SI-traceable certification of Cu, Cr, Cd and Pb in sediment and fly ash candidate reference materials

Many fields in environmental analytical chemistry deal with very low limits and thresholds as set by governmental legislations or transnational regulations. The need for the accuracy, comparability and traceability of analytical measurements in environmental analytical chemistry has significantly increased and total uncertainties are even asked for by accreditation bodies of environmental laboratories. This paper addresses achieving these goals to guarantee accuracy, quality control, quality assurance or validation of a method by means of certified reference materials. The assessment of analytical results in certified reference materials must be as accurate as possible and every single step has to be fully evaluated. This paper presents the SI-traceable certification of Cu, Cr, Cd and Pb contents in geological and environmentally relevant matrices (three sediments and one fly ash sample). Certification was achieved using isotope dilution (ID) ICPMS as a primary method of measurement. In order to reduce significantly the number of analytical steps and intermediate samples a multiple spiking approach was developed. The full methodology is documented and total uncertainty budgets are calculated for all certified values. A non-element specific sample digestion process was optimised. All wet chemical digestion methods examined resulted in a more or less pronounced amount of precipitate. It is demonstrated that these precipitates originate mainly from secondary formation of fluorides (essentially CaF2) and that their formation takes place after isotopic equilibration. The contribution to the total uncertainty of the final values resulting from the formation of such precipitates was in general < 0.1% for all investigated elements. Other sources of uncertainty scrutinised included the moisture content determination, procedural blank determination, cross-contamination from the different spike materials, correction for spectral interferences, instrumental background and deadtime effects, as well as the use of either certified values or IUPAC data in the IDMS equation. The average elemental content in the sediment samples was 30-130 micrograms g-1 for Pb, 0.5-3 micrograms g-1 for Cd and 50-70 micrograms g-1 for Cu. Cr was measured in one sample and was about 60 micrograms g-1. The concentrations in the fly ash sample were up to 2 orders of magnitude higher. Expanded uncertainty for the investigated elements was about 3% (coverae factor k = 2) except for Cr, (measured by high resolution ICPMS), for which the expanded uncertainty was about 7% (k = 2).     

Variability of pesticide residues in cauliflower units collected from a field trial and market places in Greece

To estimate the variability of pesticide residue levels present in cauliflower units, a total of 142 samples were collected from a field trial of a cooperative farmer, and 120 samples were collected from different market places in Thessaloniki, Greece. The collected samples were extracted using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction technique, and the residues were determined by liquid chromatography–tandem mass spectrometry. The developed method was validated by evaluating the accuracy, precision, linearity, limit of detection (LOD), and limit of quantification (LOQ). The average recoveries for all the analytes, derived from the data of control samples fortified at 0.01, 0.05, 0.1, and 0.2 mg/kg, ranged from 74 to 110% with a relative standard deviation of ≤8%. The correlation coefficient (R²) was ≥0.997 for all the analytes using matrix-matched calibration standards. The LOD values ranged from 0.001 to 0.003 mg/kg, and the LOQ was determined at 0.01 mg/kg for all the sought analytes. The matrix effect was found to be at a considerable level, especially for cypermethrin and deltamethrin, amounting to +90% and +145%, respectively. For the field samples, the unit-to-unit variability factors (VFs) calculated for cypermethrin and deltamethrin were 2.38 and 2.32, respectively, while the average VF for the market basket samples was 5.11. In the market basket samples, residues of cypermethrin, deltamethrin, chlorpyrifos, and indoxacarb were found at levels ≥LOQ and their respective VFs were 7.12, 5.67, 5.28, and 2.40.     

