苜蓿对土壤生态环境的影响

本文论述了黑龙港低平原缺水盐渍地区苜蓿对土壤结构、土壤水分、养分和盐分的影响。苜蓿对改善土壤生态环境,实现草地生态系统良性循环,起着重要作用。     

Lipopeptide als natürliche Adjuvantien für Impfstoffe aus Gram-negativen Bakterien

Bacterial cell wall components such as lipopolysaccharide, a variety of membrane proteins, murein, and lipoprotein can act as immunoadjuvants for bacterial vaccines, thus enhancing protection from bacterial infections. Synthetically prepared N-terminal parts of the lipoprotein from Enterobacteria carrying three fatty acid residues or lipopeptide analogs containing one to four aminoacids bound to S-glycerylcysteine act as potent immunoadjuvants in vivo in combination with or covalently linked to antiges. Here we demonstrate that the supplementation ofSalmonella vaccines with these synthetic lipopeptides significantly enhances their vaccine efficiency in mice. Variations in the native lipopeptide structure regarding chain length and amino acid sequence of the peptide moiety, as well as modifications of the lipoamino acid, lead to reduction or even complete loss of the adjuvant activity. The immunoadjuvant properties of the lipopeptides as described here are mediated by an enhancement of the humoral immune response.     

Disposal of Mine Wastes Containing Pb and Zn Near the Ocean: An Assessment of Associated Environmental Implications in the Arctic

The past two decades have witnessed an increase in the exploration for, and development of, mineral resources at Arctic latitudes. Such effort has resulted in the commencement of production at a number of different localities in close proximity to the ocean. Since proximity to a source of transportation for the conveyance of concentrates to the market is a primary requirement governing the economic decisions for the mine to proceed, it is logical that ore deposits near a coastline are primary targets for development.

Closely tied to coastal mining developments is the need to dispose of tailings and waste rock in the most economical manner. Prior to the advent of heightened public awareness and environmental concern, and the enactment of pollution legislation, disposal practices were largely based upon convenience. Currently, however, proposed disposal and operating practices receive closer scrutiny, with a view to providing adequate protection for aquatic resources and habitat. This paper summarizes some of the features of three Arctic mines, wastes from which enter the marine environment, and compares the disposal practices used at each to measures of environmental change as indicated by metal concentrations in various media.     

Field-scale rotary kiln incineration: Oxygen responses at the kiln,afterburner, and stack

There currently exists a need for better characterization and simulation of the processes that occur during the incineration of hazardous wastes in the environment of a rotary kiln. Addressing this need, a comprehensive research program was formed with the goal of developing a rudimentary predictive capability for rotary kiln incineration of hazardous wastes. This comprehensive program is headed by Louisiana State University and includes interaction with the University of Utah and also various industrial participants. Such cooperation allows use of laboratory, pilot, and field scale equipment. While laboratory scale experiments provide the necessary decoupling of complex phenomena and a high degree of experimental control, and pilot scale studies provide more realism at the expense of experimental control, the problems of scale-up make generalization of results to field scale units very tenuous. The unique aspect of the LSU program is the coupling of the laboratory and pilot scale units with afield scale unit in order to overcome these generalizations. In this study, plastic packs containing a mixture of toluene and sorbent were fed to a field-scale rotary kiln incinerator at a rate of one pack every 10 minutes. Selected continuous gas samples and temperatures were obtained from the exit of the rotary kiln, from the afterburner, and from the stack. These measurements were obtained during various operating conditions. These data provide, for the first time, an ability to compare conditions in the kiln to simultaneous conditions in the afterburner and stack. This paper outlines several new experimental features of our field-scale tests conducted in October 1990. Oxygen responses from the kiln, the afterburner, and the stack are compared during various operating conditions.     

Fluxes and pools of methane in wetland rice soils with varying organic inputs

Measurements of methane emission rates and concentrations in the soil were made during four growing seasons at the International Rice Research Institute in the Philippines, on plots receiving different levels of organic input. Fluxes were measured using the automated closed chambers system (total emission) and small chambers installed between plants (water surface flux). Concentrations of methane in the soil were measured by collecting soil cores including the gas phase (soil-entrapped methane) and by sampling soil solution in situ (dissolved methane). There was much variability between seasons, but total fluxes from plots receiving high organic inputs (16–24 g CH₄ m^–2) always exceeded those from the low input plots (3–9 g CH₄ m^–2). The fraction of the total emission emerging from the surface water (presumably dominated by ebullition) was greater during the first part of the season, and greater from the high organic input plots (35–62%) than from the low input plots (15–23%). Concentrations of dissolved and entrapped methane in the low organic input plots increased gradually throughout the season; in the high input plots there was an early-season peak which was also seen in emissions. On both treatments, periods of high methane concentrations in the soil coincided with high rates of water surface flux whereas low concentrations of methane were generally associated with low flux rates.     

Monitoring bio-available marine contaminants with mussels (Mytilus edulis L) in the Netherlands

After discussing the usefulness of mussels (e.g. Mytilus edulis) for investigating contamination in the marine environment, four cases are presented:

1. A survey of Cu bioavailability in and around the Eastern Scheldt during one winter (1974–1975);
2. A surveillance with a six years interval (1974; 1980) of the bioavailability of Zn along the Dutch North Sea coast.
3. A monitoring programme over the period 1972–1980 showing the decrease in bioavailable Hg in the water column of the Ems-Dollard estuary after decreased emissions at Delfzijl.
4. Retrospective monitoring of two PCB's, as a background for the effectiveness of legal restrictions to PCB use.

These four cases are considered a first step in understanding the effects of pollutants in marine ecosystems. In depth physiological, histological and biochemical studies could lay the basis for improved routine biological effect monitoring.     

Rapid assessment of air,water, and land pollution sources

A procedure is outlined to make a rapid across-the-board estimate of the quantities of air, water and land pollution in a given region or country. Such inventories, though not as detailed as one would eventually need, provide a first integrated view of the magnitude and quantity of pollution and can contribute to effective and comprehensive pollution control planning.This article is abstracted from Rapid Assessment of Air, Water and Land Pollution Sources, WHO Internal Document EFP/81.14, World Health Organization, Geneva, Switzerland, 1981.