ABSTRACT
Anionic surfactants have been surveyed in a choked lagoon (Piratininga, Niteroi, RJ, Brazil) in order to provide knowledge on the dynamics and distribution of this pollutant. Samples were collected from 7 stations in the drainage basin and in the laggon itself. Temperature, salinity, pH, BOD, dissolved oxygen, dissolved forms of nitrogen and phosphorus and anionic surfactants were measured in the water column. The physicochemical results show that the water quality in the river stations is low, due to the domestic sewage directly dumped into the system. The anionic surfactant concentrations show that the sources for this pollutant are not restricted to the drainage basin, but widespread in the margins of the lagoon. Furthermore, the concentrations seem to show that the biodegradation rate is low and dilution is more important in reducing contamination.