Impact of surface water conditions on preservative leaching and aquatic toxicity from treated wood products

New alternative wood preservatives contain higher levels of copper (Cu) which can promote aquatic toxicity in natural water systems. Earlier work focused on evaluating toxicity using laboratory generated leaching solutions. In this study, the impact on preservative leaching and aquatic toxicity from treated wood products was evaluated using natural surface waters including waters from two rivers, three lakes, two wetlands, and one seawater, in addition to synthetic moderate hard water and deionized water. Blocks of wood treated with Cu based alternatives such as alkaline copper quaternary (ACQ) and copper boron azole (CBA), along with chromated copper arsenate (CCA)-treated wood, were leached under quiescent conditions, and total Cu, labile Cu, and heavy metal toxicity were measured. Results show that ACQ- and CBA-treated wood leach approximately 10 and 20 times more total Cu relative to CCA-treated wood and that the presence of organic and inorganic ligands in natural waters lowered the labile fraction of Cu relative to that from laboratory generated leaching solutions. Aquatic toxicity was found to correlate with the labile Cu fraction, and hence, the aquatic toxicity of the treated wood leachates was lower in natural waters in comparison to laboratory leaching solutions. The results of the present study suggest that studies designed to evaluate the impacts of treated wood should therefore consider the role of complexation in reducing the labile Cu fraction and its potential role in decreasing toxicity.     

Embedment tests parallel-to-grain and ductility aspects using various wood species

Embedment tests parallel-to-grain using dowels with different steel grades and five wood species were carried out. The specimen sampling with regard to density was random and the specimens were tested at different moisture contents. Furthermore, own tests were extended by results from literature. Observed ductility aspects using different wood species are discussed. Comparisons with the existing design equation in Eurocode 5 were made. It was found that the equation penalises species with higher densities. An adjustment of density and embedment strength to 12 % moisture content reduced the scatter considerably. Moreover, based on the test results, the sophisticated distinction of softwood in many strength classes based on minor differences in density is considered to be overly precise as far as embedment strength is concerned. An influence of the dowel steel grade was measured although the dowels remained elastic as required by standard embedment test protocols.     

Using biodynamic models to reconcile differences between laboratory toxicity tests and field biomonitoring with aquatic insects

Aquatic insects often dominate lotic ecosystems, yet these organisms are under-represented in trace metal toxicity databases. Furthermore, toxicity data for aquatic insects do not appear to reflect their actual sensitivities to metals in nature, because the concentrations required to elicit toxicity in the laboratory are considerably higher than those found to impact insect communities in the field. New approaches are therefore needed to better understand how and why insects are differentially susceptible to metal exposures. Biodynamic modeling is a powerful tool for understanding interspecific differences in trace metal bioaccumulation. Because bioaccumulation alone does not necessarily correlate with toxicity, we combined biokinetic parameters associated with dissolved cadmium exposures with studies of the subcellular compartmentalization of accumulated Cd. This combination of physiological traits allowed us to make predictions of susceptibility differences to dissolved Cd in three aquatic insect taxa: Ephemerella excrucians, Rhithrogena morrisoni, and Rhyacophila sp. We compared these predictions with long-term field monitoring data and toxicity tests with closely related taxa: Ephemerella infrequens, Rhithrogena hageni, and Rhyacophila brunea. Kinetic parameters allowed us to estimate steady-state concentrations, the time required to reach steady state, and the concentrations of Cd projected to be in potentially toxic compartments for different species. Species-specific physiological traits identified using biodynamic models provided a means for better understanding why toxicity assays with insects have failed to provide meaningful estimates for metal concentrations that would be expected to be protective in nature.     

Thermal degradation products of wood

Woods were degraded by analytical pyrolysis at 450°C. The degradation products were separated by gas chromatography and the polysaccharide derived degradation products were characterized by mass spectrometry using electron impact (EI) and chemical ionization (CI). The complete (EI) mass spectra and structural formula of 104 polysaccharide derived products are presented. The mass spectral recognition of anhydrosugars and the presence of structure isomers from dihydro-methyl-furanones in the product mixture is discussed.     

Thermal degradation products of wood

Thermal degradation products of woods arising at 450°C have been separated by gas chromatography on a DB-1701 capillary column. GC retention times and mass spectral data of 104 polysaccharide derived pyrolysis products are tabulated. The elemental composition of 76 identified compounds are also presented. The mass spectra were obtained by electron impact ionization (EI). However, the molecular mass of all degradation products with Mw>76 was determined by chemical ionization (CI) using iso-butane as reagent gas. The peak assignment was proved in 38 cases by mass spectrometry of authentic compounds and 32 degradation products were identified according to the literature. The spectral data are presented as a Mass Peak Index showing the intensity of the nine most abundant peaks.     

Thermal degradation products of wood

After thermal degradation of wood the lignin degradation products were separated by gas chromatography and identified by mass spectrometry. The mass spectra and chemical formulae of 82 monomeric lignin derived degradation products are presented.     

