Non-carcinogenic and Carcinogenic Risk Potentials of metals Exposure from Vegetables Grown in Sharada Industrial Area Kano, Nigeria

Document Type : Original Article


1 Biochemistry Department, College of Health sciences, Bayero University, PMB 3011, Kano-Nigeria Biochemistry Department, University of Nigeria, Nsukka, 410001, Enugu-Nigeria

2 Biochemistry Department, College of Health sciences, Bayero University, PMB 3011, Kano-Nigeria

3 Biochemistry Department, University of Nigeria, Nsukka, 410001, Enugu-Nigeria


Chemical elements such as heavy metals significantly functions as trace elements but their bio-toxicity to human biochemical process poses a great concern for public health. The human exposure to heavy metals via food chain has been a documented risk factor for cancer development and other health-related implications. The levels of some carcinogenic (Chromium Cr; Cadmium Cd and Lead Pb) and non carcinogenic (Nickel Ni; Cobalt Co; Copper Cu and Zinc Zn) heavy metals in vegetables (Onion, Drumstick, Lettuce, Okra, and Carrot) grown in Sharada industrial area, Kano were evaluated. The human health risk implications were also determined by estimating the daily metal consumption, and calculating non cancer and cancer risks (Incremental Life Cancer Risk, ILCR and Target Hazard Quotients) using US-EPA probabilistic health risk assessment (US-EPA risk predicting model). The mean concentration of lead (Pb) ranged from 11.21±0.55 µg/g in Okra to 16.84±0.86 µg/g in onion. Carrot had the highest concentration of chromium (65.10±3.20 µg/g). The levels of various heavy metals found in the studied vegetables/plants differ generally with plant species. The predictive values of human developing cancer disease from the incessant intake of studied plant/vegetables was found higher than the standard threshold risk boundary set by US-EPA, (>10-4) for Cr, Pb, and Cd. The non cancer health risk values also predicted Pb, Cr and Cd as the dominant metal contaminants of the vegetables with the Health Risk Index greater than one (>1), while Ni, Co, and Zn showed safe quotients. Among the studied vegetables/plants, carrot has predicatively, the highest cancer risk (∑ILCR 1.25 with chromium contributing 92%), followed by lettuce, onion, Moringa oleifera, and okra (Carrot> Lettuce > Onion > Moringa > Okra). It is, therefore, suggests that the industrial area is unsafe for irrigation due to the heavy metals pollutions of the soil and irrigation water and the risk of high consumption of vegetables grown exposes the population to incremental cancer risks potential among others.


1. Zhuang P., Zou B., Li N.Y., Li Z.A., 2009. Heavy metal contamination in soils and food crops around Dabaoshan mine in Guangdong, China: Implication for human health. Environ Geochem Health.31, 707–715.
 2.Sun H.F., Li Y.H., Ji Y.F., Yang L.S. Wang W.Y., Li H.R., 2010. Environmental contamination and health hazard of lead and cadmium around Chatian mercury mining deposit in western Hunan province, China. Transport of Nonferrous Metals. Soc. China. 20, 308–314.
 3. Babandi A., Atiku M.K., Alhassan A.J., Ibrahim A., Shehu, D., 2012.Level Of Heavy Metals In Soil and Some Vegetables Irrigated With Industrial Waste Water Around Sharada Industrial Area, Kano, Nigeria. Chemsearch J.3(2), 34–38.
4. Pekey H., Karaka D., Bakoglu M., 2004. Source apportionment of trace metals in surface waters of a polluted stream using multivariate statistical analyses. Marine Poll Bull. 49(9), 809-818.
5. Islam M.S., Ahmed M.K., Raknuzzaman M., Habibullah-Al-Mamun M., Islam M.K., 2015. Heavy metal pollution in surface water and sediment: A preliminary assessment of an urban riverina developing country. Ecol Ind. 48, 282–291.
6. Jarup L., 2003. Hazards of heavy metal contamination. British Med Bull. 68, 167–182
7. JavedM., UsmaniN., 2012.Toxic effects of heavy metals (Cu, Ni, Fe Co, Mn, Cr, Zn) to the hematology of Mastacembelusarmatus thriving in Harduaganj Reservoir, Aligarh, India. Global J Med Res. 12, 59–64.
8. Javed M., Usmani N., Ahmad I., Ahmad M., 2015. Studies on the oxidative stress and gill histopathology in Channapunctatus of the canal receiving heavy metal-loaded effluent of Kasimpur Thermal Power Plant. Environ Monit  Assesst. 187, 41-79.
9. Powers K.M., Smith-Weller T., Franklin G.M., Longstreth W.T., Swanson P.D., Checkoway H., 2003. Parkinson’s disease risks associated with dietary iron, manganese, and other nutrient intakes. Neurology. 60, 1761–1766.
10. Muhammad S., Shah MT., Khan S., 2011. Health risk assessment of heavy metals and their source apportionment in drinking water of Kohistan region, northern Pakistan. Microchemical J. 98(2), 334-343.
11. Wei X., Gao B., Wang P., Zhou H., Lu J., 2015. Pollution characteristics and health risk assessment of heavy metals in street specks of dust from different functional areas in Beijing, China. Ecotox & Environ. Saf. 112, 186–192.
12. Li N., Kang Y., Pan W., Zeng L., Zhang Q., Luo J., 2015.Concentration and transportation of heavy Metals in vegetables and risk assessment of human exposure to bioaccessible heavy metals in soil near waste-incinerator site, South China. Sci Total Environ. 521–522, 144–151.
13. Ali H., Khan E., Sajad MA., 2013.Phytoremediation of heavy metals—Concepts and applications. Chemosphere. 91, 869–881.
14. Hu B., Wang C., Xu X., Zhang  S., Bao S., Li Y., (2016). Assessment of radioactive materials and heavy metals in the surface soil around uranium mining area of Tongliao, China. Ecotox & Environ. Safety. 130, 185–192.

