Molecular Impacts of Dietary Exposure to Nanoplastics Combined or Not with Arsenic in the Caribbean Mangrove Oysters (Isognomon alatus).

Magalie Baudrimont,Zélie Venel,Marc Lebordais,Julien Gigault,Valerie S Langlois

doi:10.3390/nano11051151

Abstract

Nanoplastics (NPs) are anthropogenic contaminants that raise concern, as they cross biological barriers. Metals’ adsorption on NPs’ surface also carries ecotoxicological risks to aquatic organisms. This study focuses on the impacts of three distinct NPs on the Caribbean oyster Isognomon alatus through dietary exposure. As such, marine microalgae Tisochrysis lutea were exposed to environmentally weathered mixed NPs from Guadeloupe (NPG), crushed pristine polystyrene nanoparticles (PSC), and carboxylated polystyrene nanoparticles of latex (PSL). Oysters were fed with NP-T. lutea at 10 and 100 µg L−1, concentrations considered environmentally relevant, combined or not with 1 mg L−1 pentoxide arsenic (As) in water. We investigated key gene expression in I. alatus’ gills and visceral mass. NP treatments revealed significant induction of cat and sod1 in gills and gapdh and sod1 in visceral mass. As treatment significantly induced sod1 expression in gills, but once combined with any of the NPs at both concentrations, basal mRNA levels were observed. Similarly, PSL treatment at 100 µg L−1 that significantly induced cat expression in gills or sod1 in visceral mass showed repressed mRNA levels when combined with As (reduction of 2222% and 34%, respectively, compared to the control). This study suggested a protective effect of the interaction between NPs and As, possibly by decreasing both contaminants’ surface reactivity.

Highlights

Plastic contamination is a worldwide environmental issue, as recognized by the UnitedNations Environment Program [1]
Aquatic ecosystems act as natural receptacles for contaminants, including plastic debris, that are eventually carried by currents and converge to five main ocean areas called gyres [5]
We demonstrated that sublethal exposures of NPs impaired cellular functions at the molecular level on native Guadeloupean oysters

Summary

Introduction

Plastic contamination is a worldwide environmental issue, as recognized by the UnitedNations Environment Program [1]. Plastic contamination is a worldwide environmental issue, as recognized by the United. Used plastic products can last in the environment for several hundred years without being completely degraded [2,3]. With an average of 8 million tons of plastic waste discarded into oceans each year, Wright and Kelly (2017). Estimated an accumulation of 250 million tons by 2025 [4]. Aquatic ecosystems act as natural receptacles for contaminants, including plastic debris, that are eventually carried by currents and converge to five main ocean areas called gyres [5]. Different sizes of plastic debris can be identified: large microplastics (size < 5 mm; [7]), microplastics (size < 0.3 mm; [8]), and nanoplastics (size < 0.001 mm; [9])

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