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Arsenic speciation in arsenic-rich Brazilian soils from gold mining sites under anaerobic incubation

  • Jaime W. V. de MelloEmail author
  • Jonathan L. Talbott
  • John Scott
  • William R. Roy
  • Joseph W. Stucki
Research Article

Abstract

Background

Arsenic speciation in environmental samples is essential for studying toxicity, mobility and bio-transformation of As in aquatic and terrestrial environments. Although the inorganic species As(III) and As(V) have been considered dominant in soils and sediments, organisms are able to metabolize inorganic forms of arsenic into organo-arsenic compounds. Arsenosugars and methylated As compounds can be found in terrestrial organisms, but they generally occur only as minor constituents. We investigated the dynamics of arsenic species under anaerobic conditions in soils surrounding gold mining areas from Minas Gerais State, Brazil to elucidate the arsenic biogeochemical cycle and water contamination mechanisms.

Methods

Surface soil samples were collected at those sites, namely Paracatu Formation, Banded Iron Formation and Riacho dos Machados Sequence, and incubated in CaCl2 2.5 mmol L−1 suspensions under anaerobic conditions for 1, 28, 56 and 112 days. After that, suspensions were centrifuged and supernatants analyzed for soluble As species by IC-ICPMS and HPLC-ICPMS.

Results

Easily exchangeable As was mainly arsenite, except when reducible manganese was present. Arsenate was mainly responsible for the increase in soluble arsenic due to the reductive dissolution of either iron or manganese in samples from the Paracatu Formation and Riacho dos Machados Sequence. On the other hand, organic species of As dominated in samples from the Banded Iron Formation during anaerobic incubation.

Discussion

Results are contrary to the expectation that, in anaerobic environments, As release due to the reductive dissolution of Fe is followed by As(V) reduction to As(III). The occurrence of organoarsenic species was also found to be significant to the dynamics of soluble arsenic, mainly in soils from the Banded Iron Formation (BIF), under our experimental conditions.

Conclusions

In general, As(V) and organic As were the dominant species in solution, which is surprising under anaerobic conditions in terrestrial environments. The unexpected occurrence of organic species of As was attributed to enrollment of ternary organic complexes or living organisms such as algae or cyanobacteria.

Perspectives

These findings are believed to be useful for remediation strategies in mine-affected regions, as the organic As species are in general considered to be less toxic than inorganic ones and even As(V) is considered less mobile and toxic than As(III).

Keywords

Anaerobic soils arsenic speciation As biogeochemistry As in aquatic and terrestrial environments biomethylation Brazil gold mining sites organic As 

