Abstract
In the Braga aquifer, groundwater quality and mineralization processes have been assessed using a qualitative hydrogeochemical data analysis. The interpretation of physico-chemical parameters indicates that all groundwater samples have TDS and EC values superior to the permissible limits of WHO standards and are classified as very hard (TH > 300). According to Gibbs diagrams, these high values are in part related to the predominance of evaporation process, which indicates the importance of the return flow phenomenon. While, the WQI classification shows that roughly 2.3% of groundwater is unsuitable for human consumption, 27.9 is very poor, 62.8 is poor, and 7% is good. For irrigation purposes, more than 93% of samples are unsuitable and 7% are suitable based on the SAR. However, the Permeability index (PI) and the Kelly Ratio (KR) demonstrate that almost all samples are suitable for irrigation. The interpretation major ion analyses demonstrate that groundwater mineralization is mainly controlled by the dissolution of evaporate minerals, the direct/reverse ion exchange process, and the leaching of nitrogen and fertilizers. A higher concentration of nitrate in the groundwater of the Braga aquifer was mainly located in the north-east and the central parts and may cause a serious impact on human health. The non-carcinogenic health risk assessment of nitrate (NO3) indicated that the children are more vulnerable to direct ingestion of drinking water than adults.