Microplastic contamination in the sediments of Qarasu estuary in Gorgan Bay, south-east of Caspian Sea, Iran

Sci Total Environ. 2022 Sep 10;838(Pt 1):155913. doi: 10.1016/j.scitotenv.2022.155913. Epub 2022 May 13.

Abstract

Given the important ecological role of estuaries and implications of microplastics (MPs) in ecosystems, we assessed the occurrence, abundance, size, and polymer types of MPs present in the sediments of the Qarasu estuary in 2019. MPs were extracted from sediments by density separation, after which they were detected under a stereomicroscope and considered according to shape, size and color. Identification was implemented using Fourier-Transform Infrared Spectroscopy (FT-IR). The abundance and size of MPs in the samples ranged between 40 and 460 particles/kg and 200-5000 μm, respectively. The dominant shape of MPs was fiber (72%), followed by fragment (26%) and film (2%). Black and white were the most abundant colors with 48% and 29%, respectively. In total, 4 MPs polymers including polypropylene (33%), polyethylene (24%), polyamide (21%), and polystyrene (14%) were identified. Results from PCA showed that stations with a high abundance of microplastics had a significant correlation with the amount of clay.

Keywords: FT-IR; Grain size; Microplastic pollution; Qarasu estuary.

MeSH terms

  • Bays
  • Caspian Sea
  • Ecosystem
  • Environmental Monitoring
  • Estuaries
  • Geologic Sediments / chemistry
  • Iran
  • Microplastics*
  • Plastics / chemistry
  • Spectroscopy, Fourier Transform Infrared
  • Water Pollutants, Chemical* / analysis

Substances

  • Microplastics
  • Plastics
  • Water Pollutants, Chemical