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

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

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

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.     

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。     

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.     

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。     

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.     

Effect of fixation time on leaching of copper-ethanolamine based wood preservatives

Zusammenfassung Fixation in copper-ethanolamine treated Norway spruce wood is finished in the first or in the second week after impregnation depending on the concentration of wood preservatives used. However, copper losses increased after four weeks of fixation again, presumably due to lignin depolymerisation caused by ethanolamine.      

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。     

Effect of fixation time on leaching of copper-ethanolamine based wood preservatives

Fixation in copper-ethanolamine treated Norway spruce wood is finished in the first or in the second week after impregnation depending on the concentration of wood preservatives used. However, copper losses increased after four weeks of fixation again, presumably due to lignin depolymerisation caused by ethanolamine.     

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。     

分光光度法测定水产品中的二甲胺

建立了分光光度法测定水产品中二甲胺(dimethylamine,DMA)含量的方法。水产样品中的DMA用三氯乙酸提取、与铜铵试剂反应显色后用苯萃取,用分光光度计在波长434 nm测定吸光度值,根据标准曲线计算样品中二甲胺的含量。结果表明:反应体系在pH 12.0、50℃水浴时间3 min下显色良好,DMA浓度在0~10 mg/L内具有良好的线性关系,回归方程为y=0.057 4x-0.005 7(R~2=0.999 7),检出限为6 mg/kg。选用6种不同品种的水产品作加标回收率试验,其加标回收率为86.7%~99.2%,相对标准偏差为1.36%~4.78%。     

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。     

水产品中亚硫酸盐应用研究进展及残留检测

对水产加工品中亚硫酸盐的应用和残留状况进行了研究。结果表明:亚硫酸盐在鱼、虾、蟹制品中应用广泛;在不同的水产品加工中,亚硫酸盐的作用不同;制品中亚硫酸盐的残留量因加工方式和添加量而异。综合检测结果表明,亚硫酸盐污染已经成为水产加工品的主要污染因素之一。