摘要

Human exposure to various N,N′-substituted p-phenylenediamine-derived quinones (PPDQs) has been of increasing concern. Recent studies have examined N-phenyl-N′-(1,3-dimethylbutyl)-p-phenylenediamine-derived quinone (6PPDQ) in human urine to evaluate human exposure. However, other PPDQs in human urine have not been thoroughly investigated. This study analyzed six PPDQs in urine collected from 149 healthy individuals in Taizhou, China. All target PPDQs were detected, with 6PPDQ (mean 2.4 ng/mL, <limit of detection (LOD)–19 ng/mL) and 2-(cyclohexylamino)-5-(phenylamino)cyclohexa-2,5-diene-1,4-dione (CPPDQ; 2.1 ng/mL, <LOD–24 ng/mL) being the most prevalent. Human urinary concentrations of 2,5-bis((5-methylhexan-2-yl)amino)cyclohexa-2,5-diene-1,4-dione (77PDQ; mean 1.5 vs. 0.87 ng/mL; p = 0.013) and 2,5-bis(o-tolylamino)cyclohexa-2,5-diene-1,4-dione (mean 1.1 vs. 0.62 ng/mL; p = 0.027) were significantly higher in females compared to males. For CPPDQ (p < 0.01) and 6PPDQ (p < 0.01), a decrease was observed in urinary concentrations as participants aged. The daily excretion (DE) of PPDQs through urine was estimated for Chinese adults. The highest average DE was recorded for 6PPDQ at 81 ng/kg-bw/day, with a range from <0.5 to 475 ng/kg-bw/day. Following this, CPPDQ had a mean DE of 68 ng/kg-bw/day (range <0.5–516 ng/kg-bw/day), and 77PDQ had a mean DE of 30 ng/kg-bw/day (<0.5–481 ng/kg-bw/day). This study is the first to explore the presence of various PPDQs in human urinary samples, which is essential for assessing the potential health risks associated with these substances.

Widespread detection of xanthate vulcanization accelerators (XVAs) in various dust samples underscores the inherent risk of their human exposure. Notably, comprehensive investigations into the presence and concentrations of XVAs in human urine, a medium particularly suited for calculating human exposure, are still lacking. To address this knowledge gap, we conducted a systematic examination of eight XVA homologues in urine specimens obtained from 218 healthy adults residing in urban Taizhou City, China. We found that all targeted XVA compounds were identified in collected human urine samples, with potassium butylxanthate (KBX; mean 32 ng/mL, range < LOD-120 ng/mL) and potassium amylxanthate (KAX; 26 ng/mL, < LOD-91 ng/mL) exhibiting the highest mean urinary levels. Males consistently demonstrated higher mean urinary concentrations of KAX, potassium propylxanthate (KPX), and potassium ethylxanthogenate (KEX) compared with females, though these differences did not reach statistical significance. Notably, age-related decreases in human urinary concentrations were observed for KAX, KBX, and KEX. The highest daily exposure (DE) was recorded for KBX at the average level of 906 ng/kg bw/day, ranging from < 38-3056 ng/kg bw/day. KAX exhibited a mean DE of 718 ng/kg bw/day (< 14 -2048 ng/kg bw/day), while KPX showed a mean DE of 403 ng/kg bw/day (< 26 -213 ng/kg bw/day). As the first comprehensive analysis of XVAs in human urine samples, this research establishes fundamental exposure data essential for evaluating their health implications.