Agricultura e ocupação urbana do solo na qualidade da água dos córregos Jaboticabal e Cerradinho

Abstract

Since the end of the twentieth century,100% of the urban sewage from the city of Jaboticabal has been collected by interceptors and routed to a treatment plant. Between 1999 and 2000,studies on the effect of this environmental care showed that it did not efficiently clean up the water from the two streams that run through the city and flow into an agricultural area. This paper focuses on assessing the influence of soil use on the water quality of surface waters from these two streams. The study was conducted 15 years after the implementation of sewage interceptors. The sampling dates were bimonthly at eight points (P1 to P8) in the Cerradinho and Jaboticabal streams,in Jaboticabal (São Paulo State,Brazil). P1 was located at the source of the Jaboticabal stream,P2 was in a farming area,P3,P4 and P5 were in an urban area,and P6,P7 and P8 were in a farming area. The physical and chemical variables of the water were assessed. We compared the ability of microorganisms to metabolize different sources of carbon using the EcoPlate (Biolog). The total phosphorus (TP) concentration exceeded the limit set by the Brazilian legislation as well as values found in previous studies,which was also observed for the chemical oxygen demand. However,the bacterial metabolic profile had no association with urban or farming practices. The results of the analysis indicated the possibility of clandestine discharge of wastewater in the streams studied and the influence of the agricultural soil.