Study of heavy metal concentrations in shale deposits of Irankouh Mine (Southwest of Isfahan)

Document Type : Original Article


Department of Geology, Faculty of Science, University of Isfahan, Isfahan, Iran


Irankuh Pb-Zn mine is located in 20 km SW of Isfahan in the Zayandehrud river drainage basin. Shale and carbonate are host rocks of the ore deposits. High concentration of Pb and Zn formed ore complex in these rocks. Weathering and erosion of the host rocks of ore deposits, waste water and waste material arising from mining have made potential for pollution of running water, ground water and agriculture soils by the heavy metals. The main objectives of this investigation were to study the total concentration  of Zn, Pb, Ni,Cu, Co, Ag, and Cd in the shale deposits of  the mine and physicochemical factors on their distribution and pollution.
Materials and methods:
For measuring heavy metals values, twenty samples were taken from the shale deposits. For distinguishing the shale forming minerals, thin sections were prepared and studied by polarizing microscope. The rock forming clay minerals, after preliminary treatments (heating at 550oc, ethylene glycol solvation), were detected by XRD. Organic carbon, calcium carbonate and Eh/pH of the shales were measured. Heavy metals values in the sample were measured by AAS after mineralization. Correlation coefficient of organic carbon and Mn with metals and also metals-metals were calculated. For comparison of the heavy metal concentration relative to their natural amount (in shale), enrichment factor was applied.
Results and discussion: 
The dark grey to olive colored shales in the studied area consist of clay to fine silt size. Quartz, biotite, muscovite, feldspar and clay minerals are the non-opaque minerals of the shales. The clay minerals are illit (60-70%), kaolinite (9-27%) and chlorite (7-22%) respectively. Sphalerite, pyrite and galena are the main opaque minerals of the mine. The mean OC content of the shale is about 2% (0.35-5.5%) and less than 1% calcium carbonate. The pH of the samples is nearly neutral (6.8-7.8) and they have an oxidizing to nearly reducing Eh (18 to -100 v).
The average concentration of heavy metals in the shales are Zn=128.05>Pb=42.55> Ni=35.24> Cu=24.18> Co=7.4> Ag=3.33> Cd=0.79 in ppm, respectively. Highly positive correlation between Ag-Pb-Cd, Cd-Zn-Pb and Co-Ni-Mn and also positive correlation between Zn with organic carbon show geochemical convenient conditions for concentration of the metals. The calculated enrichment factor has revealed extremely high enrichment for Ag and average for Cd. Other elements are depleted in the sediments. Due to relative high concentration of the metals and their extent of the shales in the study area, activation of the heavy metals in suitable conditions can be a potential source for environmental contamination in the groundwater and runoff water of the basin. 


