INITIAL STUDIES TO USE THE INDEX TRIX FOR ANALYSIS OF EUTROPHICATION IN ESTUARY POTENGI RIVER - NATAL – RN – BRAZIL

Abstract

This study tested the applicability of the trophic index (TRIX) to assess the level of eutrophication in the course of the river Potengi located in the metropolitan region of Natal - RN - Brazil. The choice of this method was due to its multiparametric nature and also for having developed and enhanced a model to process eutrophication in different coastal environments. The Potengi river receives the discharge of pollutants from loads of different sources, especially the direct release of untreated sewage and industrial effluents involving a considerable source of nutrients and eutrophication, with direct consequences on the increased productivity of its estuary. 13 points of the estuary were analyzed at two different times according to the changing of tide of the Potengi. The results indicated that the levels of eutrophication ranged from mesotrophic to eutrophic according to the TRIX index, with the worse situation in the rainy season, a result due to the drag of pollutants brought by rains from the watershed into the estuary of the river. We conclude that application of the TRIX index was valid for the evaluation of trophic status along the estuary of the river Potengi and the results indicate the need for greater control on the entry of pollutants loads to the watershed, especially with the expansion of services collection and treatment of household and industrial waste in the metropolitan region of Natal - RN.

Key Words: Eutrophication, TRIX, estuary, River Potengi, Brazil.