A Multi-day Environmental Study of Polycyclic Aromatic Hydrocarbon Exposure in a High-risk Region for Esophageal Cancer in China

Linzhou, China has one of the highest rates of esophageal squamous cell carcinoma in the world. Exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (BaP), may have a role in this increased risk. To better understand PAH sources, we measured PAHs in the air and food of 20 non-smokers over multiple days and compared the concentrations with a urinary PAH biomarker, 1-hydroxypyrene glucuronide (1-OHPG). Sampling occurred over 4 consecutive days. Kitchen air samples (days 2-3) and duplicate diet samples (days 1-4) were analyzed for 14 or more unique PAHs, including BaP. Daily urine samples (days 1-3) were analyzed for 1-OHPG. Mixed-effects models were used to evaluate the associations between air or food PAH concentrations and urine 1-OHPG concentrations. The median kitchen air BaP concentration was 10.2 ng/m(3) (interquartile range (IQR): 5.1-20.2 ng/m(3)). The median daily food BaP concentration and intake were 0.08 ng/g (IQR=0.04-0.16 ng/g) and 86 ng/day (IQR=41-142 ng/day), respectively. The median 1-OHPG concentration was 3.36 pmol/ml (IQR=2.09-6.98 pmol/ml). In mixed-effects models, 1-OHPG concentration increased with same-day concentration of food BaP (P=0.07). Although PAH concentrations in air were not associated with 1-OHPG concentrations, the high concentrations of PAHs in both air and food suggest that they are both important routes of exposure to PAHs in this population. Further evaluation of the role of PAH exposure from air and food in the elevated rates of esophageal cancer in this region is warranted.