Exploring the influence of water exchange on the distribution of polycyclic aromatic hydrocarbons in marine sediments by numerical calculation model

Abstract Polycyclic aromatic hydrocarbons (PAHs) are one of the most important pollution factors in the marine environment. It is significant to expound their distribution in the complex marine environment for pollution prevention and control. In our previous research, we found that water exchange of PAHs has an important influence on their concentration distribution in sediments. With the help of Delft3D technology, a multi-process coupled dynamic model of PAHs was constructed, being based on the survey data of Liaodong Bay from May to June 2015. The water exchange rate of PAHs was calculated and studied by using mathematical statistics and numerical simulation. The results showed that the half water exchange time of PAHs in Liaodong Bay is about 57–580 days. The water exchange rate of PAHs has a significant influence on their concentration distribution of PAHs in sediments. Where there is a high water exchange rate, there the concentration of PAHs in sediment was relatively low. The closer areas are to bay-head, the lower the water exchange rate, and the easier leading to the formation of high concentration areas of PAHs in the sediments.