Monitoramento das águas do rio Mossoró/RN, no período de abril/2005 a julho/2006

Abstract

The present study intends to realize a comparison of chemical-physical and biological water quality between three points of the River Mossoró: Barragem do Genésio (utmx 681464; utmy-9422890), Barragem Central (utmx-683867; utmy-9425546) e Barragem Passagem de Pedra (utmx-690119; utmy-9429968), all located in the city of Mossoró/RN. These points are into different entropic influences and were monitored from april/2005 to july/2006. The factors analyzed were, total coliforms, fecal coliforms, dissolvid oxygen (DO), chemical oxygen demand (COD), nitrate, zinc, copper, lead, chromium, mercury, cadmium, pH, temperature, color, turbidity. Beyond these, there were also analyzed total nitrogen, total solids, total phosphorus, biochemical oxygen demand (BOD) to match with the first ones as basis to calculate the water quality index – WQI from the first sampling of 2007 (jan 10th). Despite the climatic seasonality, diminution of river volume alters the contaminants concentrations, the Barragem do Genésio point, located amount the city, shows the minor values to the variables analyzed. The Barragem Central, located near the center of the city, responds for the higher concentrations, result of non-treated domestic and industrial sewage throwing. Another characteristic observed to this point is the abnormal proliferation of macrofit and seaweed, indicating an eutrophic process. To the WQI the conclusion is that a quality decrease from amount to the mouth route, considering the similarity of Barragem Central and Barragem Passagem de Pedra WQIs.