Levels of MN, ZN, PB and HG in sediments of the zamora river, Ecuador Academic Article in Scopus uri icon

abstract

  • © 2018, Centro de Ciencias de la Atmosfera, UNAM. All rights reserved. Artisanal and small-scale gold mining activities (ASGM) are currently performed in the Zamora River basin (Ecuadorian Amazon), mainly in the Nambija and La Herradura-Chinapintza mining district. However, the effects of ASGM on these fluvial systems have not been yet assessed. Thus, the concentrations of Mn, Zn, Pb and Hg were measured in bottom sediments of rivers of the Zamora River basin and suspended sediments of the mining effluents. The results show that bottom sediments of several tributaries of the Zamora River (Conguime River and the lower Nangaritza River) are severely contaminated with Mn, Zn, Pb and Hg. This contamination is the result of the discharge of mining effluents coming from La Herradura-Chinapintza mining district, which are rich in sediments composed by polymetallic mineral. Bottom sediments of the Nambija and the upper Zamora River show a severe contamination with Hg, suggesting the existence of ASGM in the upper Zamora River basin. The contaminated bottom sediments of these rivers are re-suspended during high water discharge periods and are transported toward the Amazon River mainstream. According to international guidelines, the high levels of Mn, Zn, Pb and Hg in river sediments of the Zamora basin can have adverse effects on aquatic biota.

publication date

  • January 1, 2018