Environmental Earth Sciences

, Volume 62, Issue 8, pp 1673–1683 | Cite as

Arsenic Eh–pH diagrams at 25°C and 1 bar

  • Peng Lu
  • Chen Zhu
Original Article


A thermodynamic dataset for arsenic species in As–O–H–S–Fe–Ba system was compiled from the literature. Using this dataset, Eh–pH diagrams for the systems As–O–H, As–O–H–S, As–O–H–S–Fe, As–O–H–Ba, and As–O–H–S–Fe–Ba were constructed at 25°C and 1 bar. The inclusion of thioarsenite species in the systems As–O–H–S and As–O–H–S–Fe results in substantial differences from previously published Eh–pH diagrams. There are considerable differences in the thermodynamic properties for orpiment, realgar, scorodite, arsenopyrite, barium arsenate, and barium hydrogen arsenate, which result in vastly different stability fields when different values are adopted.


Eh–pH diagrams Arsenic Compilation 



The authors would like to thank Dr. Zuoping Zheng for assistance with thermodynamic data compilations in the early version of this manuscript and Yanyan Chen for checking calculations.


  1. Allison JD, Brown DS, Novo-Gradac KJ (1991) MINTEQA2/PRODEFA2, a geochemical assessment model for environmental systems, version 3.0 user’s manual. U.S. Environmental Protection Agency Report EPA/600/3-91/021Google Scholar
  2. Amirbahman A, Kent DB, Curtis GP, Davis JA (2006) Kinetics of sorption and abiotic oxidation of arsenic(III) by aquifer materials. Geochim Cosmochim Acta 70:533–547CrossRefGoogle Scholar
  3. Ball JW, Nordstrom DK (1991) User’s manual for WATEQ4F, with revised thermodynamic data base and test cases for calculating speciation of major, trace, and redox elements in natural waters. U.S. Geological Survey Open-File Report 91-183Google Scholar
  4. Bethke CM (2004) The Geochemist’s Workbench, version 5.0, GWB reference manual. Hydrogeology Program, University of IllinoisGoogle Scholar
  5. Brookins DG (1986) Geochemical behavior of antimony, arsenic, cadmium and thallium: Eh-pH diagrams for 25°C, 1 bar pressure. Chem Geol 54:271–278CrossRefGoogle Scholar
  6. Brookins DG (1988) Eh–pH diagrams for geochemistry. Springer, BerlinGoogle Scholar
  7. Cherry JA, Shaikh AU, Tallman DE, Nicholson RV (1979) Arsenic species as an indicator of redox conditions in groundwater. J Hydrol 43:373–392CrossRefGoogle Scholar
  8. Christensen JJ, Eatough DJ, Izatt RM (1975) Handbook of metal ligand heats and related thermodynamic quantities, 2nd edn. Marcel Dekker, New YorkGoogle Scholar
  9. Chukhlantsev VG (1956) Solubility products of arsenates. J Inorganic Chem (USSR) 1:1975–1982Google Scholar
  10. Craw D, Falconer D, Yongson JH (2003) Environmental arsenopyrite stability and dissolution: theory, experiment, and field observations. Chem Geol 179:71–82CrossRefGoogle Scholar
  11. Dove PM, Rimstidt JD (1985) The solubility and stability of scorodite, FeAsO4·2H2O. Am Miner 70:838–844Google Scholar
  12. Essington ME (1988) DIVISION S-2—SOIL CHEMISTRY—solubility of barium arsenate. Soil Sci Soc Am J 52:1566–1570CrossRefGoogle Scholar
  13. Ferguson JF, Gavis J (1972) A review of the arsenic cycle in natural waters. Water Res 6:1259–1274CrossRefGoogle Scholar
  14. Fukushi K, Sverjensky DA (2007) A predictive model (ETLM) for arsenate adsorption and surface speciation on oxides consistent with spectroscopic and theoretical molecular evidence. Geochim Cosmochim Acta 71:3717–3745CrossRefGoogle Scholar
  15. Garrels RM, Christ CL (1965) Minerals, solutions, and equilibria. Harper and Rowley, New YorkGoogle Scholar
  16. Hollibaugh JT, Carini S, Gurleyuk H, Jellison R, Joye SB, Lecleir G, Meile C, Vasquez L, Wallschlager D (2005) Arsenic speciation in Mono Lake, California: response to seasonal stratification and anoxia. Geochim Cosmochim Acta 69:1925–1937CrossRefGoogle Scholar
