Zonation of heavy metal distribution of surface sediments in Anzali wetland Using Geographical Information System (GIS)

Sediment monitoring in aquatic environments is very important due to long-term exposure of various pollutants. This study was conducted to monitor the pollution of some heavy metals (Cd, Cu, Fe, Pb and Zn) in the surface sediments of Anzali wetland.

For this purpose, sediment samples were collected from east, west and central parts of the wetland in different seasons of 2020. Heavy metals contamination zoning for sediments in the study area was performed using Arc GIS 10.7

The results showed that the highest level of contaminants were obtained in the western part of the wetland. The average concentrations of heavy metals in the sediments were related to Cu (18.47), Zn (74.15), Cd (0.67), Pb (12.05) and Fe (1.97) mg. kg-1 in the western part. The pattern of changes of studied metals was in conformity with Cd 0.05) between Pb, Cu and Zn. According to the zoning map of the parts located in the middle of the center to the west of the wetland, higher amounts of metals have been deposited in its sediments.

In general, various human activities and the development of industries and the existence of agricultural lands in the area of Anzali Wetland and incoming rivers can be considered as factors affecting pollution. Therefore, with continuous biological and ecological monitoring of the wetland, it is possible to estimate the amount of heavy metals and the share of each in the wetland. Also, management in order to protect and monitor the wetland seems necessary.