Plants and chicken organs: Important pathways of human exposure to potentially toxic elements from e-waste recycling site in Lagos, Nigeria

Abstract

Disposal and recycling of electronic wastes (e-waste) in developing countries such as Nigeria are carried out using informal techniques. This results in human exposure and contamination of environmental and biotic systems with potentially toxic elements (PTEs). This study reports concentrations of five PTEs (Cd, Co, Cu, Pb, and Zn) in aquatic and terrestrial plants as well as the organs (skin, liver, kidney, meat and gizzard) of chicken samples collected in the oldest and largest e-waste recycling site in Nigeria, Alaba e-waste recycling site, Lagos. The concentrations of PTEs in the samples were quantified with Atomic Absorption Spectrometer after appropriate digestions with acids. Furthermore, the health risk assessment through consumption of local foods as a dietary exposure to PTEs for populations in the vicinity of the e-waste recycling site was estimated using the USEPA model. In the plant samples, the concentration range of the PTEs were 0.1 – 2.75; BDL - 0.1; 0.65 – 12.6; 0.2 – 6.85 and 2.35 – 56.9 mg/kg for Cd, Co, Cu, Pb and Zn respectively. The concentration of PTEs in the chicken organs ranged from 1.88 – 16.9; 4.38 - 28.1; 0.630 – 122 and 101 – 443 mg/kg for Cd, Cu, Pb and Zn respectively, while Co was found to be below detection limit of 0.08 mg/kg in all the chicken organs. The concentrations of PTEs in some terrestrial plants and all the chicken organs greatly exceeded WHO permissible limits whereas, the concentration in aquatic plants were below permissible limits. Based on the hazard quotient, chicken organs may pose the highest health hazard especially to children. The maximum hazard quotient of the chicken organs for Cd, Cu, Pb and Zn were 113; 4.7; 41.7 and 9.8, respectively for children and 36.2; 1.5; 13.4 and 3.2 respectively for adults. It is recommended that animals from such recycling sites should not be consumed