Mobility of SO4, Pb, and Zn in acidic forest soils of the Czech-Bavarian border region

Edzard Hangen1, Bernd Schilling1, Thorsten Scheel1
1 Preventive Soil Protection and Soil Monitoring, Bavarian Environment Agency

O 13.6 in Czech-German exchange on environmental-, soil- and hydro(geo)logical issues

30.05.2014, 12:40-13:00, H18, NW II

Soils in the Czech-Bavarian border region are still affected by acidic deposition. Franconian and Upper Palatinate Forest as well as Fichtel Mountains act as topographical barriers towards east-west directed immissions. Forest stands at higher elevation comb out elevated amouts of SO2 and NOx out of the ambient air. Due to this, soils with extremely low pH-values down to 3 are encountered above acidic parent materials. To further elucidate this problem, the Bavarian Environment Agency carried out detailed investigations in this region, which were funded by the European Union (Interreg, EFRE). For 921 soil samples of 156 sites, heavy metal contents (water extract), buffer capacity (pH-stat), status of nutrients (CEC-capacity) and iron (Feox/Fedit) as well as sulfate pools were determined.

Various subsoils of the eastern part of the investigated region stored more than 500 mg SO4 kg-1 and showed heavy metal contents of up to 5-50 mg As kg-1, 20-100 mg Pb kg-1, 10-100 mg Ni kg-1, and 50-250 mg Zn kg-1, respectively.

To evaluate the acid-induced release of sulfate and heavy metals from soil, their mobility was analysed. Sulfate and heavy metals of 180 selected soil samples were assigned to 5 classes of mobility using sequential extraction. Results suggest, that there is no abrupt release of higher amounts of sulfate and heavy metals under the current deposition regime. Thus, no impairment of the quality of ground- and surface water is to be expected.

In the current joint project the Crop Research Institute, Prague, and the Bavarian Environmental Agency, Hof, focus on the contaminant status of the riparian zone along the cross-border river Ohře / Eger. Contaminated areas shall be identified and documented.

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Letzte Änderung 14.05.2014