Concentrations of trace elements and heavy metals at selected medicinal plants harvested in two vegetation periods
Trace elements (Mn, Fe, Cu, and Zn) and heavy metals (Pb and Cd) contents were determined in leaves of medicinal plants: plantain (Plantago lanceolata), birch (Betula verrucosa) and herb of nettle (Urtica dioica) harvested in two vegetation periods: 2003 and 2004 in Branica Radzyńska (Lublin region), with the use of AAS technique. The lowest lead concentration was found in plantain leaves harvested in 2003 (0.56 mg∙kg-1 DM) and nettle herb from both periods (0.6–0.9 mg∙kg-1 DM. The highest lead contents, much exceeding permissible level of 2.0 mg∙kg-1 DM were recorded in birch leaves: 9.8 mg∙kg-1 DM in 2003 and 5.7 mg∙kg-1 DM in 2004. Nettle herbs harvested in 2004 and birch leaves collected in 2003 appeared to be largely contaminated with cadmium (0.43 mg∙kg-1 DM each), which was slightly beyond permissible limit (0.3 mg∙kg-1 DM). Trace elements contents as well as lead and cadmium depended on harvest date and plant species.