Assessment of the leaching of metallic elements in the technology of solidification in aqueous solution

Results are presented of experiments performed to optimize the solidification/stabilization system for metallic elements in aqueous solution. This system involves mixing cement and a solution of metallic elements in a conventional mixer: the paste thus obtained is transferred drop by drop into a recipient filled with an aqueous solution of NaOH at 20% by weight, in which it solidifies immediately. The separate use of chloride solutions of Li+, Cr3+, Pb2+ and Zn2+ makes it possible to obtain granules displaying various levels of compressive strength. Three different inertization matrices were used in the experiments, the first consisting solely of Portland cement, the second of Portland cement and a superplasticizer additive, and the third of Portland cement partially replaced with silica-fume and superplasticizer. The results of the tests performed showed a very low level of leaching into the alkaline solidification solution for Cr3+, the quantity leached being under 2% as against higher levels for the other metallic elements. For all the considered elements, the best results were obtained by using silica-fume in the inertization matrix.     

Regional landscape-ecological planning and desertification control in arid regions of the Commonwealth of Independent States

Scale-dependent present-day landscape mapping and assessment were used to study the relationship among physical environment, land use, and degree of landscape modification in the Aral Sea region and the Karakum Desert, areas prone to desertification in the Commonwealth of Independent States (CIS). Applying geographic information system (GIS) techniques at global (1:15,000,000), regional (1:1,000,000), and local (1:300,000) scales, researchers found that large-scale landscape assessment and mapping allow them to recognize landscape changes under desertification processes and assess the type and intensity of these processes. Remote sensing has been widely used to evaluate data reliability, to fill information gaps, and to reveal the dynamics of land use types resulting from landscape changes.     

Human Hunting of Nongame Birds at Zuni, New Mexico, U.S.A.

Abstract: Nongame bird hunting is a critical activity of the Zuni people of the southwestern United States. To help determine whether their current hunting practices may be negatively affecting bird populations on the Zuni Reservation, we interviewed 98 Zuni hunters. Nongame bird hunting was practiced by a large portion of Zuni males (45%); the most active age group was 20- to 49-year-olds. The rate a species was hunted was not a function of its abundance at Zuni but seemed instead to be related to its cultural demand. Five species—bluebirds ( Sialia currucoides , S. mexicana ), Northern Flicker ( Colaptes auratus ), woodpeckers ( Picoides villosus , P. pubescens , Melanerpes lewis ), Steller's Jay ( Cyanocitta stelleri ), and American Kestrel ( Falco sparverius )—made up 77% of all birds taken. The two most heavily hunted species were each taken in numbers> 10,000 individuals per year. Although the greatest number of hunters were active in autumn, 31% hunted in spring, despite discouragement by the tribal government. Habitats favored by hunters were coniferous forests and riparian areas. Rates of hunting of nongame birds at Zuni equaled or exceeded those reported for game birds hunted by indigenous hunters in the Neotropics and New Mexico. The Zuni believe that some heavily hunted species are decreasing in number because of hunting. Although we cannot prove this at present, we suggest measures to mitigate possible overhunting, including the creation of refugia and a reduction of spring hunting.     

Caloric values of some North Atlantic invertebrates

Nineteen marine species were analyzed for caloric value; 7 of these were analysed for seasonal trends. Variation in caloric value for the polychaetesNephtys incisa andLumbrineris fragilis was not related to season.Pandalus montagui (decapod shrimp),Leptocheirus pinguis (gammarid amphipod),Astarte undata, Arctica islandica (pelecypods) had summer maxima.Meganyctiphanes norvegica (krill) had more complex seasonal changes involving winter and summer maxima.     

Correlations between the contents of volatile compounds in needle samples from Scots pine populations of southern Siberia

Intrapopulation diversity and correlations of 30 volatile compounds in needles have been studied in Scots pine populations of southern Siberia. Significant differences between populations have been revealed in the correlation pattern of relative terpenoid contents in needle samples. Stable combinations of closely associated mono- and sesquiterpenes and specific features of the general pattern of correlations between relevant characters have been determined.     

Formation and weathering assessment of oil-suspended sediment aggregates through a laboratory investigation

Environmental Science and Pollution Research - Formation of oil-suspended sediment aggregates (OSAs) is believed to be one of the natural cleaning processes in the marine environment. In this...