Burial ability of polycyclic aromatic hydrocarbons in different functional lagoons of China

Lagoons provide critical ecological functions but also serve as important sinks for organic contaminants. Understanding the burial of organic contaminants is a primary concern in coastal lagoons. To date the burial of organic contaminants and the related mechanisms in different functional lagoons remain poorly understood. In this study, the burial ability (defined as burial flux/emission density) of sixteen priority polycyclic aromatic hydrocarbons (PAHs) and their drivers were studied in the surface sediments from 37 different functional lagoons of China by considering the sediment properties, climatic conditions, land use, and tidal conditions. The average burial ability of the individual PAHs ranged from 0.01 ± 0.04 to 4.14 ± 4.39 (n = 37) in the lagoon sediments with phenanthrene having the highest value. The burial ability of the PAHs varied with their log K_ow and the lagoon function. The average burial ability of the individual PAHs in different functional lagoons varied as follows: natural lagoons (0.01 - 5.71) > maricultural lagoons (0.03 - 3.15) ≈ harbor lagoons (0.002 - 3.08) > estuarine lagoons (ND - 2.58). The burial ability of the PAHs in the sediments of natural lagoons was related to the particle deposition process and the land use. The burial ability of low- and high-hydrophobic PAHs was correlated with the contents of total phosphorus and organic matter in the maricultural lagoons, respectively. Fine particles and organic carbon affected the burial ability of the PAHs in the sediments from the harbor lagoons. Ocean tides hindered the stable burial of the PAHs in the sediments from estuarine lagoons. The findings provide comprehensive insights into the burial of organic contaminants in coastal lagoons.