Incomplete Mixing in the Fate and Transport of Arsenic at a River Affected by Acid Drainage

  • Paula Guerra
  • Christian Gonzalez
  • Cristian Escauriaza
  • Gonzalo Pizarro
  • Pablo PastenEmail author


Acid drainage is an environmental liability that impacts the quality of surface waters. However, the precipitation of iron and aluminum oxy/hydroxides decreases the concentration of dissolved toxic metals (such as arsenic) in rivers that receive acid drainage. Additionally, hydrodynamic factors (e.g., flow velocity fields and mixing ratios) control incomplete chemical mixing. Despite the occurrence of incomplete mixing in streams, its role on the fate and transport of contaminants has not been explored. We analyzed these processes at the Azufre River (pH 2)–Caracarani River (pH 8.6) confluence, northern Chile. We performed cross-sectional measurements of pH, turbidity, and particle size distributions and sampled water and suspended solids to analyze iron, aluminum, and arsenic. To complement field measurements, mixing experiments and geochemical modeling were performed. We found that there were distinct mixing zones on the field that promoted the precipitation of iron phases (pH >3) or the precipitation of iron and aluminum phases (pH ∼5). While iron phases immobilized arsenic by sorption (up to 8700 mg kg−1 of arsenic concentration in the solid phase), aluminum contributed to produce particles with the capacity to resist shear stress (strength factors ∼90 %). More than 50 % of the total arsenic was removed from the aqueous phase within 100 m from the junction point, suggesting settling of iron and aluminum particles. These results showed that incomplete mixing was a controlling factor in the fate and transport of arsenic. Fluvial confluences receiving acid drainage are natural reactors that can attenuate toxic metals. A better understanding of the chemical-hydrodynamic interactions in fluvial confluences can lead to new strategies for enhanced attenuation of toxic metals.


Aluminum Arsenic Acid drainage Confluence Iron Particle size Suspended solids Turbidity 



We thank Marina Coquery for her useful suggestions and Veronica Morales and Fernanda Carrasco for their help in the laboratory experiments and field measurements. This research was funded by Fondo Nacional de Desarrollo Científico y Tecnológico (Fondecyt) project number 1130936/2013 and Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias (FONDAP) project number 15110020. Paula Guerra acknowledges funding from the Comisión Nacional de Investigación Científica y Tecnológica (CONICYT) scholarship folio number 2110173.

Supplementary material

11270_2016_2767_MOESM1_ESM.docx (351 kb)
ESM 1 (DOCX 351 kb)


