Hydro-geochemistry-based appraisal of summer-season groundwater from three different semi-arid basins of northeast Mexico for drinking and irrigation

Summer-season groundwater from three agricultural basins (i.e., El Potosi, Sandia and Cieneguilla) in drought-prone northeast Mexico was assessed for drinking and irrigation by evaluating their physicochemical parameters with respect to the World Health Organization Guidelines for drinking water quality (WHO, Geneva, 2011) standards, and by estimating water quality indices (DWQI and IWQI). Facies of Ca–Mg–HCO₃, Ca–Mg–Cl and Ca–Mg–SO₄ mostly reflected the influences of aquifer lithologies. Ca exceeded WHO (2011) maximum allowable limit in most of the samples due to dissolution of gypsum-bearing limestone. Most of the samples (69–93%) were in excellent and good categories (DWQI < 100) for drinking and the samples of poor to very poor categories (7–31%) had salinity above the recommendation of WHO (2011). Fluoride of > 1.5 mg/L in 13% samples from the El Potosi Basin could expose some population to dental and skeletal fluorosis. Similarly, nitrate (> 42 mg/L), mostly from synthetic fertilizers, in 13% samples of the Sandia Basin might affect human health through methemoglobinemia in infants. In the context of irrigation suitability, the samples with > 75% permeability in the Donnen classification are good for irrigation. US Regional Salinity Laboratory classification, however, grouped most groundwater the from El Potosi Basin (medium-salinity hazard) as suitable for irrigation, whereas most samples from the Cieneguilla Basin and half of the samples from Sandia Basin (high-salinity hazard) should only be used to irrigate salt-tolerant plants with enhanced drainage condition. IWQI values also suggested that most samples (low-restriction category) are suitable only for irrigating light texture and moderately permeable soils. The groundwater management in this region should involve practices to increase water holding capacity of the substrate and modify the frequency of watering as per plant demand.