饮用水中痕量溴酸盐的测定研究

选用IonPac AS19阴离子分析柱,以KOH为淋洗液梯度淋洗,对大体积进样直接测定饮用水中痕量溴酸盐的离子色谱方法进行了条件优化。结果表明,在优化好的色谱条件(即电流量87mA、淋洗液流速为1.00mL/min、梯度淋洗)下,在BrO-3为2.0~100.0μg/L的低浓度范围内,峰面积与浓度呈良好的线性关系(r=0.999 6),测定的精密度高。采用该方法测定市售瓶装水样品中的痕量BrO-3,样品的平均加标回收率为95.91%~105.50%。该方法操作简单,BrO-3的分离效果好,可与常见阴离子实现同时分析,且测定精密度高,可作为饮用水中痕量溴酸盐的测定方法。     

水体沉积物毒性鉴别与评价研究进展

综述了水体沉积物毒性鉴别与评价的主流方法以及研究进展,指出毒性测试和致毒因子鉴别方法是限制水体沉积物污染生态风险评价的关键因素,认为发展和应用以生物标记物和生物效应为导向,尤其是各种具有污染专一性指示作用的生物效应标志测试方法的建立和应用,并结合具有选择性的样品分级技术和先进的仪器进行定性定量分析,将是以生物效应为导向、以化学分析为基础的复杂水体沉积物毒性鉴别与评价的重要发展方向.     

Effect of Fenton treatment on the aquatic toxicity of bisphenol A in different water matrices

Battery tests serve as integral tools to decide whether a treatment process is ecotoxicologically safe or not. In the present study, a battery of toxicity tests was employed to elucidate the toxicity of the potential endocrine-disrupting pollutant bisphenol A (BPA) and its advanced oxidation products. For this purpose, BPA was subjected to Fenton treatment in the growth medium of the test organisms employed as well as in real lake water. Treatment results indicated that BPA removals were fast and complete within less than a minute, whereas total organic carbon (TOC) removals were rather incomplete, speaking for the accumulation of refractory degradation products. The presence of chloride and/or natural organic matter influenced H₂O₂ consumption rates and the treatment performance of the Fenton’s reagent as well. The sensitivity of the selected test organisms for BPA and its Fenton treatment products in different water matrices was found in the following decreasing order: the freshwater microalgae (Pseudokirchneriella subcapitata) > the freshwater cladoceran (Daphnia magna) > marine photobacteria (Vibrio fischeri).     

A review of the fate and toxicity of 3,4-dichloroaniline in aquatic environments

The physicochemical properties, fate and toxicity of 3,4-dichloroaniline (3,4-DCA) in aquatic environments are reviewed.     

A review on the application of microbial toxicity tests for deriving sediment quality guidelines

The results of microbial toxicity tests are needed for the risk assessment of polluted sediments. In comparison with animals the anaerobic microorganisms are more tolerant to natural sediment conditions whereas they are more sensitive for a number of specific pollutants. Microbial toxicity tests from a literature search were classified in seven categories. Category A, B and C use polluted sediments and are applied for sediment monitoring. In category D, a pure chemical is added and the organisms and the test conditions were derived from sediment. Therefore this category can be used for setting sediment quality guidelines which protect sediment functions for the toxic effects of chemicals. In category E, organisms from a polluted site are separated from the sediment and are tested with pure chemicals. Organisms from a more polluted site can be more tolerant to a local pollutant. This is called pollution-induced community tolerance and can be used as evidence for the occurrence of toxic effects in a specific sediment. In category F pure chemicals are tested with a pure culture of microorganisms under sediment conditions. The results of category F tests can be combined with single species tests with animals and plants to obtain sediment quality guidelines sufficient for species protection. This can be compared with the sediment quality guidelines which protect sediment functions. When one of these quality guidelines is exceeded for a compound at a specific location a category E test can be used to determine whether the compound shows toxic effects in that sediment.     

催化光度法测定水中痕量亚硝酸根

基于亚硝酸根对溴酸钾氧化结果紫而使其褪色的催化作用,建立了灵敏的催化光度测定痕量亚硝酸根的新方法,测定范围为０．０２－０．１６μｇ／ｍＬ,用于水样中亚硝酸根的测定,获得了满意结果。     

Studies on cadmium toxicity in plants: a review

This review emphasises cadmium toxicity on plants with regards to ecological, physiological and biochemical aspects. Cadmium toxicity in plants and problems concerning tolerance and ecological performance are discussed briefly. Efforts have been made to compare the relative sensitivity of various plant groups including micro-and macro-flora. This review may help in interdisciplinary studies to assess the ecological significance of metal stress.     

四氯乙烯污染对小麦幼苗抗氧化酶系的影响

通过室内模拟试验,采用愈创木酚法、高锰酸钾滴定法、氮蓝四唑法分别测定了四氯乙烯(PCE)污染小麦幼苗的过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物岐化酶(SOD)等抗氧化物酶系,研究了PCE污染对植物生物学指标的影响,以评价土壤PCE污染的生态毒性效应,为土壤性质的变化趋势提供依据.结果表明,PCE浓度较低时,POD、SOD活性被激活,表现出明显的抗氧化能力,但PCE浓度过高时则抑制POD和SOD的活性诱导作用;小麦幼苗中CAT活性只有在PCE为0.10mg/kg时被激活,其他浓度时CAT活性均受到抑制;随着时间的延长,POD、CAT的活性均呈激活态势,而SOD活性在PCE浓度较低时呈降低趋势,在PCE浓度较高时,SOD活性升高.     