  1. Adra, A., et al. (2014). Arsenic scavenging by aluminum-substituted ferrihydrites in a circumneutral pH river impacted by acid mine drainage. Environmental Science & Technology. doi: 10.1021/es4020234.Google Scholar
  2. Arias, M., et al. (2008). Sorption behaviour of arsenic by iron and aluminium-oxides-coated quartz particles. Fresenius Environmental Bulletin, 17(12A), 2122–2125. Available at: <Go to ISI>://000264011200019.Google Scholar
  3. Asta, M. P., et al. (2010). Natural attenuation of arsenic in the Tinto Santa Rosa acid stream (Iberian pyritic belt, SW Spain): the role of iron precipitates. Chemical Geology, 271(1–2), 1–12. Available at: Accessed 11 Dec 2015.CrossRefGoogle Scholar
  4. Asta, M. P., et al. (2015). Major hydrogeochemical processes in an acid mine drainage affected estuary. Marine Pollution Bulletin, 91(1), 295–305. Available at: Accessed 27 March 2015.CrossRefGoogle Scholar
  5. Balistrieri, L. S., Box, S. E., & Tonkin, J. W. (2003). Modeling precipitation and sorption of elements during mixing of river water and porewater in the Coeur d’Alene river basin. Environmental Science & Technology, 37(20), 4694–4701. doi: 10.1021/es0303283.CrossRefGoogle Scholar
  6. Balistrieri, L., et al. (2007). Assessing the concentration, speciation, and toxicity of dissolved metals during mixing of acid-mine drainage and ambient river water downstream of the Elizabeth copper mine, Vermont, USA. Applied Geochemistry, 22(5), 930–952. Available at: <Go to ISI>://WOS:000247460600005.CrossRefGoogle Scholar
  7. Best, J. L. (1988). Sediment transport and bed morphology at river channel confluences. Sedimentology, 35(3), 481–498. doi: 10.1111/j.1365-3091.1988.tb00999.x/abstract;jsessionid=C5767B4E7D8C38D678FF63CC0553E4EA.d02t01.CrossRefGoogle Scholar
  8. Biron, P. M., Ramamurthy, A. S., & Han, S. (2004). Three-dimensional numerical modeling of mixing at river confluences. Journal of Hydraulic Engineering, 130(3), 243–253. doi: 10.1061/(ASCE)0733-9429(2004)130:3(243).CrossRefGoogle Scholar
  9. Bouchez, J., et al. (2011). Turbulent mixing in the amazon river: the isotopic memory of confluences. Earth and Planetary Science Letters, 311(3–4), 448. Available at: Scholar
  10. Buffle, J. (2006). The key role of environmental colloids/nanoparticles for the sustainability of life. Environmental Chemistry, 3(3), 155–158.CrossRefGoogle Scholar
  11. Bugueño, M. P., et al. (2014). Differential arsenic binding in the sediments of two sites in Chile’s lower Loa river basin. Science of the Total Environment, 466–467, 387–396. Available at: Scholar
  12. Candeias, C., et al. (2015). Water–rock interaction and geochemical processes in surface waters influenced by tailings impoundments: impact and threats to the ecosystems and human health in rural communities (panasqueira mine, central Portugal). Water, Air, & Soil Pollution, 226(2), 1–30. doi: 10.1007/s11270-014-2255-8.CrossRefGoogle Scholar
  13. Canovas, C. R., et al. (2007). Hydrogeochemical characteristics of the Tinto and odiel rivers (SW Spain). Factors controlling metal contents. Science of the Total Environment, 373(1), 363. Available at: Scholar
  14. Carrero, S., et al. (2015). The potential role of aluminium hydroxysulphates in the removal of contaminants in acid mine drainage. Chemical Geology, 417, 414–423. Available at: Accessed 15 Dec 2015.CrossRefGoogle Scholar
  15. Contreras, M. T., et al. (2015). Potential accumulation of contaminated sediments in a reservoir of a high-Andean watershed: morphodynamic connections with geochemical processes. Water Resources Research, 51(5), 3181–3192. doi: 10.1002/2014WR016130.CrossRefGoogle Scholar
  16. Davies, E. J., et al. (2012). LISST-100 response to large particles. Marine Geology, 307–310, 117–122. Available at: Accessed 9 Sep 2015.CrossRefGoogle Scholar
  17. De Vitre, R., Belzile, N., & Tessier, A. (1991). Speciation and adsorption of arsenic on diagenetic iron oxyhydroxides. Limnology and Oceanography, 36(7), 1480–1485. Available at: Scholar
