Ecotoxicity of Heteroaggregates of Polystyrene Nanospheres in Chironomidae and Amphibian

Abstract

Due to their various properties as polymeric materials, plastics have been produced, used and ultimately discharged into the environment. Although some studies have shown their negative impacts on the marine environment, the effects of plastics on freshwater organisms are still poorly studied, while they could be widely in contact with this pollution. The current work aimed to better elucidate the impact and the toxicity mechanisms of two kinds of commercial functionalized nanoplastics, i.e., carboxylated polystyrene microspheres of, respectively, 350 and 50 nm (PS350 and PS50), and heteroaggregated PS50 with humic acid with an apparent size of 350 nm (PSHA), all used at environmental concentrations (0.1 to 100 µg L−1). For this purpose, two relevant biological and aquatic models—amphibian larvae, Xenopus laevis, and dipters, Chironomus riparius—were used under normalized exposure conditions. The acute, chronic, and genetic toxicity parameters were examined and discussed with regard to the fundamental characterization in media exposures and, especially, the aggregation state of the nanoplastics. The size of PS350 and PSHA remained similar in the Xenopus and Chironomus exposure media. Inversely, PS50 aggregated in both exposition media and finally appeared to be micrometric during the exposition tests. Interestingly, this work highlighted that PS350 has no significant effect on the tested species, while PS50 is the most prone to alter the growth of Xenopus but not of Chironomus. Finally, PSHA induced a significant genotoxicity in Xenopus.

Exposure of Midge Larvae (Chironomus riparius) to Graphene Oxide Leads to Development Alterations

“…Indeed, chironomids are sentinel species that are widely used as indicators of freshwater ecosystem quality [ 28 , 29 ] or for the ecotoxicological assessment of polluted sediment or water [ 30 , 31 , 32 ]. In addition, they were shown to be sensitive to nanoparticles, the exposure to which led to both physiological and behavioral impairments [ 33 , 34 , 35 , 36 , 37 ]. From an ecological point of view, chironomid larvae are benthic organisms that play a key role in the environment through direct or indirect effects on organic matter recycling, nitrogen cycling or bioturbation [ 38 , 39 , 40 ], while constituting an important food source for organisms of higher trophic levels such as fishes [ 41 ] and birds [ 42 ].…”