Relative leaching and aquatic toxicity of pressure-treated wood products using batch leaching tests

Size-reduced samples of southern yellow pine dimensional lumber, each treated with one of five different waterborne chemical preservatives, were leached using 18-h batch leaching tests. The wood preservatives included chromated copper arsenate (CCA), alkaline copper quaternary, copper boron azole, copper citrate, and copper dimethyldithiocarbamate. An unpreserved wood sample was tested as well. The batch leaching tests followed methodology prescribed in the U.S. Environmental Protection Agency toxicity characteristic leaching procedure (TCLP). The wood samples were first size-reduced and then leached using four different leaching solutions (synthetic landfill leachate, synthetic rainwater, deionized water, and synthetic seawater). CCA-treated wood leached greater concentrations of arsenic and copper relative to chromium, with copper leaching more with the TCLP and synthetic seawater. Copper leached at greater concentrations from the arsenic-free preservatives relative to CCA. Arsenic leached from CCA-treated wood at concentrations above the U.S. federal toxicity characteristic limit (5 mg/L). All of the arsenic-free alternatives displayed a greater degree of aquatic toxicity compared to CCA. Invertebrate and algal assays were more sensitive than Microtox. Examination of the relative leaching of the preservative compounds indicated that the arsenic-free preservatives were advantageous over CCA with respect to waste disposal and soil contamination issues but potentially posed a greater risk to aquatic ecosystems.     

防腐木材胶合性能的基础研究

本试验使用两种水溶性防腐剂铜铬砷(CCA)和氨溶烷基胺铜(ACQ-3)对人工林落叶松和杨树木材进行处理,分析处理后木材表面的接触角的变化,利用差示扫描量热仪分析处理后的木材对胶粘剂固化的影响。试验结果表明:经过CCA处理后的木材表面的接触角变化相对较小;经过ACQ处理后的木材,更适合用异氢酸酯进行胶合;经过CCA处理后木材,较适合用酚醛树脂和间苯二酚胶合。     

Effect of simulated rainfall and weathering on release of preservative elements from CCA treated wood

The release of arsenic from wood pressure-treated with chromated copper arsenate (CCA) can be decreased by application of wood finishes, but little is known about the types of finishes that are best suited for this purpose. This study evaluated the effects of finish water repellent content and ultraviolet (UV) radiation on the release of arsenic, copper, and chromium from CCA-treated wood exposed to simulated rainfall. Deck boards treated with CCA were either left unfinished or dipped in a finish prepared with 1%, 3%, or 5% water repellent. All specimens were exposed to leaching from simulated rainfall, and a subset of specimens was also exposed to UV radiation. The rainfall was collected and analyzed for total elemental arsenic, copper, and chromium. The water repellent significantly decreased the amounts of these elements in the runoff, but for the short duration of this study there was no difference among the three water repellent concentrations. It is possible that water repellent content would have a greater effect over a longer exposure period. Exposure to UV radiation caused a significant increase in leaching from both finished and unfinished specimens. This effect may be a result of increased surface area during weathering as well as loss of fibers caused by UV-induced surface erosion.     

Resistance based moisture content measurements on native,modified and preservative treated wood

Resistance characteristics were determined for a total of 27 wood-based materials containing native soft- and hardwoods, differently modified timbers and preservative treated timbers. A functional relation between measured electrical resistance and gravimetrical wood moisture content (MC) was established in a range between 15 and 50 % MC. Most precise MC estimation was found for salt-treated timber (±2.5 %), followed by native timber (±3.5 %) and modified timber (±7 %) in the hygroscopic range. As expected, preciseness decreased above fiber saturation, but was still sufficient for native timber (±8 %) and preservative treated wood (±5 %) at approx. 50 % MC.     

