酸和苯酚的含量,研究了分离条件对测定的影响,确定了最佳测定条件.该法简单、快速,准确度高,能满足氨基磺酸系高效减水剂合成工艺的测定要求.     

Determination of total chromium in environmental water samples

It is often desirable to quantify both dissolved Cr(VI) and total Cr in samples accurately. Various protocols are now being utilized to quantify the amount of total chromium in natural waters and each of these has possible interferences. This study describes the shortcomings of each method when particulate iron is present in a water sample, and a more rigorous digestion protocol is tested. Data from bench studies as well as a field survey of 21 water utilities are presented. Additionally, field data from several hundred water utility samples are presented to illustrate the potential for incomplete recovery of total chromium using accepted protocols.     

吹扫捕集-气相色谱法同时测定水中苯系物和氯苯化合物

利用吹扫捕集法富集样品、DB—FFAP毛细管柱分离、FID检测器同时测定水中八种苯系物和四种氯代苯。通过对捕集柱吸附剂材料、毛细管色谱柱等条件进行详细研究,确定了最佳分析条件。结果表明,使用BTEXTRAP捕集柱和DB—FFAP毛细管柱可以减少干扰,有效实现了水中苯系物各组分的完全分离。当进样体积为5．0mL时,12种组分的最低检测限在0．13～0．44μg／L之间,加标回收率为95．9％～106．8％,相对标准偏差在3．9％～7．3％之间。该方法无需溶剂萃取和浓缩,缩短了分析周期,实现了一次进样多组分同时测定,具有准确度高、灵敏度高和操作简便等特点,对实际水样进行分析,获得了良好的实验效果,适用于饮用水和地表水中挥发性苯系物和氯代苯的测定。     

Analysis of nitroaromatics in aqueous samples by capillary supercritical fluid chromatography

The extraction and analysis of nitroaromatics from aqueous environmental samples was examined. Two extraction methods; liquid‐liquid extraction with dichloromethane as extracting solvent and solid phase extraction with C₁₈ cartridge were carried out to determine the selectivity and extraction efficiencies of each method. In this investigation, eight nitroaromatics were selected as the test compounds. The extracts were then analysed using capillary supercritical fluid chromatography with flame ionization detection and with carbon dioxide as mobile phase. Satisfactory separation of the eight nitroaromatics including three pairs of isomers could be achieved. Detection limits in the range of 5 to 40 ppm were obtained using this system. Higher extraction efficiencies were obtained using the liquid‐liquid extraction method compared to the solid phase extraction method.     

声波检测技术在区域漏水检测中的应用

从声学原理角度论述了供水管道漏水声波的产生、传播途径、特点及其在漏水检测中的应用。介绍了供水管道检漏的基本方法和流程,并重点叙述了区域漏水监测系统在漏水检测中的应用及其特点。     

Occurrence of polycyclic aromatic hydrocarbons in water and sediment samples from KwaZulu Natal Province,South Africa

Solid‐phase extraction (SPE) and ultrasonic extraction (UE) techniques followed by Gas Chromatography‐Mass Spectrometry (GC‐MS) have been modified for qualitative and quantitative analysis of polycyclic aromatic hydrocarbons (PAHs) in water and sediment samples. Percentage recoveries of PAHs ranged from 85 to 121% in water and 82 to 117% in sediment samples. The limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.02 to 0.2 and 0.05 to 0.5 µg/L for SPE while for UE, they were between 0.008–0.09 and 0.02–0.30 µg/kg, respectively. The concentration levels of PAHs (naphthalene, acenaphthene, acenaphthylene, fluorine, anthracene, phenanthrene and pyrene) detected in water samples were 0.071–2.7, 2.0–10.4 and 2.5–3.5 µg/L in wastewater, river water, and dam water, respectively. In sediment samples, concentration levels of PAHs were between 2.8–42.0 and 2.8–3.9 µg/kg, in river and dam sediment, respectively.     

石墨炉原子吸收光谱法测定石英玻璃中痕量铁检出限的探讨

以铁元素为例,讨论了石墨炉原子吸收光谱法测定石英玻璃中痕量元素检出限的空白选择、方法检出限的常见两种测定方法和计算依据,以及样品检出限的计算与表示.一个月内,不同时间段,分五次测定至少20个样品空白,所得检出限为真实的方法检出限,可作为日常分析使用.结果表明,增加进样量和使用新的石墨管可以提高灵敏度.     

氯甲酸-9-芴甲酯柱前衍生液相色谱法测水中脂肪胺

对文献报道的采用氯甲酸-9-芴甲酯为柱前衍生试剂、高效液相色谱法检测水中脂肪胺的方法进行了改进,以满足快速检测痕量脂肪胺的需要。改进后的方法,分析时间缩短了一倍。采用乙腈∶水=55∶45(体积比)为流动相,用C18柱和荧光检测器对水中的7种脂肪胺进行了分离和测定。结果表明:选择激发和发射波长分别为265 nm和310 nm,流动相流量为1.0 mL/min,7种游离脂肪胺标准品配制浓度范围为1.0~1 200.0μg/L时,测定脂肪胺的相对标准偏差(RSD)≤1.8%,脂肪胺的回收率为97.3%~103.8%,脂肪胺的线性相关系数>0.998 8,检出限为0.89~2.82 fmol。改进后的方法检测快速,并具有良好的精密度和准确度。对松花江水的分析结果表明,该方法不受样品基底的干扰,可用于实际样品中伯胺和仲胺的快速定性定量分析。     

Determination of phosphate in wastewaters by ion-exclusion chromatography with flow coulometric detection

