The present study investigated the distribution of elements and potentially toxic elements (PTEs) in soil profiles in the southeastern region of Nigeria, where unrefined and primitive mining practices are common. Soil samples were collected from mine and non-mine sites in Ameka and Nkalagu and analyzed for total elemental concentration using portable X-ray fluorescence (pXRF). The results showed that the Ameka mine-affected soils were heavily polluted, while the Ameka non-mine-affected soils were moderately polluted. The Nkalagu mine and non-mine-affected soils were also moderately polluted. The potential ecological risk (PER) was high in the Ameka mine-affected site due to elevated As, Cu, and Pb levels, while the Ameka non-mine-affected site had a low PER. The enrichment factor (EF) values indicated more enrichment of PTEs in the mine-affected sites compared to the non-mine-affected sites. The geoaccumulation index (Igeo) showed moderate to extreme contamination in the Ameka mine-affected site with Cu, Zn, As, and Pb. In contrast, the Nkalagu mine-affected site had considerably lower contamination. The regression model showed that site characteristics alone were insufficient to explain elements and PTEs distribution, emphasizing the importance of considering soil properties in understanding their spatial patterns. The study highlights the higher concentrations of As, Cu, and Pb in the mine-affected sites compared to the non-mine areas and recommends remediation strategies for these elements and PTEs, especially in the vicinity of mine sites. Further laboratory analysis is recommended to understand the mobility of PTEs with depth for better remediation approaches.

Department of Plant Food and Environmental Sciences Faculty of Agriculture Dalhousie University Truro NS B2N 5E3 Canada

Department of Soil and Crop Sciences Colorado State University Fort Collins United States

Department of Soil Science Czech University of Life Sciences Prague Czech Republic

Department of Soil Science University of Calabar Nigeria

Department of Soil Science University of Nigeria Nsukka Nigeria

See more in PubMed

Ahado S.K., Nwaogu C., Sarkodie V.Y.O., Borůvka L. Modeling and assessing the spatial and vertical distributions of potentially toxic elements in soil and how the concentrations differ. Toxics. 2021;9:181. doi: 10.3390/toxics9080181. PubMed DOI PMC

Akter J., Juwon J., Taesung J., Gyu K.J., Lee H. Contamination assessment of pollutants and sediments of abandoned mines using integrated pollution index (IPI) Desalination Water Treat. 2020;200:383–389. doi: 10.5004/dwt.2020.26119. DOI

Cai X., Duan Z., Wang J. Status assessment, spatial distribution and health risk of heavy metals in agricultural soils around mining-impacted communities in China. Pol. J. Environ. Stud. 2021;30:993–1002. doi: 10.15244/pjoes/124742. DOI

Chakraborty B., Bera B., Roy S., Adhikary P.P., Sengupta D., Shit P.K. Assessment of non-carcinogenic health risk of heavy metal pollution: evidences from coal mining region of eastern India. Environ. Sci. Pollut. Res. 2021;28:47275–47293. doi: 10.1007/s11356-021-14012-3. PubMed DOI

Ofem K.I., Pawlett M., Eyong M.O., Kingsley J., Umeobi E.C., Ezeaku P.I., Asadu C.L.A. Multivariate modeling of some metals concentrations in agrarian soils: distribution and soil fertility implications in the tropics. Earth Syst. Environ. 2022;6:583–595. doi: 10.1007/s41748-021-00267-w. DOI

Dontala S.P., Reddy T.B., Vadde R. Environmental aspects and impacts its mitigation measures of corporate coal mining. Procedia Earth Planet. Sci. 2015;11:2–7. doi: 10.1016/j.proeps.2015.06.002. DOI

Agyeman P.C., Ahado S.K., Kingsley J., Kebonye N.M., Biney J.K.M., Borůvka L., Vasat R., Kocarek M. Source apportionment, contamination levels, and spatial prediction of potentially toxic elements in selected soils of the Czech Republic. Environ. Geochem. Health. 2021;43:601–620. doi: 10.1007/s10653-020-00743-8. PubMed DOI

Demková L., Jezný T., Bobuľská L. Assessment of soil heavy metal pollution in a former mining area - before and after the end of mining activities. Soil Water Res. 2017;12:229–236. doi: 10.17221/107/2016-SWR. DOI

Hamad R., Balzter H., Kolo K. Assessment of heavy metal release into the soil after mine clearing in Halgurd-Sakran National Park, Kurdistan, Iraq. Environ. Sci. Pollut. Res. 2019;26:1517–1536. doi: 10.1007/s11356-018-3597-3. PubMed DOI PMC

Dzagli M.M., Amouzouvi Y.M., Sesime K., Afoudji K.B.R. Heavy metal pollution assessment in phosphate mining and processing sites, Hahotoe and Kpeme in Togo. EQA - Int. J. Environ. Qual. 2022;47:9–21. doi: 10.6092/issn.2281-4485/13435. DOI

Chen L., Zhou M., Wang J., Zhang Z., Duan C., Wang X., Zhao S., Bai X., Li Z., Li Z., Fang L. A global meta-analysis of heavy metal(loid)s pollution in soils near copper mines: evaluation of pollution level and probabilistic health risks. Sci. Total Environ. 2022;835 doi: 10.1016/j.scitotenv.2022.155441. PubMed DOI

Han Z., Wan D., Tian H., He W., Wang Z., Liu Q. Pollution assessment of heavy metals in soils and plants around a molybdenum mine in Central China. Pol. J. Environ. Stud. 2019;28:123–133. doi: 10.15244/pjoes/83693. DOI

Khafouri A., Talbi E.H., Abdelouas A. Assessment of heavy metal contamination of the environment in the mining site of Ouixane (north east Morocco), water. Air. Soil Pollut. 2021;232:398. doi: 10.1007/s11270-021-05318-6. DOI

Luo X., Ren B., Hursthouse A.S., Thacker J.R.M., Wang Z. Soil from an abandoned manganese mining area (Hunan, China): significance of health risk from potentially toxic element pollution and its spatial context. Int. J. Environ. Res. Publ. Health. 2020;17:6554. doi: 10.3390/ijerph17186554. PubMed DOI PMC

Nekoeinia M., Mohajer R., Salehi M.H., Moradlou O. Multivariate statistical approach to identify metal contamination sources in agricultural soils around Pb–Zn mining area, Isfahan province, Iran. Environ. Earth Sci. 2016;75:760. doi: 10.1007/s12665-016-5597-2. DOI

Vuong X.T., Vu L.D., Duong A.T.T., Duong H.T., Hoang T.H.T., Luu M.N.T., Nguyen T.N., Nguyen V.D., Nguyen T.T.T., Van T.H., Minh T.B. Speciation and environmental risk assessment of heavy metals in soil from a lead/zinc mining site in Vietnam. Int. J. Environ. Sci. Technol. 2023;20:5295–5310. doi: 10.1007/s13762-022-04339-w. DOI

Obasi P.N., Akudinobi B.E.B. Pollution status of arable soils and stream sediments in mining areas of Abakaliki, Lower Benue Trough, Nigeria. Int. J. Environ. Sci. Technol. 2019;16:7869–7884. doi: 10.1007/s13762-019-02337-z. DOI

Odukoya A.M., Olobaniyi S.B., Oluseyi T.O. Assessment of potentially toxic elements pollution and human health risk in soil of Ilesha gold mining site, southwest Nigeria. J. Geol. Soc. India. 2018;91:743–748. doi: 10.1007/s12594-018-0933-7. DOI

Pandey B., Agrawal M., Singh S. Ecological risk assessment of soil contamination by trace elements around coal mining area. J. Soils Sediments. 2016;16:159–168. doi: 10.1007/s11368-015-1173-8. DOI

Bahloul M., Baati H., Amdouni R., Azri C. Assessment of heavy metals contamination and their potential toxicity in the surface sediments of Sfax Solar Saltern, Tunisia. Environ. Earth Sci. 2018;77:27. doi: 10.1007/s12665-018-7227-7. DOI

Hilson G., Zolnikov T.R., Ortiz D.R., Kumah C. Formalizing artisanal gold mining under the Minamata convention: previewing the challenge in Sub-Saharan Africa. Environ. Sci. Pol. 2018;85:123–131. doi: 10.1016/j.envsci.2018.03.026. DOI

Adefolalu A.D. vol. 65. les Editions J.A; Paris: 2002. Climate of Nigeria. (Atlas of Nigeria).

