Sökning: "heavy metals"
Visar resultat 1 - 5 av 183 avhandlingar innehållade orden heavy metals.
Sammanfattning : Levels of heavy metals in different media are high today, both in Stockholm and other urban areas. Where do the metals come from? Production emissions and point sources are not the answer, since earlier research has shown that production emissions are lower than emission from goods during use (the diffuse emission). LÄS MER
Sammanfattning : As the environmental regulations and technical progress have forced the factories’ old “end of pipe” solutions to improve, the metal emissions from point sources have decreased. Instead, the diffuse consumption emissions from goods in use now are in focus. LÄS MER
Sammanfattning : Extensive use of heavy metals in modern society influences routes followed by fluxes on the surface of the Earth. The changed flow paths may be harmful for the balance of biological systems at different levels, micro-organisms, human beings and whole ecosystems, since the toxicity of heavy metals is determined by their concentrations and chemical forms. LÄS MER
Sammanfattning : Urban areas have been considered potential ecological hot spots for metal pollution. This is the result of three trends. First, the 20th century saw a rapid increase in the use of many materials, including metals, in the industrialized world. Second, urbanization has made towns and cities areas nodes of material flows. LÄS MER
Sammanfattning : Heavy metals are well-known environmental pollutants. In this thesis predictive models for heavy metals in urban lakes are discussed and new models presented. The base of predictive modelling is empirical data from field investigations of many ecosystems covering a wide range of ecosystem characteristics. LÄS MER