Contribution of a medium-sized tropical river to the particulate heavy-metal load for the South Atlantic Ocean

Abstract

The Paraıba do Sul River is a medium-sized river, 1145 km in length with a drainage basin of 55 400 km2. The ́Ž.riverine fluxes of particulate metals Cu, Cr, Zn, Mn and Fe were investigated over 24 months. Particulate mattersamples were monthly collected from April 1994 to March 1996. The first 12-month period presented lower rainfallthan the second, although both periods presented average precipitation lower than the regional average. TheŽ.Ž.particulate matter flux in the second period 2 042 080 t was 250% higher than the first period 821 489 t . The sametrend was observed for the associated metals, which presented higher fluxes in the second period. This studyhighlights the strong dependence of the transported mass on the rainfall, and consequently with the river waterdischarge. The Paraıba do Sul River presents a low contribution to the world oceans, although the local contribution ́could be considered relevant. 2002 Elsevier Science B.V. All rights reserved