Hydrochemical considerations and heavy metal variability in the middle Parana´ River.

PASQUINI, A. I. , DEPETRIS, P. J

Environmetnal Earth Sciences

Springer

Año: 2011

1866-6299

The Parana´ River is one of the largest drainage systems in the Americas. Its hydrology is characterized by an active teleconnection with the ENSO, and by a significant discharge increase trend, evident since the mid-1970s. An Eh–pH data set collected in the Parana´’s middle stretchsuggests that large flood events, such as the one triggered by the 1982–1983 ENSO, are discernible in the plot, probably due to the influx of water draining flood plain water bodies.The total (particulate ? dissolved) concentration of a set of heavy metals (Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb) was determined in a downriver survey of the middle stretch. With the exception of Cu, Cd, and Pb, the metals exhibit a significantly increasing concentration trend towards theriver mouth. The slopes of the regression lines imply that Zn and Ni, on one hand, and Mn and Cr, on the other would have common controlling sources. Another set of analyses were performed during the 1982–1983 flooding event; besides an increased variability observable during the floodarrival, most elements, with the only exception of Pb, did not show a variability coherent with the discharge series.