  17. Keimowitz AR, Zheng Y, Chillrud SN, Mailloux B, Jung HB, Stute M, Simpson HJ (2005) Arsenic redistribution between sediments and water near a highly contaminated source. Environ Sci Technol 39:8606–8613CrossRefGoogle Scholar
  18. Krause E, Ettel VA (1988) Solubility and stability of scorodite, FeAsO4:2H2O: new data and further discussion. Am Miner 73:850–854Google Scholar
  19. Krauskopf KB, Bird DK (1995) Introduction to geochemistry. McGraw-Hill, New YorkGoogle Scholar
  20. Langmuir D (1979) Techniques of estimating thermodynamic properties for some aqueous complexes of geochemical interest. In: Jenne EA (ed) Chemical modeling in aqueous systems: speciation, sorption, solubility, and kinetics. ACS Symp. Ser. 93. American Chemical Society, Washington, pp 353–387Google Scholar
  21. Langmuir D, Mahoney J, Rowson J (2006) Solubility products of amorphous ferric arsenate and crystalline scorodite (FeAsO4·2H2O) and their application to arsenic behavior in buried mine tailings. Geochim Cosmochim Acta 70:2942–2956CrossRefGoogle Scholar
  22. Lindberg RD, Runnells DD (1984) Ground water redox reactions: an analysis of equilibrium state applied to Eh measurements and geochemical modeling. Science 225:925–927CrossRefGoogle Scholar
  23. Marini L, Accornero M (2007) Prediction of the thermodynamic properties of metal–arsenate and metal–arsenite aqueous complexes to high temperatures and pressures and some geological consequences. Environ Geol 52:1343–1363CrossRefGoogle Scholar
  24. Naumov GB, Ryzhenko BN, Khodakovsky IL (1974) Handbook of thermodynamic data. U.S. Geological Survey, RestonGoogle Scholar
  25. Nordstrom DK, Archer DG (2002) Arsenic thermodynamic data and environmental geochemistry. In: Welch AH, Stollenwerk KG (eds) Arsenic in ground water. Springer, BerlinGoogle Scholar
  26. Oremland RS, Stolz JF (2003) The ecology of arsenic. Science 300:939–944CrossRefGoogle Scholar
  27. Plant JA, Kinniburgh DG, Smedley PL, Fordyce FM, Klinck BA (2003) Arsenic and selenium. In: Lollar BS (ed) Environmental geochemistry. Elsevier, AmsterdamGoogle Scholar
  28. Pokrovski GS, Gout R, Zotov A, Schott J, Harrichoury JC (1996) Thermodynamic properties and stoichiometry of the arsenic (III) hydroxide complexes at hydrothermal conditions. Geochim Cosmochim Acta 60:737–749CrossRefGoogle Scholar
  29. Pokrovski GS, Kara S, Roux J (2002) Stability and solubility of arsenopyrite, FeAsS, in crustal fluids. Geochim Cosmochim Acta 66:2361–2378CrossRefGoogle Scholar
  30. Pourbaix M (1966) Atlas of electrochemical equilibria. Pergamon Press, OxfordGoogle Scholar
  31. Robie RA, Waldbaum DR (1968) Thermodynamic properties of minerals and related substances at 298.15 K and one atmosphere pressure and at higher temperatures. Geological Survey Bulletin No. 1259. U.S. Department of the InteriorGoogle Scholar
  32. Robie RA, Hemingway BS, Fisher JR (1978) Thermodynamic properties of minerals and related substances at 298.15 K and 1 bar (105 Pa) pressure and at higher temperatures. U.S. Geological Survey Bulletin 1452Google Scholar
  33. Robins RG (1987) Solubility and stability of scorodite, FeAsO4:2H2O: discussion. Am Miner 72:842–844Google Scholar
  34. Robins RG (1990) The stability and solubility of ferric arsenate-an update. In: Gaskell DR (ed) EPD congress ‘90, TMS annual meetingGoogle Scholar
  35. Root RA, Vlassopoulos D, Rivera NA, Rafferty MT, Andrews C, O’day PA (2009) Speciation and natural attenuation of arsenic and iron in a tidally influenced shallow aquifer. Geochim Cosmochim Acta 73:5528–5553CrossRefGoogle Scholar
  36. Sergeyeva EI, Khodakovsky IL (1969) Physicochemical conditions of formation of native arsenic in hydrothermal deposits. Geochem Inter 7:846–859Google Scholar
