Key Role of Dissolved and Particulate Organic Matter on the Partitioning and Migration of Perfluoroalkyl Acids (PFAAs): A Case Study in the Heavily Polluted Laizhou Bay, China

Abstract

The partitioning behavior of perfluoroalkyl acids (PFAAs) between water and suspended particulate matter (SPM) can significantly influence their migration and fate in aquatic environments, yet the role of natural organic matter, including dissolved organic matter (DOM) and particulate organic matter (POM), in this process has rarely been explored. This study investigated the potential influences of DOM and POM on multiphase distribution process and migration of PFAAs. Results indicated that the origin and humification degree of DOM and POM were different, leading to distinct effects on the partitioning and migration of PFAAs. Overall, DOM inhibited adsorption of PFAAs to SPM, while POM promoted it, with protein-like components playing a more significant role than humus-like components. As the humification degree of DOM increases, its inhibiting effect decreases due to a reduced affinity of DOM components for PFAAs. In contrast, this effect is less pronounced in POM due to its higher humification degree. Furthermore, during the sedimentation of particulate PFAAs, wind can shift their pollution hotspots away from the emission source, probably increasing the spread of ecological risks. These findings indicate that DOM and POM may alter the fate of PFAAs by changing their partitioning, highlighting the need for strategies to prevent potential risks in practice.