(Ecology of Jacare Pepira River basin : Influence of soil water use and effluentes discharge on water quality, São Paulo State í Brazil)

Abstract

Jacaré Pepira River, which is located in the center of the State of S. Paulo, is a tributary of Tietê River belonging to Paraná River Basin. It is 174 km long, its origin is at 47°55'W and 22°30'S at 960 m of altitude and its mouth is located at 48°55'W and 22°55'S at about 400 m of altitude. To study the polluent influence on the water quality of the Jacaré Pepira River, determinations of the following parameters were measured: air and water temperatures, turbidity, colour, pH, electrical conductivity, alkalinity, chloride, hardness, soluble silica, phosphate, ammonium, nitrite, nitrate, total iron, dissolved oxygen, oxygen saturation, oxydability, magnesium, manganese, zinc, nickel, chromium, cadmium, copper, lead, arsenic, silver, sodium, aluminium, sulphate, barium, boron and calcium. Sampling was carried out near the discharge of effluent from a sugar cane alcohol refinery and from a sugar cane brandy factory. The last one discharges its effluents on Bocaina Stream, which also receives the domestic sewage from the city of Bocaina. The determinations were undertaken monthly during two sugar cane harvest: from July to November in 1979 and 1980. The results showed that the influence of these discharges on the studied ecosystem is not significant permitting that conditions approximately natural are maintained. So, the water composition seems more influenced by the physical environment (climate, rocks and soil) than, by human activities.