Study of the risk of contamination of aquifers in Bahia sub-basins

Abstract

Groundwater is of great importance mainly in areas of northeastern Brazil, with a semiarid climate. With regard to quality, the contamination of groundwater resources, although slower, is more difficult to remediate. Pollution sources such as landfills, fuel leaks, cemeteries, diffuse releases of fertilizers and pesticides, may be penetrating the soil and increasing concentrations of pollutants in aquifers. Depending on the characteristics of the soil and the aquifer, such as depth, possible contaminants can enter more or less easily. This work aimed to measure the vulnerability of aquifers in the region of twelve sub-basins in Bahia, assess the punctual and diffuse contaminant load that may be imposed on these waters, and, therefore, observe the risk of contamination of these waters in the area in question. Hydrogeological data from wells throughout the area were collected in Brazil's information system, and information on possible sources of contamination in the official gazette and state agency website. The GOD and POSH methods were used to assess vulnerability and contaminant load in the area in question, respectively. The largest area of ​​vulnerability was observed in the Corumbataí River sub-basin area, the predominance of gas stations in the register of point sources. The protection priority regions were mapped in the total evaluated area, dividing into high, medium and low protection areas.