Hydro-geochemical Investigation of Malekan Plain, Considering the Contamination of Minor and Rare Elements

Quantitative and qualitative conservation and prevention of water resources contamination are increasingly important. The existence and accumulation of elements in drinking water, which their chemical properties are stable, higher than the acceptance criteria can cause the wide range of diseases and is one of the most important factors in water contamination. Study of the Malekan plain hydrochemistry, distribution of rare elements in the aquifer and their effects on groundwater contamination in the study area, is the main aim of the present study. In order to assess the groundwater quality, 41 samples of groundwater resources were collected and analyzed. The high electrical conductivity in the west and northwest parts of the study area is due to high concentrations of gradual increase in major elements, through groundwater flow and the water quality has decreased from the recharging areas to the end regions of the plain. The result showed the heavy metals concentration such as Zinc, Chromium, Manganese, Iron and Aluminum were less than standard, in all samples. Arsenic contamination in the northwest part is the result of groundwater evaporation at the end of the plain. Fluorine concentration was less than both WHO guidelines and the official Iranian government standard for the chemical quality of water in all samples. Furthermore results showed reveal the effect of anthropogenic activities on groundwater quality, addressing the increasing of nitrate and boron concentration. Cation exchange, leaching of salty-clayey layers, human activities and groundwater evaporation at the end of the plain could be the main reasons for the groundwater quality reduction.