Fragmentation of plastic objects in a laboratory seawater microcosm

Jan Gerritse*, Heather A. Leslie, Caroline A. de Tender, Lisa I. Devriese, A. Dick Vethaak

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


We studied the fragmentation of conventional thermoplastic and compostable plastic items in a laboratory seawater microcosm. In the microcosm, polyurethane foams, cellulose acetate cigarette filters, and compostable polyester and polylactic acid items readily sank, whereas polyethylene air pouches, latex balloons, polystyrene foams and polypropylene cups remained afloat. Microbial biofilms dominated by Cyanobacteria, Proteobacteria, Planctomycetes and Bacteriodetes grew on the plastics, and caused some of the polyethylene items to sink to the bottom. Electrical resistances (ER) of plastic items decreased as function of time, an indication that seawater had penetrated into microscopic crevices in the plastic that had developed over time. Rate constants for ER decrease in polyethylene items in the microcosm were similar to tensile elongation decrease of polyethylene sheets floating in sea, measured previously by others. Weight loss of plastic items was ≤ 1% per year for polyethylene, polystyrene and polypropylene, 3–5% for latex, polyethylene terephthalate and polyurethane, 15% for cellulose acetate, and 7–27% for polyester and polylactic acid compostable bags. The formation of microplastics observed in the microcosm was responsible for at least part of the weight loss. This study emphasizes the need to obtain experimental data on plastic litter degradation under conditions that are realistic for marine environments.

Original languageEnglish
Article number10945
Pages (from-to)1-6
Number of pages16
JournalScientific Reports
Issue number1
Early online date2 Jul 2020
Publication statusPublished - 1 Dec 2020


This project received funding from the European Union Seventh Framework Program (FP7/2007-2013) under grant agreement n° 308370 CleanSea and the SO of Deltares. Caroline De Tender received a grant of FWO with application number 12S9418N. We thank Martin van Velzen, Department of Environment and Health, VU University Amsterdam for the qualitative analysis of microplastics.

FundersFunder number
European Union Seventh Framework Program
Fonds Wetenschappelijk Onderzoek12S9418N


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