| Total phosphorus concentration was used to define the trophic state of the main sub-basins of the middle Rio Doce, in Minas Gerais State (southeast Brazil) and physical, chemical, and microbiological variables of water were analyzed during 2000 to 2001. The study evaluated changes in water quality caused by seasonality and human activities. Water temperature, conductivity, pH, total alkalinity, dissolved oxygen, and concentrations of NH4-N, NO2-N, NO3-N, total-N, PO4-P, total-P, DOC, and chlorophyll-a were measured in seven rivers stretches (sampling stations). Total yeasts, faecal and total coliforms, and heterotrophic bacteria were also determined. The studied areas were considered to be under oligotrophic to eutrophic conditions. The variables that... |
