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Water, Air, & Soil Pollution

, 224:1415 | Cite as

Particulate and Dissolved Trace Element Concentrations in Three Southern Ecuador Rivers Impacted by Artisanal Gold Mining

  • Gregory T. Carling
  • Ximena Diaz
  • Marlon Ponce
  • Lester Perez
  • Luis Nasimba
  • Eddy Pazmino
  • Abigail Rudd
  • Srinivas Merugu
  • Diego P. Fernandez
  • Bruce K. Gale
  • William P. JohnsonEmail author
Article

Abstract

Water and sediment samples were collected along river transects at three artisanal gold mining areas in southern Ecuador: Nambija, Portovelo-Zaruma, and Ponce Enriquez. Samples were analyzed for a suite of major and trace elements, including filtered/unfiltered water samples and stream flow measurements to determine dissolved/particulate loads. Results show that the Q. Calixto, Calera, and Siete rivers (corresponding to Nambija, Portovelo-Zaruma, and Ponce Enriquez mining areas, respectively) have substantial trace element contamination due to mining inputs. Dissolved concentrations were elevated at Calera and Siete relative to Q. Calixto, possibly reflecting the input of soluble cyano-metal complexes in mining zones where cyanidation is used in ore processing. A negative correlation was found between MeHg:THg ratios and pH, indicating an inverse relationship of mercury methylation with cyanidation (since cyanidation increases water pH). This was the first comprehensive study to examine an extensive suite of trace elements in both water and sediment at the three main gold mining areas of southern Ecuador, including dissolved and particulate loads, and the first study to report MeHg concentrations in the mercury-contaminated rivers.

Keywords

Cyanidation Methyl mercury Trace metals Particulate loads Dissolved loads Ecuador 

Notes

Acknowledgments

This work was conducted under a project-scoping award (0964836) from the US National Science Foundation Office of International Science and Education. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. We wish to thank Dr. Diósgrafo Chamba, former Executive Director of the Ecuadorian Agency of Regulation and Control for Mining (ARCOM), and the Ecuadorian National Institute of Research in Geology, Mining and Metallurgy (INIGEMM) for providing personnel for field work as well as vehicles and drivers for transportation to field sites. We also thank Met. Carlos Naranjo, Executive Director of the Ecuadorian National Institute of Meteorology and Hydrology (INAMHI) for providing personnel and equipment for flow measurements in the rivers. We thank Roberto Garcia for providing GIS maps of the study areas. We are grateful to the drivers and other field assistants for making this work possible and feasible, and to mine operators who allowed access to their property for sampling.

Supplementary material

11270_2012_1415_MOESM1_ESM.doc (94 kb)
ESM 1 (DOC 94 kb)
11270_2012_1415_MOESM2_ESM.xls (56 kb)
ESM 2 (XLS 56 kb)