15. Akram H.S.M., Richard S., 2013. Cancer Control in Bangladesh. Japan J Clin Oncology. 43(12), 1159–1169.

16. Prakash D., Upadhyay G., Gupta C., PushpangadanP., Singh KK., 2012. Antioxidant and free radical scavenging activities of some promising wild edible fruits. Int Food Res J. 19, 1106–1116.
17. Cui Y.J., Zhu Y.G., Zhai R.H., Chen D.Y., Huang Y.Z., Qiu Y., Liang J.Z., 2004. Transfer of metals from soil to vegetables in an area near a smelter in Nanning. China. Environ Int. 30, 785–791.
18. DMello J.P., 2003. Food safety: Contaminants and Toxins. CABI Publishing, Cambridge. pp. 191-215.
19. Liu X.M., Song Q., Tang Y., Li W.L., Xu J.M., Wu J.J., 2013. Human health risk assessment of heavy metals in the soil-vegetable system: A multi-medium analysis. Sci Total Environ. 463–464,530–540.
20. Naser H.M.  Shil N.C., Mahmud N.U., Rashid M.H., Hossain K.M., 2009.Lead, cadmium and nickel contents of vegetables grown in industrially polluted and non-polluted areas of Bangladesh. Bangladesh J Agric. 34(4), 545-554.
21. Bichi M.H., Anyata B.U., 1999. Industrial Waste Pollution in the Kano River Basin. Environ Mgmt Health. 10(2),112-11.
22. Chen W.Y., 2017. Environmental externalities of urban river pollution and restoration: A hedonic analysis in Guangzhou (China). Lands and Urban Planning. 157, 170–179.
23. Li Z., Mao X.Z., Li T.S., Zhang  S.Y.,  2016. Estimation of river pollution source using the space-time radial basis collocation method. Adv. in Water Resources.88, 68–79.
24. AOAC., 1984. Official Methods of Analysis 14th edn.AOAC, Inc. Washington. pp.152-162.
25.USEPA (the United States Environmental Protection Agency).,  1989.  Choice of Water Regulations and Standard: a Guidance manual for assessing human health risks from chemically contaminated, fish and shellfish U.S. Environmental Protection Agency, Washington, DC; EPA-503/8-89-002.
26. Cai  L.M., Xu Z.C.,  Qi J.Y., Feng Z.Z., Xiang T.S.,  2015. Assessment of exposure to heavy metals and health risks among residents near Tonglushan mine in Hubei, China. Chemosphere.127, 127–135.
27. ChristouA., Theologides C.P., Costa C., Kalavrouziotis I.K., Varnavas S.P., 2017. Assessment of toxic heavy metals concentrations in soils and wild and cultivated plant species in Limni abandoned copper mining site, Cyprus. J Geochem Expl.178, 16–22.
28. Arora  M., Kiran B., Rani  S., Rani  A., Kaur B. and Mittal  N., 2008. Heavy metal accumulation in vegetable irrigated with water from different sources. Food Chem. 111, 811-815.
29. Sajjad K., Robina F., Shagufta S., Mohammad A., Maria S., 2009. Health Risk Assessment of Heavy Metals for Population via Consumption of Vegetables. World Appld Sci J. 6,1602-1606. 
30. Rattan RK., Datta SP., Chhonkar PK., Suribabu K., Singh AK., 2005. The long-term impact of irrigation with sewage effluents on heavy metal content in soils, crops and groundwater-a case study. Agric .Ecosyst  Environ. 109, 310e - 322.
31. EPA., 2010. The  limits of pollutants in food. China: State Environmental Protection Administration. GB2762.
32. UNICEF., 2012. At a glance: Nigeria. https://www. unicef . org / infobycountry / nigeria _ statistics. html.
33. Wongsasuluk P., ChotpantaratS., Siriwong W., Robson M., 2014. Heavy metal contamination and human health risk assessment in drinking water from shallow groundwater wells in an agricultural area in Ubon Ratchathani province, Thailand. Environ Geochem Health. 36, 169-182.
 34. Micheal B., Patrick O., Vivian T., 2015. Cancer and non-cancer risks associated with heavy metal exposures from street foods: Evaluation of roasted meats in an urban setting. J Environ Poll Human Health. 3, 24–30.
35 Alloway B.J.,  DaviesB.E., 1971.Trace element content of soils affected by base metal mining in Wales. Geoderma. 5, 197–208.
