Remediation of a grey forest soil contaminated with heavy metals by means of leaching at acidic pH
- 411 Downloads
The purpose was to study the heavy-metal leaching from topsoil when acidolysis or combination of acidolysis/complexolysis was applied as an approach for in situ soil remediation. The question was how the acidolysis of ferric iron hydroxides from topsoil would effect on the heavy-metal leaching when soil pH was lowered with sulfuric acid in or without the presence of cut straw into the soil.
Materials and methods
Four zero-suction lysimeters were used in this study. The heavy-metal acidolysis was studied by the soil irrigation with diluted solutions of sulfuric acid or its in situ generation as a result of the bacterial oxidation of S° by Acidithiobacilus thiooxidans.
The sulfur requirement was calculated having in mind the higher amount of acid soluble iron in the topsoil due to its contamination by AMD. The combination of acidolysis/complexolysis was studied by cut straw addition to S° at ratio 1:1 and 3:1, respectively. Regular sampling and analyses of the pregnant soil solutions was applied. The pollutant content, their distribution among the geochemical fractions, and the content of amorphous ferric iron hydroxides were determined before and after soil bioremediation.
Results and discussion
The reducible mobile fraction was the main fraction in which almost 50 % of each heavy metal was entrapped as a result of the soil pollution by AMD. The combination of acidolysis/complexolysis, realized by elemental sulfur and cut straw addition to horizon A of the AMD-affected soil at ratio of 1:1, allowed the concentration of lead, uranium, and arsenic after 9 months of remediation to be decreased near the relevant maximum admissible concentration (MAC), as their content in the exchangeable and specific adsorbed mobile fraction were drastically reduced. It determined the lower bioavailability of the pollutants at the end of the leaching stage.
A mixture of elemental sulfur and cut straw at a ratio of 1:1 was an efficient method for in situ bioremediation of AMD-affected soil. The heavy-metal leaching from easily leachable fractions was a result of the joint action of acidolysis/complexolysis, and as a result, the contaminant content in horizon A was significantly reduced.
KeywordsBioavailability Heavy-metal leaching Mining soil Sulfur-oxidizing chemolitrophic bacteria
- APHA (1995) Standard methods for the examination of water and wastewater. American Public Health Association, WashingtonGoogle Scholar
- Bermudez GMA, Jasan R, Plá R, Pignata ML (2012) Heavy metals and trace elements in atmospheric fall-out: their relationship with topsoil and wheat element composition. J Hazard Mater 213–214:447–456Google Scholar
- CCME (Canadian Council of Ministers for the Environment) (2006) Canadian soil quality guidelines for the protection of environmental and human health, update 6.02, Publication no 1299, ISBN 1-896997-34-1Google Scholar
- Ceja-Navarro JA, Rivera-Orduna FN, Patino-Zuniga L, VilaSanjurjo A, Crossa J, Govaerts B, Dendooven L (2010) Phylogenetic and multivariate analyses to determine the effects of different tillage and residue management practices on soil bacterial communities. Appl Environ Microb 76:3685–3691CrossRefGoogle Scholar
- Gadd G (2007) Geomycology: biogeochemical transformations of rocks, minerals, metals and radionuclides by fungi, bioweathering and bioremediation. Mycol Res III:3-49Google Scholar
- Georgiev P, Groudev S, Spasova I, Nicolova M (2015) Transport of radionuclides and heavy metals during the cleaning of a polluted cinnamonic soil. J Geochem Explor (submitted)Google Scholar
- Guideline No. 3 (2008) Permissible contents of harmful substances in the Bulgarian soils. An Official gazette 71Google Scholar
- Ferdelmann TG (1988) The distribution of sulfur, iron, manganese, copper, and uranium in a salt marsh sediment core as determined by a sequential extraction method. Master thesis, Univ. DelawareGoogle Scholar
- Fujii K, Funakawa S, Kosaki T (2012) Soil acidification: natural processes and human impact. Pedologist 55:415–425Google Scholar
- Koinov V, Kabakchiev I, Boneva K (1998) Grey forest soils. In Koinov V, Boneva K (eds) Atlas of Bulgarian soils, Zemizdat, Sofia, pp 71-85Google Scholar
- Lopez-Aguirre JG, Farias-Larios J, Molina-Ochoa J (2007) Salt leaching process in an alkaline soil treated with elemental sulfur under dry tropic conditions. World J Agric Sci 3:356–362Google Scholar
- Muyzer G, Stams AJM (2008) The ecology and biotechnology of sulfate-reducing bacteria. Nat Rev Microbiol 6:441–454Google Scholar
- Nelson WL, Mehlich M, Winters E (1953) The development, evaluation, and use of soil tests for phosphorus availability. Agron 4:153–158Google Scholar
- Pansu M, Gautheyrou J (2006) Handbook of soil analysis. Mineralogical, organic and inorganic methods. Springer Verlag, BerlinGoogle Scholar
- Rao DV, Chivannavar CT, Gaddad SM (2002) Bioleaching of copper from chalcopyrite ore by fungi. Indian J Exp Biol 40:319–324Google Scholar
- Simate GS, Ndlovu S, Gericke M (2009) Bacterial leaching of nickel laterites using chemolithotropic microorganisms: Process optimisation using response surface methodology and central composite rotatable design. Hydromet 98:241–246Google Scholar
- Sobek AA, Schuller WA, Freeman JR, Smith RM (1978) Field and laboratory methods applicable to overburden and mine soils. US EPA Report 600/ 2 – 78 – 054Google Scholar
- Tang J, Valix M (2004) Leaching of low-grade nickel ores by fungi metabolic acids. Proceedings of Separation Technologies IV: New Perspectives on Very Large Scale Operations, pp 1-15Google Scholar
- Valdes J, Pedroso I, Quatrini R, Holmes DS (2008) Comparative genome analysis of Acidithiobacillus ferrooxidans, A. thiooxidans and A. caldus: insights into their metabolism and ecophysiology. Hydromet 94:180–184Google Scholar
- Yan TY (1985) In situ leaching of uranium using dilute sulfuric acid and molecular oxygen. Chem Eng Comm 33:219–230Google Scholar