Occurrence status, source analysis and risk assessment of polycyclic aromatic hydrocarbons in intertidal surface sediments of typical mangrove wetlands in Guangxi Province, China.

This study investigated the occurrence status, sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in sediments from three typical mangrove areas in Guangxi Province, China. Results showed that the PAH content in the three studied regions ranged from 39.76 ng·g^-1 to 164.93 ng·g^-1, and the average concentration was 92.87 ng·g^-1. The PAHs that were detected were mainly 3-ring and 4-ring. The source of PAHs, as traced by the diagnostic ratio method and principal component analysis, was mainly from combustion. The toxicity risk assessment showed that the content of all PAHs was lower than the Effects Range Low (ERL), and the potential ecological risk was low. The toxicity equivalent (TEQ_BaP) content ranged from 4.75 ng·g^-1 to 19.20 ng·g^-1, with an average of 12.08 ng·g^-1. Overall, the ecological risk of PAHs in mangrove sediments in Guangxi is considered low.