Ecotoxicological assessment of water and sediment of the Corumbataí River, SP, Brazil

Gm Jardim,Rtr Monteiro,Ed Armas

doi:10.1590/s1519-69842008000100008

Abstract

The Corumbataí River drains an economically important area which is mainly represented by the municipalities of Piracicaba and Rio Claro. In view of the impacts caused by the discharge of industrial waste and domestic sewage into the Piracicaba River, the Corumbataí has become increasingly significant as a source of water for the municipality of Piracicaba. However, chemical, physical, and microbiological analyses carried out prior to the present study had already indicated a decline in the quality of the Corumbataí waters. This study aimed to assess, through water and sediment samples, both acute and chronic toxicity to Daphnia magna and Daphnia similis, and to analyze acid-volatile sulfide (AVS) and simultaneously extracted metal (SEM) in the sediment. Resulting data were intended to be a contribution to future projects for the management and recuperation of this system. To that aim, water and sediment were collected at seven Corumbataí sampling stations in November 2003 and March 2004. Acute toxicity to D. similis was detected in water and sediment samples from the Piracicaba station, located at the mouth of the Corumbataí River. Chronic toxicity was identified in the water or sediment samples of all stations, with the exception of Analândia Montante (upstream), at the head of the river. This was found to affect survival, growth, and fecundity of the test-organisms. The AVS and SEM analyses showed the bioavailability of the metals, thus explaining toxicity found in bioassaying samples of water and sediment. The use of two test-organism species made it possible to obtain a better assessment of the condition of both water and sediment samples of the Corumbataí River.

Highlights

The Corumbataí River basin, which drains an area of 1,679 km, is located in São Paulo State, Brazil, between latitude 22° 05’-22° 30’ S, and longitude 47° 30’‐47° 50’ W
Chemical, and microbiological monitored parameters have demonstrated the reduction in water and sediment quality related to the high raw sewage remaining discharge (SEMA, 2005)
The sediment contamination by metals is indicated by the results presented here, a fact that is confirmed by high metal concentration data obtained by CETESB (2003, 2004, and 2005) in the Corumbataí River water analyses

Summary

Introduction

The Corumbataí River basin, which drains an area of 1,679 km, is located in São Paulo State, Brazil, between latitude 22° 05’-22° 30’ S, and longitude 47° 30’‐47° 50’ W. The river itself, which is located on the northeastern edge of the Paraná Sedimentary Basin in a cuesta zone of São Paulo State’s Peripheral Depression, drains an area of economic and industrial growth with a population estimated at 550,871 (IBGE, 2001). The Corumbataí runs through the municipalities of Analândia, Corumbataí, and Rio Claro, and flows into the Piracicaba River. Throughout the river course, industrial activity is concentrated in Rio Claro, and is represented by chemical, metallurgical, electronic, food, and beverage industries. Studies have demonstrated the influence of laminar erosion in the relation between dissolved phosphate in the river’s water and the use of fertilizers by regional sugar and alcohol industries (Conceição and Bonotto, 2000). Other studies carried out in the Corumbataí River indicate runoff as the source of compounds released in limestone mining or associated with sugarcane cultivation (see Conceição and Bonotto, 2004)

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Conclusion