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M/F PHD : Studie about Emission, fate and environmental effects of UV filters from sunscreens

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Français - Anglais

Date Limite Candidature : lundi 13 décembre 2021

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General information

Reference : UMR7330-NOEGAR-022
Date of publication : Monday, November 22, 2021
Scientific Responsible name : Labille Jérôme
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 January 2022
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly

Description of the thesis topic

Emission, fate and environmental effects of UV filters from sunscreens - Benefits and risks of chemical or nanoparticulate substances.
UV filters from sunscreens released during bathing activities raise questions about their impact on the marine environment. There are two main types: mineral filters, mainly nanoparticles of titanium dioxide TiO2 or zinc oxide ZnO, and organic filters, of various types such as oxybenzone, octyl methoxycinnamate, octocrylene. The relative impact of these UV filters on bathing water quality, and more broadly on the nearby aquatic environment, is still poorly known, although the stakeholders concerned are becoming more aware of the issue. In order to estimate the risk associated with these substances, exposure in the aquatic environment and toxicity must be taken into account. For this, the release of UV filters from the cream into the environment must be taken into account and their fate and transformation must be studied.

Work Context

The objective of this project is to evaluate the pollution of the aquatic environment by UV filters generated by the use of sunscreens in recreational bathing areas. The fate of sunscreen residues in bathing waters will be studied using a mechanistic laboratory approach and a naturalistic field approach. An ecotoxicological study will also be conducted on two species of fish representative of temperate and tropical climates.

In the laboratory, creams with a controlled UV filter composition and emulsion type will be formulated and their ageing in a synthetic aquatic environment will be reproduced. The UV filters released will be quantified and characterized. A balance sheet and distribution kinetics will be established across the different compartments of the water column (surface, column, sediment) in order to estimate exposure and understand the fate mechanisms. The mechanistic approach developed here will allow us to understand the mechanisms that determine the behavior and transformation of UV filters according to various environmental parameters. Relevant experimental approaches will be developed, notably involving a solar simulator for controlled ageing, HPLC/Q-ToF/MS chromatography for the analysis of organic filters and species generated during their degradation, FFF fractionation, coupled with sp-ICPMS and TEM for the characterisation of nanoparticles.

In the field, a naturalistic approach will be developed. Study sites have been selected in temperate climates and tropical regions in order to vary the type of sunshine and use of solar products, but also the environments impacted. Spatialized water and sediment sampling campaigns will be carried out during and outside the bathing activity. The concentration of UV filters in the different compartments will be measured and compared with laboratory results.
The toxicity of UV filters will be evaluated on the development of two biological species characteristic of temperate and tropical marine environments, the sea bass and the clownfish Amphiprion ocellaris, whose life cycles are controlled in aquariums. Relevant exposure doses will be practiced, as found in the field, and exposure scenarios will be supported by the mechanisms revealed in the laboratory. Biological effects will be analyzed through several bioindicators.
skills :
The desired candidate will have a background in environmental chemistry, ideally with a solid foundation in physical chemistry, as well as good experience in laboratory experimentation. Moreover, some experience in cosmetic formulation would be a strong added value.

Competences :
The candidate will have competences giving to him autonomy in experimental manipulation in a Geochemistry lab, and a first experience in cosmetic formulation.

Constraints and risks

This thesis is part of the UV Filter research project submitted to the APR-EST call for projects of ANSES in 2021. This project is led by the CEREGE (Aix en Provence), in collaboration with the Laboratoire de Chimie de l'Environnement (Marseille, AMU), the CEA LITEN (Grenoble), the Observatoire de Banyuls sur Mer, and the LIENSs (Univ. La Rochelle). The PhD student's research work will be organised mainly at CEREGE and LCE for the analysis of mineral and organic UV filters respectively. Occasional missions to other partners are also planned.

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