Abstract With the strengthening of source control of benzene in China, occupational benzene exposure in workplaces has gradually shifted to long-term low-concentration exposure. The chronic toxicity caused by long-term low-concentration occupational benzene exposure, especially hematotoxicity and carcinogenic effects, has become a core concern in the field of occupational health. Benzene is a human carcinogen, and its health hazards and toxicological mechanisms have received much attention. Studies have shown that benzene is metabolized in vivo by cytochrome P450 enzyme system to generate active products such as hydroquinone and benzoquinone, which induce reactive oxygen species (ROS) accumulation and trigger oxidative stress, leading to lipid peroxidation, abnormal protein oxidative regulation, DNA damage, and epigenetic modifications, ultimately mediating chronic toxic effects. This paper systematically reviewed the key mechanisms of oxidative damage caused by long-term low-concentration occupational benzene exposure, such as ferroptosis-mediated lipid peroxidation, p53/nuclear factor-κB pathway oxidative regulation, and DNA oxidative damage repair disfunction, focused on summarizing oxidative stress-related biomarkers such as 8-hydroxydeoxyguanosine, exosomal miR-34a, and heat shock proteins 90α, and summarized the current problem of insufficient specificity of biomarkers for low-concentration exposure. Future research needs to focus on multi-omics combined biomarker development, oxidative damage intervention technology, and wearable monitoring equipment application, so as to provide the evidence for early warning and occupational health protection against low-concentration benzene exposure.

Objective:To establish a method for the determination of triclocarban (TCC) and triclosan (TCS) in urine by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) after purification by QuEChERS.Methods:In May 2022, urine samples were extracted by acetonitrile, purified by QuEChERS, separated by Waters Acquity UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm), and eluated with water-acetonitrile as mobile phase gradient at a flow rate of 0.3 ml/min. The detection was conducted in negative ion mode (ESI -) and multiple reaction monitoring (MRM) scanning, it was quantified with a internal standard method, and the methodology was verified. Results:The linear ranges of TCC and TCS were 0.5-100.0 μg/L and 1.0-100.0 μg/L, and the correlation coefficients were 0.9997 and 0.9991, respectively. The limits of detection and quantitation of TCC and TCS were 0.17 and 0.33 μg/L, and 0.5 and 1.0 μg/L, respectively. The recoveries of TCC and TCS were 100.1%-102.8% and 96.7%-108.6%, and the relative standard deviations were 4.9%-6.7% and 4.1%-8.3%, respectively, at 2.0, 10.0 and 80.0 μg/L.Conclusion:QuEChERS-UPLC-MS/MS method is simple, rapid, sensitive and reproducible, and can be used for rapid and accurate simultaneous detection of TCC and TCS exposure levels in occupational population.

Objective:To establish a method for the determination of triclocarban (TCC) and triclosan (TCS) in urine by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) after purification by QuEChERS.Methods:In May 2022, urine samples were extracted by acetonitrile, purified by QuEChERS, separated by Waters Acquity UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm), and eluated with water-acetonitrile as mobile phase gradient at a flow rate of 0.3 ml/min. The detection was conducted in negative ion mode (ESI -) and multiple reaction monitoring (MRM) scanning, it was quantified with a internal standard method, and the methodology was verified. Results:The linear ranges of TCC and TCS were 0.5-100.0 μg/L and 1.0-100.0 μg/L, and the correlation coefficients were 0.9997 and 0.9991, respectively. The limits of detection and quantitation of TCC and TCS were 0.17 and 0.33 μg/L, and 0.5 and 1.0 μg/L, respectively. The recoveries of TCC and TCS were 100.1%-102.8% and 96.7%-108.6%, and the relative standard deviations were 4.9%-6.7% and 4.1%-8.3%, respectively, at 2.0, 10.0 and 80.0 μg/L.Conclusion:QuEChERS-UPLC-MS/MS method is simple, rapid, sensitive and reproducible, and can be used for rapid and accurate simultaneous detection of TCC and TCS exposure levels in occupational population.