Issue 4, 2018

Evidence of transboundary mercury and other pollutants in the Puyango-Tumbes River basin, Ecuador–Peru

Abstract

In Portovelo in southern Ecuador, 87 gold processing centers along the Puyango-Tumbes River produce an estimated 6 tonnes of gold per annum using a combination of mercury amalgamation and/or cyanidation and processing poly-metallic ores. We analysed total Hg, Hg isotopes, total arsenic, cadmium, copper, lead and zinc in water and sediment along the Puyango in 2012–2014. The highest total mercury (THg) concentrations in sediments were found within a 40 km stretch downriver from the processing plants, with levels varying between 0.78–30.8 mg kg−1 during the dry season and 1.80–70.7 mg kg−1 during the wet season, with most concentrations above the CCME (Canadian Council of Ministers of the Environment) Probable Effect Level (PEL) of 0.5 mg kg−1. Data from mercury isotopic analyses support the conclusion that mercury use during gold processing in Portovelo is the source of Hg pollution found downstream in the Tumbes Delta in Peru, 160 km away. The majority of the water and sediment samples collected from the Puyango-Tumbes River had elevated concentrations of, arsenic, cadmium, copper, lead and zinc exceeding the CCME thresholds for the Protection of Aquatic Life. At monitoring points immediately below the processing plants, total dissolved concentrations of these metals exceeded the thresholds by 156–3567 times in surface waters and by 19–740 times in sediment. The results illustrate a significant transboundary pollution problem involving Hg and other toxic metals, amplified by the fact that the Puyango-Tumbes River is the only available water source in the semi-arid region of northern Peru.

Graphical abstract: Evidence of transboundary mercury and other pollutants in the Puyango-Tumbes River basin, Ecuador–Peru

Article information

Article type
Paper
Submitted
25 אוק 2017
Accepted
07 פבר 2018
First published
09 פבר 2018

Environ. Sci.: Processes Impacts, 2018,20, 632-641

Evidence of transboundary mercury and other pollutants in the Puyango-Tumbes River basin, Ecuador–Peru

B. G. Marshall, M. M. Veiga, R. J. Kaplan, R. Adler Miserendino, G. Schudel, B. A. Bergquist, J. R. D. Guimarães, L. G. S. Sobral and C. Gonzalez-Mueller, Environ. Sci.: Processes Impacts, 2018, 20, 632 DOI: 10.1039/C7EM00504K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements