Importance of Quality of Groundwater Resources in Transboundary River with Emphasis on Hydro-geochemical Properties, Case study: Aras Transboundary River (Northern Iran)

The urban periphery and the villages around the river Aras are one of the most important agricultural areas in Iran. Against this background, the present study investigated the hydrochemistry of groundwater along the Aras River in Iran to assess the suitability of groundwater quality for agricultural irrigation. Water samples were taken from 34 groundwater sources in 2021 and 2022. The suitability of groundwater for irrigation was assessed using the sodium absorption ratio (SAR), residual sodium carbonate (RSC), magnesium absorption ratio (MAR), Kelly ratio (KR) and Wilcox classification. The Langelier Saturation Index (LSI) and the Ryznar Stability Index (RSI) were used to predict the corrosion and deposition behavior of the groundwater. The optical emission spectrometer with inductively coupled plasma was used to detect the heavy metals. Monte Carlo simulation was used to assess the non-carcinogenic and carcinogenic risks of these waters when used as drinking water. The average concentration of major ions follows for cations Na⁺˃ Ca²⁺˃ Mg²⁺˃ K⁺ and anions in both groups SO₄²⁻ > HCO₃⁻ > Cl⁻. The corrosion in all samples was found to have a low to considerable corrosion potential. The concentrations of the tested metals were within the range recommended by the WHO in most samples. In summary, it can be said that most of the groundwater sources in the area studied are appropriate for irrigation purposes. However, to reduce the risks associated with drinking, it is advisable to monitor water quality by locating sources of pollution and limiting the input of contaminants.