References

  1. Appleton, J. D., Williams, T. M., Breward, N., Apostol, A., Miguel, J., & Miranda, C. (1999). Mercury contamination associated with artisanal gold mining on the island of Mindanao, the Philippines. Science of the Total Environment, 228(2–3), 95–109.CrossRefGoogle Scholar
  2. Appleton, J. D., Williams, T. M., Orbea, H., & Carrasco, M. (2001). Fluvial contamination associated with artisanal gold mining in the Ponce Enriquez, Portovelo-Zaruma and Nambija areas, Ecuador. Water, Air, and Soil Pollution, 131(1–4), 19–39.CrossRefGoogle Scholar
  3. Beisner, K., Naftz, D. L., Johnson, W. P., & Diaz, X. (2009). Selenium and trace element mobility affected by periodic displacement of stratification in the Great Salt Lake, Utah. Science of the Total Environment, 407(19), 5263–5273.CrossRefGoogle Scholar
  4. Benoit, J. M., Gilmour, C. C., Heyes, A., Mason, R. P., & Miller, C. L. (2003). Geochemical and biological controls over methylmercury production and degradation in aquatic ecosystems. In Y. Cai & O. C. Braids (Eds.), Biogeochemistry of environmentally important trace elements (Acs Symposium Series, Vol. 835, pp. 262–297). Washington: American Chemical Society.CrossRefGoogle Scholar
  5. Betancourt, O., Narvaez, A., & Roulet, M. (2005). Small-scale gold mining in the Puyango River Basin, southern Ecuador: a study of environmental impacts and human exposures. EcoHealth, 2(4), 323–332.CrossRefGoogle Scholar
  6. Cardenas, C., & Escarate, S. (2005). Con organizacion y responsabilidad construiremos nuestro futuro. Sistematizacion de la experiencia de explotacion minera de Bella Rica y Guananche Tres de Mayo. Quito: Centro Ecuatoriano de Derecho Ambiental (CEDA).Google Scholar
  7. Cordy, P., Veiga, M. M., Salih, I., Al-Saadi, S., Console, S., Garcia, O., et al. (2011). Mercury contamination from artisanal gold mining in Antioquia, Colombia: the world's highest per capita mercury pollution. Science of the Total Environment, 410–411, 154–160.CrossRefGoogle Scholar
  8. Dominique, Y., Muresan, B., Duran, R., Richard, S., & Boudou, A. (2007). Simulation of the chemical fate and bioavailability of liquid elemental mercury drops from gold mining in Amazonian freshwater systems. Environmental Science and Technology, 41(21), 7322–7329.CrossRefGoogle Scholar
  9. Dzombak, D. A., & Morel, F. M. M. (1990). Surface complexation modeling: hydrous ferric oxide. New York: Wiley.Google Scholar
  10. Fontbote, L., Vallance, J., Markowski, A., & Chiaradia, M. (2004). Oxidized gold skarns in the Nambija District, Ecuador. Society of Economic Geologists, Special Publication, 11, 341–357.Google Scholar
  11. Fuller, C. C., & Davis, J. A. (1989). Influence of coupling of sorption and photosynthetic processes on trace element cycles in natural waters. Nature, 340(6228), 52–54.CrossRefGoogle Scholar
  12. Gray, J. E., & Hines, M. E. (2009). Biogeochemical mercury methylation influenced by reservoir eutrophication, Salmon Falls Creek Reservoir, Idaho, USA. Chemical Geology, 258(3–4), 157–167.CrossRefGoogle Scholar
  13. Guimaraes, J. R. D., Betancourt, O., Miranda, M. R., Barriga, R., Cueva, E., & Betancourt, S. (2011). Long-range effect of cyanide on mercury methylation in a gold mining area in southern Ecuador. Science of the Total Environment, 409(23), 5026–5033.CrossRefGoogle Scholar
  14. Hiller, E., Lalinská, B., Chovan, M., Jurkovič, Ľ., Klimko, T., Jankulár, M., et al. (2012). Arsenic and antimony contamination of waters, stream sediments and soils in the vicinity of abandoned antimony mines in the Western Carpathians, Slovakia. Applied Geochemistry, 27(3), 598–614.CrossRefGoogle Scholar
  15. Hyun, S., Burns, P. E., Murarka, I., & Lee, L. S. (2006). Selenium(IV) and (VI) sorption by soils surrounding fly ash management facilities. Vadose Zone Journal, 5(4), 1110–1118.CrossRefGoogle Scholar
  16. Kerin, E. J., Gilmour, C. C., Roden, E., Suzuki, M. T., Coates, J. D., & Mason, R. P. (2006). Mercury methylation by dissimilatory iron-reducing bacteria. Applied and Environmental Microbiology, 72(12), 7919–7921.CrossRefGoogle Scholar
  17. Kyle, J. H., Breuer, P. L., Bunney, K. G., Pleysier, R., & May, P. M. (2011). Review of trace toxic elements (Pb, Cd, Hg, As, Sb, Bi, Se, Te) and their deportment in gold processing. Part 1: Mineralogy, aqueous chemistry and toxicity. Hydrometallurgy, 107(3–4), 91–100.CrossRefGoogle Scholar
  18. Lambertsson, L., & Nilsson, M. (2006). Organic material: the primary control on mercury methylation and ambient methyl mercury concentrations in estuarine sediments. Environmental Science and Technology, 40(6), 1822–1829.CrossRefGoogle Scholar
  19. Lovitz, S.B. (2006). Scales of responsible gold mining: overcoming barriers to cleaner artisanal mining in southern Ecuador. M.S. Thesis. Burlington: The University of Vermont.Google Scholar