水处理工艺中摇蚊幼虫污染防治技术的研究进展

介绍了摇蚊幼虫的生活习性及其在水处理工艺中的分布规律。对其生理特性与环境因子之间的关系进行了论述；并就近年来采用物理法、化学法和生物法防治水处理工艺中摇蚊幼虫污染的研究进展、现状和局限性进行了较为系统的分析，展望了摇蚊幼虫污染防治技术的研究前景，指出目前控制饮用水中摇蚊幼虫污染必须将水源水质控制、污染治理与净水工艺处理结合起来，优化水处理工艺和强化水源水体保护是根本保障。     

Correction for water vapor in the measurement of atmospheric trace gases

The presence of water vapor in a sample of air reduces the concentration of a trace gas measured from the sample. We present a methodology to correct for this effect for those cases when the concentration of the trace gas has already been measured from a wet sample. The conversion or correction factor that takes the wet mole fraction to a dry mole fraction is determined by the mixing ratio of water vapor inside the sampling canister. For those samples where the water vapor is saturated inside the canister, the water vapor mixing ratio is largely determined by laboratory conditions; for the unsaturated samples, the mixing ratio is determined by station conditions. If the meteorology at the sampling station is known, the equations presented here can be used directly to calculate the appropriate correction factor. For convenience, we use climatological data to derive average monthly correction factors for seven common global sampling sites: Barrow, AK, US (71 degrees N, 157degrees W); Cape Meares, OR, US (45 degrees N, 124 degrees W); Mauna Loa, HI, US (19 degrees N, 155 degrees W); Ragged Point, Barbados (13 degrees N, 59 degrees W); American Samoa (14 degrees S, 171 degrees W); Cape Grim, Tasmania, Australia (41 degrees S, 145 degrees E); South Pole (90 degrees S). These factors adjust wet mole fractions upwards within a range of 0.002% for the South Pole to over 0.8% for saturated sites. We apply the correction factors to wet nitrous oxide (N2O) mole fractions. The corrected data are more consistent with our understanding of N2O sources.     

A new approach to data evaluation in the non-target screening of organic trace substances in water analysis

Non-target screening via high performance liquid chromatography-mass spectrometry (HPLC-MS) has gained increasingly in importance for monitoring organic trace substances in water resources targeted for the production of drinking water. In this article a new approach for evaluating the data from non-target HPLC-MS screening in water is introduced and its advantages are demonstrated using the supply of drinking water as an example. The crucial difference between this and other approaches is the comparison of samples based on compounds (features) determined by their full scan data. In so doing, we take advantage of the temporal, spatial, or process-based relationships among the samples by applying the set operators, UNION, INTERSECT, and COMPLEMENT to the features of each sample. This approach regards all compounds, detectable by the used analytical method. That is the fundamental meaning of non-target screening, which includes all analytical information from the applied technique for further data evaluation. In the given example, in just one step, all detected features (1729) of a landfill leachate sample could be examined for their relevant influences on water purification respectively drinking water. This study shows that 1721 out of 1729 features were not relevant for the water purification. Only eight features could be determined in the untreated water and three of them were found in the final drinking water after ozonation. In so doing, it was possible to identify 1-adamantylamine as contamination of the landfill in the drinking water at a concentration in the range of 20 ng L⁻¹. To support the identification of relevant compounds and their transformation products, the DAIOS database (Database-Assisted Identification of Organic Substances) was used. This database concept includes some functions such as product ion search to increase the efficiency of the database query after the screening. To identify related transformation products the database function “transformation tree” was used.     

Non-steady state partitioning of dry cleaning surfactants between tetrachloroethylene (PCE) and water in porous media

Trapped organic solvents, in both the vadose zone and below the water table, are frequent sources of environmental contamination. A common source of organic solvent contamination is spills, leaks, and improper solvent disposal associated with dry cleaning processes. Dry cleaning solvents, such as tetrachloroethylene (PCE), are typically enhanced with the addition of surfactants to improve cleaning performance. The objective of this work was to examine the partitioning behavior of surfactants from PCE in contact with water. The relative rates of surfactants partitioning and PCE dissolution are important for modeling the behavior of waste PCE in the subsurface, in that they influence the interfacial tension of the PCE, and how (or if) interfacial tension changes over time in the subsurface. The work described here uses a flow-through system to examine simultaneous partitioning and PCE dissolution in a porous medium. Results indicate that both nonylphenol ethoxylate nonionic surfactants and a sulfosuccinate anionic surfactant partition out of residual PCE much more rapidly than the PCE dissolves, suggesting that in many cases interfacial tension changes caused by partitioning may influence infiltration and distribution of PCE in the subsurface. Non-steady-state partitioning is found to be well-described by a linear driving force model incorporating measured surfactant partition coefficients.     

