Heavy Metal Concentration of Surface Dust Present in E-Waste Components: The Westminister Electronic Market, Lagos Case Study

Abstract

To evaluate the extent of heavy metals (Cd, Cr, Pb, Zn, Fe) contamination from e-waste, surface dust samples were collected from workshops (indoor), around the market areas (outdoor) and from a distance of about 100 metres away from the market area (control) of the Westminister Electronic market in Lagos, Nigeria. Aqua regia digestion was applied to the dust samples prior to determination of heavy metal by atomic absorption spectroscopy (AAS). The AAS analysis revealed mean concentrations in indoor dust (Pb 22.50, Cd 1.80, Fe 108.00, Cr 0.35 and Zn 295.50 mg/kg), outdoor dust (Pb 15.90, Cd 19.00, Fe 103.3, Cr 0.10 and Zn 213.00 mg/kg) and control dust ( Pb 9.40, Cd -, Fe 62.00, Cr -and Zn 78.00 mg/kg). Although the result showed a relatively low contamination in general, it could be inferred that the increased concentration of heavy metals from the indoor electronic waste could be from the interaction of heavy metals in the e-waste components with the settled dust on them over time. Risk assessment predicted that Cd and Zn in the e-waste have the potential to pose serious health risks to workers, customers and local residents of Westminister area, especially children, and this underscores the urgent intervention by relevant government agencies.

Endocrine disrupting metals lead to alteration in the gonadal hormone levels in Nigerian e-waste workers

“…Sertoli cells proliferate during the foetal, neonatal and pre-pubertal period, and each of these periods is particularly sensitive to the adverse effects of metals. (6) Whole blood heavy metals concentration of the subjects studied in this work has previously been reported (25) In the study, it was observed that heavy metals in the exposed participants were significantly elevated. Accumulation of metals in the epididymis, prostate, vesicular seminalis or seminal fluid may impair progressive sperm motility especially by causing the formation of varicocele.…”

“…Men working in battery plants and exposed to toxic levels of lead demonstrated adverse effects on their reproductive capacity. (6) Plasma levels of pituitary hormones, for example, LH, FSH, PROL and adrenocorticotropic hormone (ACTH), were also modified after cadmium exposure. (15) The endocrine disrupting properties of metals may be the sole cause of the differences in the hormonal concentrations between the exposed and unexposed participants, this is also supported by the correlation of the male fertility hormones and toxic metals ( Table 3).…”

“…The five years duration of exposure is based on the E-waste Risk Assessment Report of Adaramodu and colleagues. (6) The control subjects were recruited from the Ugbowo community, had not been exposed to e-waste and were apparently healthy without medical complication in the past 5 years. The control subjects were males aged 18 years and above.…”

“…(5) E-waste products contain intricate blends of plastics and chemicals, which when not properly handled can be harmful to humans and pose environmental hazard. (6) E-waste contains more than 1000 different chemical substances which fall under 'hazardous' and 'non-hazardous' categories. The presence of toxic elements like lead, mercury, arsenic, cadmium, selenium and hexavalent chromium and flame retardants in ewaste classifies them as hazardous waste.…”

Impact of informal electronic waste recycling on metal concentrations in soils and dusts

“…The strengths of this study are its focus on different e-waste sites in each city, analyses of more number of metals that are not usually reported in other studies, the comparison of metal concentrations in various environmental samples (top soils, floor dusts, roadside dust, and direct dust from electronics) from different e-waste recycling sites and corresponding control sites, and the comparison of the extent of metal pollution at ewaste sites across the three cities in two different geopolitical zones in Nigeria. So far most studies (Isimekhai et al, 2017;Adesokan and Gilbert, 2016;Adeyi, 2017;Adaramodu et al, 2012) on metal pollution due to informal e-waste recycling sites focused on one location and usually on one type of environmental sample only. Therefore, these did not provide a comprehensive view on the extent to which heavy metal pollution from these activities is a problem.…”