Document Type : Original Research Paper


1 Department of Geology, University of Port Harcourt, Port Harcourt, Nigeria

2 Department of Geology, University of Calabar, Calabar, Nigeria


In this study, the chemical composition of water and soils contiguous to two abandoned coal mines in southeastern Nigeria, was assessed to evaluate the impact of water flow from the mines ponds on the geoenvironment and potential for acid mine drainage (AMD). Parameters including the pH, anions and cations, and the heavy metals were measured. These were used to evaluate contamination/pollution using hybrid factors including Pollution Load Index, factors, enrichment factors, pollution load index and index of geoaccumulation. The pH range of 3.4 to 5.9 classified the water as weakly to strongly acidic, typical of AMD. The SO42– ion, which indicates pollution by mine waters, showed moderate to high concentrations. Iron, zinc lead and copper were the most abundant heavy metals. Pollution Load Index values were greater than unity which show progressive deterioration in water and sediment quality. The Enrichment Factor values of up to 1 indicated enrichment through lithogenic and anthropogenic sources. The mine dumps serve as pools that can release toxic heavy metals into the water bodies by various processes of remobilization. Based on the lithology, mineralogy, chemical concentrations and environmental factors, the study has shown that there exists a potential for the generation of AMD. The heavy metals enriched mine flow, especially iron, empty into the nearby water bodies which serve as sources of municipal water supply. Consumption of untreated water over a prolonged period from these water sources may be detrimental to health. Remedial measure and continuous monitoring are recommended for good environmental stewardship.


[1]. (2020). -i9yAcid Mine Drainage Status of Research.
[2]. Nieto, J.M., Sarmiento, A.M., Olías, M., Canovas, C.R., Riba, I., Kalman, J. and Delvalls, T.A. (2007). Acid mine drainage pollution in the Tinto and Odiel rivers (Iberian Pyrite Belt, SW Spain) and bioavailability of the transported metals to the Huelva Estuary. Environ Int, 33:445–455.
[3]. Sahoo, P.K., Tripathy, S., Equeendduin, S.M., Panigrahi, M.K. (2012). Geochemical characteristics of coal mine discharge vis-à-vis behavior of rare earth elements at Jaintia hills coalfield, northeastern India. J. Geochem. Explor., 112:235–243.
[4]. Dutta, M., Islam, N., Rabha, S., Narzary, B., Bordoloi, M., Saikia, D., ... & Saikia, B. K. (2020). Acid mine drainage in an Indian high-sulfur coal mining area: Cytotoxicity assay and remediation study. Journal of Hazardous Materials, 389, 121851.
[5]. Xie, Y., Lu, G., Yang, C., Qu, L., Chen, M., Guo, C. and Dang, Z. (2018). Mineralogical characteristics of sediments and heavy metal mobilization along a river watershed affected by acid mine drainage. PLoS One, 13(1), e0190010.
[6]. Dontala, S. P., Reddy, T. B. and Vadde, R. (2015). Environmental aspects and impacts its mitigation measures of corporate coal mining. Procedia Earth and Planetary Science, 11, 2-7.
[7]. Dzwairo, B. and Mujuru, M. (2017). Assessment of Impacts of Acid Mine Drainage on Surface Water Quality of Tweelopiespruit Micro-Catchment, Limpopo Basin. Water Quality, 337.
[8]. Gonah, T. (2017). Impact of Acid Mine Drainage on Water Resources in South Africa. Management and Mitigation of Acid Mine Drainage in South Africa: Input for Mineral Beneficiation in Africa, 41.
[9]. Han, Y. S., Youm, S. J., Oh, C., Cho, Y. C. and   Ahn, J. S. (2017). Geochemical and eco-toxicological characteristics of stream water and its sediments affected by acid mine drainage. Catena, 148, 52-59.
[10]. Yesilnacar, M. I. and Kadiragagil, Z. (2013). Effects of acid mine drainage on groundwater quality: a case study from an open-pit copper mine in eastern Turkey. Bulletin of Engineering Geology and the Environment, 72(3-4), 485-493.
[11]. Nthunya, L. N., Masheane, M. L., Malinga, S. P., Nxumalo, E. N., Mamba, B. B. and Mhlanga, S. D. (2017). Determination of toxic metals in drinking water sources in the Chief Albert Luthuli Local Municipality in Mpumalanga, South Africa. Physics and Chemistry of the Earth, Parts A/B/C, 100, 94-100
[12]. Wen, J., Tang, C., Cao, Y., Li, X., & Chen, Q. (2018). Hydrochemical evolution of groundwater in a riparian zone affected by acid mine drainage (AMD), South China: the role of river–groundwater interactions and groundwater residence time. Environmental Earth Sciences, 77(24), 794.
