seasonal changes of heavy metals in surface waters of the four areas of Anzali Wetland

Contamination of aquatic ecosystems with heavy metals is a threat to the health and life of aquatic animals and, as a result, human health. This research was conducted to investigate the concentration of heavy metals (copper, nickel, lead, cadmium and iron) in Anzali Wetland. In order to measure the amount of heavy metals in Anzali Wetland, sampling was done from four stations during four seasons (2019-2020). The concentration of heavy metals was determined using a plasma atomic spectrometer. The results showed that the average annual concentrations of Cu, Ni, Pb, Cd and Fe in water were 66/16±36/17, 16/60±12/25, 45/46±21/63, 15/51±7/24 and 75/43±26/80 μg/L, respectively. The decreasing trend of metal concentration in water was obtained as Fe>Cu>Pb>Ni>Cd. The concentration of these metals was higher in winter and autumn compared to other seasons. The concentration of all the investigated metals was lower than the national standard of Iran. Compared to WHO and USEPA standards, the amount of Cu, Ni and Fe metals was lower and the amount of Pb and Cd metals was higher than these standards. Based on the results of this survey, the amount of heavy metals in the surveyed areas is very low, which indicates the absence of serious pollution in the area.