Heavy metals in surface water

Metals are by definition not degradable and (bio)accumulative in the aquatic environment. Some of them are essential for various biochemical processes in organisms. At higher concentrations, they can become toxic to aquatic organisms. Metals occur in surface water in dissolved and bonded form. The dissolved concentrations are more ecologically relevant because in that form they are more easily absorbed by aquatic organisms. This is why the dissolved concentrations have been measured since 2010 and the environmental quality standards for surface water apply to the dissolved form. In addition to the test against the standard, the results of a statistical trend analysis per measuring site are also reported here.