[13]. Acharya, B. S. and Kharel, G. (2020). Acid Mine Drainage from Coal Mining in the United States–An Overview. Journal of Hydrology, 125061.
[14]. Jadeja, R. N., and Batty, L. (2013). Metal content of seaweeds in the vicinity of acid mine drainage in Amlwch, North Wales, UK.
[15]. Ferreira, R. A., Pereira, M. F., Magalhães, J. P., Maurício, A. M., Caçador, I. and Martins-Dias, S. (2020). Assessing local acid mine drainage impacts on natural regeneration-revegetation of São Domingos mine (Portugal) using a mineralogical, biochemical and textural approach. Science of The Total Environment, 142825.
[16]. Aguinaga, O. E., McMahon, A., White, K. N., Dean, A. P. and Pittman, J. K. (2018). Microbial community shifts in response to acid mine drainage pollution within a natural wetland ecosystem. Frontiers in Microbiology, 9, 1445 
[17]. Whitehead, P., and Jeffrey, H. (1995). Heavy metals from acid mine drainage-impacts and modelling strategies. IAHS Publications-Series of Proceedings and Reports-Intern Assoc Hydrological Sciences, 230, 55-66.
[18] Mallo, S.J. (2011). The menace of acid mine drainage: an impending challenge in the mining of Lafia-Obi coal, Nigeria. Continental J. Eng. Sci., 6:46–54.
[19]. Nganje, T.N., Adamu, C.I., Ntekim. E.E.U., Ugbaja, A.N., Neji, P. and Nfor, E.N. (2010).
Influence of mine drainage on water quality along River Nyaba in Enugu southeastern Nigeria. African
J. Environ. Sci. Tech., 4:132–144
[20]. Salufu, S.O. and Salufu, E. O. (2014). Integrated study of acid mine drainage and its environmental effects on Onyema mine and environs, Enugu, Nigeria. Journal of Multidisciplinary Engineering Science and Technology, 1(5): 7-12
[21]. Utom, A. U., Odoh, B. I., & Egboka, B. C. (2013). Assessment of hydrogeochemical characteristics of groundwater quality in the vicinity of Okpara coal and Obwetti fireclay mines, near Enugu town, Nigeria. Applied Water Science, 3(1), 271-283.
[22]. Acharya, B. S., & Kharel, G. (2020). Acid Mine Drainage from Coal Mining in the United States–An Overview. Journal of Hydrology, 125061
[23]. Nwasike, T. O. (2003). Opportunities and challenges of an integrated energy policy for Nigeria-perspectives from a competing energy product-coal. SPE conference, Abuja, Nigeria. August, 2003.
[24]. Nwajide, C. S. (2013). Geology of Nigeria’s Sedimentary Basins. CSS Press, Lagos, Nigeria.
[25]. Reyment, R.A. (1965). Aspects of Geology of Nigeria. Ibadan University Press p. 133.
[26]. Onwuka, O.S., Uma, K.O. and Ezeigbo, H.I. (2004). Potability of shallow groundwater in Enugu Town, Southeastern, Nigeria. Glob. J. Environ. Sci. 3(1): 33–69.
[27]. Offodile, M. (2002). Groundwater supply and development in Nigeria. Mecon Geol. Eng. Serv. Ltd. Jos Nigeria.
[28]. Lacutusu, R. (2000). Appraising levels of soil contamination and pollution with heavy metals In Heinike H. J., Eckselman W., Thomasson A.J., Jones R.J.A, Montanarella L. and Buckeley B. (eds.). Land information systems for planning the sustainable use of land resources. European Soil Bureau Research Report No. 4. Office of Official Publication of the European Communities, Luxembourg, 393-402.
[29]. Thomilson, D.C., Wilson, D.J., Harris, C.R. and Jeffrey, D.W. (1980). “Problem in heavy metals in estuaries and the formation of pollution index”. Helgol. Wiss. Meeresunlter. 33(1–4): 566–575.
[30]. Rubio, B., Nombela, M.A. and Vilas, F. (2000). Geochemistry of Major and Trace Elements in Sediments of the Ria de Vigo (NW Spain): An Assessment of Metal Pollution. Marine Pollution Bulletin, 40, 968-980.
[31]. Chapman, P.M. and Wang, F. (2001). Assessing Sediment Contamination in Estuaries. Environmental Toxicology and Chemistry, 20, 3-22.
[32]. Cherry, D.S., Currie, R.J., Soucek, D.J., Latimer, H.A. and Trent, G.C. (2001). An integrative
assessment of a watershed impacted by abandoned mined land discharges. Environmental
Pollution, 111(3):377-388.
[32]. Nigerian Industrial Standards (NIS) (2007). Nigerian Standard for Drinking Water, Approved by Standard Organization Nigeria (SON), ICS 13.060.20, 1-30.
