Health Risk Assessment of Heavy Metals in Soil from the Iron Mines of Itakpe and Agbaja, Kogi State, Nigeria

Document Type : Original Research Paper

Authors

Environmental Monitoring and Remediation Research Group, Environmental Biology Research Unit, Cell Biology and Genetics Department, University of Lagos, Akoka, Lagos, Nigeria

Abstract

The study evaluates associated health risks of heavy metals in the soil to inhabitants of two mining areas of Nigeria. For so doing, it collects and analyses nine homogenous soil samples for their lead, copper, cadmium, zinc, and chromium levels, using AAS. The samples are then used to calculate health risks to adults and children. For adult population in Agbaja community, the calculated hazard quotients fall below one in all considered pathways. Hazard index values for all the pathways are also less than one, taking the following order: Cu>Cr>Pb>Cd>Zn. It is shown that for all considered heavy metals, the adult population in Agbaja mining community was not at any risk of non-carcinogenic effects from these metals. As for the children in Agbaja, the calculated HQ values for Cd and Zn have been less than one in all the pathways, while the HQ values for Pb, Cr, and Cu have significantly surpassed 1, with the ingestion route being the main pathway. The HI values have been in the following order: Cu>Cr>Pb>Cd>Zn, which poses serious non-carcinogenic health risks to the children, living around this community. The carcinogenic risk has been calculated based on Pb, Cd, and Cr, with the former (Pb) proven to be the highest contributor to cancer risk. USEPA considers acceptable cancer risk within the range of 1×10−6 to 1×10−4. Though insignificant in its values, carcinogenic risk for adults in Agbaja (2.95×10-4) and Itakpe (4.71×10-4) and for children in Itakpe (4.47×10-4) have been higher than the acceptable values. Hence, the adults are more at risk, for whom ingestion is the main contributor to excess lifetime cancer risk, followed by dermal pathways. Considering the health hazards, entailed by the accumulation of these heavy metals, on human health, mining sites and areas require to get monitored properly.

