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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. [ABSTRACT FROM AUTHOR]

• Hydrogeochemical evolution in semi-arid region. • Identification of recharge areas in Sierra Madre Oriental and moisture sources. • Warm season recharge in northeast Mexico and global warming. • Further depletion of groundwater resources and agricultural productivity. Over exploitation for agricultural activities and consumption has depleted the groundwater resources of drought-prone northeast Mexico. Major ion concentrations along with δ18O H2O , δ2H H2O and d-excess values of shallow groundwater from the Cieneguilla Basin (near Tula) located at a distance of ∼200 km from coast of the Gulf of Mexico helped to contribute new data about drought vulnerability in this region through identification of the moisture source and groundwater recharge zone. Different degrees of rock-water interaction through gypsum, anhydrite and halite dissolutions and minor silicate weathering controlled the hydrochemistry. Stable isotopes yielded a least square regression and slope similar to the local as well as global meteoric water lines, indicating minimal effect of evaporation during the recharge as well as in the subsoil. Isotopic fractionations along with a digital elevation model demarcated the recharge zones at north and east of the basin, with altitudinal difference of ≥1000 m, and indicated that the recharge occurred through warm season moisture sourced from the Gulf of Mexico. Less frequent landfalling of tropical storms caused by warmer sea surface temperature, however, has reduced this rainfall over the last few decades. If the trend of global warming continues unabated, the depleted groundwater resources would trigger reduction in agricultural activities in this drought-prone region and lead to enhanced socio-economic challenges. [ABSTRACT FROM AUTHOR]