To monitor employees' work safety and exposure against air contaminants, Trans, trans-muconic acid, Hippuric acid, Methyl hippuric acid, Mandelic acid and Phenylglyoxylic acid can be used as reliable biomarkers of exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) compounds. This study aims to determine the level of urinary metabolites of BTEX compounds using biological monitoring in the employees of a wastewater treatment plant (WWTP) in the south of Iran. The study was performed on 56 employees of the WWTP of one of the southern cities of Iran in 2020. Urine samples (n total = 112) consisting of 60 samples of employees working in the operation section (exposed group) and 52 samples of employees working in the administrative section (control group) in the WWTP were collected before and at the end of their shift. The mean concentration of urinary metabolites of BTEX of both groups ranged from 546.43 (μg/g cr) for trans, trans-muconic acid to 0.006 (μg/g cr) for methyl hippuric acid, which indicates that most of the evaluated metabolites showed a higher concentration than their occupational threshold limit value urine (p < 0.05). Regression analysis results showed a significant correlation (p < 0.05) between age and utilization of flame heaters with changes in the measured BTEX metabolites in the urine. The results of this study illustrate that WWTPs should be considered as one of the workplaces with potential sources of BTEX exposure for employees. Future investigations are recommended to perform itemized appraisals of BTEX intake sources, particularly in employees of the operational sections of WWTP.

Background: Black (BL) individuals living in the United States are more likely to develop hypertension and cardiovascular disease compared to their White (WH) counterparts. However, studies investigating racial differences in blood pressure regulation and baroreflex sensitivity (BRS) are limited and have reported equivocal results. Furthermore, despite BL females also having a high prevalence of hypertension and cardiovascular disease, sex differences are often not considered. Additionally, baroreflex effectiveness index (BEI) is a newer measure used to estimate baroreflex function, yet studies have not examined the influence of sex or race on BEI. Therefore, the purpose of this project was to investigate the effects of both race and sex on cardiac BRS and BEI. We hypothesized that BL individuals would have lower cardiac BRS and BEI than WH individuals. Methods: We studied 88 young healthy adults, 28 BL males (21 ± 3 years; mean ± SD), 17 WH males (24 ± 4 years), 15 BL females (21 ± 3 years), and 28 WH females (23 ± 4 years). Heart rate (ECG) and beat-to-beat arterial blood pressure (finger photoplethysmography) were continuously recorded during a five-minute resting baseline. Cardiac BRS was measured using the Sequence Method, by identifying the gain of the relationship between systolic blood pressure and RRI from sequence(s) of three or more consecutive heartbeats in which systolic blood pressure and RRI change in the same direction. BEI was quantified by baroreflex-driven ramps relative to all systolic blood pressure ramps. Results: Cardiac BRS was significantly higher in BL individuals (31 ± 15 ms/mmHg) compared to WH individuals (25 ± 11 ms/mmHg; main effect of race, p = 0.02). Interestingly, post hoc comparisons revealed that this was only true within the males (p = 0.03), but not females (p = 0.63). However, there was no difference in cardiac BRS between males and females (main effect of sex, p = 0.35) and no interaction between sex and race (p = 0.27). There were also no effects of race (p = 0.65) or sex (p = 0.15) on BEI. Conclusion: These preliminary data suggest that, in contrast to our hypothesis, young BL individuals have higher cardiac BRS compared to WH individuals; an effect that is only present in males. In contrast, BEI was not influenced by race or sex. Collectively, our findings do not suggest that lower cardiac BRS plays a major role in the higher prevalence of cardiovascular disease in BL individuals. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.