Resistance of preservative treated rubber wood (Hevea brasiliensis) to marine borers

The susceptibility of rubber (Hevea brasiliensis) wood to marine borer attack limits its use for marine purposes. In the present study three types of biocides viz. copper creosote, arsenical creosote and a dual preservative treatment with copper- chrome- arsenic and creosote were selected for comparing their relative efficacy in preventing biodeterioration. The treated panels were exposed at the test site in Cochin harbour. The extent of internal damage through marine borer attack was assessed through visual observations, X-ray photographs and mechanical strength testing. The untreated test panels were destroyed within six months whereas it was found that preservative treatment prevented biodeterioration under marine conditions. This was confirmed by radiographic studies and comparison of compressive stress at maximum force. The service life of this cheaply and easily available timber can be increased to meet the growing demand of timber in the small-scale fisheries sector.

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Resistenz von behandeltem Gummibaumholz gegen Bohrmuscheln

Zusammenfassung Die Anfälligkeit von Gummibaumholz gegen den Angriff von Bohrmuscheln begrenzt seine Verwendung für die Seefahrt. In dieser Studie werden drei Typen von Bioziden ausgewählt, nämlich Kupfer-Kreosot, Arsen-Kreosot und eine zweifache Schutzbehandlung mit Kupfer-Chrom-Arsen und Kreosot. Die entsprechenden Schutzwirkungen gegen biologischen Abbau wurden ermittelt und verglichen. Die behandelten Platten wurden im Hafen von Conchin zur Prüfung ausgesetzt. Das Ausmaß der Schädigung durch Bohrmuscheln wurde visuell, mittels Röntgenaufnahmen sowie durch Prüfen der mechanischen Festigkeit bestimmt. Die unbehandelten Proben waren innerhalb von sechs Monaten zerstört, während die Schutzbehandlung den biologischen Abbau im Meer verhinderte. Das wurde bestätigt durch radiographische Untersuchungen und Drucktests bei maximaler Last. Die Lebensdauer dieses billigen und leicht erhältlichen Schnittholzes kann soweit erhöht werden, dass die Anforderungen des kleinen Wirtschaftssektors der Fischerei erfüllt werden.

     

水产品中氯霉素检测条件的优化

目的建立液相色谱串联质谱法测定加工水产品中的氯霉素,并对提取溶剂、净化条件、流动相进行了优化。方法样品采用乙酸乙酯提取,HLB固相萃取柱净化,C_(18)色谱柱分离,ESI源负离子模式对氯霉素进行检测。结果氯霉素在0.1~10μg/kg范围内线性关系良好,相关系数为0.999,在基质样品中添加0.1、0.2和10.0μg/kg 3个水平药物,其回收率在95.0%~103.2%之间,相对标准偏差3.72%~6.85%,方法检测限为0.1μg/kg.结论该方法可靠、稳定,可满足加工水产品中氯霉素残留检测与确证需要。     

Leachability and termite resistance of wood treated with a new preservative: ammonium borate oleate

Synthesis of a new chemical compound combining water-repellence of oleic acid and biocidal effect of boric acid linked by ammonia have been followed and validated by fourier transformed infra red (FTIR). This compound named ammonium borate oleate (ABO) has then been studied as a wood preservative. Different molar ratios of oleic acid have been involved in the synthesis of ABO and leachability of those mixes from wood observed according to Japanese industrial standard. The formulation one mole of boric acid and one of ammonia (1:1:4) for four moles of oleic acid has shown the best efficiency compared to formulations 1:1:1, 1:1:2 and 1:1:3 with about 52% of boron remaining after weathering when other formulations retained respectively 10%, 29% and 46% of boron in the case of an impregnation of Cryptomeria japonica. Seven solutions of 1:1:4 ABO in ethanol of different concentrations were then produced and sapwood blocks of C. japonica and Fagus crenata were impregnated. A toxicity threshold of around 2.0 kg/m³ for both species was determined in a termite resistance test to Coptotermes formosanus indicating the positive effect of combining water repellent and biocide. Termite mortality recording and microscopic observations complete this study indicating that the action mechanism of ABO is providing a water resistant inner coating.     

