Effect of low-concentration benzene, toluene, and xylene exposure on blood pressure of workers in a petroleum refining enterprise

Abstract

BackgroundWorkers engaged in benzene-exposed or benzene-containing solvent-exposed operations in China are predominantly subjected to a low concentration of benzene series compounds, and prolonged exposure to low concentrations of benzene, toluene, and xylene (BTX) may have implications for blood pressure. ObjectiveTo investigate the influence of low-concentration BTX exposure on the blood pressure of workers, aiming to provide a basis for enterprises to devise associated health management strategies to mitigate the occurrence of hypertension among workers exposed to low concentrations of BTX. MethodsUsing a cross-sectional design, 884 workers from a petroleum refining enterprise in Hainan who participated in an occupational health examination in 2022 were selected as the study population, and were divided into an exposure group of 649 workers and a control group of 235 workers based on their reporting of BTX exposure or not. Data on workplace BTX concentrations and health examinations of the study subjects were collected and questionnaires were administered. In addition, S-phenylmercapturic acid (S-PMA), hippuric acid (HA), and methyl hippuric acid (MHA, including the three isomers 2-MHA, 3-MHA, and 4-MHA) were measured in the urine of the workers using high-performance liquid chromatography-tandem triple quadrupole mass spectrometry to assess internal BTX burden. The effects of low-concentration BTX exposure on blood pressure were analyzed. ResultsIn 2022, the concentrations of benzene, toluene, and xylene of all monitoring points did not exceeded the national limits by either time-weighted average (TWA) or short-term exposure limit (STEL), indicating low-concentration BTX exposure. Regarding the internal burden of BTX, the concentrations of benzene metabolite S-PMA, toluene metabolite HA, and xylene metabolites 3-MHA and 4-MHA in the urine samples in the exposure group were higher than those in the control group (P 35 years, male, overweight and obese workers was significantly higher than that of age ≤ 35 years, female, and underweight workers, and the diastolic blood pressure of age > 35 years, work years > 5 years, and obese workers was higher than age ≤35 years, ≤5 years of service, and underweight workers. Low-concentration BTX exposure was one of the main influencing factors for elevated diastolic blood pressure, and the exposed workers showed a 1.337 mmHg increase in diastolic blood pressure compared to the control group (P 5 years, and obesity may elevate blood pressure among petroleum refininig workers. Regular blood pressure monitoring and enhanced health interventions for this occupational group are warranted.

Keywords

• occupational exposure
• benzene
• toluene
• xylene
• blood pressure