Diagi B. Analysis of rainfall trend and variability in Ebonyi state, South Eastern Nigeria. Environ. Earth Sci. Res. J. 2018;5:53–57. doi: 10.18280/eesrj.050301. DOI

Okolo C., Ezeaku P., Nwite J., Charles N M., Anikwe M. Environmental and agronomic implication of the levels of heavy metals contamination of the soils along Enugu-Abakaliki major highway in southeastern Nigeria. Elixir Agric. 2013;61:17040–17046.

FDALR, Reconnaissance Soil Survey of Anambra State, Nigeria. Soils Report FDALR(1985) Nkwunonwo U., Okeke F., ElijahN S., Chiemelu Free, open, quantitative and adaptable digital soil map data and database for Nigeria. Data Brief. 2020;31 doi: 10.1016/j.dib.2020.105941. PubMed DOI PMC

Land, Water Division . FAO; Rome, Italy: 2006. Guidelines for Soil Description.https://www.fao.org/documents/card/en?details=903943c7-f56a-521a-8d32-459e7e0cdae9/

Klute A., Dirksen C. Methods Soil Anal. John Wiley & Sons, Ltd; 1986. Hydraulic conductivity and diffusivity: laboratory methods; pp. 687–734. DOI

EPA . 1998. Environmental Technology Verification Report– Field Portable X-Ray Fluorescence Analyzer MetorexX-MET 920-P and 940.

Antoniadis V., Shaheen S.M., Boersch J., Frohne T., Du Laing G., Rinklebe J. Bioavailability and risk assessment of potentially toxic elements in garden edible vegetables and soils around a highly contaminated former mining area in Germany. J. Environ. Manag. 2017;186:192–200. doi: 10.1016/j.jenvman.2016.04.036. PubMed DOI

Hakanson L. An ecological risk index for aquatic pollution control.a sedimentological approach. Water Res. 1980;14:975–1001. doi: 10.1016/0043-1354(80)90143-8. DOI

Kabata-Pendias A. fourth ed. CRC Press; Boca Raton: 2011. Trace Elements in Soils and Plants.

Ji X., Abakumov E., Tomashunas V., Polyakov V., Kouzov S. Geochemical pollution of trace metals in permafrost-affected soil in the Russian Arctic marginal environment. Environ. Geochem. Health. 2020;42:4407–4429. doi: 10.1007/s10653-020-00587-2. PubMed DOI

Loska K., Cebula J., Pelczar J., Wiechuła D., Kwapuliński J. Use of enrichment, and contamination factors together with geoaccumulation indexes to evaluate the content of Cd, Cu, and Ni in the Rybnik water reservoir in Poland, Water. Air. Soil Pollut. 1997;93:347–365. doi: 10.1007/BF02404766. DOI

Rinklebe J., Antoniadis V., Shaheen S.M., Rosche O., Altermann M. Health risk assessment of potentially toxic elements in soils along the Central Elbe River, Germany. Environ. Int. 2019;126:76–88. doi: 10.1016/j.envint.2019.02.011. PubMed DOI

Shaheen S.M., Antoniadis V., Kwon E., Song H., Wang S.-L., Hseu Z.-Y., Rinklebe J. Soil contamination by potentially toxic elements and the associated human health risk in geo- and anthropogenic contaminated soils: a case study from the temperate region (Germany) and the arid region (Egypt) Environ. Pollut. 2020;262 doi: 10.1016/j.envpol.2020.114312. PubMed DOI

Xu Z.Q., Ni S., Tuo X.G., Zhang C.J. Calculation of heavy metal's toxicity coefficient in the evaluation of Potential Ecological Risk Index. Environ. Sci. Technol. 2008;31:112–115.

