Advances in Quantification, Degradation and Ecotoxicology of Microplastics in Marine Resources

Plastic pollution and associated ecological risks are prominent environmental issues in marine resources worldwide. Previous studies have demonstrated that 82% of marine debris' hazardous impacts were associated with plastic pollution. Physical, chemical, and biological aging processes decompose these plastic wastes into miniature fragments, including fibers, fragments, spheres, and particles, referred to as nanoplastics (microplastics (MPs, 1-1000 µm). Compared with MPs could pose more serious ecological risks owing to their small particle size, large surface area, and higher internalization potential. These tiny plastics can adhere to algae and plankton or be ingested by aquatic organisms such as fish, invertebrates, bivalves, and shrimp. A recent review article summarized the MPs abundance in the gills, foot, mantle, intestine, muscle, and visceral mass of bivalves. This study further revealed multifaceted toxicological implications associated with MPs exposure in mussels, including an increase in ROS levels, cytotoxicity, inflammation, and a decrease in filtration activity and lysosomal membrane stability. Moreover, the quantification and treatment methods are still in a developing stage. Regarding quantification and characterization of MPs in marine resources, a large number of studies are available while those for MPs studies are extremely elusive due to challenges in extraction and quantification methods. Moreover, the degradation of large plastic fragments through a variety of mechanisms, including oxidation, biodegradation, photodegradation, hydrolysis, and mechanical abrasion, has also been explored recently in marine resources. A recent study demonstrated the most efficient hypothetical model of the mechanisms responsible for the breakdown of aquatic plastics, namely, (1) biological degradation that includes the biochemical activity of microbes in biofilms, taking place in cracks and crevices on plastics, and (2) physicochemical degradation that primarily includes thermal oxidation (infrared radiation), thermal degradation (visible light), photodegradation (UV-A and UV-B lights), hydrolysis and mechanical abrasion, all of which depolymerize plastic litter into oligomers and monomers. Therefore, highlighting the quantification, degradation and ecotoxicology of microplastics in marine resources is of immense importance and need of the hour.

This Research Topic aims to collect recent cutting-edge studies on recent advancements in extraction and quantification of microplastics in environmental and biological samples from marine resources. Moreover, highlighting the new findings for the treatment of plastic pollution, especially through biological and physicochemical degradation methods, for the abatement of current pollution levels. Last but not least, the ongoing research on the ecotoxicological implications of plastic particles, mainly on nanoplastics both in wild and laboratory animal models, including invertebrates, benthos, fish, and large fauna species, will be an integral part of this Research Topic.

The following subtopics are covered in the Research Topic, but are not limited to
• Extraction, quantification, and characterization of microplastics in environmental and biological samples from marine resources
• New treatment technologies for the removal and degradation of microplastics
• Interaction of microplastics with organic and inorganic pollutants in seawater
• Interaction of microplastics with biomolecules and associated ecological implications
• Ecotoxicology and associated mechanistic pathway of microplastics in the wild and laboratory studies