An investigation of qualitative variations of groundwater resources under municipal wastewater recharge using numerical and laboratory models, Nazarabad plain, Iran.

Municipal wastewater irrigation induces elevated concentrations of heavy metals in the soil which their further leaching leads to groundwater contamination in the long run. In this study, both column experiment and 5-year prediction modeling using HYDRUS-1D were conducted to investigate the probable adsorption and transport of 10 different metals including As, Ba, Cr, Cu, Mo, Ni, Pb, Rb, Sr, and Zn in an alkaline soil from Nazarabad plain in Iran which has been irrigated with treated urban wastewater for several years. The obtained results revealed that reaching the equilibrium rate for the mentioned elements during 1825 days (= 5 years) was as follows: Mo > Cr > Rb > Zn > Ni > Ba> Sr > Pb > As> Cu. The finding implies that molybdenum (Mo) and copper (Cu) are the most mobile and the most adsorbent heavy metals in the soil, respectively. Higher mobility poses the greater potential risk of leaching into groundwater resources. Overall, experimental and numerical modelings had good accordance and were capable of describing the actual condition.