Assessing the Heavy Metals Contamination of Surface Dust from Waste Electrical and Electronic Equipment (E-waste) Recycling Site in Accra, Ghana

摘要

The objective of this was to assess the levels of heavy metals contamination within the vicinity of the Agbogbloshie scrap market. Surface dust samples were collected from various points at the scrap market and its environs. Atomic absorption spectrophotometry preceded by acid digestion was used to evaluate the concentration of the heavy metals in the samples. Heavy metals such as Zn, Cu, Pb and Cd gave concentrations in the range of (10,575-30, 384 mg/kg), (34-16, 952 mg/kg), (351-5, 105 mg/kg) and (2-72 mg/kg), respectively which were over thousand times more than the levels for which intervention is required. The scrap weighing site, the electronic waste dismantling site and the burning site (where electrical cables are burnt to retrieve metals) recorded the highest levels of heavy metals. Index of geoaccumulation which was employed to determine the level of pollution of the various elements gave the values in the range of 6.7-8.2 for Zinc (Zn), 4.2-8.1 for lead (Pb) and 3.0-7.8 for Cadmium (Cd) indicating extreme pollution from all the sites. This was also confirmed by contamination factor calculations. To assess the extent of pollution of each of the site, degree of contamination was calculated which revealed that the most contaminated site is the Weighing Site (WS) which recorded C_deg value of 1482.93, followed by Dismantling Site (DS) 1221.6, Burning Site (BS) 1196.9, Road Dust (RD) 1061.9, School Compound (SC) 651.44, Commercial Area (CA) 618.6 and Church Premises (CP) 187.6, respectively. The results also indicate that children living around the scrap market face a very high risk from the ingestion of toxic metals such as Pb and Cd. The weighing site (HI = 205) at the scrap market by far pose the greatest cumulative risk followed by the dismantling site (HI = 130), road dust (HI = 88), burning site (HI = 60), school compound (HI = 52), commercial area (HI = 50) and church premises (HI = 15).