Speciation, bioaccessibility and health risk assessment of Pb in soils affected by mining activity: a case study of the Irankuh Pb-Zn mine (SW Esfahan)


Hydrology and Environmental Geology Department, Faculty of Earth Sciences, Shahrood University of Technology, Shahrood, Iran


The present study aims to investigate the speciation, bioaccessibility, and health risk of Pb in the soils around the Irankuh mine. For this purpose, 20 soil samples were collected and the physicochemical parameters of the samples were determined. The total and bioaccessible concentrations of Pb were determined using the total digestion and in vitro methods, respectively. The speciation of Pb in selected soil samples was investigated using a sequential extraction approach. The values of pH, organic matter, carbonate and cation exchange capacity of the studied soil samples vary between 6.7 to 8.2, 0.2 to 4.8 %, 6 to 48.5%, and 18 to 11.2 meq/100 g, respectively. The total concentration of Pb changes between 18.4 and 2869 mg/kg (average value of 273.4 mg/kg). Pb is dominantly present in reducible fraction, confirming the anthropogenic source of Pb and its potential mobility. Based on the in vitro test results, the bioaccessibility of Pb is very variable (between 0.2 to 45.4% of the total concentration), which is due to the difference in the physico-chemical characteristics of the samples and the source of the element. The hazard coefficient values for ingestion, dermal contact and inhalation routes are higher for children than adults, and for the ingestion route than other exposure pathways. The carcinogenic risk (CR) values indicate that there is no risk through dermal contact and inhalation routes; however, CR values for the ingestion route using both bioavailable and total concentrations confirm the probability of cancer risks for residents living near the mining site.


