The necessity of investigating a freshwater-marine continuum using a mesocosm approach in nanosafety: The case study of TiO2 MNM-based photocatalytic cement

Abstract

Production of Manufactured Nanomaterials (MNMs) has increased extensively due to economic interest in the current years. However, this widespread use raises concern about their impact on human and environment. Current efforts are made, both at national and international levels to help developing safer MNMs in the market. In order to assess hazards of MNMs, it is important to take into account exposome parameters in order to link fate and behavior of MNMs to their potential toxicity. In that context, the aim of this study was to compare exposure and impact of TiO 2 MNMs-based cement at different levels of its life cycle (TiO 2 MNMs, cement containing TiO 2 MNMs) between two exposure mesocosm scenarios mimicking : marine conditions using the bivalve Scrobicularia plana and freshwater conditions using the gastropod Planorbarius corneus, for 28 days. These approaches allows measurements of physical-chemical parameters throughout the duration of the exposure. Similar results were observed in both exposure conditions since in the two scenarios Ti was removed from the water column and accumulated in surficial sediments. While in P. corneus, statistically different concentrations of Ti were measured in the digestive glands compared to controls following exposure to TiO 2 MNMs, elevated background of Ti concentrations were measured in the controls of S. plana that did not allow to discriminating any bioaccumulation process. In addition, both TiO 2 MNMs and TiO 2 MNM-based cement exposed S. plana did not present any activation of the p38 mitogen-activated protein kinase (MAPKs).This study demonstrates the challenge of using freshwater-marine continuum using a mesocosm approach in nanosafety.

Aquatic Mesocosm Strategies for the Environmental Fate and Risk Assessment of Engineered Nanomaterials

“…In addition, the paint matrix prevented (bio)­transformation of the ENMs, with regard to dissolution and complexation. More recently, Châtel et al reported an enhanced bioaccumulation of pristine Ti-ENMs compared to cement-embedded counterparts in freshwater snails …”

Comparative study of the sensitivity of two freshwater gastropods, Lymnaea stagnalis and Planorbarius corneus, to silver nanoparticles: bioaccumulation and toxicity

“…However, they have different shell morphology and P. corneus presents a deeper and longer diving behaviour compared with L. stagnalis (Bekius, 1971). Moreover, these species are considered good environmental pollution indicators given their wide geographic distribution, ease of availability, and sensitivity toward chemicals (Amorim et al, 2019;Châtel et al, 2020;Herbert et al, 2021). The L. stagnalis has been used as an excellent biological model for ecotoxicological studies and is applied in OECD test guidelines (Amorim et al, 2019;Ducrot et al, 2014).…”