Anthropogenic particles (including microfibers and microplastics) in marine sediments of the Canadian Arctic

Jennifer K Adams; Bethany Y Dean; Samantha N Athey; Liisa M Jantunen; Sarah Bernstein; Gary Stern; Miriam L Diamond; Sarah A Finkelstein

doi:10.1016/j.scitotenv.2021.147155

Anthropogenic particles (including microfibers and microplastics) in marine sediments of the Canadian Arctic

Sci Total Environ. 2021 Aug 25:784:147155. doi: 10.1016/j.scitotenv.2021.147155. Epub 2021 Apr 17.

Authors

Jennifer K Adams¹, Bethany Y Dean², Samantha N Athey¹, Liisa M Jantunen³, Sarah Bernstein², Gary Stern⁴, Miriam L Diamond⁵, Sarah A Finkelstein⁶

Affiliations

¹ Department of Earth Sciences, University of Toronto, 22 Ursula Franklin Street, Toronto, Ontario M5S 3B1, Canada.
² Air Quality Processes Research Section, Environment and Climate Change Canada, 6248 Eighth Line, Egbert, ON L0L1N0, Canada.
³ Department of Earth Sciences, University of Toronto, 22 Ursula Franklin Street, Toronto, Ontario M5S 3B1, Canada; Air Quality Processes Research Section, Environment and Climate Change Canada, 6248 Eighth Line, Egbert, ON L0L1N0, Canada.
⁴ University of Manitoba, 586 Wallace Bld, 125 Dysart Rd. Winnipeg, Manitoba R3T 2N2, Canada.
⁵ Department of Earth Sciences, University of Toronto, 22 Ursula Franklin Street, Toronto, Ontario M5S 3B1, Canada; School of the Environment, University of Toronto, 33 Willcocks St., Toronto, Ontario M5S 3E8, Canada.
⁶ Department of Earth Sciences, University of Toronto, 22 Ursula Franklin Street, Toronto, Ontario M5S 3B1, Canada. Electronic address: sarah.finkelstein@utoronto.ca.

PMID: 34088044
DOI: 10.1016/j.scitotenv.2021.147155

Abstract

We report the first Canadian Arctic-wide study of anthropogenic particles (APs, >125 μm), including microfibers (synthetic, semi-synthetic and anthropogenically modified cellulose) and microplastics, in marine sediments from 14 sites. Samples from across the Canadian Arctic were collected between 2014 and 2017 from onboard the CCGS Amundsen. Samples were processed using density separation with calcium chloride (CaCl₂). APs >125 μm were identified and a subset (22%) were characterized using Raman spectroscopy. Following blank-correction, microfiber numbers were corrected using Raman data in a novel approach to subtract possible "natural" cellulose microfibers with no anthropogenic signal via Raman spectroscopy, to estimate the proportion of cellulose microfibers that are of confirmed anthropogenic origin. Of all microfibers examined by Raman spectroscopy, 51% were anthropogenic cellulose, 11% were synthetic polymers, and 7% were extruded fibers emitting a dye signal. The remaining 31% of microfibers were identified as cellulosic but could not be confirmed as anthropogenic and thus were excluded from the final concentrations. Concentrations of confirmed APs in sediments ranged from 0.6 to 4.7 particles g^-1 dry weight (dw). Microfibers comprised 82% of all APs, followed by fragments at 15%. Total microfiber concentrations ranged from 0.4 to 3.2 microfibers g^-1 dw, while microplastic (fragments, foams, films and spheres) concentrations ranged from 0 to 1.6 microplastics g^-1 dw. These concentrations may exceed those recorded in urban areas near point sources of plastic pollution, and indicate that the Canadian Arctic is a sink for APs, including anthropogenic cellulose fibers. Overall, we provide an important benchmark of AP contamination in Canadian Arctic marine sediments against which to measure temporal trends, including the effects of source reduction strategies and climate change, both of which will likely alter patterns of accumulation of anthropogenic particles.

Keywords: Beaufort Sea; Canada; Canadian Arctic Ocean; Cellulose; Microparticle; Plastic.