Extraction of hexavalent chromium from chromated copper arsenate treated wood under alkaline conditions

Information on chromium (Cr) oxidation states is essential for the assessment of environmental and health risks associated with the overall life-cycle of chromated copper arsenate (CCA) treated wood products because of differences in toxicity between trivalent [Cr(III)] and hexavalent [Cr(VI)] chromium compounds. Hypothetical Cr(VI) fixation products were investigated in CCA type C treated sawdust of aspen and red pine during or following preservative fixation by extraction with Cr(VI)-specific extractants. Cr(VI) was found only in alkaline extracts of treated wood. A major source of Cr(VI) was method-induced oxidation of fixed Cr(III) during alkaline extraction, as confirmed by demonstrated oxidation of Cr(III) from CrCl3 treated wood. Oxidation of nontoxic and immobile Cr(III) to toxic and mobile Cr(VI) was facilitated by the presence of wood at pH > 8.5. Thermodynamic equilibrium between Cr(III) and Cr(VI) is affected by pH, temperature, rates of dissolution of CrIII) compounds, and oxygen availability. Results of this study recommend against alkaline extraction protocols for determination of Cr(VI) in treated wood. This Cr oxidation mechanism can act as a previously unrecognized route for generation of hazardous Cr(VI) if CCA treated wood is exposed to alkaline conditions during its production, use, or waste management.     

涂层技术在木制品表面修整中的应用

本文阐述了涂镀技术在木制品修整处理中的应用原理、现状和发展前景。     

磷酸盐保水机理及其对水产品保水作用的研究进展

磷酸盐是目前国内外应用最广泛的食品保水剂之一,磷酸盐及其复配产品常应用在水产品加工以及贮藏过程中,以提高水产品的保水性,最大限度减少水分、风味物质及营养成分的流失,磷酸盐种类繁多,结构复杂,中国已允许添加在食品中的磷酸盐共有16种,对水产品的保水效果取决于磷酸盐的添加种类和添加量,中国明确规定了磷酸盐在不同水产品中的添加量,在冷水水产品中磷酸盐的添加量不得超过5 g/kg(以PO_4~(3-)计)。磷酸盐可以通过提高肌肉中pH、螯合金属离子、增大蛋白质的离子强度、促进肌动球蛋白的解离对水产品产生保水作用。由于其价格低廉,保水效果明显常应用在鱼、虾、贝等水产品中。本文综述了磷酸盐保水剂的研究现状、作用机理及其对水产品保水作用的应用,以期为磷酸盐在水产品中的应用提供参考。     

糟辣椒复合防腐剂配方的优化

采用响应面的方法优化了复合防腐剂对糟辣椒中腐败菌的佳抑菌配方。采用微量释法测定出三种防腐剂对从糟辣椒中分离出的13种腐败菌的小抑菌浓度MIC值,得到X2和X9作为实验菌;采用响应面优化法设计,以抑菌圈直径为响应值,对复合防腐剂进行复配。经响应面分析后建立多元回归模型,确定佳配方的添加量为:脱氢醋酸钠0.1 mg/mL,苯甲酸钠0.22 mg/mL,山梨酸钾0.14 mg/mL。     

新冠肺炎疫情对我国进出口水产品行业影响及应对

当前,新冠肺炎疫情在全球加速蔓延,各国经济大面积停摆,实体经济遭受重创。水产行业所涉及的企业绝大多数为劳动密集型企业,属于实体经济,具有稳就业、稳外贸等作用。受疫情影响,行业生产端、需求端及物流端均面临较大困难和挑战。水产行业是我国农业生产的重要组成部分,更是广东粤西地区的支柱产业,对于促进当地经济发展具有重要作用。本论文着重分析疫情对我国水产行业的影响,并提出相应的对策建议。     

水产品及养殖水中丁香酚类化合物风险研究

目的 检测水产品及养殖水中丁香酚类化合物。方法 应用食品补充检验方法BJS 201908《水产品及水中丁香酚类化合物的测定》，以海水鱼、淡水鱼、海水虾、淡水虾及养殖水作为基质，测定6种丁香酚类化合物的含量。结果 通过对实际样品测定后发现，在水产品中检出了丁香酚类化合物，主要为丁香酚，检出率为28.9%，其中海水鱼相对突出。结论 本研究为丁香酚作为渔用麻醉剂提供了方法论，为丁香酚类化合物在水产运输的合理使用提供理论依据。     

