Airborne volatile organic compounds at an e-waste site in Ghana: Source apportionment, exposure and health risks

Highlights

• This is the first study to assess both personal and ambient VOCs in e-waste site.

• VOC levels in personal samples were much higher than that in fixed-site samples.

• Local industrial use, fuel evaporation and combustion were the main sources.

• VOC emissions from the e-waste site polluted the neighboring environment.

• Health risks exceeded guideline levels and were mainly due to naphthalene and benzene.

Abstract

Informal e-waste recycling processes emit various air pollutants. While there are a number of pollutants of concern, little information exists on volatile organic compounds (VOCs) releases at e-waste sites. To assess occupational exposures and estimate health risks, we measured VOC levels at the Agbogbloshie e-waste site in Ghana, the largest e-waste site in Africa, by collecting both fixed-site and personal samples for analyzing a wide range of VOCs. A total of 54 VOCs were detected, dominated by aliphatic and aromatic compounds. Mean and median concentrations of the total target VOCs were 46 and 37 μg/m³ at the fixed sites, and 485 and 162 μg/m³ for the personal samples. Mean and median hazard ratios were 2.1 and 1.4, respectively, and cancer risks were 4.6 × 10^-4 and 1.5 × 10^-4. These risks were predominantly driven by naphthalene and benzene; chloroform and formaldehyde were also high in some samples. Based on the VOC composition, the major sources were industry, fuel evaporation and combustion. The concentration gradient across sites and the similarity of VOC profiles indicated that the e-waste site emissions reached neighboring communities. Our results suggest the need to protect e-waste workers from VOC exposure, and to limit emissions that can expose nearby populations.

Introduction

Electrical and electronic equipment (EEE) is indispensable and ubiquitous in modern societies. Globally, EEE production reached 53.6 million tons in 2019, or 7.3 kg/year per capita, and is estimated to increase by 2.5 million tons/year and reach 74.7 million tons by 2030 (Forti et al., 2020). This massive production has generated a parallel stream of EEE waste or e-waste. In the relatively small West African country of Ghana, e-waste recycling has become an important revenue source in the informal economy (Asibey et al., 2020). While Ghana has enacted e-waste legislation and is trying to adopt the Basel Convention that would restrict e-waste imports, as well as establish funds to support related facilities and support research and public education addressing recycling (Daum et al., 2017), e-waste imports have grown from about 149,000 tons in 2009 to an estimated 300,000–840,000 tons in 2020 (Amoyaw-Osei et al., 2011). Described as Africa's largest electronic waste dumpsite, Agbogbloshie in central Accra, the capital of Ghana, has attracted international attention. Approximately 4500–6000 workers and another 1600 indirectly work at this well-organized scrapyard (Grant and Oteng-Ababio, 2012), where e-waste is processed using rudimentary methods, e.g., manual stripping to remove electronic boards for resale, open burning of wires to recover metals (copper, aluminum, iron), and open dumping of bulk components such as cathode-ray tubes (CRTs) (Ackah, 2017). Enforcement of environmental and workplace health and safety regulations is largely absent.

EEE itself can contain hazardous substances, including toxic metals (e.g., mercury, cadmium, lead) and persistent organic pollutants (polychlorinated biphenyls or PCBs, flame retardants). Open burning at e-waste sites can emit these chemicals, as well as polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) and particulate matter (PM) (An et al., 2014, Tue et al., 2017, Wang et al., 2020). Chemicals found at e-waste sites have been associated with DNA damage, tissue damage, increased glucose levels, reproductive and genital disorders, and carcinogenicity (Ji et al., 2010, Li et al., 2019, McDonald, 2002, Zani et al., 2013). Attention to pollutant exposure and health impacts associated with e-waste recycling has increased (Asante et al., 2012, Bruce-Vanderpuije et al., 2019, Feldt et al., 2014, Moeckel et al., 2020), and stress, body aches, shortness of breath, chest pain, cough and dizziness have been reported among e-waste workers and in neighboring communities (Amphalop et al., 2020, Burns et al., 2016, Li et al., 2008, Ma et al., 2013, Yu et al., 2017).

While PM and metals measurements have been reported at e-waste sites in Ghana and elsewhere (Ackah, 2019, Kwarteng et al., 2020, Laskaris et al., 2019), information on VOCs is scarce. VOCs include a diverse set of chemicals, e.g., formaldehyde, benzene, chloroform, toluene, and ethylbenzene, and they include many known or suspected toxicants that cause irritation to eyes, skin and nose, damage to the respiratory system, liver and kidney; reproductive effects, and cancer (Anderson et al., 2007, Wolkoff et al., 2000, Wolkoff et al., 2006). Several e-waste recycling processes, especially heating and burning, have been reported to produce extremely high concentrations of VOCs, especially aromatic hydrocarbons (An et al., 2014).

This study focuses on VOC exposures at e-waste sites with the overall objective of characterizing levels and exposures to a wide set of VOCs at the Agbogbloshie e-waste site. We used both fixed-site and personal measurements at the e-waste site, as well as measurements at up- and down-wind sites, to identify background levels and evaluate possible effects on neighboring communities. We examined the distributions of VOC concentrations, identified possible sources, and assessed exposure and health risks.