International Journal of Science and Engineering Invention ISSN: 2455-4286 Volume 05, Issue 08, August 2019 | DOI: 10.23958/ijsei/vol05-i08/176 132 ARTICLE OPEN Assessment of heavy metal percolation from electronic waste (mobile phones) through different soil layers in the Niger Delta, Nigeria Aroloye O. Numbere 1* and Gabriel George 2 1, 2 Department of Animal and Environmental Biology, University of Port Harcourt, Choba, Nigeria. +2348056002989 *Corresponding author: aroloyen@yahoo.com Abstract: The proliferation of electronic waste is a global problem. It is hypothesized that heavy metals from buried decomposing mobile phones will percolate through different layers (i.e. top. middle and bottom) of mangrove and farm soils. Sixteen mobile phones were collected and buried in two containers (volume 14, 142.86 cm3) bearing mangrove and farm soils and left for I year to decompose. A total of 60 soil samples were analyzed for Arsenic, Cadmium, Copper, Lead, Nickel and Zinc. There was a significant difference in the concentration of metals (F5, 66 = 36.64, P < 0.0001). Zinc, Copper, and Nickel had the highest concentration while Cadmium had the least concentration in both soils. Mangrove soil had a higher heavy metal concentration than farm soil even though there was no significant difference (P > 0.05). Similarly, there is no significant difference in heavy metal concentration between soil layers and seasons (i.e. dry and wet ) (P > 0.05). During the dry season heavy metal was higher in the top and middle layers while during the wet season heavy metals was higher in the middle and bottom layers of the soil. The result implies that heavy metal concentration between soil layers was influenced by seasonal fluctuations. Improper disposal of electronic waste in the environment should be discouraged to prevent the contamination of surface and ground water. Keywords: electronic waste, ground water, heavy metals, mobile phone, pollution, soil profile, waste dump 1 Introduction Electrical and electronic equipment [1] wastes are made up of refrigerators, air-conditioners, cell phones, stereo systems and computers that are discarded [2] .They are any household appliances that are no longer useful and eventually end up in landfill. Electronic and electric wastes cause hazardous effects on the environment. This situation is more serious in many African countries, which over the years had become the destination of manufactured electronic goods from other parts of the world [3, 4] . E-waste recycling in Africa has not gained much attention as experienced in America, Asia and Europe. E-waste recycling involves much labor and environmental legislation [5] . Thus global production of e-waste is put at 20-50 Militonn/year (Mt/yr), which makes 1-3% of global urban waste production. It is predicted that PCs, cell phones and televisions will contribute > 14.0 Mt/yr in 2020. Thus, there has been steady rise in the amount of e-waste in Africa. In Nigeria with rapidly growing population of close to 200 million people [6] , the use of different electronic products had increased. Most especially, the use of mobile phones had increased since the late 1990’s. Almost every member of a household above ten years has a mobile phone. Some of the phones are sophisticated and expensive while others are simple and less expensive. The life span of these phones is short, i.e. between 2-3 years making them to be easily disposed as compared to other kind of e-waste [7] . Technological advancement and improved income has made many to exchange their old phones for new ones. In addition, the influx of sub-standard phones had resulted to the increase in mobile phone waste at dump sites [8] . Lack of proper management and recycling of e-wastes [9, 10, 11] can lead to their disposal in aquatic environment resulting to public health crisis [12] . Electronic waste is inimical to health because it contains toxic elements such as lead, cadmium, mercury, polychlorinated biphenyls and brominated flame retardant [13, 14, 15, 16] . In some rural areas e-waste is disposed in open dump or land fill situated on farm land or virgin forest where they are incinerated. Incineration of phones lead to the melting of the internal components (diode, mother board, IC), which contain heavy metals leading to toxic emissions [17] . Liquefaction of the internal parts of mobile phones makes it possible for heavy metals to enter and contaminate ground water [18] . The farm soil is also contaminated with heavy metals from burnt or decomposing phones [19]. High concentration of heavy metals in the soil lead to high mobility and movement into plants parts via the roots [20] . Contaminated plants when consumed affect human and animal health [21, 22, 23] leading to organ failure and other life-threatening diseases and deficiencies. There is limited data on electronic waste in the Niger Delta. In this study, two kinds of soils were used namely farm soil and mangrove soil. Farm soil was used because of the significance of soil-crop- food pathway of heavy metals [24]. Similarly, mangrove soil was used because mangrove forest is gradually becoming a dumping