O Impacto da Exposição aos BTEX nos Telômeros dos Trabalhadores de Postos de Combustíveis e as Implicações nas Mudanças Climáticas

Abstract

The composition of gasoline contains the BTEX solvents (benzene, toluene, ethylbenzene, and xylene), with benzene classified as a Group 1 carcinogen in humans by the International Agency for Research on Cancer (IARC). Occupational exposure to benzene poses a significant health risk to fuel station workers, contributing to genomic instability and increasing the risk of cancer development. Several alterations in laboratory parameters have been documented in these workers, including changes in telomere length, telomerase activity, and genotoxic effects. The aim of this study was to evaluate the clinical and genetic impact of these substances on fuel station workers, comparing them with a control group. This cross-sectional study was conducted at five fuel stations near the State University of Rio de Janeiro (UERJ) in the municipality of Rio de Janeiro. Healthy individuals with no prior exposure to BTEX were used as controls. Peripheral blood samples were collected for routine laboratory tests (complete blood count, total and fractionated bilirubin), relative telomere length analysis, telomerase activity quantification, and comet assay. Alterations suggesting reduced mean corpuscular hemoglobin and leukocyte count were observed in the workers' samples, along with subtle changes in monocyte numbers and direct and indirect bilirubin concentrations. No significant differences were observed in the comet assay when comparing directly (n=6) and indirectly exposed workers (n=5), although all individuals exhibited some degree of DNA damage. However, one worker displayed significantly higher DNA damage rates (p<0.05). The relative telomere length (T/S ratio) was measured by quantitative PCR (qPCR) in samples from 58 BTEX-exposed workers and 58 unexposed controls. No significant difference in T/S ratio was found between the groups (p = 0.26), although a subtle elongation of telomeres was noted in the workers’ samples. When stratified by duration of BTEX exposure, workers with prolonged exposure (>100 months) exhibited significantly longer telomeres compared to the unexposed group (p = 0.04). Telomerase activity in leukocytes from exposed workers (n = 9) was found to be eight times higher than in the unexposed group (n = 9), which may account for the observed telomere elongation. Regarding TERRA expression, the subtelomeric region of chromosome 10q demonstrated elevated expression levels in the workers’ samples. These findings suggest that alterations in telomere length may contribute to increased genomic instability in workers occupationally exposed to benzene. The transition from gasoline to biofuels in automobiles is highly recommended to protect the health of these workers and help mitigate the environmental impacts associated with fossil fuel combustion.