Development and application of an LC-MS/MS method for urinary DNA adduct profiling in residents of environmentally vulnerable areas

DNA adducts, formed by the covalent binding of reactive electrophiles to DNA, serve as biomarkers of genotoxic exposure and early biological effects. However, non-invasive, high-throughput biomonitoring methods remain underdeveloped. This study developed and validated a robust LC-MS/MS method for simultaneous quantification of six urinary DNA adducts and applied it to assess environmental exposure among residents of polluted and control areas. A novel LC-MS/MS method was established to analyze six urinary DNA adducts. Method validation included assessments of linearity, sensitivity, accuracy, precision, matrix effects, and recovery. Urine samples from 953 environmentally exposed and 204 control residents were analyzed. DNA adduct levels were compared using multivariable regression models adjusted for potential confounders. The method demonstrated excellent performance (R² ≥ 0.994, accuracy 98.5-100.6 %, and minimal matrix effects). Exposure area residents had significantly higher N3-methyladenine (β = 0.548, p < 0.001) and N6-methyl-2'-deoxyadenosine (β = 0.207, p = 0.030) levels than controls. N3-methyladenine and N6-methyl-2'-deoxyadenosine levels were significantly elevated among subjects residing near a coal-fired power plant, a crowded area of factories, and a high particulate matter exposure area compared to controls. However, N3-methyladenine levels were also significantly higher in an abandoned smelter or metal mine, and a cement factory, whereas N6-methyl-2'-deoxyadenosine levels were notably elevated in an operating smelter and waste incinerator, indicating distinct patterns by exposure source. The developed LC-MS/MS method enables sensitive, non-invasive detection of multiple urinary DNA adducts and supports their application as biomarkers for environmental exposure. The findings highlight the potential of urinary DNA adduct profiling for environmental exposure surveillance.