Valorization of solid waste products from olive oil industry as potential adsorbents for water pollution control—a review

The global olive oil production for 2010 is estimated to be 2,881,500 metric tons. The European Union countries produce 78.5 % of the total olive oil, which stands for an average production of 2,136,000 tons. The worldwide consumption of olive oil increased of 78 % between 1990 and 2010. The increase in olive oil production implies a proportional increase in olive mill wastes. As a consequence of such increasing trend, olive mills are facing severe environmental problems due to lack of feasible and/or cost-effective solutions to olive-mill waste management. Therefore, immediate attention is required to find a proper way of management to deal with olive mill waste materials in order to minimize environmental pollution and associated health risks. One of the interesting uses of solid wastes generated from olive mills is to convert them as inexpensive adsorbents for water pollution control. In this review paper, an extensive list of adsorbents (prepared by utilizing different types of olive mill solid waste materials) from vast literature has been compiled, and their adsorption capacities for various aquatic pollutants removal are presented. Different physicochemical methods that have been used to convert olive mill solid wastes into efficient adsorbents have also been discussed. Characterization of olive-based adsorbents and adsorption mechanisms of various aquatic pollutants on these developed olive-based adsorbents have also been discussed in detail. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed.     

Biotransformation of atrazine and metolachlor within soil profile and changes in microbial communities

Biotransformation studies of atrazine, metolachlor and evolution of their metabolites were carried out in soils and subsoils of Northern Greece. Trace atrazine, its metabolites and metolachlor residues were detected in field soil samples 1 year after their application. The biotransformation rates of atrazine were higher in soils and subsoils of field previously exposed to atrazine (maize field sites) than in respective layers of the field margin. The DT₅₀ values of atrazine ranged from 5 to 18 d in the surface layers of the adapted soils. DT₅₀ values of atrazine increased as the soil depth increased reaching the value of 43 d in the 80-110 cm depth layer of adapted soils. Metolachlor degraded at slower rates than atrazine in surface soils, subsoils of field and field margins with the respective DT₅₀ values ranging from 56 to 72 d in surface soils and from 165 to 186 d in subsoils. Hydroxyatrazine was the most frequently detected metabolite of atrazine. The maximum concentrations of metolachlor-OXA and metolachlor-ESA were detected in the soil layers of 20-40 cm depth after 90 d of incubation. Principal Component Analysis (PCA) of soil Phospholipid Fatty Acids (PLFAs), fungal/bacterial and Gram-negative/Gram-positive ratios of the PLFA profiles revealed that the higher biotransformation rates of atrazine were simultaneously observed with the abundance of Gram-negative bacteria while the respective rates of metolachlor were observed in soil samples with abundance of fungi.     

富里酸对重金属在沉积物上吸附及形态分布的影响

以连续碱提取法获得的乌梁素海沉积物中的富里酸为基础,以原状沉积物和去除有机质沉积物为吸附剂,开展了富里酸对重金属在沉积物上吸附行为和形态分布的影响实验研究.结果表明,有机质的去除和富里酸的添加对沉积物吸附重金属均有一定影响;未添加富里酸条件下,有机质的去除对Cu~(2+)影响最大,可导致沉积物对Cu~(2+)的吸附率下降17.85%;随富里酸添加量的增加,2种沉积物对重金属离子的吸附率均逐渐降低,下降速率表现为Cu~(2+)?Cd~(2+)Zn~(2+)Pb~(2+);当富里酸添加量超过5%时,富里酸逐渐成为影响重金属离子吸附率下降的主导因素;随富里酸添加量的增加,原状沉积物和去除有机质沉积物中重金属的形态分布均有明显变化,添加富里酸增加了体系中H~+的浓度,H~+能够置换碳酸盐结合态金属,使碳酸盐结合态金属从沉积物中释放出来,从而导致重金属的碳酸盐结合态与富里酸添加量呈显著负相关,重金属的有机硫化物结合态含量与富里酸添加量呈显著正相关,Cd因亲有机性较弱,其有机硫化物结合态的含量最低且变化幅度最小.     

