Effects of acid rain on growth and nutrient concentrations in Scots pine and Norway spruce seedlings grown in a nutrient-rich soil

The effects of artificially applied acid precipitation on growth and nutrient concentrations of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst.) seedlings were investigated in a long-term acid irrigation experiment in field conditions. Seedlings of northern and southern origin were planted in boxes containing peat and composted soil rich in nutrients, and sprinkler irrigated with water acidified with nitric and sulphuric acids to pH 3 or pH 4 for periods varying from two to three and a half growing seasons during 1986-1989. Water irrigated (pH 5.4-7.6) and non-irrigated groups of seedlings were also included in the experiment. At the end of the experiment needles, main and lateral shoots and roots were collected from the seedlings for the determination of height growth and biomass partitioning, and for the analysis of S, N, Mg, P, K, Ca, Mn and Fe concentrations. The treatment effects compared to the irrigated control were studied using multivariate analyses of variance and covariance. In the pine seedlings the total dry matter production increased by 25-70% compared with the irrigated controls when the total wet deposition to the seedlings exceeded 67 kg S ha(-1) and 36 kg N ha(-1) (e.g. after two growing seasons' exposure of the pH 3 treatment). The increase was mainly due to an increase in needle dry weight (54-72% greater at pH 3) and root weight (20-65% greater at pH 3), whereas the height growth or shoot weight growth were less affected. The northern provenance pine seedlings responded more clearly to the pH 3 irrigation than the southern ones. The treatments had no consistent effects on any of the growth variables studied in the spruce seedlings, however. The pines had higher root and foliage Ca concentrations as a result of the acid irrigation, whereas in spruce, acid rain decreased the Ca concentration in needles and shoots. Root Mn and Fe concentrations were higher in both species as a result of the pH 3 treatment. A higher soil conductivity and Ca concentration resulted from the prolonged pH 3 treatment. The results strongly support the hypothesis that the long-term growth and nutrient allocation response of conifers to acid precipitation is dependent both on the tree species and on the nutritional status of the soil.     

阳离子共聚物的反相悬浮聚合

采用反相悬浮聚合方法合成颗粒状的阳离子型高分子絮凝剂。选用丙烯酰胺(Am)和氯化[N,N,N-三甲基乙醇丙烯酸酯]盐(AQ)两种单体,研究反应体系的特征及影响分子量的基本因素,诸如温度、单体浓度、引发剂浓度、分散剂浓度、水相和油相的体积比(Vw/Vo)对分子量的影响。为了选择出最佳原料比,本文对两种单体的原料比进行了研究。实验中还发现亚硫酸钠是一种优良的缩短反应诱导期、加速反应进程的试剂。     

Ecoprofit-Styria-prepare Thirteen pollution prevention case studies in the Styrian industry

The paper focuses upon the organization of a federal state-funded pollution prevention project in the Styrian industry. The project includes 13 companies from the textile, pulp and paper, machine building, wood working and printed circuit board manufacturing industries, covering most of the sectors and sizes in the Styrian industry. It started in January 1994 and will last for one year. It will demonstrate the possibilities of pollution prevention and the need for further research work. This project will make use of the methods and tools that were refined in the Austrian Prepare project. As a first step, a systematic balance of all the inputs and outputs of a company is made, after which the weak points and inefficiencies of material and energy use are identified and the options for improvements, both economical and ecological, are defined. Consequently, modifications in products and production lead to a situation with less waste and emissions. The preliminary lessons from these projects are presented: as a rule, the utilities (consumption of process materials and water, cleaning, energy, preparatory and finishing steps) are treated as black boxes and usually represent a considerable optimization potential. In these areas especially there is usually a lack of information and coordination as well as a need for a systematic and comprehensive approach. Leadership in the company and creative consultants are needed for starting lasting successful pollution prevention projects.     

Promotive effect of pyridine on indole degradation by activated sludge under anoxic conditions

Batch experiments were carried out to investigate the promotive effect of pyridine on indole degradation under denitrifying conditions. The seed sludge was obtained from a local coal-coking wastewater treatment facility and was acclimated in the laboratory. Indole and pyridine were supplemented to the synthetic wastewater at different ratios. The optimum ratio of chemical oxygen demand (COD) to nitrate (C/N) was 8.4–8.9 for both denitrification and indole and pyridine degradation. At a temperature of 28°C and pH of 7.0–7.5, the nitrate reductase activity (NRA) was in the best state. The addition of pyridine could promote NRA and the degradation of indole. When the initial concentration of indole was 150 mg/L, the concentration ratio of indole to pyridine was in the range of 1–10. Under optimum C/N conditions, the degradation of indole could be described with pseudo-zero-order kinetics. There was no accumulation of nitrite during the reaction. When the concentration ratio of pyridine to indole was less than 0.25 with an increase in the pyridine proportion, there were more significant augment rates for NRA and the degradation of indole than the situation when the concentration ratio was more than 0.25. __________ Translated from Environmental Science, 2006, 27(2): 300–304 [译自: 环境科学]     

斯德哥尔摩,人类环保之船从这里启航

1969年。经由瑞典政府提议．联合国大会决定1972年在瑞典首都斯德哥尔摩召开联合国人类环境会议。这是联合国历史上首次以环保为主题的会议．是人类环境意识觉醒的标志．在人类社会发展史上具有里程碑式的意义。1972年6月5日，会议在斯德哥尔摩隆重开幕。133个国家的1300多名代表出席了这次会议。会议通过了《联合国人类环境会议宣言》和《行动计划》。宣告了人类环境新观念的诞生，达成了“只有一个地球”．人类与环境是不可分割的“共同体”的共识。1972年6月5日。全球环境保护的航船从斯德哥尔摩启航。33年过去了，让我们重回斯德哥尔摩，去寻找历史的轨迹．去了解这座环保之都的未来航向。[编者按]     

Biologie und Biochemie des Elements Selen

The importance of selenium as an essential trace element has progressively emerged during the last years due to the analysis of selenium deficiency diseases and to the identification and characterization of a number of selenoenzymes. Selenium is incorporated in the catalytic site of the enzymes as an integral selenocysteine residue. The pathway of selenocysteine biosynthesis and incorporation has been elucidated recently for Escherichia coli. This article presents an overview on these subjects and describes the mechanisms which confer selenocysteine specificity in the framework of protein biosynthesis. In addition, some considerations concerning the phylogeny of selenocysteine incorporation are presented and a model for the evolution of the selenocysteine pathway is proposed.     

PHBV表面疏水改性用作吸油材料的研究

利用多种表面改性剂对生物可降解材料PHBV进行了表面改性实验研究，测定了不同改性剂改性后PHBV的吸油率以及温度对其吸油效果的影响，并探讨了改性机理，研究结果表明：不同改性剂对PHBV的改性效果有所差异，从疏水和吸油的共同效果来看，最佳疏水改性剂为添加量5％时的硅油，温度对未改性PHBV和改性PHBV的吸油率及吸油速度均有影响。