Water and sand pollution at three beaches of Fortaleza, Ceará State, Brazil

Abstract

This study presents the colimetric readings obtained for 108 samples of water, wet sand and dry sand collected from the beaches, namely Formosa, Meireles and Futuro, located at Fortaleza county, Northeastern Brazil. The samples from Meireles beach yielded from <30 to 11,000/100 mL coliform bacilli per 100 mL, the highest concentration in the study, Formosa and Futuro beaches came in second and third places, respectively. In general, the dry sand conteined more fecal coliform bacilli than the wet sand, and a sample from Meireles beach yielded as much as 110,00/100 mL. The indices of pollution in the three beaches varied in a decreasing order as follows: Formosa, Meireles and Futuro. Applying the criteria stated in CONAMA Law No. 274/2000, Meireles presented the most samples above the pollution rates permited for swimming activity. Strains of Escherichia coli were identified on all locations, with Futuro displaying the greatest number. One strain of E. coli O123 and two strains of EPEC O25, identified in the water samples from Meireles, were susceptible to antibiotics when tested with a CECON Sensibiodisc kit. Tem non-toxicogenic E. coli strains were resistant to the following antibiotics: tetracycline, ampicillin, chloranfenicol, sulfametoxazol-trimetoprim and cefalotine. Strains of Klebsiella and Proteus were also isolated form water samples collected at Meirelles and Futuro beaches. Our findings suggest that the water and sand of the three beaches surveyed are polluted to the extent of being potentially hazardous to the health of children and adults beachgoers.