Limnological research in a stretch of the Moji-guaçu River. III. The influence of sugar factory effluents (washing sugar cane)

Abstract

This paper is part of a limnological study of Moji-Guaçu River, which is located between 22°l6'S, 46°42'W and 20°47'S, 48°ll'W. The entire length of the river is approximately 473 km. The research was carried out from June 1974 to September 1975, and was based on the investigation of some physical and chemical characteristics in a stretch of the river, to study the influence of washing sugar cane (sugar factory effluents) on the water quality. The pollutants come from a factory of sugar and alcohol, which delivers its residuals in Baguaçu Stream, a tributary of Moji-Guaçu River. The parameters studied in seven stations were: temperature, color, turbidity, Secchi disc visibility, alcalinity, pH, electrical conductivity, ammonia, nitrite, nitrate, phosphate, iron, soluble silica, dissolved oxygen and biochemical oxygen demand (BOD). In the studied     stretch, the effects of the pollutants introduced are readily eliminated, probably because of the high recovery capacity and/or the rapid flow of the river. The effects would be, thus, rather local than extending downstream.