Keywords


Adedokun, A.H., Njoku, K.L., Akinola, M.O., Adesuyi, A.A. and Jolaoso, A.O. (2016). Potential human health risk assessment of heavy metals intake via consumption of some leafy vegetables obtained from four markets in Lagos metropolis, Nigeria. J Appl Sci Environ Manag. 20(3): 530-539.
Adekoya, J.A. (2003). Environmental effect of solid minerals mining. Journal of Physical Science in Kenya, 1: 625–640.
Aderinola, O.J., Clarke, E.O., Olarinmoye, O.M., Kusemiju, V. and Anetekhai, M.A. (2009). Heavy metals in surface water, sediments, fish and periwinkles of Lagos Lagoon. Amer-Eurasian J Agri & Environ Sciences. 5(5): 609-617.
Adesuyi, A.A., Njoku, K.L. and Akinola, M.O. (2015). Assessment of Heavy metals pollution in soils and vegetation around selected Industries in Lagos, South western Nigeria. J GEP, 3: 11-19.
Department of Environmental Affairs (2010). The Framework for the Management of Contaminated Land, South Africa. 79pp.
FAO/WHO (2004). Fruit and vegetables for health: Report of joint FAO/WHO workshop, 1–3 September 2004.
Ha, N.T.H., Sakakibara, M., Sano, S. and Nhuan, M.T. (2011). Uptake of metals and metalloids by plants growing in a lead–zinc mine area, Northern Vietnam. J Hazard Mater. 186: 1384–1391.
Hseu, Z.Y., Chen, Z.S., Tsai,  C.C., Tsui, C.C., Cheng, S.F., Liu, C.L. and Lin, H.T. (2002). Digestion methods for total heavy metals in sediments and soils. Water Air Soil Pollut.141: 189–205.
Jolaoso, A.O., Njoku, K.L., Akinola, M.O., Adesuyi, A.A. and Adedokun, A.H. (2016). Heavy metal analyses and nutritional composition of raw and smoked fishes from Ologe and Lagos Lagoon, Lagos, Nigeria. J Appl Sci Environ Manag. 20(2): 277-285.
Kabata-Pendias, A. and Pendias, H. (2011). Trace Elements in Soils and Plants. 4th Editions, CRC Press, Boca Raton. 520pp.
Kamunda, C., Mathuthu, M. and Madhuku, M. (2016). Health Risk Assessment of Heavy Metals in Soils from Witwatersrand Gold Mining Basin, South Africa. Int. J. Environ. Res. Publ. Health. 13: 663 – 674.
Kien, C.N., Noi, N.V., Son, L.T., Ngoc, H.M., Tanaka, S., Nishina, T. and Iwasaki, K. (2010). Heavy metal contamination of agricultural soils around a chromite mine in Vietnam. Soil Sci. Plant Nutr. 56(2): 344-365.
Lar, U.A. (2012). Solid Mineral sector and inclusive green growth strategy in Nigeria. Commissioned by the African Centre for Shared Development Capacity Building, Ibadan, Nigeria, September 2012. 37pp.
Li, Z., Ma, Z., van der Kuijp, T.J., Yuan, Z. and Huang, L. (2014).A review of soil heavy metal pollution from mines in China: Pollution and health risk assessment. Sci. Total Environ. 468–469: 843–853.
Luo, X.S., Ding, J. and Xu, B. (2012). Incorporating bioaccessibility into human health risk assessments of heavy metals in urban park soils. Sci. Total Environ. 424: 88–96.
Mahfuza, S.S, Rana, S., Yamazaki, S., Aono, T. and Yoshida, S. (2017). Health risk assessment for carcinogenic and non-carcinogenic heavy metal exposures from vegetables and fruits of Bangladesh. Cogent Environmental Science, 3: 1-17.
Njoku, K.L., Rumide, T.J., Akinola, M.O., Adesuyi, A.A., and Jolaoso, A.O. (2016). Ambient Air Quality Monitoring in Metropolitan City of Lagos, Nigeria. J Appl Sci Environ Manag. 20(1): 178-185.
NRC-National Research Council (1999). Arsenic in Drinking Water; National Research Council: Washington, DC, USA, 1999; pp. 251–257.
NSC (2009). Lead Poisoning. National Safety Council. 6pp.
Ogunkunle, C.O., Fatoba, P.O., Ogunkunle, M.O. and Oyedeji, A.A. (2013). Potential Health Risk Assessment for Soil Heavy Metal Contamination of Sagamu, South-west Nigeria due to Cement Production. IJAST.3(2): 89-96.
Olatunji, K.J. (2008). Heavy metal Contamination of Plants and Soil in Itakpe Iron Ore Deposit Area of Kogi State, Nigeria. Environmental Research Journal, 2(3): 122 – 124.
Ordóñez, A., Álvarez, R., Charlesworth, S., De Miguel, E. and Loredo, J. (2011). Risk assessment of soils contaminated by mercury mining, Northern Spain. J Environ Monit., 13:128–36.
Podsiki, C. (2008). Chart of Heavy Metals, Their Salts and Other Compounds. 24pp.
RAIS (2008). The Risk Assessment Information System, 2008.
Scragg, A. (2006). Environmental biotechnology. Oxford, UK, Oxford University Press, 2nd edition. Pp. 1-67.
U.S. Environmental Protection Agency. (2010). Recommended Use of BW3/4 as the Default Method in Derivation of the Oral Reference Dose.
U.S. Environmental Protection Agency. (2007). Framework for Determining a Mutagenic Mode of Action for Carcinogenicity: Review Draft.
U.S. Environmental Protection Agency. (1991). Human Health Evaluation Manual, Supplemental Guidance: Standard Default Exposure Factors; USEPA: Washington, DC, USA.
U.S. Environmental Protection Agency. (1989). Risk Assessment Guidance for Superfund Volume 1: Human Health Evaluation Manual (Part A); Office of Emergency and Remedial Response: Washington, DC, USA, 1989.
U.S. Environmental Protection Agency. (2004). Risk Assessment Guidance for Superfund Volume I: Human Health Evaluation Manual (Part E, Supplemental Guidance for Dermal Risk Assessment); USEPA: Washington, DC, USA.
U.S. Environmental Protection Agency. (2001). Toxics Release Inventory: Public Data Release Report. USEPA: Washington, DC, USA.
Wang, X., Sato, T. and Xing, B. (2005). Health risks of heavy metals to the general public in Tianjin, China via consumption of vegetables and fish. Sci. Total Environ. 350, 28–37.
Wuana, R.W. and Okieimen, F.E. (2011). Heavy metals in contaminated soils: A review of sources, chemistry, risks and best available strategies for remediation. ISRN Ecology. doi:10.5402/2011/402647.
Xiao, M.S., Li, F., Zhang, J.D., Lin, S.Y., Zhuang, Z.Y. and Wu, Z.X. (2017). Investigation and health risk assessment of heavy metals in soils from partial areas of Daye city, china. IOP Conference Series: Earth and Environmental Science, 64: 012066.
Zhang, X.W., Yang, L.S., Li, Y.H., Li, H.R., Wang, W.Y. and Ye, B.X. (2012). Impacts of lead/zinc mining and smelting on the environment and human health in China. Environ Monit Assess. 184:2261–2273.