Frequência de coliformes termotolerantes em praias do litoral potiguar (Rio Grande do Norte, Brasil)

Abstract

Development of tourism in Brazil is related to natural resources and landscapes, including the Brazilian Northeast littoral beaches, where there is a huge concerning about water quality for recreation (balneability). In Brazil, impacts on the coastal environments are caused by lack of basic sanitation and disordered land use, dispersing pollutants on the sea, affecting public health especially because thermotolerant coliforms spreading, the main indicators of balneability to beaches. In this work, we analyzed the dynamics of on the 48 beach spots of Rio Grande do Norte State (Brazil) between 2010 and 2016, proposing also a Balneability Index (BALI) that summarizes, based on visual and physical aspects, the beaches sanitary and environmental conditions. Results appointed that: i) 7% of the samplings has thermotolerant coliforms above to the maximum accepted limit (1000 NMP/100ml); ii) there is none pattern in coliforms temporal dynamic; iii) all the points have high variation in relation to mean values; iv) beaches close rivers’ mouth have greater frequency of coliforms, especially in Potengi River which have, 25% of the samplings above accepted limit; v) correlations between precipitation and coliforms concentration are not high (r < 0,369), nonetheless are significant; vi) the proposed index (BALI) had low values only for the Natal city and in general also it shows low correlation to coliforms concentrations. Our main conclusion is that beaches close rivers should be avoided. Moreover, it is necessary more investments on sanitation, inclusive waste care, especially in Ponta Negra, Praia dos Artistas e Redinha beaches (all in Natal City).