The content of microelements (Cu and Zn) in reeds (Phragmites australis (Cav.) Trin. ex Steud.) of a constructed wetland system

The method for purification of municipal waste waters with the use of constructed wetland system (CWS) was put in operation in Serbia for the first time in 2004, in the Gložan village near Novi Sad. Biological factors in this anthropogenic ecosystem are microorganisms and reeds (Phragmites communis (Cav.) Trin. ex Steud.). In the process of bioaccumulation, among other substances, emergent plants often accumulate large quantities of microelements. Although microelements are present in plants in relatively small quantities, in emergent plants that grow on the surface where wastewater (which contains various substances, including microelements) flows, their quantity in plant dry weight can be higher. This paper presents the results of the three-year study (2004–2006) of Cu and Zn concentration in different organs of reed plants (leaf, stem, rhizome with root and inflorescence) grown in the “Gložan” CWS. The study was carried out on three fields. The first year of the study was taken as control, as that’s when the “Gložan” CWS was established, while 2005 and 2006 were the first and the second years of the system exploitation. In 2004 Cu concentration varied from 3.20 ppm in reed stems to 5.30 ppm in inflorescences. In 2005 Cu concentrations were lower in comparison to the first year, while in the third year the trend of reduction of Cu concentration was present in all analyzed organs in the third field. Concentration of Cu had diminishing tendency in all three fields over time, with exception of inflorescences where it was mostly constant.In the first year of the study the highest concentrations of Zn were recorded, ranging from 13.97 ppm in rhizomes with roots to 34.60 ppm in inflorescences. In the second year, concentration of Zn was the lowest in all three fields, and in the third year overall concentration of Zn (except for inflorescences) was lower in comparison to the first year of the study (control).