Internal biomarkers and external estimation of exposure to polycyclic aromatic hydrocarbons and their relationships with cancer mortality in a high cancer incidence area.

This study aimed to evaluate internal biomarkers and external estimation of exposure to polycyclic aromatic hydrocarbons (PAH) in a high cancer mortality area in southeast China and identify which of these showed a stronger association of PAH with cancer mortality. A retrospective death survey was conducted to determine the mortality rate of cancer. Cumulative and aggregate external exposures to PAHs of local residents were estimated by field sampling. Three regions in southwest China with gradient PAH exposure levels from high to low (H, M, and L) were selected in this study. Research participants were selected from these three regions using a statistical sampling method. To determine the internal exposure, urinary OH-PAHs were measured using the first morning urine samples. From the retrospective death survey, the highest age-standardized lung cancer mortality rate occurred in Region H (78 per 100,000 person-years), followed by that in Regions M (33 per 100,000 person-years) and L (15 per 100,000 person-years), and the rate was nearly four times China's national mortality rate (20 per 100,000 person-years). Residents estimated daily aggregate exposure doses per unit body weight to carcinogenic benzo(a)pyrene equivalent concentration were 159 ± 14 ng-kg-1-day-1, 7.41 ± 2.76 ng-kg-1-day-1, and 6.13 ± 2.89 ng-kg-1-day-1 in Region H, M, and L, respectively. The participants in Region M had the greatest urinary OH-PAH concentration (9.10 ± 4.92 μg-g-1 crt), followed by Region H (8.01 ± 4.22 μg-g-1 crt) and L (7.12 ± 3.10 μg-g-1 crt). The spatial difference in the total OH-PAHs was not statistically significant. Aggregate and cumulative exposure to 16 PAHs from external routes were found, and external exposure had a stringer relationship with lung cancer mortality than internal exposure.