Pollution of polycyclic aromatic hydrocarbons (PAHs) in drinking water of China: Composition, distribution and influencing factors.

Polycyclic aromatic hydrocarbons (PAHs) are a kind of persistent toxic substances, which have been frequently detected in environmental media. However, studies on their occurrences and distributions in drinking water are insufficient and their composition profiles in drinking water are still not clear. In this study, we investigated 16 priority polycyclic aromatic hydrocarbons (PAHs) in drinking water from different administrative level cities throughout mainland China, analyzed the influences of anthropogenic activities on PAHs, and assessed the health risk of the PAHs in drinking water. On the national scale, the sum concentration of the 16 priority-controlled PAHs (∑16PAHs) designated by the U.S. Environmental Protection Agency (USEPA) was in a range of 3.89-231.39 (mean 56.25) ng L-1. With the decline of ∑16PAHs, the concentration of 3-ring PAHs decreased, while its proportion increased, indicating 3-ring PAHs might be more difficult to remove than other PAHs in drinking water. The geographical distribution of PAHs in drinking water of China was in a descending order of West (69.81 ng L-1) > South (61.95 ng L-1) > North (58.63 ng L-1) > East (39.21 ng L-1) > Northeast China (37.93 ng L-1). ∑16PAHs in drinking water of Prefecture-level City was the greatest (71.49 ng L-1) followed by Provincial Capital (52.12 ng L-1), County-level City (50.98 ng L-1) and Municipality (33.92 ng L-1). ∑16PAHs was significantly negatively correlated with the per capita GDP of sampling city (P < 0.01, n = 78), implying that waterworks is an effective way to control and reduce PAH pollution in drinking water. The carcinogenic risk of the 16 PAHs in drinking water of China was much greater than the non-carcinogenic risk.