Children are particularly vulnerable to adverse effects from exposure to environmental chems., necessitating comprehensive assessment to mitigate health risks.In this study, we analyzed 477 serum samples from children aged 2-6 years in North Shandong, China, using liquid chromatog.-mass spectrometry (LC-MS) to create an exposure profile of 184 exogenous chems.These chems. encompass pesticides, pharmaceuticals, industrial and consumer chems., and food additives.Of these, 113 exogenous chems. were identified above the limit of detection in the serum of at least one child participant, and 37 were detected in more than 30% of the children.Notably, 17 of the 24 selected perfluoroalkyl and polyfluoroalkyl substances (PFAS) were detected.PFOA, PFBA, and PFHxS exhibited the highest concentrations, with geometric means of 38.11 ng/mL, 17.39 ng/mL, and 7.35 ng/mL, resp.The elevated levels of short-chain PFBA suggests increased production and environmental release in recent years.Anal. of sex-based differences revealed significant differences in the serum levels of 11 chems., with nine compounds displaying higher concentrations in girls than in boys.Notably, long-chain PFAS, including PFUnDA, PFDA, and PFTrDA, were present at higher concentrations in girls, while short-chain PFHpA and PFBS were higher in boys.Addnl., serum levels of di-Ph phosphate and fipronil sulfone declined slightly with age, indicating heightened exposure risk during early childhood.Pos. associations between monoethyl phthalate and fipronil sulfone concentrations with BMI categories were observed, suggesting a potential obesogenic effect of these compoundsThis study provides critical insights into the profiles of exogenous chems. in young children and highlights the need for targeted risk assessment of environmental pollutants impacting pediatric health.