Evaluation of the cytotoxic and genotoxic potential of waters of the Paraíba do Sul River Basin - RJ through the Allium cepa test system

Emanoelly Barbosa Sacramento,Saulo Tavares Abreu,Helcio Resende Borba,Viviane Moreira De Lima,Caroline De Almeida Azevedo

doi:10.4136/ambi-agua.2521

Abstract

The public water supply of the Rio de Janeiro metropolitan region is highly dependent on transposition from the Paraíba do Sul River: 70% of the water is diverted to the Piraí River and then passes through a series of other rivers and reservoirs, finally discharging in the Guandu River. During this path, the water is exposed to many sources of pollution. This makes the quality of the raw water that reaches the Guandu Treatment Station (WTS) highly vulnerable. This article reports the analysis of the cytogenotoxic potential of water samples collected at four different points along the Piraí River downstream from the transposition point, utilizing the Allium cepa test system. The samples were collected in two periods, the dry and wet seasons. The water at all four collection points presented some level of cytogenotoxicity, with the presence in the test cells of large nucleoli, multiple nucleoli, nuclear buds, lagging chromosomes, sticky chromosomes, karyorrhexis, cytoplasmic shrinkage and changes of the mitotic index. The samples collected during the dry season had a larger number of cells with alterations, indicating that the cytogenotoxic potential varies in function of the time of year, depending on the volume of contaminated effluents. The results obtained along with data from the Rio de Janeiro State Environmental Institute (INEA) for the same period reveal the importance of monitoring along with proper sanitation and sewage treatment, and that the presence of pollutants not only hampers water treatment, but also poses risks to organisms at different trophic levels, including humans.

Highlights

The Paraíba do Sul River originates in the state of São Paulo with the confluence of the Paraibuna and Paraitinga Rivers, passes through the entire Paraíba Valley and traverses the state of Rio de Janeiro before emptying into the Atlantic Ocean in the municipality of São João da Barra, flowing for more than 1,100 Km (Marengo and Alves, 2005). most of the water consumed in the Rio de Janeiro metropolitan region comes from the Guandu River, much of that volume originates from the Paraíba do Sul River, through transposition, first into the Santa Cecília Reservoir in the municipality of Barra do Piraí (RJ), where there is a pumping station that diverts the water to the Piraí River
Most of the water consumed in the Rio de Janeiro metropolitan region comes from the Guandu River, much of that volume originates from the Paraíba do Sul River, through transposition, first into the Santa Cecília Reservoir in the municipality of Barra do Piraí (RJ), where there is a pumping station that diverts the water to the Piraí River
Since the state of Rio de Janeiro is the downstream user of the water from the Paraíba do Sul River, it is completely vulnerable to pollution and interferences caused by upstream users, in addition to the effects of human activities that occur in the state itself (INEA, 2010)

Summary

INTRODUCTION

The Paraíba do Sul River originates in the state of São Paulo with the confluence of the Paraibuna and Paraitinga Rivers, passes through the entire Paraíba Valley and traverses the state of Rio de Janeiro before emptying into the Atlantic Ocean in the municipality of São João da Barra, flowing for more than 1,100 Km (Marengo and Alves, 2005). Most of the water consumed in the Rio de Janeiro metropolitan region comes from the Guandu River, much of that volume originates from the Paraíba do Sul River, through transposition, first into the Santa Cecília Reservoir in the municipality of Barra do Piraí (RJ), where there is a pumping station that diverts the water to the Piraí River. In this region alone, the Paraíba do Sul River contributes to the supply of some 9 million people (CBH Guandu, 2015; Demanboro, 2015). The objective of this study was to analyze the water from the Paraíba do Sul River regarding the presence of pollutants with cytogenotoxic potential, using the Allium cepa test system as a bioindicator

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS