The colours of the ocean plastics

Characterisation of the colour is often included in studies on plastic pollution. However, the comparability and relevance of this information is limited by methodology or observer subjectivity. Based on the analysis of thousands of floating plastic fragments from a global collection, here we propose a systematic semi-automatic method to analyse colours by using a reference palette of 120 Pantone colours. The most abundant colours were white and transparent/translucent (47 %), yellow and brown (26 %) and blue-like (9 %). The white colour increased in the smallest pieces (< 5 mm) and far from coastal sources (> 500 km). Both fragmentation and discolouration of ocean plastics may occur because of longer exposure time to sunlight in nature. In addition, yellow items peaked at around 1 cm and brown colours at around 1 mm, supporting the notion that yellowing precedes tanning in the aging process, which is paralleled by fragmentation. Apart from the effects of the weathering, our results suggest a second-order modulation of the colour distributions of marine plastic microplastics by the selective action of visual predators. The present work provides methodological tools and a wide empirical background to further the interpretation and applicability of the colour information on ocean plastics.

Marti, E., Martin, C., Galli, M., Echevarría, F., Duarte, C. M., & Cozar, A. (2020). The colours of the ocean plastics. Environmental Science & Technology. doi:10.1021/acs.est.9b06400

This study is an outcome of Malaspina 2010 expedition (Consolider-Ingenio 2010, CSD2008-00077). E.M. was supported by the Campus de Excelencia Internacional del Mar (CEIMAR) through a PhD Research Project Grant. We received additional support from PLASTREND (BBVA Foundation) and MIDaS (CTM2016- 77106-R,AEI/FEDER/UE) projects. We thank personnel from Malaspina 2010 expedition, MEDSea (EU contract number FP7-2010-265103), TARA Arctic Ocean, MAFIA (Migrants and Active Flux In the Atlantic Ocean), MEGAN (Mesoscale and submesoscale processes in the Strait of Gibraltar: The Trafalgar-Alborán connection), Seagrass and Mangrove Cruise through Red Sea and ETO y NST Cruise along Bay of Biscay, for the help with the sample collection.

American Chemical Society (ACS)

Environmental Science & Technology


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