Airborne lead in the Springfield, Missouri, area during a 19-year period (1975-1993)

Concentrations of airborne lead at Springfield, Missouri, in 1975-1993 have been determined by analysis of particulate material collected on glass-fiber filters during the 19-year period. Nitric acid-soluble lead in 1100 samples collected at a total of 19 monitoring stations was determined by atomic absorption spectroscopy and by differential pulse polarography. Ambient concentrations of airborne lead were found to decrease steadily (by more than 90%) during this period in spite of increases in area population and in automobile traffic. The decrease is significantly correlated with national trends in total emissions of lead to the atmosphere and with US ambient lead levels. Airborne lead from a coal-fired power plant was small compared with that from gasoline burning.     

Response types in Collembola towards copper in the microenvironment

Laboratory studies were carried out to cast light on differences in density responses among collembolan species to copper (Cu)-polluted environments. In a recolonisation experiment, mesofauna originating from a copper (Cupolluted arable field were allowed to colonise defaunated Cu-contaminated and uncontaminated soil cores for 3 months. The abundances of Pseudosinella alba and gamasid mites were higher in the uncontaminated soil, whereas the majority of other collembolans tended to be more abundant in the Cu-enriched soil. Behavioural experiments were conducted to test the ability of single Collembola species to distinguish between filter paper and food soaked in water, Cu, and calcium (Ca) solutions. Onychiurus armatus avoided both Cu and Ca, whereas Folsomia quadrioculata and Folsomia manolachei showed a significant preference for Cu. Isotomurus palustris was not able to distinguish between Cu and water. The results are compared and discussed with regard to other studies on the occurrence and behaviour of Collembola in Cu-contaminated environments. We suggest that microsite selection according to preference or avoidance of high salinity of pore water may partly explain the community structure of Collembola in Cu-polluted soils which are characterised by an increase of euedaphic species. More studies have to be carried out to generalise this concept and to explore to what extent reduced predation by gamasid mites contribute to the success of certain Collembola in Cu-contaminated sites.     

线性溶剂化能相关方法应用及参数估算

简要介绍了线性溶剂化能相关方法的原理，回顾了该方法在溶解度、辛醇／水分配系数和生物毒性预测中的成功应用，重点讨论了参数估算规则，以利于该方法进一步推广。     

Forest reflectance modeling: theoretical aspects and applications

Forest reflectance models are able to contribute to the interpretation of satellite images over forested areas. A multipurpose forest reflectance model, its basic ideas, model input and output options are briefly described. The possibility to apply the model in forest remote sensing is demonstrated through the following simulation examples: the age dependence of forest reflectance, the seasonal course of forest reflectance, defoliation effects on forest reflectance, sensitivity of chlorophyll and water indices with respect to leaf chlorophyll and water content, respectively, and uncertainties in these indices introduced by the variation in stand parameters. When used together with the atmospheric radiative transfer and sensor calibration models, the forest reflectance model is applicable in satellite-imagery-aided forest ecology and health assessment, forest inventory and management.     

含铜制药有机废水的处理研究

通过试验，采用将化学沉淀和生物处理相结合的工艺流程及方法处理含铜有机废水，经处理后的出水Cu^2 符合排放标准。     

冶金厂矿废水泵联运增效改造

冶金厂矿输送废水的离心水泵常会在低效区工作。选择一台合适的小离心泵与主泵联运，使主泵工况点移到高效区，增效明显。介绍废水泵联运增效原理方法和实例。     

关于区域环境保护政策的思考

本从通过分析我国环境保护政策存在的缺口和目前对这种理念的研究进展，并根据环境问题本身的特性以及环境问题产生的背景差异提出重新确立环境保护政策的调控范围的观点，并提出了这种观点对于对我国环境保护政策以及环境保护工作的重要意义。     

Maternal cell contamination in chorionic villus samples assessed by direct preparations and three different culture methods

Presumptive maternal cell contamination (MCC) was monitored in identified male cases during cytogenetic comparison of direct techniques and three different culture regimes from 140 thoroughly dissected chorionic villus samples. Of the 66 identified male cases, 11(16·7 per cent) showed MCC, the mean number of cells examined per case being 8·2 (direct) and 14·5 (cultures); in the direct preparations only one of a total of 457 cells examined was female, while preparations from cultures revealed MCC in 11 cases. Four of these had MCC in more than one culture regime and four had only a single female cell. The results showed that (1) dependence on the culture system alone would have given a diagnosis based on maternal cells in one (1·5 per cent) male case, thus underlining the danger of this approach (a similar undetected rate of misdiagnosis being expected in the female cases) and (2) MCC was significantly lower in cultures grown in Chang medium as compared with the other two regimes, McCoy's 5A + 15 per cent fetal calf serum and 1 per cent Ultroser G, and McCoy's 5A + 25 per cent fetal calf serum, the latter expressing the highest level of MCC.