A performance-based tabular approach for joint systematic improvement of risk control and resilience applied to telecommunication grid,gas network,and ultrasound localization system

Environment Systems and Decisions - Organizational and technical approaches have proven successful in increasing the performance and preventing risks at socio-technical systems at all scales....     

Determination of acibenzolar-S-methyl and its acidic metabolite in soils by HPLC-diode array detection

A simple and accurate method for the analysis of acibenzolar-S-methyl (benzo[1,2,3]thiadiazole-7-carbothioic acid-S-methyl ester; CGA 245 704; ASM) and its major conversion product, benzo[1,2,3]thiadiazole-7-carboxylic acid (CGA 210 007; BTC), in soils is presented. ASM extraction from soil samples was performed using acetonitrile and BTC was extracted with a mixture of potassium phosphate buffer (0.5 M, pH 3) and acetonitrile (70:30 %, v/v). Both extracts were directly analyzed in a high-performance liquid chromatography-diode array detection (HPLC-DAD) system. Pesticide separation was achieved on a C18 (4.6 mm × 150 mm, 5 μm) analytical column with a isocratic elution of acetonitrile:water 40:60 % (v/v) with 0.6 mL L?1 acetic acid at a flow rate of 1 mL min?1. Linear regression coefficients (r (2)) of the external calibration curves were always above 0.9997. The limits of detection (LOD) and quantification (LOQ) of the method were 0.005 and 0.02 mg kg?1 for ASM, and 0.01 and 0.05 mg kg?1 for BTC, respectively. Recoveries were investigated at six fortification levels and were in the range of 90-120 % for ASM and 74-96 % for BTC with relative standard deviations (RSDs) below 11 % in all cases. The method was also validated by analyzing freshly spiked soil samples with 2.7% organic matter content at 0.5 mg kg?1 level, with slightly lower recovery values only for ASM. Moreover, recoveries for intermediate aged residues of the analytes were similar to fresh residues. This method was also applied to determine ASM half-life (t(?) = 8.7 h) and the rate of the acidic metabolite formation.     

40.5kV真空灭弧室内部电场强度分布的仿真分析

40.5 kV/2.5 kA/63 kA真空灭弧室作为363 kV/5 kA/63 kA快速断路器串联模块的子单元,研究其内部电场强度分布以确保其绝缘性能,对于整套快速断路器装置的安全可靠运行尤为重要。根据实际参数搭建了40.5 kV真空灭弧室的基本模型,利用Ansoft 有限元计算仿真软件搭建了40.5 kV真空灭弧室的仿真模型,进行了电场强度分布的仿真计算,得到了灭弧室中的动触头台阶倒角区域、动触头倒角区域、静触头台阶倒角区域、静触头倒角区域的电场强度最大,最有可能发生击穿的结论。提出了通过改变台阶倒角和触头倒角以改善电场分布进行优化设计的建议,并利用Ansoft 仿真软件进行改变台阶倒角值和触头倒角值后的仿真计算,得到了触头台阶处倒角取值2mm、动静触头倒角2mm或3mm的设计较优,只设置1个触头片时触头倒角取值3 mm设计较优。     

DEVELOPMENT OF DESIGN STORM HYETOGRAPHS FOR CINCINNATI,OHIO1

ABSTRACT A synthetic storm rainfall hyetograph for a one-year design frequency is derived from the one-year intensity-duration curve developed for Cincinnati, Ohio. Detailed rainfall data for a three-year period were collected from three raingages triangulating the Bloody Run Sewer Watershed, an urban drainage areas of 2380 acres'in Cincinnati, Ohio. The advancement of the synthetic storm pattern is obtained from an analysis of the antecedent precipitation immediately preceding the maximum period of three selected durations. Rains which produced excessive runoff at least for some duration were considered only. The same approach can be used for other design frequencies. The purpose of this study is to provide synthetic storm hyetographs to be used as input in deterministic mathematical models simulating urban storm water runoff for the design, analysis and possible surcharge prediction of sewer systems.