Mugoša B., Đurović D., Nedović-Vuković M., Barjaktarović-Labović S., Vrvić M. Assessment of ecological risk of heavy metal contamination in coastal municipalities of Montenegro. Int. J. Environ. Res. Publ. Health. 2016;13:393. doi: 10.3390/ijerph13040393. PubMed DOI PMC

Saleh S., Amer A., Al-Alawi A.-H. Southern Yemen; 2018. Potential Ecological Risk of Heavy Metals in Surface Sediments from the Aden Coast. DOI

Sahoo P.K., Equeenuddin SkMd, Powell M.A. Trace elements in soils around coal mines: current scenario, impact and available techniques for management. Curr. Pollut. Rep. 2016;2:1–14. doi: 10.1007/s40726-016-0025-5. DOI

Zhang Y.-Y., Wu W., Liu H. Factors affecting variations of soil pH in different horizons in hilly regions. PLoS One. 2019;14 doi: 10.1371/journal.pone.0218563. PubMed DOI PMC

Agyeman P.C., John K., Kebonye N.M., Ahado S.K., Borůvka L., Němeček K., Vašát R. Multi-geochemical background comparison and the identification of the best normalizer for the estimation of PTE contamination in agricultural soil. Environ. Geochem. Health. 2022;44:3597–3613. doi: 10.1007/s10653-021-01109-4. PubMed DOI

Mensah A.K., Marschner B., Antoniadis V., Stemn E., Shaheen S.M., Rinklebe J. Human health risk via soil ingestion of potentially toxic elements and remediation potential of native plants near an abandoned mine spoil in Ghana. Sci. Total Environ. 2021;798 doi: 10.1016/j.scitotenv.2021.149272. PubMed DOI

Nogueirol R.C., Monteiro F.A., Gratão P.L., Borgo L., Azevedo R.A. Tropical soils with high aluminum concentrations cause oxidative stress in two tomato genotypes. Environ. Monit. Assess. 2015;187:73. doi: 10.1007/s10661-015-4282-3. PubMed DOI

Taylor S.R., McLennan S.M. 1985. The Continental Crust: its Composition and Evolution.https://www.osti.gov/biblio/6582885

Chen Q., Zhang P., Hu Z., Li S., Zhang Y., Hu L., Zhou L., Lin B., Li X. Soil organic carbon and geochemical characteristics on different rocks and their significance for carbon cycles. Front. Environ. Sci. 2022;9 https://www.frontiersin.org/articles/10.3389/fenvs.2021.784868 DOI

Cornu S., Lucas Y., Lebon E., Ambrosi J.P., Luizão F., Rouiller J., Bonnay M., Neal C. Evidence of titanium mobility in soil profiles, Manaus, central Amazonia. Geoderma. 1999;91:281–295. doi: 10.1016/S0016-7061(99)00007-5. DOI

Bansah K.J., Addo W.K. Phytoremediation potential of plants grown on reclaimed spoil lands. Ghana Min. J. 2016;16:68–75. doi: 10.4314/gmj.v16i1.8. DOI

Mensah A.K., Marschner B., Shaheen S.M., Wang J., Wang S.-L., Rinklebe J. Arsenic contamination in abandoned and active gold mine spoils in Ghana: geochemical fractionation, speciation, and assessment of the potential human health risk. Environ. Pollut. 2020;261 doi: 10.1016/j.envpol.2020.114116. PubMed DOI

Wu J., Teng Y., Lu S., Wang Y., Jiao X. Evaluation of soil contamination indices in a mining area of Jiangxi, China. PLoS One. 2014;9 doi: 10.1371/journal.pone.0112917. PubMed DOI PMC

Esshaimi M., Ouazzani N., Gharmali A.E., Berrekhis F., Valiente M., Mandi L. Speciation of heavy metals in the soil and the tailings, in the zinc-lead Sidi Bou Othmane abandoned mine. J. Environ. Earth Sci. 2013;3:138.

Uchendu U.I., Biose E., Ubuoh E.A. Assessment of heavy metal concentration in soil impacted mining-overburden in Enyigba, Abakaliki, Ebonyi state, Nigeria. J. Appl. Sci. Environ. Manag. 2020;24:1169–1173. doi: 10.4314/jasem.v24i7.7. DOI

Antoniadis V., Golia E.E., Shaheen S.M., Rinklebe J. Bioavailability and health risk assessment of potentially toxic elements in Thriasio Plain, near Athens, Greece. Environ. Geochem. Health. 2017;39:319–330. doi: 10.1007/s10653-016-9882-5. PubMed DOI

Chileshe M.N., Syampungani S., Festin E.S., Tigabu M., Daneshvar A., Odén P.C. Physico-chemical characteristics and heavy metal concentrations of copper mine wastes in Zambia: implications for pollution risk and restoration. J. For. Res. 2020;31:1283–1293. doi: 10.1007/s11676-019-00921-0. DOI

