Spatial distribution, sources and quantitative human health risk assessments of polycyclic aromatic hydrocarbons in urban and suburban soils of Chile

This work investigated the concentrations and health risks of polycyclic aromatic hydrocarbons (PAHs) found in Chilean soils for the first time. The urban and suburban soils were collected from 28 sampling sites in three regions of Chile: Magallanes (in Punta Arenas commune), Valparaíso and the Santiago metropolitan area. The PAH concentrations, fractions and their potential sources were studied. Statistical analyses using t tests (p < 0.01) showed that (a) PAH concentrations in the urban sites were higher than those in the suburban sites; (b) the presence of anthracene and chrysene was significantly greater in the urban sites than the suburban sites; and (c) the fraction of four-ring PAHs to total PAHs was larger in the urban sites than the suburban sites. The primary PAH source in urban soils was determined to be the combustion of gasoline, grass, wood and coal. In contrast, PAHs in suburban soils were possibly derived from pyrogenic sources (e.g. incomplete combustions). The total cancer risks (TCRs) and the total hazard index (HI) were quantified from 12 PAHs in both urban and suburban soils in terms of cancer and non-cancer risks, respectively. The average TCR of all sites was within an acceptable level (TCR < 10−6), and none of the HIs from any locations were deemed harmful (HI < 1).