  20. Machesky, M. L. (1990). Influence of temperature on ion adsorption by hydrous metal oxides. In R. L. Bassett & D. C. Melchoir (Eds.), Chemical modeling of aqueous systems II (American Chemical Symposium Series, Vol. 416). Washington: American Chemical Society.CrossRefGoogle Scholar
  21. Mitchell, C. P. J., Branfireun, B. A., & Kolka, R. K. (2008). Spatial characteristics of net methylmercury production hot spots in peatlands. Environmental Science and Technology, 42(4), 1010–1016.CrossRefGoogle Scholar
  22. Parkhurst, D. L., & Appelo, C. A. J. (1999). User's guide to PHREEQC (Version 2)—a computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations. US Geological Survey, Water-Resources Investigation Report 99–4259.Google Scholar
  23. Ramirez-Raquelme, M. E., Ramos, J. F. F., Angelica, R. S., & Brabo, E. S. (2003). Assessment of Hg-contamination in soils and stream sediments in the mineral district of Nambija, Ecuadorian Amazon (example of an impacted area affected by artisanal gold mining). Applied Geochemistry, 18(3), 371–381.CrossRefGoogle Scholar
  24. Tarras-Wahlberg, N. H. (2002). Environmental management of small-scale and artisanal mining: the Portovelo-Zaruma goldmining area, southern Ecuador. Journal of Environmental Management, 65(2), 165–179.CrossRefGoogle Scholar
  25. Tarras-Wahlberg, N. H., & Lane, S. N. (2003). Suspended sediment yield and metal contamination in a river catchment affected by El Nino events and gold mining activities: the Puyango river basin, southern Ecuador. Hydrological Processes, 17(15), 3101–3123.CrossRefGoogle Scholar
  26. Tarras-Wahlberg, N. H., Flachier, A., Fredriksson, G., Lane, S., Lundberg, N., & Sangfors, O. (2000). Environmental impact of small-scale and artisanal gold mining in southern Ecuador—implications for the setting of environmental standards and for the management of small-scale mining operations. Ambio, 29(8), 484–491.Google Scholar
  27. Tarras-Wahlberg, N. H., Flachier, A., Lane, S. N., & Sangfors, O. (2001). Environmental impacts and metal exposure of aquatic ecosystems in rivers contaminated by small scale gold mining: the Puyango River basin, southern Ecuador. Science of the Total Environment, 278(1–3), 239–261.CrossRefGoogle Scholar
  28. Taylor, H., Appleton, J. D., Lister, R., Smith, B., Chitamweba, D., Mkumbo, O., et al. (2005). Environmental assessment of mercury contamination from the Rwamagasa artisanal gold mining centre, Geita District, Tanzania. Science of the Total Environment, 343(1–3), 111–133.CrossRefGoogle Scholar
  29. USEPA Method 1630: Methylmercury in water by distillation, aqueous ethylation, purge and trap, and CVAFS, January 2001.Google Scholar
  30. USEPA Method 1631, Revision E: mercury in water by oxidation, purge and trap, and cold vapor atomic fluorescence spectrometry, August 2002.Google Scholar
  31. USEPA Method 1669: Sampling ambient water for trace metals at EPA water quality criteria levels, July 1996.Google Scholar
  32. Velasquez-Lopez, P. C., Veiga, M. M., & Hall, K. (2010). Mercury balance in amalgamation in artisanal and small-scale gold mining: identifying strategies for reducing environmental pollution in Portovelo-Zaruma, Ecuador. Journal of Cleaner Production, 18(3), 226–232.CrossRefGoogle Scholar
  33. Velasquez-Lopez, P. C., Veiga, M. M., Klein, B., Shandro, J. A., & Hall, K. (2011). Cyanidation of mercury-rich tailings in artisanal and small-scale gold mining: identifying strategies to manage environmental risks in Southern Ecuador. Journal of Cleaner Production, 19(9–10), 1125–1133.CrossRefGoogle Scholar
  34. Williams, T. M., Dunkley, P. N., Cruz, E., Acitimbay, V., Gaibor, A., Lopez, E., et al. (2000). Regional geochemical reconnaissance of the Cordillera Occidental of Ecuador: economic and environmental applications. Applied Geochemistry, 15(4), 531–550.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Gregory T. Carling
    • 1
    • 6
  • Ximena Diaz
    • 2
  • Marlon Ponce
    • 3
  • Lester Perez
    • 4
  • Luis Nasimba
    • 3
  • Eddy Pazmino
    • 1
  • Abigail Rudd
    • 1
  • Srinivas Merugu
    • 1
  • Diego P. Fernandez
    • 1
  • Bruce K. Gale
    • 5
  • William P. Johnson
    • 1
    Email author
  1. 1.Department of Geology & GeophysicsUniversity of UtahSalt Lake CityUSA
  2. 2.Department of Extractive MetallurgyEscuela Politécnica NacionalQuitoEcuador
  3. 3.Instituto Nacional de Investigación Geológico Minero Metalúrgico, INIGEMMQuitoEcuador
  4. 4.Instituto Nacional de Meteorología e Hidrología, INAMHIQuitoEcuador
  5. 5.Department of Mechanical EngineeringUniversity of UtahSalt Lake CityUSA
  6. 6.Department of Geological SciencesBrigham Young UniversityProvoUSA

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