36. 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,2004.
37. Nkoom M., Cobbina J.S., Kumi M., 2013. Assessment of endocrine disrupting trace metals in River Samre at Samreboi in the Wassa Amenfi west district of the western region of Ghana. J Water Resources & Protection. 5(10), 983–992.
38. Forti E., SalovaraS., CetinY., Bulgheroni  A., Pfaller RW., PrietoP., 2011. In vitro evaluation of the toxicity induced by nickel soluble and particulate forms in human airway epithelial cells. Toxicol In vitro. 25, 454–461.
39. Singh A., Sharma R.K., Agrawal M., Marshall, F.M., 2010. Risk assessment of heavy metal toxicity through contaminated vegetables from waste water irrigated area of Varanasi, India. Tropical Ecol. 51(2S), 375-387.
40. NYSDOH (New York State Department of Health)., 2007.  Hopewell precision area contamination: appendix C-NYS DOH. Procedure for evaluating potential health risks for contaminants of concern. ny. gov/environmental /investigations /hopewell/appendc. htm
41. Islam M.S., Ahmed M.K., Al-Mamun M.H., Islam K.N., Ibrahim M., Masunaga S., 2014. Arsenic and lead in foods: a potential threat to human health in Bangladesh. Food Additives and Contaminants Part A. doi:10.1080/19440049.2014.974686.
42. Zodape G.V., 2014. Metal contamination in commercially important prawns and shrimps species collected from Kolaba market of Mumbai (west coast) India. Int J Agric Sci. 4, 160–169.
43. USEPA (the United States Environmental Protection Agency), 2012. EPA Region III Risk-Based Concentration (RBC) Table 2008 Region III, 1650 Arch Street, Philadelphia, Pennsylvania 19103.
44. EPA, 1999. Guidance for performing aggregate exposure and risk assessments.Office of Pesticide Programs, Environmental Protection Agency (EPA), Washington, DC.
45. H2M Group, 1997. Baseline human health risk assessment report: Operable unit 1. Lockheed Martin Tactical Defense Division of Lockheed Martin Tactical Systems, Inc., (Former Unisys Corp. Site) Great Neck, New York, January 1997. pp. 4-16, 38, 39.
46. Harmanescu M., Alda L.M., Bordean D.M., Gogoasa I., Gergen I., 2011. Heavy metals health risk assessment for population via consumption of vegetables grown in old mining area; a case study: Banat County, Romania. Chem Central J. 5,64.
47. Abdou H.M., Hassan M.A., 2014. Protective role of Omega-3 polyunsaturated fatty acid against lead acetate-induced toxicity in liver and kidney of female rats. Biomed Res Int. doi:10.1155/2014/435857.
48. JovicM., StankovicS., 2014. Human exposure to trace metals and possible public health risks via consumption of mussels Mytilusgalloprovincialis from the Adriatic coastal area. Food and Chem Toxicol. 70, 241–251.
49. Khan S., Farooq R., Shahbaz S., Khan  MA., Sadique M., 2009.  Health risk assessment of heavy metals for population via consumption of vegetables. World Appld Sci. J. 6, 1602–1606.
50. Covello V.T.,Merkhoher M.W., 1993. Risk AssessmentMethods: Approaches for Assessing Health and Environmental Risks.Plenum Press, USA.pp. 3-5.
51. Ma Y., Egodawatta  P., McGree J., Liu A., Goonetilleke A.,  2016. Human health risk assessment of heavy metals in urban stormwater. Sci Total Environ.557–558, 764–772.
52. Cher A., Achour M., Cher M., Otmani S., Morsli A., 2015. Health risk assessment of heavy metals through the consumption of vegetables irrigated with reclaimed urban wastewater in Algeria. The process of Safety &.Environ Protection. 98, 245–252.
53. Obiri S., 2005. Risk assessment of toxic chemicals in mining operations in Ghana master's thesis. Kumasi, Ghana: Department of Chemistry, Kwame Nkrumah University of Science and Technology. pp.30.
54. Liu H., Probst A., Liao B., 2005. Metal contamination of soils and crops affected by the Chenzhou lead/zinc mine spill (Hunan, China). Sci & Total Environ. 339, 153–166.

