Using SFA indicators to support environmental policy

In order to improve the link from Substance Flow Analysis (SFA) studies to environmental policy, a translation is made from the SFA overview of flows and stocks into a limited set of indicators. This set is designed to evaluate a region’s substance regime with regard to environmental quality and sustainable development, including problem shifting in time and space.     

Tolerance of an Albino Fish to Ultraviolet-B Radiation

We exposed albino and pigmented medakaOryzias latipes to simulated solar ultraviolet-B (UVB) radiation to determine if albino medaka were less tolerant of UVB radiation than medaka pigmented with melanin. There was no difference in the number of albino and pigmented medaka that died during the exposure period. Spectrophotometric analyses of the outer dorsal skin layers from albino and pigmented medaka indicated that, prior to exposure, both groups of fish had similar amounts of an apparent colorless non-melanin photoprotective substance that appears to protect other fish species from UVB radiation. Our results indicate that albino medaka were as tolerant of UVB radiation as pigmented medaka because they had similar amounts of this photoprotective substance in the outer layers of the skin.     

Simultaneous gas chromatographic determination of chlorpyrifos and its impurity sulfotep in liquid pesticide formulations

An analytical method for simultaneous determination of the active substance (chlorpyrifos) and its relevant impurity (sulfotep) in commercial pesticide formulations has been developed and validated. The proposed method entails extraction of the analytes from samples by sonication with acetone and analysis by gas chromatography-flame ionization detection (GC-FID). The proposed method was characterized by satisfactory accuracy and precision. The repeatability expressed as relative standard deviation (RSD) was lower than the acceptable values calculated from the modified Horwitz equation whereas individual recoveries were in the range of 98–102% and 80–120% for chlorpyrifos and sulfotep, respectively. The limit of quantification (LOQ) for the impurity (sulfotep) was 0.003 mg mL^?1 corresponding to the maximum permitted level according to Food and Agricultural Organization of the United Nations (FAO) specifications for the active substance (chlorpyrifos) being 3 g kg^?1 of the chlorpyrifos content found. The main advantage of the proposed method was a considerable reduction in the analysis time since both analytes were determined based on a single injection into the GC-FID. Analysis of real samples of commercial pesticide formulations confirmed fitness-for-purpose of the proposed method.     

Does quinone or phenol enrichment of humic substances alter the primary compound from a non-algicidal to an algicidal preparation?

Dissolved organic matter (DOM) has been shown to affect phytoplankton species directly. These interactions largely depend on the origin and molecular size of DOM and are different in prokaryotes and eukaryotes. In a preceding study, however, two humic substance preparations did not adversely affect coccal green algae or cyanobacterial growth even at high concentrations of dissolved organic carbon (DOC). These results contradicted previous findings, showing a clear, negative response of different phototrophs to much lower DOC concentrations. To test whether or not at least defined building blocks of humic substances (HSs) are effective algicidal structures, we enriched two humic preparations with hydroquinone and p-benzoquinone, respectively, and exposed two different green algae, Pseudokirchneriella subcapitata and Monoraphidium braunii, and two cyanobacterial species, Synechocystis sp. and Microcystis aeruginosa, to the unmodified and enriched HSs. As response variables, growth rates in terms of biomass increase, chlorophyll-a content, and photosynthetic yield were measured. The highest concentration (4.17 mM DOC) of the modified HSs clearly inhibited growth; the cyanobacterial species were much more sensitive than the green algal species. However, realistic ecological concentrations did not adversely affect growth. Aerating the exposure solution for 24 h strongly reduced the inhibitory effect of the modified HSs. The algicidal effect was obviously caused by monomers and not by polymerised high molecular weight HSs themselves. Furthermore, the maximum quantum yield (Φ PSII max) was stimulated in the green algal species by low and medium DOC concentrations, but reduced in the cyanobacterial species upon exposure to higher HS concentrations. The quinone- and phenol-enriched HSs only showed algicidal activity at high concentrations of 4.17 mM DOC and lost their effects over time, presumably by oxidation and subsequent polymerisation. This study confirms that the applied humic substances themselves are not effective algicides even if enriched in effective structures.     

生物接触氧化处理微污染地面水的实验研究

生物接触氧化处理微污染地面水的实验结果表明,该方法处理效果显著、稳定性好、操作方便、容易实施,是解决污染给水处理问题的经济可行办法。     

白沙蒿种皮胶质等因素对其植株再生的影响

对白沙蒿原生质体培养得到的愈伤组织进行分化诱导,得到完整植株。培养其中６－ＢＡ的浓度是芽分化的关键因素,白沙蒿种皮胶质对芽的再生有促进作用。不同抗菌素对芽分化的作用不尽相同,其中头孢霉素可增加芽的分化,而卡那霉素则抑制芽的分化。对白沙蒿种皮胶质进行定性、红外光谱和固体核磁共振分析,表明它为纤维素类物质,并带有羧基和甲基。图４表４参１５     

MBR膜污染形成机理及控制

膜污染问题是影响膜生物反应器(MBR)技术推广使用的一大障碍.本文通过对MBR膜污染的形成机理及主要影响因素的分析研究,认为造成膜通透性能降低及工艺运行成本增加的主要污染因素是膜孔的堵塞和凝胶层的形成,在膜过滤过程中,采用优化选择膜组件及运行操作条件、改善污泥混合液的生化特性、确定临界污泥浓度、膜清洗等方法可减少膜孔的堵塞,抑制凝胶层的形成,有效的控制膜污染.     

微塑料对变形杆菌生物膜生长发育的影响

微塑料对生物膜的影响现阶段主要集中于对成熟生物膜群落组成结构变化的研究,缺乏对不同发育阶段生物膜的研究.为探究微塑料对不同发育阶段生物膜的影响,选用环境中广泛存在的变形杆菌和1 μm聚苯乙烯微塑料(PS-MPs)作为研究对象,通过暴露实验研究PS-MPs对生物膜生物量、胞外聚合物(EPS)组成和胞外酶活性的影响.结果表...     

发光细菌毒性测试条件的优化与毒性参照物的应用

针对传统发光细菌毒性测试方法中存在的结果重现性不高、使用剧毒物质氯化汞作为毒性参照物容易造成环境污染等问题,通过一系列实验优化了发光细菌生物毒性测试的条件:适宜pH值为5 0～9 0,最佳暴露时间为20min。同时筛选出了Zn2+作为毒性参照物代替传统方法中的剧毒物质HgCl2。Zn2+具有毒性中等、结果稳定、价格便宜等诸多优点。而且Zn2+与HgCl2的毒性之间存在一定相关性:Zn2+毒性为HgCl2毒性的1 12 5。采用Zn2+作为参照物不仅可以方便地表征不同化学物质的毒性,而且可以直观地表征复杂环境样品的毒性,是一种简便可行的方法。      

污泥性质的重要影响物质-胞外聚合物(EPS)

介绍了胞外聚合物的产生和组成(多聚糖,蛋白质,少量DNA,脂和腐质酸等);胞外聚合物在污泥处理系统中对污泥的絮凝性能、沉降性能、脱水性能及重金属吸附性能的影响;以及胞外聚合物本身的生物降解性。胞外聚合物在废水生物处理中发挥着重要作用。