[33]. Zsefer, P., Glasby, G.P., Sefer, K., Pempkowiak, J. and Kaliszan, R. (1996). Heavy-Metal Pollution in Superficial Sediments from the Southern Baltic Sea off Poland. Journal Environmental Science Health, Part A: Environmental Science and Engineering and Toxicology, 31, 2723-2754.
[34]. Muller, G. (1969). “Index of geo-accumulation in sediments of the Rhine River”, Geojournal, 2: 108-118.
[35]. Lu, X., Wang, L., Lei, K., Huang, J. and Zhai, Y. (2009). “Contamination assessment of copper, lead, zinc manganese and nickel in street dust of Baoji, NW China”, J. Hazardous Materials, 161: 1058-1062.
[36]. Sikakwe, G. U. Ephraim, B. E. Nganje, T. N. Ntekim, E. E. U. and Amah, E. A. (2015). Geoenvironmental impact of Okpara coal mine, Enugu, Southeastern Nigeria. Adv. Appl. Sci. Res., 6(4):5-16.
[37]. [33]. Ezeigbo, H. and Ezeanyim, B. N. (1993). Environmental pollution from coal mining activities in Enugu Area, Nigeria. International Journal of Mine Water and the Environment, 12: 53 – 61
[38]. Adaikpoh, E.O., Nwajei, G.E., and Ogala, J.E. (2005). Heavy metal concentration in coal and
sediments from River Ekulu in Enugu, coal city of Nigeria. J. Appl. Sci. Environ. Manag. 9:5–8.
[39] Ameh, E.G. (2013). Multivariate Statistical Analysis and Enrichment of Heavy Metal Contamination of Soil around Okaba Coal Mines. American-Eurasian Journal of Agronomy, 6(1):09-18.
[40]. Jurkovic J., Babajic E. Muhic-Sarac T Kolar M and Kazlagic A. (2020). Gold Silver and Iron in Iron Oxy-hydroxide Precipitate Formed in Process of Acid Mine Drainage. Journal of Mining and Environment. Published online 28 February 2020. DOI: 10.22044/jme.2020.906.1811
[41]. World Health Organization (WHO) (2006). International Standards for Drinking Water and Guidelines for water quality. World Health Organization, Geneva.
[42]. NESREA: National Environmental Standards Regulations and Enforcement Agency (2009). National Environmental (Mining and Processing of Coal Ores and Industrial Minerals Regulations. Federal Republic of Nigeria Official Gazette No 63 Vo. 96
[43]. Campaner V.P., Luiz-Silva W. and Machado W. (2014). Geochemistry of acid drainage from coal mining areas and processes controlling metal attenuation in stream waters, Southern Brazil. Anais da Academia Brasileira de Ciências 86(2): (Annals of the Brazilian Academy of Sciences) 86(2)539-554
[44]. Birth, G.A. (2003). A Scheme for Assessing Human Impacts on Coastal Aquatic Environments Using Sediments. Woodcoffe, C.D. and Furness, R.A., Eds., Coastal GIS 2003, Wollongong University Papers in Centre for Maritime Policy, 14, Wollongong.
[45]. Odewande, A. A. and Abimbola, A. F. (2008). Contamination indices and heavy metal concentrations in urban soil of Ibadan metropolis, southwestern Nigeria, Environ. Geochem. Health, 30, 243-254.
[46]. Edet, A.E., Merkrel, B.J. and Offiong, O.E. (2004). Contamination risk assessment of fresh groundwater using the distribution and chemical speciation of some potentially toxic elements in Calabar (Southeastern Nigeria). Environ Geol. 45: 1025 –1035.
[47]. Lewis, M.E., Clark, M.L. (1996). US Geological Survey Fact Sheet, 226 – 296.
[48]. Wilkin, R.T. (2007). Metal Attenuation Processes at Mining Sites. United States Environmental Protection Agency, Ground Water Issue.
[49]. Thomas, L. (2002). Coal Geology. John Wiley and Sons Ltd, England.
[50]. Awalla, C. O. C. (2013). An appraisal of the water related contaminants as they affect the environment around the Enugu coal mines of Enugu state, southeastern Nigeria. International Journal of Physical Sciences, 8(44):2023-2028.
[51]. García, C., Ballesterb, A., González, F. and Blázquez, M. L. (2005). Pyrite behaviour in a tailings pond, Hydrometallurgy, 76: 25–36.
[52]. de Mello J. W. V, Dias L. E, Daniel A. M, Abrahao W. A. P, Deschamps E., and Schaefer C. E. G (2006). Preliminary evaluation of acid mine drainage in Minas Greis State, Brazil. Rev. Bras. Cienc. Solo 30 (2) .