Formation and emission of chloroanisoles as indoor pollutants

GOAL, SCOPE AND BACKGROUND: Complaints by residents of frame-houses about musty odour in the houses has become an increasing problem within the last years. An additional problem is that the odour is transferred to clothes and skin. The persons themselves do not recognize the smell after a while because of adaptation. Serious social problems are the result. For a long time, the smell was explained to be from mould due to construction-based humidity problems. However, in an increasing number of houses, no indications were found for elevated levels of mould growth. METHODS: Air and material samples were taken from 5 houses, which show typical musty odours, and analysed with respect to chlorophenols and chloroanisoles. Additionally, some samples were analysed for lindane and its metabolites, because lindane was commonly used together with pentachlorophenol (PCP) for wood protection. RESULTS AND DISCUSSION: Meticulous analysis resulted in the identification of chloroanisoles, mainly 2,3,4,6-tetrachloroanisole. These substances are known from corky wines and from contamination of food from pentachlorophenol (PCP) treated pallets and result from microbiological metabolic processes. Pentachlorophenol was commonly used to protect wood from fungi in Germany mainly in the later 60s and 70s. Details of these processes, as well as effective methods to identify chloroanisoles in the problem houses, are described. CONCLUSIONS: Chloroanisoles formed by metabolism of PCP have been well known to contaminate food or wine. Here, they were identified and are probably responsible for the musty odours in the frame houses. Since it is quite clear that these substances were not components of building materials used in the houses, an explanation for chloroanisole formation is proposed. Localized dampness probably favours microbial growth associated with metabolic conversion of chlorophenols to the corresponding chloroanisoles, primarily 2,3,4,6-tetrachloroanisol, which spread throughout the buildings, resulting in the observed odours. RECOMMENDATIONS AND OUTLOOK: The group of chloroanisoles has been recognized as important indoor pollutants as they possess musty odours at extremely low concentrations, e.g. for 2,4,6-trichloroanisole in a range of 5-10 ppt in air (Staples 2000). On the basis of currently available toxicological data, exposure of the occupants to the concentrations of chloroanisoles measured is not associated with a health risk. No correlation could be observed between concentrations of chloroanisoles and PCP in house dust and indoor air. However, chloroanisoles are good indicators for possible PCP-treatment of wood in frame houses and their detection should initiate investigations on PCP contamination. Research is continuing to identify the microorganisms involved and to devise a remediation procedure for affected houses.     

Persistence of methyl <Emphasis Type="Italic">tertiary</Emphasis> butyl ether (MTBE) against metabolism by Danish vegetation

BACKGROUND: Methyl tertiary butyl ether (MTBE) is the second most highly produced industrial chemical in the US and a frequent groundwater pollutant. At the same time, MTBE is quite persistent to biotic and abiotic decomposition. The goal of this study was to find plant species that could degrade MTBE and might be used in phytoremediation. METHODS: Excised roots and leaves (0.3 g) from more than 24 Danish plant species out of 15 families were kept in glass vessels with 25 ml spiked aqueous solution for 2 to 4 days. MTBE concentrations were 1 to 5 mg/L. Samples were taken directly from the solution with a needle and injected to a purge and trap unit. MTBE and the main metabolite, TBA, were measured by GC/FID. RESULTS AND DISCUSSION: Solutions with roots of poplar (Populus robusta) and a willow hybrid (Salix viminalis x schwerinii) produced TBA in trace amounts, probably stemming from bacteria. Significant MTBE reduction (> 10%) was not observed in any of the tests. Leaves from none of the species (trees, grasses and herbs) reduced the concentration of MTBE in the solution and no TBA, nor any other known metabolite of MTBE, was detected. CONCLUSION: It was not possible to find plants capable of efficiently degrading MTBE. This gives rise to the conclusion that plants probably cannot degrade MTBE at all, or only very slowly. RECOMMENDATIONS AND OUTLOOK: For phytoremediation projects, this has, as consequence, that the volatilization by plants (except with genetically engineered plants) is the only relevant removal process for MTBE. For risk assessment of MTBE, degradation by the plant empire is not a relevant sink process.     

Preliminary evidence for the metabolism of benzo(a) pyrene by Plantago lanceolata

Polycyclic aromatic hydrocarbons (PAHs) have long been recognised as potential carcinogens in animals in which biotransformation into reactive metabolites can lead to DNA damage. In animals PAHs metabolism mainly occurs in hepatic microsomes and is associated with the cytochrome p-450 mediated mixed functional oxidase (MFO) system. PAH metabolism in plants has been shown to occur via a similar enzyme system, but has received relatively little attention. This study is looking at how the plant species Plantago lanceolata metabolises benzo(a)pyrene (B(a)P), which is one of the PAHs whose metabolism has been studied extensively in animals. The aim of the work is to establish firstly that the B(a)P is taken up and secondly that it is biotransformed by the plant to products possibly similar to those found in animals. This work is achieved by using C-14-B(a)P along with whole body autoradiography, scintillation analysis and chromatography techniques to locate the B(a)P and its metabolites.     

