Current advances in microplastic contamination in aquatic sediment: Analytical methods, global occurrence, and effects on elemental cycling

The ubiquitous presence of microplastics in aquatic sediment represents an anthropogenic stressor on benthic organisms and elemental cycling. However, a comprehensive understanding of the identification methods, global distribution, and their effects on elemental cycling in aquatic sediment is still lacking. Identification methods and concentrations of microplastics in sediment were compiled from 185 peer-reviewed articles by searching the Web of Science with keywords "microplastic", "identification", and "sediment" during 2013-2022. Microscopy and infrared spectroscopy were predominantly used for detecting microplastics in the sediment. China and the United States were the research hotspots. Microplastics can influence carbon cycling directly by impacting the carbon storage in sediment or indirectly by affecting the activities of microbial communities and benthic organisms. Additionally, the effects of microplastics on elemental cycling were closely related to the type, size, concentration, and exposure time of microplastics. Future studies are still needed to explore the long-term effects of microplastics on the elemental cycling in aquatic ecosystems.