Hydrogeochemical Assessment of Arsenic and Physicochemical Contaminations in Groundwater Wells in Kabul, Afghanistan

Groundwater is a critical source of drinking water in semi-arid regions; however, integrated assessments of arsenic (As) contamination alongside key physicochemical parameters remain limited in the study area. Therefore, this study was conducted to measure the concentration of As, salinity, electrical conductivity (EC), temperature, pH, and total dissolved solids (TDS) in 21 wells across 4 districts of Kabul city. Groundwater samples were collected from selected sites and analyzed for As, salinity, EC, temperature, pH, and TDS, and compared with World Health Organization (WHO) drinking water guidelines to determine suitability for consumption. Arsenic concentrations exhibited pronounced spatial variability, ranging from 0 to 25 mg/L, with all detected values exceeding the World Health Organization (WHO) guideline of 0.01 mg/L by several orders of magnitude. The highest As concentration (25 mg/L) was recorded in the Areba antenna area, indicating a critical contamination hotspot. Salinity values ranged from 0 to 1.9 ppt, while EC ranged from 111 to 3630 µS/cm; 75% of sampled sites exceeded the WHO permissible limit for EC. TDS concentrations ranged from 710.4 to 2323.2 mg/L, with 79% of samples surpassing the recommended drinking water limit. Groundwater pH remained within the WHO guideline range (7.1–8.1), yet these neutral-to-alkaline conditions likely enhanced As mobilization. The combined results indicate widespread mineralization and severe As contamination, rendering much of the groundwater unsuitable for direct consumption without treatment. These findings underscore the urgent need for policy interventions, including systematic groundwater monitoring, arsenic mitigation strategies, and the provision of alternative, safe water supplies to protect local communities.