engleski

Distribution of elements in stream water

Systematic geochemical mapping of stream water on the European scale shows that most patterns be controlled less directly by geology, but more by climate-related parameters such as rainfall, temperature, acidity and organic matter, in combination with topography and distance from ocean, i.e., the source of precipitation. There is a wide range of electrical conductivity (EC) values reflecting different ionic strenghts and total dissolved solids. The range of EC covers two orders of magnitude from <mSm-1 in stream water draining catchments associated with crystalline rocks throughout Scandinavia, northern Britain and wales, the north west Iberian Penninsula and over the Massif Central, to values >500 mSm-1 in stream water associated with sedimentary rocks in Lithuania, southeast England and over the Pannonian basin in Hungary, Croatia and Slovenia. Conductivity, pH, dissolved organic carbon (DOC) and the concentration of major ionic species have been used to interpret data for individual elements. There is a wide variation in the concentration of potentially harmful elements, such as arsenic, cadmium, nickel, chromium and lead. levels of arsenic are consistently low (<0.05 &#956; l-1) over much of the Baltic Shield and the Caledonides, whilst the highest values (>8 &#956; l-1) occur oricipally over the rhine delta of the Netherlands, eastern france, the Pannonian basin and volcanic areas of central Italy.

geochemical surveys, baseline studies, stream water, geochemical maps, atlas, Europe

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