植物次生代谢:功能、调控及其基因工程

植物次生代谢物具有多种重要的生物学功能 ,在工农业生产和人们日常生活中具有广阔的应用前景 .随着可持续农业的发展 ,植物次生代谢物的化学生态学功能及其对农产品品质的影响倍受关注 .植物次生代谢调控的生物化学、分子生物学和基因工程已成了当今国际生物界十分活跃的前沿研究领域 .本文仅就植物次生代谢物功能、代谢调控及基因工程研究进行简要的概述 .1　植物次生代谢物的功能1.1　植物次生代谢物的化学生态学功能植物次生代谢物按其合成方式可分为组成型和诱导型两种类型 ,它们在植物与植物、植物与微生物及植物与昆虫之间的关系中行…     

水体突发污染事件在线生物监测技术的发展和应用分析

自1800s以来,经过2个世纪的发展,针对水体突发污染事件的在线生物监测技术越来越完善,其所采用的分析指标主要包括生物行为变化(1900s至目前)、生物新陈代谢变化(1800s至目前)和生物电变化(1980s至目前)等3种,其中,应用最广泛、发展最完善的为基于生物行为指标的在线生物监测技术。进入21世纪以来,在线生物监测技术得到快速发展和普遍应用。中国、美国、德国、韩国和瑞典等国家已经大规模应用基于不同生物指标的在线生物监测技术,以实现对水体突发污染事件的有效监管。随着计算和分析技术的进一步发展,在线生物监测技术也会越来越完善,在维持社会稳定、保证经济可持续发展以及保障人民饮水安全方面将会发挥越来越重要的作用。     

Sequestration of phorbol esters by aposematic larvae of Hyles euphorbiae (Lepidoptera: Sphingidae)?

Summary. The larvae of the hawkmoth species Hyles euphorbiae have a conspicuous aposematic colouration and show gregarious behaviour. It has thus been suggested that they sequester phorbol esters from their food plants which include different species of the genus Euphorbia (Euphorbiaceae) for chemical protection against predators. To test this hypothesis in more detail, we fed larvae an artificial diet with three doses of 12-tetradecanoyl-phorbol-13-acetate (TPA), then examined the faeces and the larval tissues, such as integument, haemolymph and gut of the caterpillars for the presence of TPA. In order to determine the ability of the larvae to detoxify phorbol esters, other larvae were directly injected with a TPA solution and analysed in the same manner. Our study indicates that the larvae of Hyles euphorbiae do not sequester phorbol esters. Upon oral application TPA was not found in the larval integument or the haemolymph. Instead, it was mostly metabolised (about 70–90%). Nevertheless, about 10-30% were retained and recovered in the faeces. The larvae were also able to metabolise and thus detoxify the phorbol ester when TPA was injected directly into the body. These hawkmoth caterpillars are relatively large and have a gut full of plant material, which they regurgitate into the direction of the predator when attacked in nature. Since phorbol esters are very potent toxins and irritants, we postulate that the gut content (and especially the plant slurry disgorged as regurgitant from the anterior gut) alone could be aversive for a potential predator, even if some metabolism has taken place. Thus, although H. euphorbiae caterpillars do not actively sequester phorbol esters, their aposematic colouration appears to be based on chemical defence through phorbol esters retained in the gut.     

农药杀虫双的代谢毒理学研究

杀虫双为我国首创的农用杀虫剂，属沙蚕毒互类农药，以同位素示踪法和现代化学分离技术相结合的手段，进行了杀虫双在动物体内吸收、分布、排泄、转化、动力学以及代谢产物的分离鉴定等一系列研究，杀虫双进入体现人首先转化成沙蚕毒素，胃是主要转化部位，进入体循环，在血液中主要存在于红细胞中，且吸收、分布、排泄迅速，不易蓄积，杀虫双与沙蚕毒素、巴丹、易卫杀的最终代谢产物轮相符，杀虫双中毒死者血液中分离鉴定出沙蚕毒素     

区域系统物质代谢研究——以江苏省南通市为例

为定量地描述一个区域对其自然环境的负荷,论文利用区域系统物质代谢的方法研究了南通市全市范围内食物、能量、水、物质和废弃物的输入与输出。在研究期限内(1996～2002年),固体废弃物输出的增长率高于固体物质输入的增长率,而废水输出的增长率低于淡水输入的增长率。南通市区域代谢的速率正在持续上升。2002年非食物性资源的消耗总量是食物需求的15.8倍。化石燃料能量及电能的消耗是人体能量需求的17.9倍,光合作用固定太阳能的48.36倍。南通市区域代谢的趋势是上升的。尽管各种物质与能量的利用效率提高了,部分物质的循环利用率也上升了,但是还不足以降低其对陆地、水体和大气环境的压力。最后提出降低区域代谢脆弱性、提高代谢效率的相关建议。     

硼污染的个人暴露剂量及其代谢的研究

 以62名处于不同生活、工作环境下的人群为对象,研究了其通过空气粉尘、饭菜和饮水的日硼暴露剂量及通过尿液、粪便的代谢状况.结果表明,从事硼作业的53名工人日硼暴露均值11.8mg/d,是对照人群(1.52mg/d)的7.8倍;通过尿液代谢的硼占总代谢量的94%以上,且班后尿硼与24h全尿硼浓度的相关系数为0.952,班后尿样可代替全尿并反映硼的代谢水平;下班后尿硼浓度与日硼暴露剂量显著相关.多元线性回归可以反映不同暴露途径对尿硼水平的贡献,方程拟合度为43.0%,与实测值的平均相对偏差为23.6%.     

二噁英类化合物的毒性作用机制及其生物检测方法

二噁英类化合物具有高毒性,来源多样且分布广泛,是持久性有机物的典型代表,二噁英类污染物及其对健康的危害已引起了公众的普遍关注。一些二噁英类同系物具有代谢稳定性,其毒性效应主要是通过芳香烃受体介导,而越来越多的研究表明二噁英类毒性作用机制的复杂性。在此背景下,综述了近些年在二噁英类毒性作用机制及其代谢途径的新认识,评价比较了主要二噁英类高通量生物检测方法,以期为该类污染物的环境污染物筛查和风险评估提供参考。