Health Risk Assessment on Selected Essential and Non-Essential Elements in Food Crops Grown in Kibera Slum, Nairobi-Kenya
- 1 Department of Chemistry, Kenyatta University, Nairobi, Kenya
- 2 Department of Chemistry, Kenyatta University, Nairobi, Kenya
- 3 Department of Chemistry, Kenyatta University, Nairobi, Kenya
Abstract
Peri-urban agriculture of food crops is practiced in many slum areas in developing countries. This often uses waste water whose levels of essential and non-essential elements are largely unknown but would be feared to contaminate soils, consequently exposing man to associated health risks. Inhabitants in Kibera slum, Nairobi City practice these growing kales, amaranthus, arrowroots, and spinach. Health risk assessment was done using daily intake of metals (DIM), target hazard quotient (THQ) and incremental lifetime cancer risk (ILCR). Atomic absorption spectroscopy was employed for elemental analysis. The levels of essential elements ranged as follows; Mn 91.04 - 374.44, Mg 261.28 - 532.96, Fe 350.74 - 1273.68, and Zn 1.18 - 6.3 μg/g per dry weight were found to be below the recommended limits by FAO/WHO. Non-essential elements ranged as follows; Cr 1.15 - 4.32 and Pb 0.14 - 0.91 μg/g above the EU recommendation. DIM of Fe 5.81 - 27.61 and Mn 1.97 - 8.12 μg/g is above the recommended daily intake amounts. THQ values for Mn and Fe were more than unit. THQ values for non-essential elements were generally below unit. ILCR showed that from lead alone 73 people (0.043% of 0.17M residents) are likely to develop cancer. There are foreseen health risks associated with consumption of food crops grown in Kibera slum that requires immediate address.
- World Economic Report (2016) The Global Competitiveness Report. World Economic Forum.
- Kenya National Bureau of Statistics (2009) Kenya Population and Housing Census (Vol. 1). Kenya National Bureau of Statistics.
- Balkhair, K.S. and Ashraf, M.A. (2016) Field Accumulation Risks of Heavy Metals in Soil and Vegetable Crop Irrigated with Sewage Water in Western Region of Saudi Arabia. Saudi Journal of Biological Sciences, 23, S32-S44. https://doi.org/10.1016/j.sjbs.2015.09.023
- Budambula, N.L.M. and Mwachiro, E.C. (2006) Metal Status of Nairobi River Waters and Their Bioaccumulation in Labeo Cylindricus. Water, Air, & Soil Pollution, 169, 275-291. https://doi.org/10.1007/s11270-006-2294-x
- Shakir, E., Zahraw, Z. and Al-Obaidy, A.H.M.J. (2017) Environmental and Health Risks Associated with Reuse of Wastewater for Irrigation. Egyptian Journal of Petroleum, 26, 95-102. https://doi.org/10.1016/j.ejpe.2016.01.003
- Liu, X., et al. (2013) Human Health Risk Assessment of Heavy Metals in Soil—Vegetable System: A Multi-Medium Analysis. Science of the Total Environment, 463-464, 530-540. https://doi.org/10.1016/j.scitotenv.2013.06.064
- Omer, S.A., et al. (2012) Cadmium Bioaccumulation and Toxicity in Tilapia Fish (Oreochromis niloticus). Journal of Animal and Veterinary Advances, 11, 1601-1606. https://doi.org/10.3923/javaa.2012.1601.1606
- Mahmood, A. and Malik, R.N. (2014) Human Health Risk Assessment of Heavy Metals via Consumption of Contaminated Vegetables Collected from Different Irrigation Sources in Lahore, Pakistan. Arabian Journal of Chemistry, 7, 91-99. https://doi.org/10.1016/j.arabjc.2013.07.002
- Chove, B., Ballegu, W. and Chove, L. (2006) Copper and Lead Levels in Two Popular Leafy Vegetables Grown around Morogoro Municipality, Tanzania. Tanzania Journal of Health Research, 8, 37-40. https://doi.org/10.4314/thrb.v8i1.14269
- Das, S., de Oliveira, L.M., da Silva, E., Liu, Y. and Ma, L.Q. (2017) Fluoride Concentrations in Traditional and Herbal Teas: Health Risk Assessment. Environmental Pollution, 231, 779-784. https://doi.org/10.1016/j.envpol.2017.08.083
- Xiao, R., Wang, S., Li, R., Wang, J.J. and Zhang, Z. (2017) Soil Heavy Metal Contamination and Health Risks Associated with Artisanal Gold Mining in Tongguan, Shaanxi, China. Ecotoxicology and Environmental Safety, 141, 17-24. https://doi.org/10.1016/j.ecoenv.2017.03.002
- WHO/FAO, Codex Alimentarius Commission (2001) Food Additives and Contamination. Joint FAO/WHO Food Standards Programme, ALINORM 01/124, 1129.