  18. Dixit, S., & Hering, J. G. (2003). Comparison of arsenic(V) and arsenic(III) sorption onto iron oxide minerals:  implications for arsenic mobility. Environmental Science & Technology, 37(18), 4182. doi: 10.1021/es030309t.CrossRefGoogle Scholar
  19. Duan, J., & Gregory, J. (2003). Coagulation by hydrolysing metal salts. Advances in Colloid and Interface Science, 100-102, 475–502. Available at: Scholar
  20. Dzombak, D. A., & Morel, F. M. M. (1990). Surface complexation modeling: hydrous ferric oxide. New York: Wiley.Google Scholar
  21. EPA, 2007. 3051A - Microwave Assisted Acid Digestion of Aqueous Samples and Extracts U. S. E. P. Agency, ed. Wastes - Hazardous Waste - Test Methods - 3000 Series Methods. Available at:
  22. Filipek, L. H., Nordstrom, D. K., & Ficklin, W. H. (1987). Interaction of acid mine drainage with waters and sediments of west squaw creek in the west Shasta mining district, California. Environmental Science & Technology, 21(4), 388. doi: 10.1021/es00158a009.CrossRefGoogle Scholar
  23. Jarvis, P., et al. (2005). A review of floc strength and breakage. Water Research, 39(14), 3121–3137. Available at: Scholar
  24. Keon, N. E., et al. (2001). Validation of an arsenic sequential extraction method for evaluating mobility in sediments. Environmental Science & Technology, 35(13), 2778–2784. Available at: <Go to ISI>://000169600100041.CrossRefGoogle Scholar
  25. Kim, J. J., & Kim, S. J. (2003). Environmental, mineralogical, and genetic characterization of ochreous and white precipitates from acid mine drainages in Taebaeg, Korea. Environmental Science & Technology, 37(10), 2120–2126. doi: 10.1021/es026353a.CrossRefGoogle Scholar
  26. Kimball, B. A., et al. (2002). Assessment of metal loads in watersheds affected by acid mine drainage by using tracer injection and synoptic sampling: Cement Creek, Colorado, USA. Applied Geochemistry, 17(9), 1183–1207. Available at: Accessed 10 July 2015.CrossRefGoogle Scholar
  27. Kvech, S., & Edwards, M. (2002). Solubility controls on aluminum in drinking water at relatively low and high pH. Water Research, 36(17), 4356–4368. Available at: Scholar
  28. Laraque, A., Guyot, J. L., & Filizola, N. (2009). Mixing processes in the Amazon River at the confluences of the negro and Solimões Rivers, Encontro das Águas, Manaus, Brazil. Hydrological Processes, 23(22), 3131. doi: 10.1002/hyp.7388.CrossRefGoogle Scholar
  29. Leiva, E. D., et al. (2014). Natural attenuation process via microbial oxidation of arsenic in a high Andean watershed. Science of the Total Environment, 466–467, 490. Available at: Scholar
  30. Liao, B. Q., et al. (2006). Effect of solids retention time on structure and characteristics of sludge flocs in sequencing batch reactors. Water Research, 40(13), 2583–2591. Available at: <Go to ISI>://000239469400014.CrossRefGoogle Scholar
  31. McKnight, D. M., et al. (1992). Sorption of dissolved organic carbon by hydrous aluminium and iron oxides occurring at the confluence of Deer Creek with the Snake River, Summit County, Colorado. Environmental Science & Technology, 26(7), 1388–1396.CrossRefGoogle Scholar
  32. Meng, X., et al. (2002). Combined effects of anions on arsenic removal by iron hydroxides. Toxicology Letters, 133(1), 103–111. Available at: Scholar
  33. Mines, R., 2014. Environmental Engineering: Principles and practice First. J. W. & Sons, ed., Chichester: Wiley Blackwell.Google Scholar
  34. Nordstrom, D. K. (2011). Hydrogeochemical processes governing the origin, transport and fate of major and trace elements from mine wastes and mineralized rock to surface waters. Applied Geochemistry, 26(11), 1777–1791. Available at: Scholar
  35. Osawa, T., et al. (2011). The role of river confluences and meanderings in preserving local hot spots for threatened plant species in riparian ecosystems. Aquatic Conservation: Marine and Freshwater Ecosystems, 21(4), 358. doi: 10.1002/aqc.1194.CrossRefGoogle Scholar
  36. 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.Google Scholar
  37. Root, R. A., et al. (2007). Arsenic sequestration by sorption processes in high-iron sediments. Geochimica et Cosmochimica Acta, 71(23), 5782–5803. Available at: <Go to ISI>://000251366800016.CrossRefGoogle Scholar