A review of personal care products in the aquatic environment: environmental concentrations and toxicity

Considerable research has been conducted examining occurrence and effects of human use pharmaceuticals in the aquatic environment; however, relatively little research has been conducted examining personal care products although they are found more often and in higher concentrations than pharmaceuticals. Personal care products are continually released into the aquatic environment and are biologically active and persistent. This article examines the acute and chronic toxicity data available for personal care products and highlights areas of concern. Toxicity and environmental data were synergized to develop a preliminary hazard assessment in which only triclosan and triclocarban presented any hazard. However, numerous PCPs including triclosan, paraben preservatives, and UV filters have evidence suggesting endocrine effects in aquatic organisms and thus need to be investigated and incorporated in definitive risk assessments. Additional data pertaining to environmental concentrations of UV filters and parabens, in vivo toxicity data for parabens, and potential for bioaccumulation of PCPs needs to obtained to develop definitive aquatic risk assessments.     

Reduction of hexachloroethane to tetrachloroethylene in groundwater

At the Canadian Forces Base, Borden, hexachloroethane (HCE) that was introduced into an unconfined sand aquifer disappeared rapidly, with a half-life of about 40 days. Laboratory-scale studies, initiated to help assess the fate of HCE, indicated that it is reductively biotransformed to tetrachloroethylene (PCE) both by aerobic cultures of wastewater microflora and by microcosms containing unhomogenized Borden aquifer material. The results also indicate that the agents involved in the aquifer transformation of HCE to PCE are not homogeneously distributed in the aquifer material.     

A review of toxicity and mechanisms of individual and mixtures of heavy metals in the environment

The rational for the study was to review the literature on the toxicity and corresponding mechanisms associated with lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As), individually and as mixtures, in the environment. Heavy metals are ubiquitous and generally persist in the environment, enabling them to biomagnify in the food chain. Living systems most often interact with a cocktail of heavy metals in the environment. Heavy metal exposure to biological systems may lead to oxidation stress which may induce DNA damage, protein modification, lipid peroxidation, and others. In this review, the major mechanism associated with toxicities of individual metals was the generation of reactive oxygen species (ROS). Additionally, toxicities were expressed through depletion of glutathione and bonding to sulfhydryl groups of proteins. Interestingly, a metal like Pb becomes toxic to organisms through the depletion of antioxidants while Cd indirectly generates ROS by its ability to replace iron and copper. ROS generated through exposure to arsenic were associated with many modes of action, and heavy metal mixtures were found to have varied effects on organisms. Many models based on concentration addition (CA) and independent action (IA) have been introduced to help predict toxicities and mechanisms associated with metal mixtures. An integrated model which combines CA and IA was further proposed for evaluating toxicities of non-interactive mixtures. In cases where there are molecular interactions, the toxicogenomic approach was used to predict toxicities. The high-throughput toxicogenomics combines studies in genetics, genome-scale expression, cell and tissue expression, metabolite profiling, and bioinformatics.     

Hydrocarbon fuel spill dispersion on water: A literature review

The literature concerning the fate of light hydrocarbon fuel spills on water is reviewed. The review focuses on jet fuels and contains some discussion of gasoline, diesel, marine and kerosene fuel spills. The two major fates of light hydrocarbon spill on water are evaporation and dissolution, although biodegradation, photooxidation and adsorption onto suspended sediments can also be of some importance.     

磷酸钕共沉淀选择性分离富集-原子吸收测定环境水样中痕量铅

研究提出了用磷酸钕(NdPO4)作为共沉淀捕集剂分离富集环境水样中的痕量Pb2 ,用火焰原子吸收光谱(FAAS)测定的方法.共沉淀受pH、NdCl3和H3PO4溶液用量的影响.结果显示,在溶液pH为3.2时,20 mL水样中加入5 mg/L NdCl3 2 mL、0.5 mol/L H3PO4 3 mL条件下,铅的加标回收率为96.6%～104.2%,方法的检测限为5.7×10-3 mg/L,水体中常见碱金属、碱土金属离子及阴离子在一定范围内不影响测定.     

Interconversions and toxicity changes in hexachlorocyclohexane isomers on dispersion in water

Abstract

Studies on the transformations of hexachlorocyclohexane isomers, α‐, β‐, γ‐ and δ‐, in aqueous solution were carried out at 25 ± 1°C over a period of four weeks. Gas liquid chromatographic technique was used for analysis. The results indicated a loss as well as interconversion of all the four isomers with time. The resulting changes in toxicity of the aqueous solution were studied against Drosophila using topical application. Toxicity studies with aqueous solution of technical hexachlorocyclohexane were simultaneously carried out for comparison. Toxicity of the aqueous solutions of α‐, β‐, and δ ‐isomers showed an increase while that of the γ‐isomer decreased significantly during the four week experimental period. Aqueous solution of technical HCH was equally toxic as that of the γ‐isomer initially and did not show much decrease in its toxicity at the end. Changes in toxicity of the individual isomer solutions were considered to be due, in part, to interconversions of HCH isomers.