Total soil heavy‐metal concentrations and mobile fractions after 10 years of biowaste‐compost fertilization

The accumulation of heavy metals (HMs) in soils is the most often cited potential risk of compost application. As the ecological effects of metals are related to mobile fractions rather than to total concentrations in the soil, we measured the total (aqua regia–extractable) HM concentrations, the readily available water‐soluble and the potentially bioavailable LiCl‐extractable fraction of soil HMs in a field experiment after 10 y with total applications of 95, 175, and 255 t ha^–1 biowaste compost (fresh matter). Total soil concentrations of Cd, Cr, Cu, Ni, and Pb in the compost treatments were not significantly higher than in the unfertilized control. Total Zn concentrations increased in the treatment with the highest application rate, as expected from the calculation of the Zn load in the composts. In the mobile fractions, as measured in soil saturation extract and LiCl extract, Cd and Pb were not detectable. Concentrations of Cr, Ni, and Zn were in the range published for unpolluted soils in other studies and did not show any differences according to treatment. Easily exchangeable Cu (in LiCl extract) was increased with compost fertilization, most probably due to complexation with low‐molecular organic complexants. Except for Cd and Zn, the results of the mobile HM fractions in the soil were in good agreement with plant HM concentrations. In conclusion, fertilization with high‐quality biowaste compost at such rates and after 10 y of application gives no cause for concern with regard to both total HM concentrations and available HM fractions.     

Long‐term application of biowaste compost versus mineral fertilization: Effects on the nutrient and heavy metal contents of soil and plants

In recent years the use of biowaste compost (BC) as a soil amendment is of increasing interest. The aim of the experiment was to investigate the influence of different fertilization systems: biowaste compost, annual average of 32 Mg ha^—1 BC (fresh matter) and mineral fertilizer (83:52:95 kg ha^—1 NPK fertilizer) on the nutrient and heavy metal contents of soil and plants. Soil samples (1997) and harvest products (1996—1998) from a field trial (initiated 1992) were analyzed for K, Mg, P, Cu, Mn, Mo, Zn, Cd, Ni, and Pb. The five‐year fertilization with composted biowaste did not influence the total contents of Cd, Mn, Mo, and Ni in soil. The total soil contents of Zn and Pb were significantly higher in soils of the BC treatment than in the unfertilized control. Both fertilized plots tended to have higher Cu and Zn contents in harvest products than the unfertilized control. The mineral fertilization inhibited the Mo uptake by plants. In 1998 the mineral fertilization led to higher, and the biowaste compost application to lower, Cd contents in potato tubers as compared to the control.     

Chemistry,stereochemistry and biological properties of KWG 4168

KWG 4168 (8-tert-butyl-1,4-dioxaspiro[4,5]decan-2-ylmethyl(ethyl)(propyl)amine; proposed common name spiroxamine) is a new fungicide consisting of four biologically active isomers (two diastereomers, four enantiomers). The four isomers were separated by preparative HPLC on a chiral stationary phase. The diastereoisomers were synthesised from the corresponding chirally pure glycerol derivatives and were separated by preparative HPLC. COSY, HSQC and NOESY NMR spectroscopy were used to asign the configuration of the amino residue relative to the cyclohexyl ring. Studies of the activity against wheat powdery mildew, as well as the inhibition of sterol biosynthesis in fungi by the four stereoisomers, indicate the contribution of each isomer to the biological activity of spiroxamine.     

影响钢模板及循环钢模带使用寿命的各种因素

花纹钢模板及循环钢模带目前正广泛地应用于层压板的生产工艺,其品质的优劣好坏会直接影响到最终产品的质量。笔者结合所在公司——山特维克传动     

Caco-2细胞模型在茶叶生物活性成分研究中的应用

Caco-2细胞单层的形态和功能特性都类似于人小肠上皮细胞,是研究营养素或药物吸收、转运和代谢的一个重要体外模型,近年来在茶叶生物活性成分的研究中也得到广泛应用.本文对Caco-2细胞中儿茶素、茶氨酸、没食子酸和咖啡碱的吸收和转运机制,儿茶素的代谢以及茶叶生物活性成分药效机理的研究进行了综述,并对采用Caco-2细胞模型快速评价茶叶生物活性成分的吸收特性以促进茶叶保健产品和制剂的开发进行了展望.     

电化学法快速测定茶多酚含量的研究

基于电化学循环伏安法,讨论了3种低成本自制工作电极——银电极、碳糊电极和玻碳电极在茶多酚含量测定应用上的可行性。通过分析茶多酚在电极表面的氧化还原行为,发现所制银电极不适宜检测茶多酚,碳糊电极、玻碳电极的氧化电流峰值与茶多酚含量有良好的线性关系。所制玻碳电极测定绿茶茶样中的茶多酚含量的重复性和准确性较碳糊电极好。与国标方法相比,碳糊电极、玻碳电极检测茶多酚所需时间大大缩短。结果表明,电化学方法可应用于茶多酚含量的快速测定,从而为快速、低价、便捷检测茶多酚提供一条新思路。