Trace Metal Budgets for Forested Catchments in Europe̶Pb, Cd, Hg, Cu and Zn

Abstract

Input/output budgets for cadmium (Cd), lead (Pb) and mercury (Hg) in the years 1997-2011 were monitored and determined for 14 small forest-covered catchments across Europe as part of the Integrated Monitoring program on the effects of long-range pollutants on ecosystems. Metal inputs were considered to derive from bulk deposition, throughfall and litterfall. Outputs were estimated from run-off values. Litterfall plus throughfall was taken as a measure of the total deposition of Pb and Hg (wet?+?dry) on the basis of evidence suggesting that, for these metals, internal circulation is negligible. The same is not true for Cd. Excluding a few sites with high discharge, between 74 and 94 % of the input Pb was retained within the catchments; significant Cd retention was also observed. High losses of Pb (>1.4 mg?m-2?year-1) and Cd (>0.15 mg?m-2?year-1) were observed in two mountainous Central European sites with high water discharge. All other sites had outputs below or equal to 0.36 and 0.06 mg?m-2?year-1, respectively, for the two metals. Almost complete retention of Hg, 86-99 % of input, was reported in the Swedish sites. These high levels of metal retention were maintained even in the face of recent dramatic reductions in pollutant loads.<P>Quelle: Internet, 27.03.2013 <BR> http://link.springer.com/article/10.1007/s11270-013-1502-8<P>