Microplastics in the Weddell Sea (Antarctica): A Forensic Approach for Discrimination between Environmental and Vessel-Induced Microplastics

• Main Authors: Clara Leistenschneider (11742349), Patricia Burkhardt-Holm (592071), Thomas Mani (640165), Sebastian Primpke (2161900), Heidi Taubner (8319843), Gunnar Gerdts (127866)
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 1753
• Subjects: Medicine; Microbiology; Ecology; Inorganic Chemistry; Space Science; Environmental Sciences not elsewhere classified; Chemical Sciences not elsewhere classified; two antarctic gyres; previously reported values; measured fragments could; global thermohaline circulation; differentiation based purely; sd )) concentrations; ray fluorescence spectroscopy; 04 (± 0; reference paints via; recovered mp derived; 01 (± 0; induced microplastics microplastic; ftir spectroscopy might; reference paints; 01 sd; induced contamination; 1 sd; weddell sea; visual characteristics; subsurface samples; study demonstrates; regions south; putative mp; present study; polar front; n </; ftir spectra; forensic approach; antarctica ): Antarctic; Southern Ocean; Weddell; Weddell Sea; Antarc*; Antarctica
• Online Access: https://doi.org/10.1021/acs.est.1c05207.s001

Microplastic (MP) pollution has been found in the Southern Ocean surrounding Antarctica, but many local regions within this vast area remain uninvestigated. The remote Weddell Sea contributes to the global thermohaline circulation, and one of the two Antarctic gyres is located in that region. In the present study, we evaluate MP (>300 μm) concentration and composition in surface ( n = 34) and subsurface water samples ( n = 79, ∼11.2 m depth) of the Weddell Sea. All putative MP were analyzed by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. MP was found in 65% of surface and 11.4% of subsurface samples, with mean (±standard deviation (SD)) concentrations of 0.01 (±0.01 SD) MP m –3 and 0.04 (±0.1 SD) MP m –3 , respectively, being within the range of previously reported values for regions south of the Polar Front. Additionally, we aimed to determine whether identified paint fragments ( n = 394) derive from the research vessel. Environmentally sampled fragments ( n = 101) with similar ATR-FTIR spectra to reference paints from the research vessel and fresh paint references generated in the laboratory were further subjected to micro-X-ray fluorescence spectroscopy (μXRF) to compare their elemental composition. This revealed that 45.5% of all recovered MP derived from vessel-induced contamination. However, 11% of the measured fragments could be distinguished from the reference paints via their elemental composition. This study demonstrates that differentiation based purely on visual characteristics and FTIR spectroscopy might not be sufficient for accurately determining sample contamination sources.