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References

  1. Bentley R, Chasteen TG (2002): Microbial methylation of methaloids: Arsenic, antimony, and bismuth. Microbiol Molecular Biol Reviews 66, 250–271CrossRefGoogle Scholar
  2. Brookins DG (1998): Eh-pH diagrams for geochemistry. Springer-Verlag, Berlin, New York, 174 ppGoogle Scholar
  3. Carlson L, Bigham JM, Schwertmann U, Kyek A, Wagner F (2002): Scavenging of As from acid mine drainage by Schwertmannite and Ferrihydrite: A comparison with synthetic analogues. Environ Sci Technol 36, 1712–1719CrossRefGoogle Scholar
  4. Deschamps E, Ciminelli V, Weidler PG, Ramos AY (2003): Arsenic sorption onto soils enriched in Mn and Fe minerals. Clays Clay Miner 51, 197–204CrossRefGoogle Scholar
  5. Geiszinger A, Goessler W, Kosmus W (2002): Organoarsenic compounds in plants and soil on top of an ore vein. Appl Organom Chem 16, 245–249CrossRefGoogle Scholar
  6. Gomez Ariza JL, Morales E, Sanchez-Rodas D, Giraldez I (2000): Stability of chemical species in environmental matrices. Trends Anal Chem 19, 200–209CrossRefGoogle Scholar
  7. Gong Z, Lu X, Ma M, Watt C, Le XC (2002): Arsenic speciation analysis. Talanta 58, 77–96CrossRefGoogle Scholar
  8. Hamon RE, Lombi E, Fortunati P, Nolan AL, McLaughlin MJ (2004): Coupling speciation and isotope dilution techniques to study arsenic mobilization in the environment. Environ Sci Technol 38, 1794–1798CrossRefGoogle Scholar
  9. Hasegawa H, Sohrin Y, Matsul M, Hojo M, Kasashima M (1994): Speciation of arsenic in natural waters by solvent extraction and hydride generation atomic absorption spectrometry. Anal Chem 66, 3247–3252CrossRefGoogle Scholar
  10. Jain CK, Ali I (2000): Arsenic: Occurrence, toxicity and speciation. Water Res 24, 4304–4312CrossRefGoogle Scholar
  11. Keon NE, Swartz CH, Brabander DJ, Harvey C, Hemond HF (2001): Validation of an arsenic sequential extraction method for evaluating mobility in sediments. Environ Sci Technol 35, 2778–2784CrossRefGoogle Scholar
  12. Manning BA, Fendorf SE, Bostick B, Suarez DL (2002): Arsenic (III) oxidation and arsenic (V) adsorption reactions on synthetic birnessite. Environ Sci Technol 36, 976–981CrossRefGoogle Scholar
  13. Manning BA, Goldberg S (1997): Adsorption and stability of arsenic (III) at the clay mineral-water interface. Environ Sci Technol 31, 2005–2011CrossRefGoogle Scholar
  14. Mello JWV, Roy WR, Talbott JL, Stucki JW (2006): Mineralogy and Arsenic mobilization in arsenic-rich Brazilian soils and sediments. J Soils Sediments 6, 9–19CrossRefGoogle Scholar
  15. Meng X, Korfiatis GP, Jing C, Christodoulatus C (2001): Redox transformations of arsenic and iron in water treatment sludge during aging and TCLP extraction. Environ Sci Technol 35, 3476–3481CrossRefGoogle Scholar
  16. Moore JN, Walker JR, Hayes TH (1990): Reaction scheme for the oxidation of As(III) to As(V) by birnessite. Clays Clay Miner 38, 549–555CrossRefGoogle Scholar
  17. Murray LA, Raab A, Marr IL, Feldmann J (2003): Biotransformation of arsenate to arsenosugars by Chlorella vulgaris. Appl Organom Chem 17, 669–674CrossRefGoogle Scholar
  18. Nascimento SM, Azevedo SMFO (1999): Changes in cellular components in a cyanobacterium (Synechocystis aquatilis f. salina) subjected to different N/P ratos — An ecophysiological study. Environ Toxicol 14, 37–44CrossRefGoogle Scholar
  19. Oscarson DW, Huang PM, Liaw WK, Hammer UT (1983): Kinetics of oxidation of arsenite by various manganese dioxides. Soil Sci Soc Am J 47, 644–648CrossRefGoogle Scholar
  20. Redman AD, Macalady DL, Ahmann D (2002): Natural organic matter affects arsenic speciation and sorption onto hematite. Environ Sci Technol 36, 2889–2896CrossRefGoogle Scholar
  21. Smedley PL, Kinniburgh DG (2002): A review of source, behaviour and distribution of arsenic in natural waters. Appl Geochem 17, 517–568CrossRefGoogle Scholar
  22. USEPA (2000): National primary drinking water regulations arsenic and clarifications to compliance and new source contaminants monitoring; proposed rule. Federal Register, v.65, n.121, pp 38888–38983Google Scholar

Copyright information

© ecomed publishers 2007

Authors and Affiliations

  • Jaime W. V. de Mello
    • 1
    Email author
  • Jonathan L. Talbott
    • 2
  • John Scott
    • 2
  • William R. Roy
    • 3
  • Joseph W. Stucki
    • 4
  1. 1.Soil DepartmentFederal University of ViçosaViçosaBrazil
  2. 2.Waste Management and Research CenterUniversity of Illinois at Urbana-Champaign (UIUC)ChampaignUSA
  3. 3.Illinois State Geological SurveyUIUCChampaignUSA
  4. 4.Department of Natural Resources and Environmental SciencesUIUCUrbanaUSA

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