  1. Anushka U.R., Meththika V., Christopher O., 2012. Nickel and manganese release in serpentine soil from the Ussangoda Ultramafic Complex, Sri Lanka. Geoderma. 189, 1-9.
  2. Armienta M. A., Villasenor G., Cruz O., Ceniceros N., Aguayo A., 2012.Geochemical process and mobilization of toxic metals and metalloids in an As-rich base metal waste pile in Zimapan, Central Mexico. Applied Geochemistry. 11, 2225-2237.
  3. Bradl H., 2005. Heavy Metals in the environment: Elsevier; p. 269.
  4. Brookins D., 1988. Eh-pH diagrams for geochemistry: Springer; p. 176.
  5. Buhmann C., Fey M. V., De Villiers J. M., 1985. Aspects of the X-ray identification of swelling clay minerals in soils and sediments. South African Journal of science. 81, 505-509.
  6. Eckert D., Sims J. T., 1995. Recommended soil pH and lime requirement tests: in .T. Sims and A. Wolf, Recommended soil testing procedures for the Northeastern United States: New York. Agricultural Experiment Station. 493, 11-16.
  7. Forstner U., 2004. Sediment dynamics and pollutant mobility in rivers: an interdisciplinary approach: Lakes and reservoir. Research and management. 9(1): 25-40.
  8. Ghasemi A., 2004. Geological studies, facies analysis and geochemistry of Kolahdarvazeh Ghodzendan and Kanehgorghi lead deposits on south of the Irankouh range, southwest of Isfahan. M.Sc.: Tarbiatmodares University, Tehran. (In Persian with English abstract).
  9. Garrels R., Christ C., 1965. Minerals, solutions and equilibria. Harperand Row; p. 450.
  10. Hem J. D., Durum W H., 1973. Solubility and occurrence of lead in surface water. Journal American Water Works Association. 65, 562-568.
  11. Hudson-Edwards A. K., Wright K., 2011. Computer simulation of the interactions of the (0 1 2) and (0 0 1) surfaces of jarosite with Al, Cd, Cu and Zn. Geochimica Et Cosmochimca Acta. 75, 52-62
  12. Kartal S., Aydin Z., Tokalioglu S., 2006. Fractionation of metals in street sediment samples by using the BCR sequential extraction procedure and multivariate statistical elucidation of the data. Journal of Hazardous Materials. 132, 80-89
  13. Kossoff D., Hudson-Edwards A. K., Dubbin W. E., Alfredsson M. A., 2011. Incongruent weathering of Cd and Zn from mine tailing: A column leaching study. Chemical. Geology. 281, 52-71.
  14. Kossoff D., Hudson-Edwards A. K., Dubbin W. E., 2012. Major and trace metal mobility during weathering of mine tailing: Implications for floodplain soils. Applied Geochemistry. 27, 562-576.
  15. Krauskopf, K. B., 1979. Introduction to geochemistry. New York: McGraw-Hill; 617p.
  16. Lindsay, W. L., 1979. Chemical equilibria in soils: John Wiley and Sons; p. 449.
  17. Lueth V., Megaw K. M., Pingitore N. E., Goodell, P. C., 2000. Systematic variation in galena solid solution compositions at Santa Eulalia, Chihuahua, Mexico. Economic Geology. 95, 1673-1687.
  18. Maynard J., 1983. Geochemistry of sedimentary ore deposits. Springer-verlag. p. 305.
  19. McBride M. B., 1994. Environmental chemistry of soils. New York: Oxford University Press; p. 411.
  20. Micό C., Recatala M., Sanchez J., 2008. Discrimination of lithogenic and anthropogenic metals in calcareous agricultural soils. Soil and Sediment Contamination. 17, 467-485.
  21. Miriam I. N., Peter O., Maria E. N., Jon Petter, G., 2012. Metal speciation in rivers affected by enhanced soil erosion and acidity. Applied Geochemistry. 27, 906-916.
  22. Rose A. W., Hawkes H. E., Webb J. S., 1979. Geochemistry in Mineral Exploration (2nd edition). London: Academic Press.
  23. Safari A., 2009. The accumulation of zinc and nickel in Irankoh indigenous plant species on a contaminated land. Soil and Sediment Contamination. 18, 525- 534.-
  24. Safari A., 2008. The potential of Irankoh indigenous plant species for the phytoremidiation of cadmium and lead contaminated land. Soil and Sediment Contamination. 17, 181- 188.
  25. Schultz L. G.,1964. Quantitative interpretation of mineralogical composition from X-ray and chemical data for the Pierre Shale. U.S. Geological Survey Professional Paper. 391, 1-31.
  26. Street J., Sabey B., Lindsay W., 1978. Influence of pH [hydrogen ion concentration], phosphorus, cadmium, sewage sludge, and incubation time on the solubility and plant uptake of cadmium [Corn, soil pollution]. Journal of Environmental Quality. 7, 286-290.
  27. Storer D. A., 1984. A simple high volume ashing procedure for determining soil organic matter, Soil Sci journal; 7: 759-772.
  28. Teymouri F., Pakzad H., Bagheri H., 2011. Investigation of the source of of the metals and fluids in the Irankouh lead deposit. Stratigraphy and sedimentary researches. 44, 83-102 (In Persian with English abstract).
  29. Yongming H., Peixuan D., Junji C., Posmentier E. S., 2006. Multivariate analysis of heavy metal contamination in urban dusts of Xi'an, Central China. Science of the Total Environment. 355, 176-186.