Urinary concentrations of bisphenol analogues among school-aged children in South China: exposure characterization and risk assessment

Human exposure to bisphenol analogues (BPs) and their health risks have raised increasing concern due to their potential toxicity. However, limited data are available on exposure levels and associated risks in school-aged children. In this study, we quantified 26 BPs in urine samples from 184 school-aged children living in representative rural and urban areas of South China, using a high-throughput, sensitive analytical method. The aim was to assess the co-exposure levels and potential non-carcinogenic risks. The detection frequency (DF) of the total concentration of 26 BPs (∑BPs) was 100.0%. Concentrations of ∑BPs ranged from 0.089 to 45.33 μg/L, with a median of 2.14 μg/L. The predominant compounds were bisphenol A (BPA, median 0.803 μg/L, DF 97.8%), 2,4’-bisphenol S (2,4-BPS, 0.068 μg/L, DF 93.5%), 4,4’-dihydroxytetraphenyl methane (BPBP, 0.041 μg/L, DF 66.3%), and bisphenol F (BPF, 0.033 μg/L, DF 61.4%), accounting for 77.2%, 6.5%, 4.0%, and 3.2% of ∑BPs, respectively. Both the concentration and DF of 2,4-BPS were much higher than those of bisphenol S (BPS, <0.003 μg/L, DF 48.9%), suggesting that 2,4-BPS was the predominant derivative. BPA concentrations were positively associated with family income levels, while 2,4-BPS concentrations were linked to plastic-bottled water consumption. BPF concentrations were associated with both instant noodle consumption frequency and maternal education level. The median estimated daily intakes of BPA, 2,4-BPS, and BPF were 0.035, 0.003, and 0.002 μg/kg-bw/day, respectively. Although non-carcinogenic risk assessments indicated minimal risk, revised tolerable daily intake values suggested potential health concerns for school-aged children. These findings highlight the need for continued monitoring of BPs in susceptible populations, and further research should focus on cumulative risks and exposure sources of BPs.