Coastal aquifer water quality for domestic supply of small communities in the semiarid Potiguar - Brazilian Northeast

This study analyzed groundwater quality used to supply small communities in the coastal zone of the Brazilian Northeast, identifying the risks from domestic use of water, and potential contaminants from domestic effluents. We realized analyses of 24 chemical and physical parameters in 15 samples of water from shallow wells. The data was processed through quality modeling, descriptive statistics, principal component analysis, and geoespacialization through kriging. The groundwater used by communities showed some limitations to domestic use. Parameters of Br, hardness, Na+, NO3−, Cl−, SO4−, and turbidity exceed the allowed for Brazilian Health Minister (Ministerial Order n. 888/2021). Furthermore, TDS values present low water quality, predominantly brackish and saltwater, most salinity waters are related to depth and sea proximity. Depth of saturated zone probably is a determinant in nitrate concentrations, comparing the study areas. Water self-supply is considered a risk by health because inferior natural quality of water used and contaminations from domestic sewage determine concentrations of some parameters above of legislation.