Metal Exposures, Noise Exposures, and Audiometry from E-Waste Workers in Agbogbloshie, Ghana

Abstract

Metals, such as lead, may be ototoxic, but this property is not well understood, especially in conjunction with noise. This cross-sectional study investigated hearing, noise, and metal biomarkers in informal electronic waste (e-waste) recycling workers in Accra, Ghana. Workers (N = 58) participated in audiometric testing, a survey, blood collection, and personal noise dosimetry. Sixty percent of participants displayed audiometric notches indicative of noise-induced hearing loss (NIHL). Most workers (86%) reported high noise while working. Daily average noise levels were in the range 74.4–90.0 dBA. Linear regression models indicated participants who lived at Agbogbloshie Market for longer periods were significantly associated with worse hearing thresholds at 4 and 6 kHz. The models did not identify blood levels of lead, mercury, or cadmium as significant predictors of worse hearing thresholds or larger noise notches, but increased levels of selenium were significantly associated with better hearing at 6 kHz. Models of thresholds at 4 and 6 kHz were improved by including an interaction term between the maximum noise exposure and the level of zinc in whole blood, suggesting that zinc may protect hearing at lower noise levels, but not at higher levels. Further study of the relationships between elements, noise, and NIHL is needed.

Health Risks Associated with Informal Electronic Waste Recycling in Africa: A Systematic Review

“…The included studies assessed a wide range of health indicators including musculoskeletal diseases and symptoms [ 26 ], observed and self-reported physical injuries, and respiratory symptoms [ 27 , 30 , 31 , 37 , 38 , 39 ], markers of cardiovascular health [ 25 , 35 , 36 , 40 ], perceived stress [ 32 ], markers of respiratory health [ 21 ], noise-induced hearing loss [ 28 ], markers of hepatic damage [ 41 ], epigenetic modification (DNA methylation) [ 42 ], and markers of DNA damage [ 16 ] ( Figure 2 ). Ten out of the seventeen studies [ 25 , 26 , 27 , 30 , 31 , 32 , 37 , 38 , 39 , 41 ] used the e-waste recycling methods such as dismantling and burning as the main exposures, four studies [ 16 , 28 , 40 , 42 ] measured metals in the blood as the main exposure biomarkers, and three studies measured the breathing-zone PM as the main exposures [ 21 , 35 , 36 ] ( Table 1 ).…”

“…In three studies, metals exposure associated with e-waste recycling were investigated as the main toxic agent associated with hearing loss [ 28 ] and DNA damage [ 16 , 42 ]. In one of the studies [ 28 ], the authors measured the levels of toxic (cadmium (Cd), lead (Pb), arsenic (As), and total mercury (Hg)) and essential elements (selenium (Se), manganese (Mn), copper (Cu), iron (Fe), and zinc (Zn)) in blood, and administered audiometric tests on e-waste workers ( n = 58). The average levels of Pb (mean = 9.72 µg/dL), Cd (mean = 2.98 ppb), Mn (mean = 12.6 µg/L), and Se (mean = 163.6 µg/L) were all higher than the US adults average [ 28 ].…”

“…In one of the studies [ 28 ], the authors measured the levels of toxic (cadmium (Cd), lead (Pb), arsenic (As), and total mercury (Hg)) and essential elements (selenium (Se), manganese (Mn), copper (Cu), iron (Fe), and zinc (Zn)) in blood, and administered audiometric tests on e-waste workers ( n = 58). The average levels of Pb (mean = 9.72 µg/dL), Cd (mean = 2.98 ppb), Mn (mean = 12.6 µg/L), and Se (mean = 163.6 µg/L) were all higher than the US adults average [ 28 ]. Even though the toxic metals (Pb, Cd, and Hg) did not significantly predict noise-induced hearing loss (NIHL), participants who lived at the e-waste recycling site (Agbogbloshie) for longer periods were significantly associated with worse hearing thresholds at 4 and 6 kHz.…”

“…Grant et al [ 1 ] further concluded that there were limited studies on the effects of e-waste on health in developing countries in Africa. Since then, researchers have shown an increased interest in examining the health risks of informal e-waste recycling in African countries including Ghana [ 26 , 27 , 28 , 29 ], Nigeria [ 16 , 30 ], Benin, Burkina Faso, the Ivory Coast, Mali, and Senegal [ 31 , 32 ]. However, there is a current paucity of evidence-based literature describing the health impacts of e-waste exposure in Africa where African nations continue to be major recipients of e-waste shipped from developed nations.…”

Iron- and protein rich diets may boost hemoglobin levels among informal electronic waste recyclers exposed to metals at Agbogbloshie, Ghana

“…In low and middle-income countries (LMICs) today, it is widely believed that the recycling of electronic waste is a significant contributor of metal discharge into the ambient environment. In and around sites that e-waste recycling occurs, there is considerable discharge of metals into the environmental media as revealed by research conducted in Ghana, China and other parts of the world because of the use of crude recycling methods such as open-air burning, dismantling, collection and sorting ( Takyi et al, 2021 ; Srigboh et al, 2016 ; Carlson et al, 2021 ). The adoption of such inappropriate techniques potentiates the release of chemicals (e.g.…”