Characteristics and impacts on the groundwater of the Guriri beach resort, São Mateus, ES, Brazil
2021
Cotta, Aloísio José Bueno | Fachetti, Priscila Silvestre | de Andrade, Renato Pereira
Water abstraction from phreatic aquifers allows easy access at low cost. However, these waters’ direct consumption can be harmful, especially in unsewered areas where domestic effluents are discharged into cesspits. This study assesses the quality of the groundwater explored by the Guriri beach resort residents. Samples from 35 residential wells were characterized, considering physicochemical and microbiological parameters. The water balance (rainfall–evapotranspiration), proximity to the shoreline, and separation between the well and the cesspit were taken into account in the interpretations. The evaluation with statistical tests (mean and correlation), graphs (Piper and Gibbs), and multivariate techniques (PCA and HCA) allowed the separation of two chemically distinct groups of waters. One from shallow wells (3 to 4 m depth) with lower electrical conductivity (EC) and acidic characteristics and the other gathering the deeper wells (11 to 13 m) with higher EC and neutral pH. All samples were classified as freshwater (TDS < 1 g/L), but its quality was compromised by permissible values infractions for pH, FeT, Cl⁻, HCO₃⁻ and by the presence of thermotolerant coliforms and E. Coli, in 50 and 20% of the wells, respectively. The participating residents were instructed on how to treat the waters by filtration and chlorination techniques. The effects of marine intrusion were absent. Moreover, the alternation between months with negative and positive water balance explains the groundwater EC values variation due to the accumulation and leaching of salts to the aquifer. The study revealed the aquifer vulnerability and the need for higher protection of this vital water source.
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