Atmospheric occurrences of nitrated and hydroxylated polycyclic aromatic hydrocarbons from typical e-waste dismantling sites

Abstract

Primitive electronic waste (e-waste) dismantling activities have been shown to be an important emissions source for a variety of toxic organic compounds, including carcinogenic polycyclic aromatic hydrocarbons (PAHs). Previous studies have found that some nitrated PAHs (NPAHs) are more toxic than their parent PAHs, however, little attention has been paid to the formation of PAH derivatives during e-waste processing and there is a lack of comprehensive data from field observations. In this study, the spatial distribution, temporal trends and atmospheric fate of NPAHs and hydroxylated PAHs (OH-PAHs) were investigated at typical e-waste dismantling sites, with monitoring data collected over three consecutive years. Compared to background levels, higher levels of NPAHs and OH-PAHs were found in air samples from an e-waste dismantling industrial park, with their seasonal and annual changes shown to be affected by e-waste dismantling activities. Atmospheric PM2.5 particles were found to have high relative abundances of NPAHs (76.9%–95.1%) and OH-PAHs (73.3%–91.6%), with particle-bound concentrations ranging from 20.1 to 88.8 and 37.1 to 107 pg m−3, respectively. The most abundant NPAH isomers were found to be 9-Nitroanthracene and 2-Nitrofluoranthene, while OH-PAH isomers containing 2–4 rings were predominant. Source identification was performed based on the specific diagnostic ratios of NPAH isomers, confirming that NPAH and OH-PAH emissions have multiple sources, including emissions related to the e-waste dismantling process, atmospheric photochemical reactions and traffic emissions. Further research on the fate of such derivatives and their potential use as markers for source identification, is urgently required.