  37. Shock EL, Helgeson HC (1988) Calculation of the thermodynamic and transport properties of aqueous species at high pressure and temperature: correlation algorithm for ionic species and equation of state predictions to 5 kb and 1000°C. Geochim Cosmochim Acta 52:2009–2036CrossRefGoogle Scholar
  38. Shock EL, Sassani DC, Willis M, Sverjensky DA (1997) Inorganic species in geologic fluids: correlations among standard molal thermodynamic properties of aqueous ions and hydroxide complexes. Geochim Cosmochim Acta 61:907–950CrossRefGoogle Scholar
  39. Sillen LG, Martell AE (1964) Solubility constants. Spec. Publ. No. 17. The chemical society, LondonGoogle Scholar
  40. Smedley PL, Kinniburg DG (2002) A review of the source, behaviour and distribution of arsenic in natural waters. Appl Geochem 17:517–568CrossRefGoogle Scholar
  41. Stumm W, Morgan JJ (1996) Aquatic chemistry, chemical equilibria and rates in natural waters, 3rd edn. Wiley, New York, p 1022Google Scholar
  42. Sverjensky DA, Fukushi K (2006) A predictive model (ETLM) for As(III) adsorption and surface speciation on oxides consistent with spectroscopic data. Geochim Cosmochim Acta 70:3778–3802CrossRefGoogle Scholar
  43. Swartz CH, Blute NK, Badruzzman B, Ali A, Brabander D, Jay J, Besancon J, Islam S, Hemond HF, Harvey CF (2004) Mobility of arsenic in a Bangladesh aquifer: inferences from geochemical profiles, leaching data, and mineralogical characterization. Geochim Cosmochim Acta 68:4539–4557CrossRefGoogle Scholar
  44. Takeno N (2005) Atlas of Eh–pH diagrams. Intercomparison of thermodynamic databases. Geological Survey of Japan Open File Report No. 419Google Scholar
  45. Tamaki S, Frankenberger WTJ (1992) Environmental biochemistry of arsenic. Rev Environ Contam Toxicol 124:79–110Google Scholar
  46. Turner RR (1981) Oxidation state of arsenic in coal ash leachate. Environ Sci Technol 15:1062–1066CrossRefGoogle Scholar
  47. Vink BW (1996) Stability relations of antimony and arsenic compounds in the light of revised and extended Eh–pH diagrams. Chem Geol 130:21–30CrossRefGoogle Scholar
  48. Wagemann R (1978) Some theoretical aspects of stability and solubility of inorganic arsenic in the freshwater environment. Water Res 12:139–145CrossRefGoogle Scholar
  49. Wagman DD, Evans WH, Parker VB, Schumm RH, Halow I, Bailey SM, Churney KL, Nuttall RL (1982) The NBS tables of chemical thermodynamic properties: selected values for inorganic and C-1 and C-2 organic-substances in SI units. J Phys Chem Ref Data 11:1–390CrossRefGoogle Scholar
  50. Whiting KS (1992) The thermodynamics and geochemistry of arsenic, with application to subsurface waters at the Sharon Steel Superfund Site at Midvale, Utah. MS Thesis, Colorado School of Mines, Golden, COGoogle Scholar
  51. WHO (2001) Environmental Health Criteria 224: arsenic and arsenic compounds. World Health Organization, GenevaGoogle Scholar
  52. Wilson FH, Hawkins DB (1978) Arsenic in streams, stream sediments, and ground water, Fairbanks Area, Alaska. Environ Geol 2:195–202CrossRefGoogle Scholar
  53. Wolery TJ (1992) EQ3/6, A software package for geochemical modeling of aqueous systems: package overview and installation guide (version 7.0). URCL-MA-110662-PT-I, Livermore, Calif., Univ. California, Lawrence Livermore LaboratoryGoogle Scholar
  54. Zhu Y, Merkel BJ (2001) The dissolution and solubility, FeAsO4:2H2O evaluation and simulation with PHREEQC2. Wiss. Mitt. Inst. Fur Geologie, TU Bergakedemie Freiberg, Germany 18:1–12Google Scholar
  55. Zhu YN, Zhang XH, Xie QL, Chen YD, Wang DQ, Liang YP, Lu J (2005) Solubility and stability of barium arsenate and barium hydrogen arsenate at 25°C. J Hazard Mater 120:37–44CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Department of Geological SciencesIndiana UniversityBloomingtonUSA

Personalised recommendations