Distribution, sources, and health risk of polycyclic aromatic hydrocarbons and their derivatives in the watershed: the case of Yitong River, China

Polycyclic aromatic hydrocarbons (PAHs) and substituted PAHs (SPAHs) are persistent organic pollutants prevalent globally, and SPAHs have received widespread attention in recent years due to their stronger toxicity and carcinogenicity compared to PAHs. There is a lack of systematic examination of PAHs and their derivatives in watersheds. Thus, to clarify the current status, possible sources, and potential risks of PAHs and their derivatives in watersheds, a study was conducted on Yitong River in China. The results showed that the concentrations of Sigma PAHs, Sigma OPAHs, and Sigma NPAHs ranged from 297.9-1158.3 ng/L, 281.1-587.2 ng/L, and 65.7-269.1 ng/L, respectively. Diagnostic ratio analysis showed that the PAHs were mainly derived from petroleum sources, agricultural waste, and coal combustion. Nitrated PAHs (NPAHs) were mainly derived from liquid combustion sources, and oxygenated PAHs ( OPAHs) were derived mainly from petroleum source emissions and atmospheric deposition. The exposure risk model of PAHs revealed that 86% of the studied sites would pose carcinogenic risks after dermal contact. The contaminant causing a major carcinogenic risk was DahA, and none of the sites produced non-carcinogenic risks. The lifetime carcinogenic risk of NPAHs was 8.85 x 10(-10)-1.44 x 10(-4), and some surface waters presented with potential carcinogenic risks.

Automated summary

PAHs and SPAHs are persistent organic pollutants found globally. SPAHs have attracted more attention recently due to their higher toxicity and carcinogenicity compared to PAHs. However, there is a lack of systematic examination of these compounds in watersheds. This study aimed to investigate the current status, possible sources, and potential risks of PAHs and their derivatives in the Yitong River, China. The results revealed petroleum sources, agricultural waste, and coal combustion as the main contributors to PAHs, while liquid combustion sources and petroleum emissions accounted for NPAHs and OPAHs, respectively. The exposure risk model indicated a significant carcinogenic risk in 86% of the studied sites after dermal contact, primarily due to the presence of DahA. Despite this, non-carcinogenic risks were not observed, and some surface waters showed potential carcinogenic risks from NPAHs.