气相色谱法同时测定水产品中28种多氯联苯同系物

建立了气相色谱法同时测定水产品中28种多氯联苯同系物的分析方法。该方法用正己烷和二氯甲烷混合溶液超声辅助提取,提取液依次用浓H2SO4、中性Al2O3和弗罗里硅土净化,气相色谱定量,气相色谱串联质谱确证。结果显示,在2.00~200μg/L浓度范围内,28种多氯联苯同系物线性良好,相关系数r0.999 1;加标量为0.5μg/kg和10.0μg/kg时,加标回收率范围分别为82.4%~106%和88.2%~97.8%,相对标准偏差范围分别为0.34%~5.95%和5.97%~13.3%;方法检测限和定量限范围分别为0.021~0.12μg/kg和0.07~0.40μg/kg。该方法适合批量水产品中28种多氯联苯同系物的同时测定。     

Thermal degradation products of wood

The analysis of volatiles after thermal degradation of wood allows specific characterization of wood and its potential use as raw material for different purposes. Thermal degradation products from analytical pyrolysis have been separated by gas chromatography and characterized by mass spectrometry. Up to 82 different degradation products of lignins are tabulated. In following publications also degradation products derived from polysaccharides will be presented.     

Seasonal and spatial relationship of chemistry and toxicity in atmospheric particulate matter using aquatic bioassays

In light of current interest in better understanding the environmental impact of atmospheric particulate matter (PM), a new strategy has been employed to screen the relative toxicities of ambient and source aerosols. Short-term and acute aquatic bioassays using Ceriodaphnia dubia and a green alga (Selenastrum capricornutum) as test organisms have been in use for many years in the regulation of wastewater effluents. These tests have been employed in the present study to compare the toxicity of water extracts of atmospheric particulate matter and dichloromethane (DCM) extracts that have been transferred to dimethyl sulfoxide and diluted in water. Atmospheric PM was collected at four sites located near the south shore of Lake Michigan and one site in Michigan's Upper Peninsula at discrete events during three seasons. Parallel chemical analyses of the two extracts directly assessed the relation between the chemical composition and the toxicity of the extract. Inductively coupled plasma analysis of the metals in the water extract and gas chromatography-mass spectroscopy of the organics in the DCM extract showed a relationship between high toxicity and high water-soluble copper concentration and high secondary organic aerosol tracers in the extracted aerosol. Although previous fractionation studies have not looked at water-soluble copper, significant toxicity has been measured in the semipolar and polar organic fractions of ambient aerosols and diesel exhaust particles, which are the fractions in which secondary organic aerosol components would be expected. For the water extracts, the summer samples were consistently more toxic than the autumn or spring samples. There was not a seasonal pattern for the toxicity of the DCM extracts; however, spatial differences were apparent. The toxicity end points of select samples from one site qualitatively correlate with the high polycyclic aromatic hydrocarbon concentrations. Additionally, high toxicity in the July DCM extracts from another site may be tied to the presence of the insecticide carbaril. The seasonal and spatial variations captured in the toxicity results in this study tend to qualitatively correlate with trace organic components and metals and not bulk particulate matter composition.     

Effects of high-pressure process on kinetics of leaching oil from soybean powder using hexane in batch systems

Mass transfer models of leaching oil from soybean (Glycine max) flour with hexane after high-pressure process (HPP) treatment were developed. High pressure (450 MPa) was applied to the soybean flour (mean diameter of flour particle: 365 μm) for 30 min before leaching the oil components in the solvent. The ratio of solvent (volume, mL) to soybean flour (mass, g), such as 1:10 and 1:20, was employed to characterize the effect of solvent ratio on the leaching rate in the batch type of extraction process. Ultraviolet absorbance at 300 nm was used to monitor the extraction rate. Saturation solubility (C(AS)) was determined to be 21.73 kg/m3. The mass transfer coefficients (k) were determined based on the 1st- and 2nd-order kinetic models. The 2nd kinetic model showed better fit. The HPP treatment showed a higher extraction rate and yield compared to the control, while the amount of solvent did not affect the extraction rate and yield. The scanning electron microscope showed that HPP-treated soybean particles included more pores than the untreated. The pores observed in the HPP-treated soybean flours might help increase the mass transfer rate of solvent and solute in the solid matrix. PRACTICAL APPLICATION: High-pressure processing can help increase the extraction rate of oil from the soybean flour operated in batch systems. The conventional solid to solvent ratio (1:20) used to extract oil composition from the plant seed did not help increase the amount of oil extracted from the soybean flour.     

Species identification of formed fishery products and high pressure-treated fish by electrophoresis: a collaborative study

The suitability and reliability of three electrophoretic methods of fish species identification, urea isoelectric focusing (IEF), sodium dodecyl sulfate poly-acrylamide gel electrophoresis (SDS-PAGE) and native IEF, were evaluated on formed fish fillets and high pressure fish flesh by a collaborative study among four institutes. By following optimized standard operation procedures, the protein patterns of processed fish were compared to patterns of raw reference samples. The method to use depended of the effect of processing on the protein pattern. The proteins obtained from formed products were not denatured and therefore any of the three methods proved to be adequate, with a preference for native IEF which had a better discriminatory power for the species used. The high pressure process altered the proteins, and so only urea IEF and SDS-PAGE methods could be used. For these products, the chosen method should then be the one with the better discriminating power for the species being examined.     