臭氧水在水产品保鲜中的应用研究

本文就臭氧水杀灭鱼体表细菌的条件及其对四种淡水鱼的杀菌效果进行了探讨,并对它在草鱼片保鲜中的应用进行了初步研究。结果表明,臭氧水杀灭鱼体表细菌的最佳条件为:处理方式,冲洗:处理时间,10 min;臭氧水浓度,5ppm;水量,5倍。还表明,臭氧水对鲫鱼、鳊鱼、鲢、鳙四种淡水鱼体表均具有良好的杀菌效果。臭氧水处理可改善草鱼片的感官及微生物质量,并将其保鲜期延长约1.5d。     

防腐剂和抗氧化剂在肉制品中的应用

肉制品已逐渐成为我国的主要食品之一，人们在生活中对它的要求，除了营养和良好的质地外，适当的保质期同样也很重要，特别是现代社会，生产相对集中，而销售又比较分散的情况下，肉制品的防腐保鲜尤为重要，科学地选择、规范化地使用防腐剂确实是很必要的。     

木材胶粘剂废水污染及治理

分析了当前木材胶粘剂废水污染的现状和原因;提出了治理废水污染的建议;综述了处理废水的方法和研究现状。     

Arsenic leaching from mulch made from recycled construction and demolition wood and impacts of iron-oxide colorants

Mulch made from recycled construction and demolition (C&D) wood has been reported to contain elevated levels of arsenic from inadvertent inclusion of chromated copper arsenate (CCA)-treated wood. Such mulch is also commonly colored with iron oxide, a compound known to bind arsenic. The objectives of this study were to quantify the releases of arsenic from mulch made from C&D wood, to evaluate the impacts of an iron-oxide colorant in potentially decreasing arsenic leaching rates, and to evaluate the relative significance of additional variables on leachate concentrations. Atotal of 3 sets of mulch samples (0%, 5%, or 100% CCA-treated wood) were prepared containing a sample either with or without colorant addition. Each sample was subjected to two tests: a field leaching test and the Synthetic Precipitation Leaching Procedure (SPLP). Results showed that arsenic concentrations in the field leachate from the 0% treated wood mulches were consistently low (<0.003-0.013 mg/L) whereas leachates from 5 and 100% treated wood mulches were characterized by higher arsenic concentrations (0.059-2.23 mg/L for 5%; 0.711-22.7 mg/L for 100%). The mass of arsenic leached from the field samples during the 1-year monitoring period was between 10 and 15% of the initial mass of arsenic. The colorant reduced the leaching of arsenic by more than 20% for the field leachate and 50% for the SPLP leachate, on average. However, the study showed that the effect may not last for long periods. Besides colorant addition other factors were observed to affect the amount of arsenic leached from contaminated mulch. These include the proportion of CCA-treated wood in the mulch, time, and pH of rainfall.     

肉制品的防腐措施与复合防腐剂

肉制品的防腐理论和方法最广泛、最被接受的是栅栏理论在防腐中的应用。肉制品防腐的栅栏因子的作用效果是相互协同叠加的，微生物的生长由于栅栏因子的设置足以使微生物被抑制时，就达到了我们防腐的目的，正确的栅栏因子设置可以达到事半功倍的效果。主要介绍了肉制品的防腐措施与复合防腐剂的应用。     

响应面法优化水产品低温保鲜冰配方的研究

为解决保鲜介质温度波动大以及保冷时间短对水产品鲜度的影响,本文以聚丙烯酸钠、氯化钠、丙二醇为主要成分,对水产品低温保鲜冰的配方进行优化。在单因素实验的基础上,依据Box-Behnken实验设计原理,采用响应面进行分析,以优化最佳的低温保鲜冰配方。结果表明:低温保鲜冰的最佳配方为聚丙烯酸钠1.0%、氯化钠0.6%、丙二醇2.1%,此低温保鲜冰可在水产品微冻温度带（-3^-1.5℃）维持130 min,与传统盐水介质相比延长约60 min。该低温保鲜冰维持低温时间更长、温度更加稳定,能更有利于水产品的贮藏加工。