Heavy metal content of common reed (Phragmites australis/Cav./Trin. ex Steudel) and its periphyton in Hungarian shallow standing waters

In order to reveal the actual effects of common reed (Phragmites australis (Cav) Trin. ex Steudel) and its periphyton complex on the water quality, st udies on the heavy metal contents of common reed and its periphyton are imp ortant. This paper discusses the results of studies on heavy metal contents of the host plant-periphyton complex carried out in Lake Balaton, Lake Vel ence, Lake Ferto and Kis-Balaton Reservoir. A second goal was to study the effects of reed stands in different condition (healthy, transitional, die-b ack) on the structure of its periphyton and their role in water quality ind ication. Simultaneously with the reed and periphyton sampling, water sample s were taken for investigation. We determined the wet mass of periphyton an d after drying at 105 degrees C; the dry mass was measured and ash contents of reed and its periphyton samples were also determined. The concentration of 27 (Na, Mg, Ca, K, Zn, Cu, Cd, Cr, Pb, Mo, etc.) cations was determined from the reed, periphyton and water samples by ICP-AES method. The heavy m etal content of reed and periphyton was especially high at places impacted by high anthropogenic loadings. On the basis of our results, the biofilter role of periphyton-reed complex can be confirmed. Since the main reasons of reed decline have not been revealed, future research has to focus on invol ving reed-periphyton studies also, which may provide good basis to find the most appropriate ways to protect and restore the reed communities of shall ow standing waters.