  38. Ruiz Cánovas, C., Olías, M., & Nieto, J. (2013). Metal(loid) attenuation processes in an extremely acidic river: the Rio Tinto (SW Spain). Water, Air, & Soil Pollution, 225(1), 1–16. doi: 10.1007/s11270-013-1795-7.Google Scholar
  39. Russel, M. A., Walling, D. E. & Hodgkinson, R. A. (2000). Appraisal of a simple sampling device for collecting time-integrated fluvial suspended sediment samples. In: The Role of Erosion and Sediment Transport in Nutrient and Contaminant Transfer. Waterloo: IAHS.Google Scholar
  40. Sánchez-España, J., et al. (2005). The impact of acid mine drainage on the water quality of the odiel river (Huelva, Spain): evolution of precipitate mineralogy and aqueous geochemistry along the concepción-tintillo segment. Water, Air, and Soil Pollution, 173, 121–149.CrossRefGoogle Scholar
  41. Sánchez-España, J., et al. (2006). The impact of acid mine drainage on the water quality of the odiel river (Huelva, Spain): evolution of precipitate mineralogy and aqueous geochemistry along the concepción-tintillo segment. Water, Air, and Soil Pollution, 173(1–4), 121–149. doi: 10.1007/s11270-005-9033-6.CrossRefGoogle Scholar
  42. Sánchez-España, J., Yusta, I., & Diez-Ercilla, M. (2011). Schwertmannite and hydrobasaluminite: a re-evaluation of their solubility and control on the iron and aluminium concentration in acidic pit lakes. Applied Geochemistry, 26(9–10), 1752–1774. Available at: Accessed 7 July 2015.CrossRefGoogle Scholar
  43. Sarmiento, A. M., et al. (2009). Hydrochemical characteristics and seasonal influence on the pollution by acid mine drainage in the Odiel river Basin (SW Spain). Applied Geochemistry, 24(4), 697–714. Available at: Scholar
  44. Schemel, L. E., Kimball, B. A., & Bencala, K. E. (2000). Colloid formation and metal transport through two mixing zones affected by acid mine drainage near Silverton, Colorado. Applied Geochemistry, 15(7), 1003–1018. Available at: Accessed 10 Feb 2015.CrossRefGoogle Scholar
  45. Schemel, L. E., et al. (2006). Multiple injected and natural conservative tracers quantify mixing in a stream confluence affected by acid mine drainage near Silverton, Colorado. Hydrological Processes, 20(13), 2727–2743. doi: 10.1002/hyp.6081.CrossRefGoogle Scholar
  46. Schemel, L. E., et al. (2007). Formation of mixed Al-Fe colloidal sorbent and dissolved-colloidal partitioning of Cu and Zn in the Cement Creek - Animas River Confluence, Silverton, Colorado. Applied Geochemistry, 22(7), 1467–1484. Available at: Scholar
  47. Theobald Jr, P. K., Lakin, H. W. & Hawkins, D. B. (1963). The precipitation of aluminum, iron and manganese at the junction of Deer Creek with the Snake River in Summit County, Colorado. Geochimica et Cosmochimica Acta, 27(2), pp.121–122, IN1–IN2, 123–132. Available at:
  48. Tonkin, J. W., Balistrieri, L. S., & Murray, J. W. (2002). Modeling metal removal onto natural particles formed during mixing of acid rock drainage with ambient surface water. Environmental Science & Technology, 36(3), 484–492. Available at: <Go to ISI>://000173626900042.CrossRefGoogle Scholar
  49. Yukselen, M. A., & Gregory, J. (2004). The effect of rapid mixing on the break-up and re-formation of flocs. Journal of Chemical Technology & Biotechnology, 79(7), 782–788. doi: 10.1002/jctb.1056.CrossRefGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  • Paula Guerra
    • 1
    • 2
  • Christian Gonzalez
    • 1
  • Cristian Escauriaza
    • 1
    • 3
  • Gonzalo Pizarro
    • 1
    • 4
  • Pablo Pasten
    • 1
    • 4
    Email author
  1. 1.Departamento de Ingeniería Hidráulica y AmbientalPontificia Universidad Católica de ChileSantiagoChile
  2. 2.Departamento de Ingeniería Química y AmbientalUniversidad Técnica Federico Santa MaríaSantiagoChile
  3. 3.Centro Nacional de Investigación para la Gestión Integrada de Desastres NaturalesCIGIDEN, Pontificia Universidad Católica de ChileSantiagoChile
  4. 4.Centro de Desarrollo Urbano SustentableCEDEUS, Pontificia Universidad Católica de ChileSantiagoChile

Personalised recommendations