Effects of fluoride on growth and reproduction of the army worm, Mythimna separata (Walker)

This paper deals with effects of airborne fluorine on the army worm, Mythimna separata (Walker), by rearing the larvae on the wheat foliage exposed to HF or fumigating the larvae on the artificial diet with the pollutant. Larval relative growth rate (GR) and index of population trend of the insect reduced by 5% and 11%, respectively, when the larvae were reared on the foliage taken from the wheat plants exposed to 0.87 g·dm-2·day-1 of fluorine compared with those of the control. An extra instar appeared in a majority of the larvae treated. Survival rate and GR of the larvae on the wheat plant being exposure to the same concentration of fluorine in field open-top fumigation device were 40% and 15% lower than that of the control, respectively. Similar experiment with the insect on the artificial diet also showed that direct impact of the pollutant on the army worm was greater than its indirect effect via their host plant.     

Preliminary study on organic contaminants in the water of northwest part of the Lake Chao

The waterquality of the downstream of Nanfei River and the northwest area of Lake Chao is evaluated from organic analysis aspect. PAHs such as fluoranthene, pyrene are detected in the waters collected from downstream river and river mouth. More phenolic compounds are found in the river water. Some halogenated hydrocarbons are present in the river and lake waters. A great many of aliphatic hydrocarbons and benzene hydrocarbons found in all the water samples are about one third of the total organics detected. The hydrophobic components are found to be present not only in water but also in suspended sediment. The ratio of the amount existing is 0.4 in sediment and 1 in particle-free water. The quantity of humic materials existing in lake water is larger than that in river water. The proportion of the humic materials in lake water to that in river water is 1.9 to 1. In the lake water, some natural substances, such as dimethyl disulfide, alpha-pinene, azulene, and 6- methyl -2-heptanone are observed.     

A study on Se application for improving the soil in the environment at lower Se level

A result that application of sodium selenite or fly ash to some of soilin loess plateau can increase Se content in wheat grain has been demonstrated by the pot and field experiments, and added Se in soil can last its availability for 3 years. So this is a good measure for improving the low Se soils and preventing the Kaschin-Beck disease.     

Study on nitrile-degrading microorganisms

Two strains of bacteria were isolated from nitrile polluted soils, and identified as Corynebacterium boffmanii and Arthrobacter flavescens. Acetonitrile, propionitrile, butyronitrile and acrylonitrile were degraded by these bacteria to yield corresponding amides, carboxylic acids and ammonia. The nitrile-degrading abilities of these strains were investigated. The removal rates for the nitrile were nearly 100%, after these bacteria were grown in medium containing 10000 ppm of aceto-, propio-, or butyronitrile at 28 ℃ for 24h. When the reaction mkture consisting of 5000 ppm of above mentioned nitriles or acrylonitrile and 20g (dry cell) /L resting cells of the two strains in 0.06mol/L phosphate buffer (pH7.5) was incubated separately at 25 ℃ with moderate shaking for 15 or 45 min, the nitrile could be degraded completely. The optimum growth conditions for C.hoffmanii and A.flavescens were studied as well.     

Atmospheric pollution in Beijing, China, as recorded in sediments of the Kunming Lake

The fluxes of heavy metals and magnetite, a fly-ash component, from coal burning, to sediments of the Kunming Lake in Beijing have increased measurably over the last fifty years. Ages were introduced to the sediment strata through Pb-210 geochronologies. Even with a doubling of coal usage by the year 2000, the anthropogenic metal fluxes will still be less than those recorded in metropolitan Tokyo and U.S. lakes.     

A study on the interactions among several plant secondary compounds and aphids

The research, focused on the specific interactions among seven plant secondary compounds and aphids, was carried out and the preliminary results showed: (1) "T-typed tube method" was regarded as the best method compared with others designed to observe the interactions. (2) Cabbage aphid was able to be attracted by laurolene while it was not susceptible to α-pinene, β-pinene and diamylene. (3) Gossypol, a major secondary substance in cotton, was able to be implicated as feeding attractant to cotton aphid. (4) Rutin might be implicated repellent to cotton aphid.     

Resourcefulization approaches to pollution control of chromate residues in China

Over 2 million tons of chromate residues as hazardous wastes have been accumulated from chromate production processes during the past more than 30 years in China. Some serious pollution problems have been caused due to no appropriate technology and management. Approaches are reviewed to pollution control of chromate residues by utilizing them as secondary resources in this paper. In addition to legislation for pollution control, chromate residues can be used as raw materials to produce a great diversity of useful industrial products. Strategies are also recommanded for the resourcefulization of chromate residues.     

中国各省区生态环境质量评价与排序

本文建立了区域生态环境质量综合评价的指标体系,并应用这一指标体系,通过层次分析和综合评价方法对我国各省区的生态环境质量做了定量评价与分析,为生态环境管理和宏观决策提供依据。     

Determination of dissolved selenium species in environmental samples

This article reports on the technique for the determination of selenium at ppt level and the procedure for the speciation of dissolved selenium in the environmental samples. By combining the high-performance liquid chromatography (HPLC) and a fluorescent detector (FLD), this technique permits the determination of selenium at 0.001 μg/L for Se(IV) and 0.005 μg/L for Se(VI) and the total concentration of selenium for a sample volume of 20 ml. In the speciation procedure, Se(IV) is firstly determined based on the selectivity of 2, 4 - diaminonaphthalene (DAN), the Se (VI) and the total element concentration are determined after reduced to Se(IV) by boiling in 4 mol/L HCl and by digesting in HNO3-HClO4 mixture, respectively. Discussions are given on the relationship between selenium speciation in waters and soil water extract and solution pH, EH and total organic carbon concentration (TOC).     

高应变速率反挤压超塑Zn-Al_(22)合金管材

此文简要地叙述了工业性试生产Zn-Al_(22)超塑性管材的工艺流程。采用慢速等液面浇注法和几次均匀化处理实现晶粒细化。在ε=2×10~(-2)S~(-1)的高应变速率下进行反挤压Φ49×2.25×250mm管材1200只,超塑性能最高值δ=1620％,流变应力σ_b=2.36MPa。