Substituted Polycyclic Aromatic Hydrocarbons (SPAHs) in Petrochemical Park Workers: External and Internal Exposure Assessment and Half-Lives

Petrochemical industry is responsible for severe contamination by substituted polycyclic aromatic hydrocarbons (SPAHs), posing a significant risk, especially for those occupationally exposed. However, their exposure characteristics and toxicokinetics remain unclear. This study, conducted at a typical petrochemical park in northern China, is the first to systematically integrate biomonitoring data, external exposure assessment, and in vitro experiments to characterize SPAH body burden and total elimination half-lives in workers. Alkylated PAHs (APAHs) (1.86 ± 1.08 ng/mL) were the predominant SPAHs in blood, with concentrations 5.36 and 22.7 times greater than monohydroxylated PAHs (OH-PAHs) (0.347 ± 0.133 ng/mL) and nitrated PAHs (NPAHs) (0.0820 ± 0.0114 ng/mL), respectively. In urine, OH-PAHs (14.4 ± 11.9 ng/mL) exceeded APAHs (4.34 ± 2.82 ng/mL) and NPAHs (0.605 ± 0.384 ng/mL). External exposure assessment also identified APAHs and OH-PAHs, including 1-methylphenanthrene/3,6-dimethylphenanthrene (1-Me-Phe/3,6-DiMe-Phe), 1-methylpyrene (1-Me-Pyr), 3-hydroxybenzo[a]pyrene (3-OH-BaP), 2-hydroxyphenanthrene (2-OH-Phe), and 1-hydroxypyrene (1-OH-Pyr), as dominant contributors (25.3% of total PAH exposure). Estimated total elimination half-lives of representative SPAHs (1-OH-Pyr: 147 days; 3-OH-BaP: 191 days; 1-Me-Phe/3,6-DiMe-Phe: 828 days) may be markedly longer than those in the general population, possibly due to the impaired metabolism under chronic high exposure. Body mass index significantly influenced the SPAH elimination kinetics. This study provides critical insights into assessing the health impacts of SPAHs on highly exposed populations.