不同粒径土壤活性有机碳测定方法的探讨

选择不同肥力的沙质栗钙土、潮褐土和草甸栗钙土三种土壤.采用干筛法对其进行处理,获得四种不同粒级的土壤,分别为:<0.15 mm、0.15～0.25 mm、0.25～0.50 mm和0.5～1.0 mm,用目前最常用的两种化学方法分别对不同粒级土壤活性有机碳进行了测定.结果表明:不同粒级土壤活性有机碳含量差异显著(P<0.05),并且土壤活性有机碳含量随粒级增大而降低,其大小顺次为:小于0.15 mm土壤>0.15～o.25mm土壤>0.25～o.5 mm土壤>0.5～1.0mm土壤;与KMnO4氧化法相比,0.2 mol·L-1(1/6K2Cr2O7-1:3H2SO4)氧化,130～140℃油浴煮沸5 min测定土壤活性有机碳的方法结果稳定,重现性好,变异系数小,且时间短,适宜大批土壤样品活性有机碳的测定.     

Comparison of masking agents for antimony speciation analysis using hydride generation atomic fluorescence spectrometry

A sensitive atomic spectrometric method for the redox speciation analysis of Sb in water is described. The proposed method is based on the selective generation of stibine from Sb(III) in a continuous flow system using non-dispersive atomic fluorescence spectrometry for detection. The effects of the HCl concentration on the fluorescence intensities of Sb(III) and Sb(V) were investigated. The results indicated that atomic fluorescence emission due to Sb(V) can constructively interfere with the determination of Sb(III). For the determination of Sb(III), four compounds were tested as masking agents to inhibit the generation of stibine from Sb(V). The effects of the concentrations of the masking agents and of HCl on the fluorescence signals from Sb(III) and Sb(V) were studied. The results indicated that citric acid and NaF can successfully suppress hydride generation from Sb(V). To evaluate the developed methodology and the influence of the matrix, the recovery of Sb(III) from natural water that was spiked with different Sb(III) and Sb(V) concentrations was tested.     

广州大气总悬浮颗粒物中可提取有机物的分布及源析

采用N,O-双(三甲基硅烷基)三氟乙酰胺(BSTFA)衍生化预处理和GC/MS分析技术,于2002~2003年对广州市大气气溶胶中的有机化合物进行了定量检测.结果表明,在广州市TSP样品中有机物的种类共分为9大类:烷烃、多环芳烃、酯类、正烷醇、酚类、酸类、甾类、二萜类、糖类化合物.在总定性有机化合物中,酸类(24.65%~40.38%)化合物的百分含量最高,其次为糖类(15.57%~36.18%).全年样品中最丰富的脂肪酸为正十六酸、正十八酸,高碳数脂肪酸(>C20)含量最高的酸是正二十四酸.广州市二元羧酸的浓度以冬季最高,气象条件(风向、雨水和逆温)是影响二元羧酸浓度变化的主要因素.利用分子标志物可以讨论源解析和源贡献,化石燃料对有机质的贡献率最高(平均值为64.28%),其次为植物蜡脂质 (平均值为10.99%)和生物质燃烧(平均值为8.58%).     

吹扫—捕集/气相色谱法测定水中挥发性卤代烃

建立了吹扫—捕集 /气相色谱 /电子捕获检测器联用测定水中 5种挥发性卤代烃分析方法 ,且按国家水质分析标准方法 (GB/T 1 71 3 0 -1 997)所确定的三氯甲烷、四氯化碳、三氯乙烯、四氯乙烯、三溴甲烷 5种挥发性卤代烃进行实验 ,采用 Supelcoport担体层析柱对去离子水处理 ,所获得的纯水无色谱干扰峰 ,本法按国家水质分析标准方法列出的 5种挥发性卤代烃进行测定在国内尚未见报导。当纯水的进样体积为 5 .0 ml时 ,其最低检出浓度为 1× 1 0 - 2～ 6× 1 0 - 4(μg/L)之间 ;相对误差在 1 .1 %～ 2 .4%之间 ;加标回收率在 82 .5 %～ 1 0 8%之间 ;相关系数在 0 .9980～ 0 .9999之间。可快速、高灵敏度、简便、准确、精密地测定水中 5种挥发性卤代烃 ,本法适用于饮用水和地表水中挥发性卤代烃的测定     

快速测定饮用水中的石油类

使用F2000型红外光度测油仪，测定水质中的石油类，方法是采用一次定量萃取代替两次萃取定容，用直接流出比色代替无水硫酸钠过滤吸水后的比色，而不采用盐析的方法来快速测定饮用水中的石油类。方法的精密度和准确度均达到国家标准要求，减轻了工作强度，节省了时间和药品，适应快速测定的要求。     

