Soil and plant tissues samples were collected monthly and
transported to the laboratory for the determination of total Hg concentration. Plants were initially separated into roots, stems and leaves. Afterwards, they were washed three times with sterile water and stored in paper bags for three-day drying at 40 Cina
Binder forced convection oven with a capacity of 115 L. Next, biomass accumulation was determined by weighing the samples using a digital balance OHAUS Adventurer. The room conditions were maintained with a temperature of 27–30 C and relative humidity between 55% and 65%.