Contamination by heavy metals in the south of Ecuador associated to the mining activity

Abstract

In this work was made a compilation of the oldest and most important mining zone of Ecuador, from its pre-Columbian times until the present time. Data were collected that show concentrations of some non-essential heavy metals (Hg, Pb, As, Mg, Zn, Cd) in Zaruma and Portovelo cantons of the El Orós province. The results revealed that the route of the affected sites is from the beginning of the Calera, Amarillo and Pindo rivers along the basin until arriving the Puyango river, where the lowest values of these elements are obtained, except for Manganese because its level rises again due to the mineralogical presence of the Petrified Forest of Puyango. The data taken from the FONSAD were obtained by the material processed from grinding tailings and cyanidation tails in 2004, which showed that the lead and arsenic concentrations exceeded the limits values of reference for these metals in soils. In other studies, made to the settlers, biological samples (blood, urine and hair) were taken, and it allowed to determine the majority habitants of the population near the Puyango basin river are poisoned with Hg and Pb in small amounts.