Compound-specific recording of gadolinium pollution in coastal waters by great scallops

Gadolinium-based contrast agents (GBCAs), routinely used in magnetic resonance imaging (MRI), end up directly in coastal seawaters where gadolinium concentrations are now increasing. Because many aquatic species could be sensitive to this new pollution, we have evaluated the possibility of using shellfish to assess its importance. Gadolinium excesses recorded by scallop shells collected in Bay of Brest (Brittany, France) for more than 30 years do not reflect the overall consumption in GBCAs, but are largely controlled by one of them, the gadopentetate dimeglumine. Although its use has been greatly reduced in Europe over the last ten years, gadolinium excesses are still measured in shells. Thus, some gadolinium derived from other GBCAs is bioavailable and could have an impact on marine wildlife.

Fig. 3b : Gadolinium anomalies (a: Gd/Gd*), gadolinium excesses (b: ΔGd) recorded by scallop shells sampled from 1960 to 2018 in Bay of Brest, and GBCA consumption in France recorded in the Medic’AM database22 maintained by the CPAM (French Health Insurance agency) (c: total consumption and macrocyclic GBCAs, d: linear GBCAs).

These excesses in scallop shells (ΔGd = 0–2.3 ng/g) display a complex temporal evolution (Fig. 3b). The oldest sample collected in 1960, before the use of GBCAs, does not show any significant excess in gadolinium. A marked increase in gadolinium excesses is seen from 1989 to 2005, followed by a sharp decline until 2010 when normal levels are observed again. Afterwards, the excesses seem to increase again without reaching the 2005 maximum, but the data show some spread. Such an evolution is unexpected because the use of GBCAs has always been increasing since their introduction on the market. It could depend on the bioavailability of anthropogenic gadolinium as determined by its speciation in seawater.


Le Goff, S., Barrat, J.-A., Chauvaud, L., Paulet, Y.-M., Gueguen, B., & Salem, D. B. (2019). Compound-specific recording of gadolinium pollution in coastal waters by great scallops. Scientific Reports, 9(1), 8015.


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GDR “Polymers and Oceans”

GDR-plolymeres et Ocean

The environmental issues related to the presence of plastics are now unanimously recognized. The national (governments) and international (European Union, United Nations) institutions have taken action to better understand the consequences of the presence of these plastic debris in the environment and to try to reduce their releases

The mission of the GDR “Polymers and Oceans”, recently created under the aegis of the CNRS, is to federate the French scientific community (composed by chemists, physicists, biologists, ecologists, ecotoxicologists, oceanographers, economists and sociologists) working on the fate of plastics in the environment to support the emergence of multi-scale and new interdisciplinary research.

The main objectives of this GDR are:

  • to define the main scientific questions and methodological obstacles around this topic;
  • to structure very diverse scientific communities and facilitate the establishment of scientific and technical collaborations between disciplinary fields to support multidisciplinary approaches that are essential to meet the challenges of this topic;
  • to promote collaboration between academic research and industrial research/innovation in relation to competitiveness clusters (e.g. Brittany-Atlantic and Mediterranean MER Poles, IAR) and learned societies (e.g. SFP, SCF, GFP) ;
  • play an active role in the implementation of new experimental protocols to assess the fate of polymers in the aquatic environment ;
  • create an information exchange platform offering an open window to respond to the many requests from economic actors, the media, NGOs and politicians and influence institutional prospects ;
  • participate in the dissemination of scientific knowledge acquired through the organization of an annual national conference and thematic schools.

More information on the website of the first meetings of this GDR

Ika Paul-Pont and Arnaud Huvet are involved in the scientific council of this GDR.

Impacts of environmental changes

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Coastal ecosystems are characterized by high natural variability at high frequency of the main abiotic factors.

Determining the possible reactions of living communities to anthropogenic pressures (chemical and plastic contamination, global warming, eutrophication, overexploitation of living resources) that generate proven global change is a real challenge for environmental scientists. In coastal marine environments where most of the ecological productivity is concentrated, the impact of chronic pollution raises additional questions for managers of these environments and producers of fish and aquaculture resources. Some alterations (genotoxicity, immunotoxicity, reprotoxicity) lead to population effects that may compromise the maintenance of certain species in the affected environments.

The number of coastal sites in the world ocean subjected to hypoxia and even anoxia events, more or less regularly and more or less pronounced, has increased dramatically since the 1950s. Most often, these phenomena are one of the consequences of the eutrophication of coastal areas, linked to the increasingly massive supply of nutrients to these waters. The latter stimulate phytoplankton production which, by sedimentation, induces a massive consumption of dissolved Oxygen at the water-sediment interface (bacterial degradation of this influx of organic matter). When the waters are stratified (e.g. during the summer), the bottom layer is isolated and is subjected to more or less prolonged hypoxic episodes, with serious consequences on benthic biocenoses.

Faced with various environmental pressures, marine organisms present adaptive responses of a behavioural, physiological (phenotypic plasticity), ontogenic and evolutionary nature that are individually reflected in their life traits and, at the individual and population level, in spatial-temporal dynamics.

Through a combination of experimental approaches (laboratory or in situ) and field observation studies, LEMAR will conduct several types of approaches including:

  • Mechanistic approach: characterize the adaptive responses of individuals from populations from contrasting sites in terms of exposure to chronic contamination.
  • Diagnostic approach: apply phenotypic descriptors corresponding to disturbances in essential physiological systems such as energy metabolism and the immune system, which are particularly important for the survival and development of populations.