Occupational exposures to particulate matter and PM2.5-associated polycyclic aromatic hydrocarbons at the Agbogbloshie waste recycling site in Ghana

Abstract

Electronic waste (e-waste) disposal and recycling activities such as burning and smelting can emit particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and other pollutants that expose workers and nearby communities. At informal e-waste recycling facilities, both emission controls and protective measures for workers are absent. This study characterizes personal exposures (breathing zone) of PM and PAHs of e-waste workers at the large Agbogbloshie e-waste site in Accra, Ghana. We collected gravimetric and optical measurements of PM_2.5 and PM₁₀ using shift samples for workers and for an age- and gender-matched reference population. PM_2.5 filters were analyzed for 26 PAHs using gas chromatography/mass spectroscopy. Among e-waste workers, PM_2.5 and PM₁₀ concentrations were 99 ± 56 and 218 ± 158 µg/m³ (median ± interquartile range, optical measurements), respectively; these levels were 78 and 57% higher, respectively, than levels measured at a fixed site that was centrally located at the waste site. In the reference community, breathing zone PM_2.5 and PM₁₀ levels were lower, 49 ± 20 and 131 ± 108 µg/m³, respectively, and the fraction of coarse PM was larger. We detected all 26 target PAHs, of which naphthalene and phenanthrene were the most abundant. PAH concentrations were weakly correlated to PM levels, but PAH abundances, representing the fraction of PAH mass to the total PM_2.5 mass collected, were strongly and inversely correlated to PM levels, suggesting multiple and different sources of PAHs and PM that affected exposures. Both PM and PAH levels were elevated for workers performing burning and dismantling, and both exceeded standards or risk-based guidelines, e.g., lifetime excess cancer risks for several PAHs were in the 10^-4 to 10^-6 range, indicating the need to reduce emissions as well as provide respiratory protection. The study emphasizes the importance of using personal and shift samples to accurately characterize worker exposure.

Keywords: Air pollution; Breathing zone; Occupational exposure; Personal sampling; Polycyclic aromatic hydrocarbons.

Fig 1.

Comparison of gravimetric and adjusted optical PM_2.5 concentrations for first three sampling rounds. (N=346)

Fig 2.

Trends of personal PM_2.5 concentrations at Agbogbloshie and Madina over the entire study. Uses adjusted optical concentrations; points show individual measurements. Trend lines fitted with 3^rd order polynomial.

Fig 3.

Trends of personal PM₁₀ concentrations at Agbogbloshie and Madina. Otherwise as Fig. 2.

Fig. 4.

Median PAH concentrations at Agbogbloshie (N=24) and Madina (N=10) ranked by concentration. Statistically significant differences shown by “*” and “x” at P=0.05 and P=0.10 levels, respectively.

Fig 5.

A. ΣPAH concentrations versus PM_2.5 concentrations. B. ΣPAH abundance in PM_2.5 versus PM_2.5 concentrations. Dashed lines show linear and exponential model fits. N=34.