Mohammad Javad Nematollahi - Department of Earth Sciences, College of Sciences, Shiraz University, Shiraz, Iran
Rolf David Vogt - Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Oslo (UiO), Oslo, Norway
Hassan Nasrollahzadeh Saravi - Caspian Sea Ecology Research Center (CSERC), Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research, Education and Extension Organization (AREEO), Sari, Iran
Farid Moore - Department of Earth Sciences, College of Sciences, Shiraz University, Shiraz, Iran
Behnam Keshavarzi - Department of Earth Sciences, College of Sciences, Shiraz University, Shiraz, Iran

The occurrence of microplastic (MP) particles in shoreline sediments from the coastal region of the southern Caspian Sea, Mazandaran province, Iran, was investigated. A total of 312 MP items were visually detected in 17 sediment samples. The mean abundance of MP particles was 18 items kg-1. The MP particles were mainly fibers, and black color dominated. The dominant size class of MP particles was between 250 and 500 μm. Polyethylene terephthalate (PET), polystyrene (PS), and nylon (NYL) were the major polymers and/or copolymers comprising MP particles in both sediment samples. The number of MP particles in sediment samples showed a general decrease from west to east in the study area. This may be reflecting the spreading of MP loading from the outlets of Sefidrud, Tonekabon, Chalus, the major rivers entering the Caspian Sea just west of the study area, and the overall decrease in the spatial distribution of touristic and fishery activity.

Microplastic (MP), shoreline sediment, Caspian Sea, Mazandaran