Analysis of bacterial pollution indicators in the Anil and Bacanga rivers, on the Island of S. Luís, Maranhão State, Brazil

Abstract

Sampling of liquids was carried out monthly at both high and low tide, for one year, at 5 sites on the Anil river and at 3 sites on the Bacanga river, for bacteriological pollution study. Total viable bacteria/100ml, MPN (Most Probable Numbers) of coliforms/100ml and MPN fecal coliforms/100ml were determined by the use of nutrient agar, lactose broth, brilliant green - lactose bile broth and E C broth. The results indicated that both rivers contained a higher bacterial concentration at the sources and showed a seasonal bacteriological pollution variation directly related to the tidal phases. According to the Brazilian Ministry of the Interior's standards, the water of both rivers presented a high degree of microbial pollution.