Abd Elnabi M.K., Elkaliny N.E., Elyazied M.M., Azab S.H., Elkhalifa S.A., Elmasry S., Mouhamed M.S., Shalamesh E.M., Alhorieny N.A., Abd Elaty A.E., Elgendy I.M., Etman A.E., Saad K.E., Tsigkou K., Ali S.S., Kornaros M., Mahmoud Y.A.-G. Toxicity of heavy metals and recent advances in their removal: a review. Toxics. 2023;11:580. doi: 10.3390/toxics11070580. PubMed DOI PMC

Léopold E.N., Sabine D.D., Philémon Z.Z., Jung M.C. Physical and metals impact of traditional gold mining on soils in Kombo-Laka area (Meiganga, Cameroon) Int. J. Geosci. 2016;7:1102. doi: 10.4236/ijg.2016.79084. DOI

Wahsha M., Maleci L., Bini C. The impact of former mining activity on soils and plants in the vicinity of an old mercury mine (Vallalta, Belluno, NE Italy) Geochem. Explor. Environ. Anal. 2019;19:171–175. doi: 10.1144/geochem2018-040. DOI

Essandoh P.K., Takase M., Bryant I.M. Impact of small-scale mining activities on physicochemical properties of soils in Dunkwa east municipality of Ghana. Sci. World J. 2021;2021 doi: 10.1155/2021/9915117. PubMed DOI PMC

Antoniadis V., Levizou E., Shaheen S.M., Ok Y.S., Sebastian A., Baum C., Prasad M.N.V., Wenzel W.W., Rinklebe J. Trace elements in the soil-plant interface: phytoavailability, translocation, and phytoremediation–A review. Earth Sci. Rev. 2017;171:621–645. doi: 10.1016/j.earscirev.2017.06.005. DOI

Mazurek R., Kowalska J.B., Gąsiorek M., Zadrożny P., Wieczorek J. Pollution indices as comprehensive tools for evaluation of the accumulation and provenance of potentially toxic elements in soils in Ojców National Park. J. Geochem. Explor. 2019;201:13–30. doi: 10.1016/j.gexplo.2019.03.001. DOI

Pędziwiatr A., Kierczak J., Waroszewski J., Ratié G., Quantin C., Ponzevera E. Rock-type control of Ni, Cr, and Co phytoavailability in ultramafic soils. Plant Soil. 2018;423:339–362. doi: 10.1007/s11104-017-3523-3. DOI

Xu X., Cao Z., Zhang Z., Li R., Hu B. Spatial distribution and pollution assessment of heavy metals in the surface sediments of the Bohai and Yellow Seas. Mar. Pollut. Bull. 2016;110:596–602. doi: 10.1016/j.marpolbul.2016.05.079. PubMed DOI

Manna A., Maiti R. Geochemical contamination in the mine affected soil of Raniganj Coalfield – a river basin scale assessment, Geosci. Front. Times. 2018;9:1577–1590. doi: 10.1016/j.gsf.2017.10.011. DOI

Swarnalatha K., Letha J., Ayoob S., Sheela A.M. Identification of silicon (Si) as an appropriate normaliser for estimating the heavy metals enrichment of an urban lake system. J. Environ. Manag. 2013;129:54–61. doi: 10.1016/j.jenvman.2013.05.039. PubMed DOI

Uduma A.U., Awagu E.F. 2013. Silicon as a Reference Element for Determining Zinc Enrichment and Depletion in Contaminated Farming Soils of Nigeria.

Kinimo K.C., Yao K.M., Marcotte S., Kouassi N.L.B., Trokourey A. Distribution trends and ecological risks of arsenic and trace metals in wetland sediments around gold mining activities in central-southern and southeastern Côte d'Ivoire. J. Geochem. Explor. 2018;190:265–280. doi: 10.1016/j.gexplo.2018.03.013. DOI

Li L., Lu J., Wang S., Ma Y., Wei Q., Li X., Cong R., Ren T. Methods for estimating leaf nitrogen concentration of winter oilseed rape (Brassica napus L.) using in situ leaf spectroscopy. Ind. Crops Prod. 2016;91:194–204. doi: 10.1016/j.indcrop.2016.07.008. DOI