Inhalation bioaccessibility of polycyclic aromatic hydrocarbons in heavy PM pollution days: Implications for public health risk assessment in northern China.

Abstract

Airborne (PM) with aerodynamic diameter ≤ 2.5 μm was collected from 4 types of cities in northeast China during the heating period. The objectives of this study were to assess the concentrations variation of PM-bound 12 carcinogenic polycyclic aromatic hydrocarbons (PAH), to study the influence of simulated lung fluids on bioaccessibility of PAH and to estimate the variation of lifetime excess cancer risk to the residents, artificial lysosomal fluid (ALF) and Gamble's solution were used. The number of lifetime excess cancer cases (determined by California Environmental Protection Agency method) as a result of PAH exposure (total concentration) was 4.00-430 (provincial central cities), 24.0-261 (energy-mining cities), 17.0-109 (forested city), and 20.0-69.0 (agricultural city) per million people, which relatively corresponded to a 92.2% and 96.2%, 92.6% and 97.3%, 92.2% and 94.2%, and 86.5% and 92.6% decrease after considering bioaccessibility following 24-h of Gamble's solution and ALF extraction, respectively. Phenanthrene (Phe), dibenz[a,h]anthracene (DahA) and benzo[a]pyrene (BaP) were found to be the most bioaccessible types of PAH after the Gamble's solution and ALF extraction in the PM samples from all the studied cities. Based on the point-estimate approach, short-term predictions of pulmonary toxicity caused by potential inhalation of airborne PM into the pulmonary system might be overestimated if bioaccessibility of PM-bound PAH is not fully evaluated.