DETERMINATION OF WATER QUALITY INDEX (WQI) IN SUB-BASIN STREAM ANDRé OF THE MIRASSOL D’OESTE, MATO GROSSO, BRAZIL

This study aimed to investigate the water quality of the sub-basin of the stream André municipality of MirassolD'Oeste, Mato Grosso, by implementing the Water Quality Index (WQI). Data were collected at five pointsequidistant sampling of traversing the source to its mouth in the month of June/2008 (dry season), andoctubro/2010 March/2009 (rainy period). We analyzed the physical-chemical variables, such as, temperature,turbidity, pH, total phosphorus, total nitrogen, dissolved oxygen, biochemical oxygen demand and total solids,microbiological aspects was seen as the presence of fecal coliform. With these variables, the WQI wasestablished for each site during periods of drought and rain. According to the transitional and final provisions ofResolution CONAMA 357/2005, the indexes of water quality stream Andre presented the analysis fall into thewaters of Class 2. The analysis of WQI classifies the waters of the stream André quality regular in mostsampling sites, with progressive loss of water quality from the source to the mouth. The results indicated that theWQI used responds to accumulation of sediment and organic matter runoff showing changes in water qualityresulting from human activities in Sub-basin study.