The shape and speciation of Ag nanoparticles drive their impacts on organisms in a lotic ecosystem

Melanie Auffan (1) , Catherine Santaella (2) , L Brousset (3) , M Tella (4, 5) , E Morel (1) , P Ortet (2) , M Barakat (2) , C Chaneac (6, 7) , J Issartel (3) , B Angeletti (1) , C. Levard (1) , J-L Hazemann (8) , M Wiesner (9) , J. Rose (1, 9) , A Thiéry (3) , J-y Bottero (1, 9)

1 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement
2 LEMIRE - Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes
3 IMBE - Institut méditerranéen de biodiversité et d'écologie marine et continentale
4 US Analyses - Analyses des eaux, sols et végétaux
5 Cirad-PERSYST - Département Performances des systèmes de production et de transformation tropicaux
6 LCMCP - Laboratoire de Chimie de la Matière Condensée de Paris
7 SU - Sorbonne Université
8 NEEL - MRS - Matériaux, Rayonnements, Structure
9 Duke University [Durham]

Silver nanomaterials with different shapes (spheres, plates, wires, rods, cubes) are valued by industries and scientists for their shape-dependent properties which make them useful for diverse applications. In a saferby-design perspective, controlling the shape of Ag nanomaterials could be an option to increase their properties while lowering either their hazard or their exposure potentials. Nine indoor aquatic mesocosms reproducing a lotic ecosystem were contaminated with chronic low-level additions of Ag nanospheres (Sp-Ag) and nanoplates (Pl-Ag) for a month. A shape-dependent impact under such environmentally relevant exposure conditions was observed. Pl-Ag induced a moderate oxidative stress in adult Gammarus fossarum (after molting) and a hormesis effect on planktonic microbial communities, while Sp-Ag had no effect. In an environmental risk perspective, our results highlight which ecological niches of a lotic ecosystem would be more impacted by Pl-Ag: (i) >72% of the total Ag was found fully sulfidized in surficial sediment and had only a moderate impact on benthic macro-organisms, (ii) only 11% to 15% of the Ag remained in the water column after 1 month, but Ag was under a more reactive speciation that impacts the planktonic community.

Domaines: Sciences de l'environnement

Melanie Auffan, Catherine Santaella, L Brousset, M Tella, E Morel, et al.. The shape and speciation of Ag nanoparticles drive their impacts on organisms in a lotic ecosystem. Environmental science‎.Nano, 2020, 7, pp.3167 - 3177. ⟨10.1039/d0en00442a⟩. ⟨hal-03065323⟩