Sustainable Assessment of Groundwater Quality: Arsenic and Sodium Exposure Risks to Food Safety and Public Health

ABSTRACT Groundwater contamination by arsenic (As) and related hydrochemical components poses major threats to human health and food safety in South Punjab, Pakistan. To assess aquifer susceptibility and establish the relatively safest groundwater source for domestic use in Multan City, this study methodically assessed depth‐dependent variation in arsenic and important physicochemical properties. Sixty‐four groundwater samples at four urban areas at three depth intervals (100, 200, and 300 ft) were measured and analyzed on 12 physicochemical parameters. The obtained results were compared with drinking water recommendations by the World Health Organization (WHO) to find out the level of compliance and risk exposure. The contamination was more prevalent in shallow aquifers (100–200 ft) with electrical conductivity (323–1193 µS/cm), alkalinity (2.22–5.77 mmol/L), calcium (28.75–73.7 mg/L), bicarbonate (111–288 mg/L), and potassium (2.16–20.35 mg/L) above the WHO limits, but chloride, hardness, magnesium, total dissolved solids, and pH remained within safe limits. The level of contamination of arsenic (28.75–48.75 µg/L) was higher than the WHO recommended value of 10 µg/L in all the depth ranges, which proves the consistent geogenic contamination regardless of the aquifer depth. Sodium levels (38.25–101.75 mg/L) were less than 200 mg/L but greater in the shallow areas. The overall quality of groundwater improved with depths, with the safest being 300 ft, followed by 200 and 100 ft. This depth‐sensitive evaluation presents new data on aquifer‐specific contamination trends in Multan and confirms the increased risk of chronic exposures in shallow aquifers, supporting the selective groundwater abstraction and targeted treatment of the shallow aquifers along with risk‐informed water resource management approaches in arsenic‐prone areas.