Main Subjects

Ahirvar, Bh.P., Das, P., Srivastava, V., Kumar, M., 2023. Perspectives of heavy metal pollution indices for soil, sediment, and water pollution evaluation: An insight. Total Environment Research Themes 6, 100039. https://doi.org/10.1016/j.totert.2023.100039.
Billmann, M., Hulot, C., Pauget, B., Badreddine, R., Papin, A., Pelfrêne, A., 2023. Oral bioaccessibility of PTEs in soils: A review of data, influencing factors and application in human health risk assessment. Science of The Total Environment 896, 165263. https://doi.org/10.1016/j.scitotenv.2023.165263.
Bosso, S.T., Enzweiler, J., 2008. Bioaccessible lead in soils, slag, and mine wastes from an abandoned mining district in Brazil. Environmental Geochemistry and Health 30(3), 219–229. https://doi.org/10.1007/s10653-007-9110-4.
Bonberg, N., Pesch, B., Ulrich, N., Moebus, S., Eisele, L., Marr, A., Arendt, M., Jöckel, K.-H., Brüning, T., Weiss, T., 2017. The distribution of blood concentrations of lead (Pb), cadmium (Cd), chromium (Cr) and manganese (Mn) in residents of the German Ruhr area and its potential association with occupational exposure in metal industry and/or other risk factors. International Journal of Hygiene and Environmental Health 220(6), 998–1005. https://doi.org/10.1016/j.ijheh.2017.05.009.
Broadway, A., Cave, M.R., Wragg, J., Fordyce, F.M., Bewley, R.J.F., Graham, M.C., Ngwenya, B.T., Farmer, J.G., 2010. Determination of the bioaccessibility of chromium in Glasgow soil and the implications for human health risk assessment. Science of The Total Environment 409 (2), 267-277. https://doi.org/10.1016/j.scitotenv.2010.09.007.
Chaithanya, M.S., Das, Bh., Vidya, R., 2023. Distribution, chemical speciation and human health risk assessment of Metals in soil particle size fractions from an industrial area. Journal of Hazardous Materials Advances 9, 100237. https://doi.org/10.1016/j.hazadv.2023.100237.
Demetriades, A., Li, X., Ramsey, M. H., Thornton, I., 2010. Chemical speciation and bioaccessibility of lead in surface soil and house dust, Lavrion urban area, Attiki, Hellas. Environmental Geochemistry and Health 32(6), 529–552. https://doi.org/10.1007/s10653-010-9315-9
Du, P., Xue, N., Liu, L., Li, F., 2008. Distribution of Cd, Pb, Zn and Cu and their chemical speciations in soils from a peri-smelter area in northeast China. Environmental Geology 55(1), 205–213. https://doi.org/10.1007/s00254-007-0976-3
Ferreira-Baptista, L., Miguel, E.D., 2005. Geochemistry and risk assessment of street dust in Luanda, Angola: a tropical urban environment. Atmospheric Environment 39 (25), 4501–4512. https://doi.org/10.1016/j.atmosenv.2005.03.026.
Forghani, G, Mokhtari, A.R., Kazemi, Gh., Davoodi Fard, M., 2015. Total  concentration,  speciation  and  mobility  of  potentially  toxic elements  in  soils  around  a  mining  area  in  central  Iran. Chem. Erde, 323–334. https://www.sciencedirect.com/science/article/abs/pii/S000928191500029X.
Håkanson, L., 1980. An ecological risk index for aquatic pollution control. A sedimentological approach. Water Research 14, 995-1001. https://www.sciencedirect.com/science/article/abs/pii/0043135480901438.
Han, Q., Wang, M., Cao, J., Gui, C., Liu, Y., He, X., He, Y., Liu, Y., 2020. Health risk assessment and bioaccessibilities of heavy metals for children in soil and dust from urban parks and schools of Jiaozuo, China. Ecotoxicology and Environmental Safety 191, 110157. https://doi.org/10.1016/j.ecoenv.2019.110157.
Haque, E., Thorne, P.S., Nghiem, A.A., Yip, C.S., Bostick, B.C., 2021. Lead (Pb) concentrations and speciation in residential soils from an urban community impacted by multiple legacy sources. Journal of Hazardous Materials 416, 1125886. https://doi.org/10.1016/j.jhazmat.2021.125886.
IARC, 2006. Monographs Lead and lead compounds International Agency for Research on Cancer. Press release 87, World Health Organization. Available at: file:///C:/Users/Mohammad%20Hossien/Desktop/TR42-1%20(1).pdf  (accessed February 21, 2022).
Integrated Risk Information System (IRIS), 2020. Environmental protection agency, advanced research. U.S. https://cfpub.epa.gov/ncea/ iris/search/index.cfm?keyword.
Kabata-Pendias, A., 2011. Trace elements in soils and plants, 4th ed. Taylor & Francis Group, Boca Raton London New York, P. 548
Karimpour, M.H., Malekzadeh Shafaroudi, A., Alaminia, Z., Esmaeili Sevieri, A., Stern, Ch.R., 2019. New hypothesis on time and thermal gradient of subducted slab with emphasis on dolomitic and shale host rocks in formation of Pb-Zn deposits of Irankuh-Ahangaran belt. Journal of Economic Geology 10(2), 677-706. https://econg.um.ac.ir/article_33591.html?lang=en.
Li, Y., Demisie, W., Zhang, Mk., 2015. Digestion Tests to Measure Heavy Metal Bioavailability in Soils. In: Lichtfouse, E., Schwarzbauer, J., Robert, D., (Eds.), CO2 Sequestration, Biofuels and Depollution. Environmental Chemistry for a Sustainable World, vol 5. Springer, Cham. https://doi.org/10.1007/978-3-319-11906-9_7.
Li, Z., Feng, X., Li, G., Bi, X., Sun, G., Zhu, J., Qin, H., Wang, J., 2011. Mercury and other metal and metalloid soil contamination near a Pb/Zn smelter in east Hunan province, China. Applied Geochemistry 26(2), 160–166. https://doi.org/10.1016/j.apgeochem.2010.11.014.
Liu, B., Ai, S., Zhang, W., Huang, D., Zhang, Y., 2017. Assessment of the bioavailability, bioaccessibility and transfer of heavy metals in the soil-grain-human systems near a mining and smelting area in NW China. Science of the Total Environment 609, 822–829. https://doi.org/10.1016/j.scitotenv.2017.07.215.
Metson, A. J., 1957. Methods of chemical analysis for soil survey samples. Soil Science 83(3), P. 245.
Oomen, A.G, Rompelberg, C.J.M., Bruil, M.A., Dobbe, C.J.G., Pereboom, D., Sips, A., 2003. Development of an in vitro digestion model for estimating the bioaccessibility of soil contaminants. Archives of Environmental Contamination and Toxicology 44(3), 281–287. https://www2.bgs.ac.uk/barge/docs/Oomen_et_al_2003.pdf
Štupar, J., Dolinšek, F., Er┼żen, I., 2007. Hair-Pb longitudinal profiles and blood-Pb in the population of young Slovenian males. Ecotoxicology and Environmental Safety 68(1), 134–143. https://doi.org/10.1016/j.ecoenv.2006.03.010.
Sundaray, S.K., Nayak, B.B., Lin, S., Bhatta, D., 2011. Geochemical speciation and risk assessment of heavy metals in the river estuarine sediments—A case study: Mahanadi basin, India. Journal of Hazardous Materials 186, 1837–1846. https://doi.org/10.1016/j.jhazmat.2010.12.081.
Tessier, A., Campbell, P.G. C., Bisson, M., 1979. Sequential extraction procedure for the speciation of particulate trace metals. Analytical Chemistry 51(7), 844–851. https://doi.org/10.1021/ac50043a017.
USEPA, 1986. Cation Exchange Capacity, Method 9080. EPA, Washington, D.C. https://www.epa.gov/sites/default/files/2015-12/documents/9080.pdf
USEPA, 1989. Risk assessment guidance for superfund volume I human health evaluation manual (Part A). Office of Emergency and Remedial Response. U.S, Environmental Protection Agency Washington, 20450. EPA/540/1-89/002. https://www.epa.gov/sites/default/files/2015-09/documents/rags_a.pdf.
USEPA, 1998. Test methods for evaluating solid waste, Method 9045D. EPA, Washington, D.C. https://www.epa.gov/sites/default/files/2015-12/documents/9045d.pdf.
USEPA, 2017. In vitro bioaccessibility assay for lead in soil, Method 1340, EPA, Washington, D.C. https://www.epa.gov/hw-sw846/sw-846-test-method-1340-vitro-bioaccessibility-assay-lead-soil.
Wang, L., Liu, R., Liu, J., Qi, Y., Zeng, W., Cui, B., 2023. A novel regional-scale human health risk assessment model for soil heavy metal(loid) pollution based on empirical Bayesian kriging. Ecotoxicology and Environmental Safety 258, 114953. https://doi.org/10.1016/j.ecoenv.2023.114953.
Yang, Z.P., Lu, W.Z., Long, Y.Q., Bao, X.H., Yang, Q.C., 2011. Assessment of heavy metals contamination in urban topsoil from Changchun City, China. Journal of Geochemical Exploration 108, 27-38. https://www.sciencedirect.com/science/article/abs/pii/S037567421000138X.