垃圾焚烧炉烟气中二噁英的测定

采用标准采样分析方法,对垃圾焚烧炉烟气样品中的二喃英进行取样、提纯和HRGC/HRMS分析,对样品中4～8个氯取代的二噁英取得定量结果。      

Estimate of sea loading by pollutants originating from the littoral counties in the Republic of Croatia

The paper reviews the data of 10 yr of following up sewage (waste water) inflows of anthropological origin into the sea from all the coastal settlements in Croatia. In particular, we report the sea loading by biochemical oxygen demand (BOD₅), expressed by the inhabitant equivalent (I.E.), for seven littoral counties. We estimated the loading of a coastal sea area for each county separately. The objective was to avoid any over- or underestimation of amounts and significance of sewage inflows into the seawater. For this purpose, a precisely determined sea volume up to the 10 m isobath has been chosen. Because of the inadequate treatment of wastewater, the total loading of that maritime territory expressed in terms of i.e. was found to be 26% higher than expected from the actual number of inhabitants. However, daily input represents only 12‰ of the considered volume of the sea. Recipient spent only 0.7% of the disposable oxygen quantity in the sea.     

Ultrasound-assisted emulsification/microextraction based on solidification of trace amounts of thallium prior to graphite furnace atomic absorption spectrometry determination

In the present work, determination of ultratrace amounts of thallium in water samples was performed by ultrasound-assisted emulsification microextraction based on solidification of a floating organic drop as sample preparation method prior to furnace atomic absorption spectrometry. 1-(2-Pyridylazo)-2-naphthol was used as chelating agent. The factors influencing the complex formation and extraction, such as pH of the aqueous solution, the type and the volume of extraction solvent, the volume of chelating agent solution, and the extraction time were investigated. Under optimized conditions, the enrichment factor was 200. The calibration graph was linear from 0.2 to 10.0 μg L^?1 with a correlation coefficient of 0.9966, the detection limit was 0.03 μg L^?1 and reproducibility was ±3.3% (C = 5.0 μg L^?1, n = 8). The method was successfully applied for the determination of thallium in water samples.     

Environmental impact assessment for aquatic ecosystems of industrial effluents†

A system of environmental impact assessment of industrial effluents is presented and discussed. Environmental assessment consists of three phases, hazard assessment, risk determination, and societary evaluation. It is regarded an integrated study of natural sciences, i.e. ecochemicology (chemical fate), ecotoxicology (toxical effects), and ecoepidemiology (biological damages); and social sciences, e.g. geography, sociology, and economy. And the outcome should be the basis of political decision making. Hazard assessment may be divided into a subphase of hazard identification from a base set of scientific information on the industrial effluent, and a second subphase of hazard analysis at a more elevated level of scientific information akin to the procedures suggested elsewhere for single chemicals. Methods of hazard assessment are laboratory experiments, e.g. chemical analysis, degradation and bioaccumulation studies, acute and chronic toxicity assessments, physical modelling, etc. Risk determination may then be conducted by extrapolation of the obtained results from laboratory to field, i.e. by risk estimation to the receiving waters, using methods of hydraulic modelling, biological surveillance, etc. Risk‐benefit evaluation is conducted in the society evaluation phase by balancing environmental consequences against the society value of the production. The outcome is determined by the interaction between hazard‐makers (industry), risk‐takers (administrators), guardians (regulators), and assessors (scientists) in risk management, the crank of environmental assessment.     

Detection of metallothionein in the intestinal mucosa and brain with 109cadmium∗

Metallothionein (MT) has a great capacity of binding metal ions showing an interesting connection with metal toxicology, as a biochemical marker for environmental metal pollution.

To normal male Wistar rats (200±10 g) and other groups with ferropenic anemia, are administered 1 mg Cd/Kg/day, during 6 days, and MT labelled with the administration 2 h before sacrifice of 3 μCi ¹⁰⁹CdCl₂, also through intragastric catheter. The MT concentration in the intestinal mucosa is expressed in μg MT/g fresh tissue, being for control rats 1.4 ± 0.5; for rats administered with 6 doses of Cd 2.5 ± 0.6 (P<0.05); with ferropenic anemia 4.3±0.7 (P<0.001), and for anemic rats treated with 6 doses Cd 12 + 0,3 (P<0.001) μg MT/g fresh tissue respectively. PAGE 15% T, 2% C_Bis show for intestinal mucosa 2 MT peaks and for brain 3 MT peaks. Anemia induce MT accumulation and increases cadmium incorporation, being anemic subjects eligibles to be submitted first to control and detoxication than the rest of the population, and also MT should be studied as biochemical marker of the pollution.