Hydrogeochemical study of groundwater in the southeast of Mashkan aquifer, Khorasan Razavi province

Understanding chemical changes in groundwater and their mapping play a substantical role in optimal management of groundwater in an area. The aim of this study was to investigate hydrogeochemical charactristics of groundwater resources of south Mashkan in 2020.To achieve this goal,10 water samples were taken from the region wells. The hydrogeochemical analysis was carried out in the laboratory through induction plasma method and statistical analysis were performed in ArcGis, AqQA and Excle software environment. Geochemical ion ratios were used to determine the source of ions and combination diagram in the studied aquifer. Geochemical diagram confirmed the activity of water- rock reactions in the studied aquifer and showed the natural ion exchange process in most resources. Based on the results obtained in all wells,the ratio is Cl/Sum anions>0.8, Mg/Mg+Ca<0.5 , Ca/Ca+So4<0.5.In most wells, the ratio is Na/Cl>1, Na/Na+Cl>0.5 ,and So4/Hco3<1. In most wells, is 1<Ca/Mg<3 According to the results of using Kriging method zoning the concentration of ions, the concentration of calcium, magnesium, sulfur and chlorin ions increase in the west and southwest and sodium in the west of the region.