Polycyclic aromatic hydrocarbons (PAHs) and esophageal carcinoma in Handan-Xingtai district, North China: a preliminary study based on cancer risk assessment.

Abstract

Extremely high risk of esophageal carcinoma (EC) occurs in Handan-Xingtai district of North China. In spite of various preventive measures and epidemiological investigations that have been conducted for years, incidence and mortality of EC are still in the highest level of China. The etiology of EC remains unclear in the region. Previous studies of our research group proposed that polycyclic aromatic hydrocarbons (PAHs) that derived from numerous coal gangue dumps and atmospheric particulates were major contaminants in these regions. In consideration of mutagenic, teratogenic, and carcinogenic characteristics of PAHs, the authors hypothesized that severe exposure to PAHs could preform as a causative factor for EC. Therefore, four data sets documented in our previous studies were employed in this paper. To quantitatively evaluate the carcinogenic risk imposed by sixteen priority PAHs, incremental lifetime cancer risks (ILCRs) via three exposure pathways were calculated. The results showed that total ILCRs for adult group ranged from 2.08E-05 to 8.63E-02, with an average of 2.00E-02. Total ILCRs for childhood group ranged from 1.09E-05 to 4.48E-02, with an average of 1.04E-02. Total ILCR value of 94% samples exceeded 10-4, indicating a particularly high carcinogenic risk to local residents. Furthermore, ingestion and dermal contact conducted as principal pathways of exposing to PAHs for each population group, rather than inhalation. It can be speculated that severely exposing to PAHs may be a pathogenesis of EC in Handan-Xingtai district. The rigorous supervise and governance are imperative to avoid severe exposure to PAHs that derived from coal gangue dumps.