Unveiling the landscape of BPS derivatives in urine from eastern and western Chinese population

The widespread use of bisphenol S (BPS) as a substitute for bisphenol A has raised concerns about exposure to its derivatives, a topic largely unexplored in human populations. This study presents an investigation of multiple BPS derivatives in human urine in three cities from eastern and western China. Among the 317 urine samples, we revealed a landscape of widespread co-exposure. The geometric mean concentrations of BPS derivatives were 0.422 ng/mL, 0.548 ng/mL, and 0.376 ng/mL for Wuxi, Chengdu, and Shehong cities, respectively. Significant geographic differences were observed, with higher concentrations in Chengdu than in Shehong (p < 0.05). Demographic factors such as age were remarkably associated with elevated urinary levels, with concentrations generally decreasing as age increased. A nationwide analysis revealed spatial variation across Chinese provinces, with concentrations negatively correlated with compound hydrophobicity. Additionally, estimated daily intakes of BPS derivatives (median: 9.50 ng/kg bw/day) suggest relatively low human exposure. These findings underscore the pervasive and varied exposure to BPS derivatives among the Chinese urban population, shifting the focus beyond BPS itself and highlighting the urgent need for comprehensive risk assessments of bisphenol-based substitutes.