Assesment of dispersion of heavy metals (As, Pb, Zn and Cd) in Varamin city water supply network and their spatial distribution pattern by GIS

Drinking water pollution has become one of the most important issues in everyday human life. This study covered a 1580 square kilometers area. In this research, the quality of Varamin drinking water was studied in terms of heavy metal contaminants including lead, zinc, arsenic, and cadmium.

In this study, 30 samples of Varamin drinking water were collected and analyzed using ICP-OES EOP after preparation in the laboratory. The map of heavy metal distribution was prepared using Arc GIS to determine the degree of heavy metal pollution and distribution in the region’s drinking water. Two indices of Heavy Metal Evaluation Index (HEI) and Heavy Metal Pollution Index (HPI) based on concentration and heavy metals in the region proportionate to the maximum allowed concentration for drinking were used to determine the degree of regional drinking water pollution.

The results of the study on heavy metal contaminants including lead, zinc, cadmium, copper, arsenic, chromium, and iron using two methods of pollution index evaluation showed that the heavy elements were less than 10 according to Heavy Metal Evaluation method and the pollution degree was low. The results of Heavy Metal Pollution method showed that these elements were at pollution threshold value in most stations under study.

Based on the zoning in this region by inverse distance weighting (IDW) interpolation in ArcGIS, it was concluded that the highest degree of heavy elements was in northwestern and western part of the city and the lowest degree was in northeastern part of the city.