Hidrologia: Pesquisa Atual

Microbiology Water Quality of Three Coastal Beaches at Madeira Island, Atlantic Ocean

Abstract

Costaa G, Caladob G, Errab F, Freitasa M, Krehla K and Pinheiro de Carvalhoc MAA

The microbial water quality of three different coastal beaches located in the south coast of Madeira Island, were monitored from May to December 2005 (Formosa and São Roque), and from October 2006 to June 2007 (Gavinas). Total and fecal coliforms and enterococci counts in two of the beach sites, showed a seasonal dependence, with highest values in autumn and winter suggesting a positive relationship with rainfall and a negative relationship with temperature. Of the three sampled beaches, Formosa beach showed the highest water quality and São Roque beach the poorest water quality. Impacted freshwater discharges and deficient water circulation in this recreational zone could be the causes for the lower quality of this beach. However beach rating was shown to be dependent on the indicator microbe chosen. The results obtained emphasized the need of differential sampling strategies according to beach specific characteristics, when assessing the water quality, as well as further sampling taking into consideration other variables, such as time of the day, tide, and microbial analysis of the freshwater inputs.