Abstract
Polycyclic aromatic hydrocarbons （PAHs） are a class of persistent organic pollutants that are widely present in various environmental media such as air， soil， and water. They are highly environmentally stable and are mainly derived from combustion processes and industrial emissions. Although numerous studies have shown that PAHs are carcinogenic， mutagenic， and neurotoxic， their exposure levels and associated health risks in specific populations require further study. Children and adolescents are in a critical stage of growth and development， with immature physiological and immune systems， making them more sensitive to PAHs than adults. Hence， their internal exposure levels to PAHs and the associated health risks warrant particular attention. However， most of the existing studies have focused on adults， and there are relatively few studies on PAHs exposure in children and adolescents. Therefore， a total of 1 096 children and adolescents aged 6-18 years in a city located in western China were investigated. The concentrations of 12 PAHs in serum samples were simultaneously determined by solid-phase extraction coupled with gas chromatography-tandem mass spectrometry （SPE-GC-MS/MS）， and the effects of demographic characteristics， lifestyles， socioeconomic factors， and dietary habits on the concentrations of PAHs in serum were investigated using multiple linear regression models. The total estimated daily intake （TEDI） of PAHs was calculated based on their serum concentrations， and the hazard quotient （HQ） was derived using the reference dose （RfD） to evaluate non-carcinogenic health risk. Meanwhile， carcinogenic risk was evaluated based on the benzo［a］pyrene equivalent （BaPeq） concentrations. The results showed that six PAHs were detected in the serum of more than 50% of children and adolescents， in descending order， with anthracene （Ant） （87.2%）， phenanthrene （Phe） （76.3%）， fluorene （Flu） （69.3%）， acenaphthene （Acp） （62.1%）， pyrene （Pyr） （54.3%）， and acenaphthylene （AcPy） （53.7%）. Phe showed the highest median mass concentration of 3.03 ng/mL. Age was positively associated with serum concentrations of all six PAHs （AcPy： β=0.097， 95% CI： 0.033-0.160； Acp： β=0.103， 95% CI： 0.032-0.174； Ant： β=0.056， 95% CI： 0.016-0.097； Flu： β=0.085， 95% CI： 0.009-0.162； Phe： β=0.098， 95% CI： 0.029-0.167； Pyr： β=0.136， 95% CI： 0.078-0.195）； overweight and obese participants exhibited lower levels of AcPy （β=-0.538， 95% CI： -1.022- -0.053） and Acp （β=-0.566， 95% CI： -1.104- -0.028）； lower PAHs levels were also found in children and adolescents from families with higher maternal education； higher frequency of vegetable intake was positively associated with Acp （β=0.088， 95% CI： 0.012-0.165）， while higher milk intake was inversely associated with AcPy （β=-0.072， 95% CI： -0.145- -0.000）， Acp （β=-0.087， 95% CI： -0.167- -0.007） and Phe （β=-0.095， 95% CI： -0.173- -0.017）； the use of water cooler jug was positively linked to serum levels of Ant （β=0.462， 95% CI： 0.149-0.774） and Phe （β=0.898， 95% CI： 0.367-1.428）. HQ values for Pyr were all less than 1， indicating that the level of Pyr exposure in the serum is insufficient to pose a significant non-carcinogenic health risk. The carcinogenic risk assessment revealed that Ant and Phe were the major individual compounds contributing to the carcinogenic risk posed by PAHs exposure in children and adolescents， accounting for 85% of the total BaPeq concentration. In summary， exposure to PAHs is common among children and adolescents in this region. Age， body mass index （BMI）， maternal education level， and diet may be the main factors influencing serum PAHs concentrations. The overall non-carcinogenic risk among the studied population was low， and Ant and Phe were identified as the individual compounds with the greatest carcinogenic potential. These findings highlight the need for strengthened monitoring and targeted health interventions regarding long-term， low-dose PAHs exposure in children and adolescents.