The role of the arroio pavuna river in the transport of particulate heavy metals to Jacarepaguá Lagoon, Brazil

Abstract

Estuarine regions are very sensitive to urban and industrial activities due to their large biomass production and accumulation and concentration of pollutants. Among the pollutants derived from industrial activities, heavy metals are of special interest, because they may be incorporated into the biota and thereby reach man through the food chain. Jacarepaguá Lagoon, located in south Rio de Janeiro (Brazil), receives the effluents from 235 factories; the Arroio Pavuna River carries most of the pollutants to the lagoon. The aim of this study was to establish the transportation pattern and to estimate the main sources of the various metals (Cd, Zn, Pb, Cr, Ni, Cu, Fe and Mn) in the total fluvial discharge. The partitioning of metals in bottom sediment along the longitudinal profile of the river was studied in order to assess the bioavailability of metal species in suspended sediments. The results obtained demonstrate a dilution of the pollutant metals with increase in sediment flow. The average loads of the different metals transported to the lagoon are derived.