Occurrence and characterization of surface sediment microplastics and litter from North African coasts of Mediterranean Sea: Preliminary research and first evidence

Abstract

The aim of this research work is to investigate the abundance of macroplastics and microplastics from North African coasts of Mediterranean Sea in the Gulf of Annaba (Algeria). The study areas are well known for the high population and high industrial activities that can contribute to the plastic pollution. In this case, microplastics were sampled from the surface sediments at four different stations representing different local activities. The microplastics were extracted by the density separation method from collected samples. Each particle was identified using Fourier transform infrared spectroscopy (ATR-FTIR). Furthermore, beach litters were obtained according to the adopted methodology - guidance on monitoring of marine litter in European seas.The obtained mean concentrations are 182.66 ± 27.32 and 649.33 ± 184.02 kg−1 sediment (DW), respectively. A detailed spatial and quantitative analysis revealed that their distribution was a function of proximity to populated areas and associated with wastewater effluents, industrial installations, degree of shore exposure and complex tidal flow patterns. Five types of microplastics were identified; the most common were fibers (70%), fragments (21%), pellets (5%), films (2%) and foams (2%). Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis showed that the main polymers detected in the studied microplastics were polyethylene (48%), polypropylene (16%), polyethylene terephthalate (14%), polystyrene (9%), butyl branham (7%), ethylene propylene (3%) and cellulose tri acetate (3%).The obtained results provided a holistic view of the abundance, distribution, and characteristics of microplastics in the Gulf of Annaba. This study confirmed the presence of microplastics in the Gulf of Annaba, albeit further studies remain necessary for better understanding of sources and fate.