Ion-exclusion chromatography of PO₄³⁻ in wastewaters has been investigated on a cation exchange resin in the H⁺-form. Phosphate ion was chromatographed by ion-exclusion as H₃PO₄ formed by cation exchange, and monitored with a flow coulometric detector based on the electrochemical reaction of H⁺ ion from H₃PO₄ and p-benzoquinone at a constant applied potential (+0.45 V vs Ag-AgI) or a conductometric detector. A reasonable separation of PO₄³ from strong acid anions (Cl⁻ SO₄²⁻ and NO₃⁻) and CO₃²⁻ as coexisting anions could be accomplished by isocratic elution with 60% (v/v) acetone-water. The calibration graph for PO₄³⁻ with the flow coulometric detector was linear over the concentration range 1–150 ppm (slope = 0.982), but not with the conductometric detector. The agreement of the analytical results of PO₄³⁻ between the ion-exclusion chromatography with the flow coulometric detector and the colorimetry (molybdenum-blue method) was excellent for some industrial wastewater and domestic sewage samples.     

Statistics of enumerating total coliforms in water samples by membrane filter procedures

A commonly used assumption is that the microbial counts of a given water sample are randomly distributed according to Poisson statistics and, in particular, that replicate analyses of the same sample are so distributed. Using Fisher's index of dispersion, as well as a newly developed test, analysis of prior data on membrane filter total coliform organisms in a variety of water samples indicated that, in many cases, the assumption of Poisson statistics was incorrect, but that the data were consistent with a negative binomial distribution. This finding has significance in the interpretation of total coliform counts for regulatory as well as research purposes, and further research to delineate the responsible mechanisms is required.     

微波流动注射在线光度法测定废水中的铬

研究了在磷酸介质下二安替比林邻溴苯基甲烷（DAoBM）和Cr（Ⅵ）形成橙红色螯合物的过程，并对影响其显色反应的因素进行了优化试验，建立了检测印染废水中总铬和铬（Ⅵ）的微波流动注射在线光度法。该方法的线性范围为0～2．0mg／L，检出限为0．01mg／L，测定相对标准偏差为1．7％～2．3％，加标回收率为98．5％～102．0％。     

Accumulation of oil and grease in soils irrigated with greywater and their potential role in soil water repellency

The potential impact of oil and grease (O and G) to soils irrigated with greywater (GW) was investigated. Greywater streams were sampled and analyzed for O and G content, along with corresponding GW-irrigated soils. Untreated kitchen GW averaged 200 mg L(-1) O and G, over an order of magnitude more than other GW streams. GW-irrigated soils showed O and G accumulation of up to 200 mg kg(-l) within the first 20-cm of depth. To determine the potential effects of such O and G accumulation on water movement in soil, capillary rise and water drop penetration time (WDPT) experiments were conducted. The results showed up to 60% decrease in capillary rise when sand containing 250 mg kg(-1) O and G was used. Interestingly, no additional reduction in capillary rise was observed at concentrations above 250 mg kg(-1). WDPT was observed to increase linearly with increased O and G content, up to 1000 mg kg(-1). This work demonstrated that O and G in GW used for irrigation can accumulate in soil and may lead to a significant reduction in the soils ability to transmit water.     

Field testing of an optimal sensor placement methodology for event detection in an urban water distribution network

This paper presents a method to identify ‘optimal’ locations of pressure sensor instruments for the detection of leak/burst events and the results of a set of field trials conducted to evaluate the approach. The identification method is based on complete enumeration studies using hydraulic model simulations of a wide range of burst events and evaluating the response to each event at all possible monitoring points. The field trials simulated leak/burst events through the opening of fire hydrants within a selected District Metered Area (DMA), five different hydrants were opened systematically in the DMA to simulate different leak/burst events. By installing pressure instrumentation at different locations in the DMA, an understanding of how accurately the model methodology can determine sensitivity of instrument location can be obtained. Prior to and during the hydrant openings pressure data was collected at eight different instrument locations within the DMA. These pressure instruments were installed to cover different model predicted sensitivities and to provide good spatial coverage. The results show that pressure instrumentation location is crucial to sensitivity and that the modelling methodology is able to predict instrument location sensitivity to leak/burst events and thus offer an improvement over current industry practice for instrument deployment. It should be noted that this field application made use of current UK standard models, with no additional calibration or updating.     

Analytical fractionation of dissolved organic matter in water using on-line carbon detection

A routine method is described for the analytical fractionation of dissolved organic matter (DOM) in natural freshwater and in used waters. The fractionation is based on the different adsorption behaviours of various constituents of the DOM on octadecyl-silica as a function of pH. The DOM is separated into a hydrophilic, an acid and a hydrophobic fraction. The detection is carried out by an on-line carbon detector. The method requires only small water samples (20 ml) with low dissolved organic carbon (DOC) concentrations (1–5 mg Cl⁻¹). The samples can be analysed rapidly with no preconcentration. Fractionation of model compounds and mixtures demonstrates the performance of the method. The application of the method is illustrated by an investigation of the changes of the DOC composition occurring in a longitudinal transect of a river and during the infiltration of river water to groundwater.     

液相色谱-柱后衍生法检测水中草甘膦残留量的研究

建立了饮用水中草甘膦残留量的高效液相色谱一柱后衍生检测方法,该方法采用柱后衍生,水样直接进200μL经钾阳离子交换色谱柱分离后水样中的草甘膦衍生成一种强荧光物质,以荧光检测器进行检测;我们还对该方法的准确性和精密度进行了试验,结果表明该方法快速、灵敏度高、精密度好,能够满足生活饮用水中草甘膦的检测要求。草甘膦的方法检出限为9．0μg／L,几个浓度水平的添加回收率为82．0％～96．7％,相对标准偏差为1．52％～6．22％。