Evaluation of the quality of streamlet Franquinho's water, Basin Loud Tiete, Sao Paulo

The present work evaluated the water quality in Tiete River Basin, particularly of the streamlet Franquinho. The streamlet Franquinho, is located east zone of Sao Paulo metropolitan area, and receives a great load of domestic sewers. To evaluate the Franquinho's water quality, physical, chemical, biological and ecotoxicological parameters were used. The Aquatic Preservation Life Index (IVA) were applied. For physical, chemical, biological and ecotoxicological, 8 samples were taken from five stations, from 1999/March to 2000/May. Physical and chemical results indicate the eutrophic conditions, particularly the high content of organic matter and phosphorus. Toxicity tests with Daphnia similes (acute), Ceriodaphnia dubia and algae Selenastrum capricomutum (chronic) were used. The program TOXTAT 3,3 was used for the evaluation of the toxicity test results. The results of the toxicity tests show that all samples of water presented toxicity, it was verified that the toxicant agent's dilutions does not exist along the system. Metallic elements, low oxygen content and high-suspended solid were the main factors for the high toxicity. The toxicity tests, chemical analyses and the Aquatic Preservation Life Index (IVA) indicated critical conditions in the streamlet Franquinho. These findings indicated the necessity of precautionary measures and solutions to improve the water quality in these localities. (author)