EXPLOPE (2021-2023)

Exploring the environmental occurrence and links between organophosphate esters additives and micro-plastics in sediments and benthic organisms from the Loire estuary

Coordination Ifremer

Type de projet


 Durée du projet


J. Castro-Jiménez


Ifremer DS (Politique de Site)


Organophosphate ester (OPE) flame retardants and plasticizers are organic plastic additives and contaminants of emerging concern. Due to their physical-chemical properties, most OPEs exhibit a strong tendency to bind with carbon-rich suspended particulate matter, accumulating in sediments. Marine sediments are also final repositories of micro-plastics (MPs). Determining the environmental occurrence in sediments of both MPs and their additives thus becomes crucial to better understand their current stocks, potential transfer to benthic communities, and possible impacts on the global functioning of marine ecosystems. The Loire estuary represents an ecosystem of high ecological value as well as an ocean/land interface for sea trade and associated industrial activities. Despite the presence of major cities and other potential sources in the catchment area, the presence of MPs is poorly documented in the area, and no data on the occurrence and environmental levels of OPEs is available in the Loire estuary sediments and/or benthos.

The main objectives of the project EXPLOPE are:

  1. to determine the current concentrations of OPEs and micro-plastics (MPs) in sediments and benthic organisms from the estuary;
  2. to investigate the OPE bioaccumulation (transfer sediment-benthos);
  3. to explore the links between MPs abundance and OPE concentrations in both compartments.

Personnels Ifremer
Les partenaires

CCEM  : Y. Aminot, C. Pollono, N. Bely, B. Idjaton
LER-MPL : L. Bizzozero, O. Pierre-Duplessix

Université Gustave Eiffel : J. Gasperi


Résultats :

Two sampling campaigns were conducted in the Loire Estuary, in September 2021 and February 2022, allowing the collection of surface sediments and the bivalve mollusk Scrobicularia plana in four intertidal zones subjected to different anthropogenic pressures:

  • First results confirmed the overall occurrence of OPEs (for the first time) and microplastics in sediments and Scrobicularia plana in the study area.
  • Higher levels of both families of contaminants of emerging concern were measured in the zones under industrial and petrochemical pressures, with no seasonal variations observed.
  • Microplastic fragments of less than 500µm predominated in sediments and polyethylene (PE) was the most abundant polymer found in both sediments and Scrobicularia plana.
  • Tris(2-ethylhexyl) phosphate (TEHP) and its degradation metabolite (BEHP) and tris-(2-chloro, 1-methylethyl) phosphate (TCIPP) were the most abundant OPEs in sediments, and TCIPP showed a clear predominance in the benthic organism.
  • The estimated biota-sediment accumulation factors (BSAFs) indicate the potential bioaccumulation of chlorinated-OPEs (the most toxic ones).
  • A preliminary investigation of the correlations between the concentrations of OPEs and the abundance of microplastics in sediments suggested the potential role of microplastics as an ‘in-situ’ source of some OPEs in the area, although further research is needed to confirm this observation.
  • The sediment organic carbon content seems to play a relevant role on the study of OPE-microplastic interactions.

First results have been presented at the SETAC Europe 32nd conference (May 2022) and at the GDR Polymères & Océans 3rth Annual Meeting (June 2022) (references below). In addition, a peer-review paper presenting and discussing the whole data set is under preparation (expected publication in 2023).

  • Castro-Jiménez, J., Aminot, Y., Pollono, C., Idjaton, B., Bizzozero, L., Pierre Duplessix, O., Phuong, N.N., Gasperi, J. (2022). Environmental occurrence of organophosphate esters and microplastics in sediments and benthic organisms from the Loire Estuary (France).  SETAC Europe - 32nd Annual Meeting. 15-19 May 2022, Copenhagen, Denmark + Online (Poster presentation).
  • Castro-Jiménez, J., Aminot, Y., Pollono, C., Idjaton B, Bizzozero, L., Pierre Duplessix, O., Phuong N.N, Gasperi, J. (2022). Micro-plastics and organophosphate ester additives in sediments and benthic organisms from the Loire Estuary (France). 3ième rencontre du GDR Polymères & Océans. 17-19 June 2022, Brest – France (Oral presentation).