Contaminant Release from Aged Microplastic

Microplastics (MPs) have become one of the most pervasive emerging pollutants in the environment because of their wide occurrence and high sorption ability for contaminants. Sorption and desorption by microplastics may play important roles in the fate of contaminants in aquatic ecosystems. The releasing of these contaminants from plastics into the environment and food chain may pose a greater risk to ecosystem health than the sorption and desorption processes of these contaminants from microplastics after ingestion. To better understand the environmental and ecological impacts of microplastics, there is an urgent need to study the adsorption and desorption behaviors of contaminants and microplastics in the environment. The absorption study of contaminants with microplastics is increasingly being studied. However, there is less knowledge about the release and the impact on the environment of compounds originating from the microplastics themselves. The previously released studies on inorganic and organic contaminants with MPs were reviewed. The contaminants include heavy metals, flame retardant, pesticides, antibiotics, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxin, etc. For heavy metals, it can be released from MPs under higher ionic strength biological fluids such as gut saline, especially for aged MPs. It indicates that the presence of MPs enhanced the bioavailability and toxicity of heavy metals on marine animals. More comprehensive risk assessment is required to study. For other organic contaminants, as the hydrophobic partitioning leads to adsorption between pesticides and MPs. Organic contaminants can therefore be released from MPs through leaching and emission because of lack of chemically bound to the MPs matrix. The research on the interaction between MPs and organic contaminants has been just started. More comprehensive risk assessment is required to study. More attention should be paid to the release and bioavailability study of organic contaminants with MPs. And as closer to our living environment, the combined pollution of soil MPs with contaminants should be paid more attention.