Microplastic contamination in the western Arctic water column: A transition from pristine to polluted

The Arctic Ocean, once regarded as a pristine and untouched icy expanse, now faces an increasing threat from microplastic (MPs, <5 mm) pollution. This study presents quantitative data on MP contamination in the water column of the western Arctic Ocean. A total of 324 replicate water samples were collected using a CTD (Conductivity, Temperature, and Depth) rosette sampler from depths ranging from 9 to 297 m. The isolated MPs were analyzed using micro-Fourier Transform Infrared Spectroscopy (μ-FTIR). The average abundance of MP was 0.06 particles L^-1, and the Beaufort Sea station (BFS 26) recorded the highest concentration (0.22 particles L^-1). Blue-coloured and fibrous nature, small MPs (<500 μm) primarily composed of polyolefins were dominant. The distribution of MPs in the water column was as follows: Polar Mixed Layer (59 %), Pacific or Atlantic halocline (22 %), and the Intermediate layer of Atlantic water (19 %). This study provides valuable insights into the vertical distribution of MPs, their characteristics, and the probable sources of the influx of MPs into this region.