Constructed wetland Čìčenice, South Bohemia, Czech Republic, was designed for treatment of municipal sewage from 450 PE. The system consists of mechanical pretreatment (screens, grit chamber and Imhoff tank) with four equally sized beds filled with washed gravel (8–16 mm) with a total area of 2400 m2. The system was planted with Reed canarygrass (P. arundinacea) in 2010 and provided full vegetation cover in 2011 ( Fig. 1). The average air temperatures at the site were 9.7 °C and 9.5 °C in 2011 and 2012, respectively. The lowest and highest average monthly temperatures during the monitored period were −4 °C (February 2012) and 18.5 °C (August 2011). The average inflow and outflow concentrations of monitored heavy metals, BOD5, COD and TSS are given in Table 2.