Potential risk assessment of groundwater to address the agricultural and domestic challenges in Ordos Basin

The safety of groundwater has been a great concern for irrigation and drinking purposes in recent decades due to the increasing impacts of anthropogenic activities. There are several standards to evaluate the groundwater quality for different utilization purposes. In this paper, 804 samples covering the entire Ordos Basin across five provinces were used to evaluate the irrigation suitability and human health risks. The results showed that the sequence of cationic concentration was Na+ > Ca2+ > Mg2+ > K+ > NH4 +, and the anion concentration was HCO3 − > SO4 2− > Cl− > NO3 − > F− > NO2 −. For drinking purposes, TDS, Na+, SO4 2−, F−, TH and NO3 − exceed seriously the regulated standard in the study area. For irrigating purposes, 80% of the water in the study area belongs to “good water” according to the evaluation of salinity and alkalinity. Saline water which is not suitable for irrigation accounts for about 9%. High health risks of fluoride ions are mainly observed to the samples representing the western part of the study area, while the health risks of nitrates spread throughout the study area. Health risk is not only related to location, but also varies with age, and it is found that children suffer more threats than adults.