55. Li S., Zhang Q., 2010.  Risk assessment and seasonal variations of dissolved trace elements and heavy metals in the Upper Han River, China. J Hazardous Mat. 181, 1051-1058.

56. Li P.H., Kong S.F., GengC.M., Han B., Lu B., Sun R.F., Zhao R.J., BaiZ.P., 2013. Assessing the Hazardous Risks of Vehicle Inspection Workers’ Exposure to Particulate Heavy Metals in Their Work Places. Aerosol and Air Qual Res.13, 255-265.
57. Snow E.T., 1992. Metal carcinogenesis: mechanistic implications. Pharmacol &Therap. 53, 31-65.
58. Sies H., 1997. Oxidative stress: oxidants and antioxidants. Exp Physiol. 82, 291-5.
59. Vertuani S., Angusti A., Manfredini S., 2004. The antioxidants and pro-antioxidants network: an overview. Curr Pharmacol Dis. 10, 1677-1694.
60. Bower J.J., Leonard S.S., Shi X., 2005.Conference overview: Molecular mechanisms of metal toxicity and carcinogenesis. Mol Cell Biochem. 279, 3-15.
61. Beyersmann D., HartwigA., 2008. Carcinogenic metal compounds: Recent insight into molecular and cellular mechanisms. Arch of Toxicol. 82, 493–512.
62. Poli G., Leonarduzzi G., Biasi F.,Chiarpotto E., 2004. Oxidative stress and cell signalling. Curr Med Chem.11, 1163–1182.
63. Valko M., Rhodes C.J., Moncol  J., Izakovic  M.,  Mazur  M., 2006. Free radicals, metals, and antioxidants in oxidative stress-induced cancer. Chem & Bio Interact.160, 1–40.
64. IARC 1993. Cadmium and cadmium compounds. IARC Monograph: Evaluation of carcinogenic risk of humans. 58,119-237.
65. Staessen J.A., Roels H.A., Emelianov D., Kuznetsova T., Thijs L., VangronsveldJ., Fagard R., 1999.Environmental exposure to cadmium, forearm bone density, and risk of fractures: a prospective population study. Lancet. 353(9159), 1140–4.
66. Alfven T., Elinder C.G., Carlsson M.D., Grubb A., Hellstrom L., PerssonB., Pettersson C., Spang G., Schutz A., Jarup L., 2000. Low-level cadmium exposure and osteoporosis.  J  Bone and Mineral Resources.15(8), 1579–86.
67. Wu J.P., Chang L.P., Yao  H.T., 2008. Involvement of oxidative stress and activation of aryl hydrocarbon receptor in elevation of CYP1A1 expression and activity in lung cells and tissues by arsenic: An in vitro and in vivo study. Toxicol & Sci. 107, 385-93.
68. Ke Q., Ellen T.P., Costa M., 2008. Nickel compounds induce histone ubiquitination by inhibiting histone deubiquitinating enzyme activity. Toxicol & Appld Pharmacol. 228, 190-9.
69. Lee Y.W., Broday L., Costa M., 1998. Effects of nickel on DNA methyl-transferase activity and genomic DNA methylation levels. Mut Res.415, 213-8.
 70. Kasprzak  K.S., 1995. The possible role of oxidative damage in metal-induced carcinogenesis. Cancer Invest.13, 411-30.
71. HartwigA., 1994. Role of DNA repair in inhibition in lead and cadmium-induced genotoxicity:  a review. Environ Health Perspectives. 102, 45-50.
72. WHO., 1995. Environmental health criteria 165: inorganic lead Internet. Geneva, Switzerland: World Health Organization; 1995 cited 2015 Nov 11. pp. 300. Available from: http:// www. Inchem . org / documents / ehc / ehc / ehc165 . htm
73. Steenland K., Boffetta P., 2000. Lead and cancer in humans: where are we now? Am J of Ind and Med. 38(3), 295-9.
Volume 10, Issue 1
February 2020
Pages 1-15
  • Receive Date: 28 January 2019
  • Revise Date: 22 February 2019
  • Accept Date: 14 December 2019
  • First Publish Date: 01 February 2020