水产品深加工的开发动向

调味料及食品添加剂 日本开发出的牡蛎健康调味料是以牡蛎精汁和糖类为主要成分的低盐(5%以下)粘稠性风味调料.利用生牡蛎煮汁进行减压浓缩或膜滤浓缩20倍左右得到牡蛎精汁,再配以糖醇或蜂蜜或饴糖,得到健康的调味料产品.其含有精汁中的各种鲜厚风味的谷氨酸、核苷酸、琥珀酸及与鲜味物质有协同效应的糖原.核酸能促进人体的新陈代谢,维持和恢复人体生理功能.牡蛎精汁有抗癌强骨、补虚安神、清热、除烦、美肤等功用,这些功能使它成为健康的调味料产品.     

谷氨酰胺转胺酶在水产品中的应用研究

简要介绍了谷氨酰胺转胺酶的来源、生产工艺、作用机理、特性以及它在水产品加工中的应用研究情况。     

Relative quantification of walnuts and hazelnuts in bakery products using real-time polymerase chain reaction

Two versions of real-time polymerase chain reaction (PCR) for relative quantification of walnuts and hazelnuts in bakery products were developed. The first method is a duplex real-time PCR with 5′-nuclease (TaqMan) probes labelled with FAM and JOE for walnuts and hazelnuts, respectively. The second method uses two real-time PCR assays for walnuts and hazelnuts with TaqMan probes labelled with FAM, carried out in separate microtubes, with normalisation of the results achieved by adding wheat as an internal standard. The internal standard is quantified in a duplex format using the TaqMan probe labelled with JOE. Both methods produced linear calibration curves (r² = 0.9813 for the former method, r² = 0.9992 for the latter) in the range 10–90% (w/w) for walnut–hazelnut mixtures. Almost identical calibration curves were obtained also for walnut–hazelnut mixtures diluted with inert matrix (oat flakes; the inert matrix accounting for 80 and 96% (w/w), respectively). Practical applicability of the developed methods was demonstrated on bakery products from the market. The developed methods will be useful for food control laboratories to facilitate authentication of bakery products with nut filling.     

水产品中孔雀石绿AlphaLISA检测方法的建立

建立孔雀石绿(malachite green,MG)的光激化学发光纳米均相时间分辨荧光免疫法(AlphaLISA)分析方法。将待测物,生物素化-MG-BSA,抗体加入到孔板中,再加入供体微珠和受体微珠。生物素化-MG-BSA和游离的待测物对抗体的竞争使得信号值减小,从而优化检测条件并进行方法学验证。结果表明:该方法特异性良好,与无色孔雀石绿,无色结晶紫无交叉反应,灵敏度为0.42 ng/m L,MG在2种鱼样品中的回收率在81.0%~105.0%和84.0%~90.8%之间,批内精密度RSD9.5%,批间精密度RSD16.0%。MG-AlphaLISA方法可以简单、快速的对鱼类进行MG测定,具有特异性强、灵敏性高、稳定等特点。     

微冻技术在水产品保鲜中的研究进展

本文概括介绍了微冻保鲜技术的原理与发展现状,从反映鲜度的K值、TVB-N值、p H、微生物指标、汁液损失与质构等指标着手,结合水产品肌肉组织结构的微观观察,分析微冻贮藏期间冰晶的形成机理,阐述微冻保鲜对水产品贮藏期间品质影响的应用研究进展与存在的问题。     

微冻技术在水产品保鲜中的研究进展

本文概括介绍了微冻保鲜技术的原理与发展现状,从反映鲜度的K值、TVB-N值、p H、微生物指标、汁液损失与质构等指标着手,结合水产品肌肉组织结构的微观观察,分析微冻贮藏期间冰晶的形成机理,阐述微冻保鲜对水产品贮藏期间品质影响的应用研究进展与存在的问题。      

茶多酚在水产品保鲜中的应用研究

介绍了茶多酚在水产品中的保鲜机理,综述了茶多酚在水产品贮藏保鲜中的最新进展,分析了目前研究中存在的问题,并展望了茶多酚的应用前景。     

蛋白质免疫印迹技术在水产品中的应用

蛋白质免疫印迹技术作为一门新兴的技术,可对待测样品中目的蛋白质进行定性定量分析,在蛋白质组学研究中得到广泛应用,也为探究水产品中蛋白质组成及变化规律研究带来了新的途径。本文在介绍蛋白质免疫印迹技术原理及特点的基础上,总结了近年来该技术在水产品加工、贮藏、品质鉴别及质量安全方面的应用研究进展,探讨了蛋白质免疫印迹技术在蛋白质组学、多组学技术联用等研究水产品中蛋白质变化的应用前景并进行了展望,以期为水产品中品质与安全领域的蛋白质免疫印迹技术相关研究提供参考与借鉴。