This project aims to characterize the photochemical fate of marine organic micropollutants in a specific and ubiquitous media, the Sea Surface MicroLayer (SSML). The SSML, that includes the air-water interface as well as the few hundreds of micrometers below, is a very particular photoreactor due to both significant enrichment in organic material, mainly biogenic one, and constant interactions with the atmosphere. The SSML is also known to accumulate numerous organic contaminants but is for now surprisingly almost ignored when talking about reactive fate of contaminants in marine surface waters. The first aspect of this project will be to study the effects of the organic material accumulation in the SSML on the photo-induced degradation of organic pollutants. We will develop an original experimental approach in order to kinetically and mechanistically evaluate the impacts of each main class of SSML components. The objective is to test the following hypotheses: the SSML is a sufficiently different media than the underlying water to modify reaction kinetics and thus lifetime of pollutants therein; the concentration of organic material can lead to SSML specific chemical routes and to the formation of degradation products unexpected in the underlying water. The investigation of multiphase and heterogeneous physico-chemical processes constitutes the second aspect of this project. The first objective will be to characterize the parameters leading to the enrichment of organic micropollutants in the SSML, in order to provide the classes of organic pollutants that can be significantly impacted by SSML specific processes. This SSML enrichment in pollutants will be tentatively linked with pollutant volatilization, via the relative quantification of this transfer as a function of SSML composition. In addition, the heterogeneous reactions of organic pollutants with some major atmospheric photooxidants will be investigated. We will provide kinetic and mechanistic data, with a focus on specific degradation products. The objective is to answer the question of the significance (quantitative and qualitative) of these heterogeneous reactions as a loss process of organic pollutants in marine surface waters. The third part of this project will aim to confirm laboratory-based conclusions through the case-study of the SSML in the marine coastal area of Marseille (Mediterranean Sea, France). In particular, SSML enrichment factors will be determined and SSML-specific transformation products will be extensively searched for.

In order to significantly reduce water pollution of marine and continental waters, the European Union is now subjected to a series of measures (WFD: Directive 2000/60/EC and MSFD: Directive 2008/56/EC). A list of priority substances was established amongst those presenting a significant risk to or via the aquatic environment. Among all the 33 priority substances and 8 other pollutants concerned by the WFD, toxic metals such as Cd, Pb, Hg and their compounds are listed for “priority action”. Only few analytical equipments allow field measurement directly in large aquatic ecosystems, such as estuaries and marine environment. Although some electrochemical or optical sensors are widely used in this context to measure some physico-chemical parameters (oxygen, turbidity, pH, organic matter,...), there is no analytical system for on-line field simultaneous measurement of toxic metals such as Cd, Pb and Hg. The Lab-on-Ship project aims squarely at the preservation of natural aquatic resources by developing a field-deployable instrument to easily, cheaply and accurately determine environmental levels of toxic metal contaminants in various aqueous matrices. Among all the substances concerned by the Directives, we have first selected Cd, Pb, and Hg because they are the most toxic metals at low concentrations (with Environmental Quality Standards < 10 µg.L-1) and the partners involved in this project have already developed a considerable expertise on these metals quantification. In practical terms, the objectives of the Lab-on-Ship project are to design and produce a modular, high performance and field deployable on-line analytical system by developing a lab-on-valve (LOV) system hyphenated with a MultiPumping Flow System (MPFS). This analytical system will be based on miniaturized modules directly integrated into a 3D printed LOV that will include all pre-treatment steps of sample. The LOV-MPFS will be validated by deploying the system in a progressive and interactive manner in order to i) validate the analytical performances in the laboratory and evaluate the applicability to field samples and then ii) deploy the system on-site during field campaigns. In this project, selectivity and sensitivity will be paramount considerations. To achieve the selectivity and sensitivity necessary for such analytical systems, the developed flow analytical system will be based on a selective Solid Phase Extraction (SPE) step of Cd, Pb and Hg, followed by detection of each metal by absorptiometry or fluorescence after derivatization with a specifically formulated reagent for each one. Although selectivity is a challenging concern for sample preparation for quantification, it is difficult to achieve with commonly used materials based on ion exchange or chelating functions. In this project, solid phase extraction step will be carried out by Ion-Imprinted Polymers (IIPs). Such imprinted materials show remarkable recognition properties for a target ion because of the memory effect induced during their preparation process. On another hand, an important fraction of metals is complexed by natural or anthropogenic organic ligands in environmental samples. For total dissolved trace metal determinations, it is thus necessary to release the trace metal from the metal–organic complex prior to analysis. This pre-treatment step of samples will be carried out by photo-oxidation process with UV LEDs which will substitute to the conventional UV lamp or UV lamp/persulfate digestion method. The last phase of the project development will be to validate the analytical LOV system by a field deployment in environments where the WFD and the MSFD are to be implemented. During this operation, uniformity of on-line data from automated method will be compared to data from reference methods. This will ensure that the project will have achieved its scientific and technical objectives.

Contamination of aquatic environments by heavy metals is a major concern in the scientific community and for societal issues. Indeed, these pollutants are generally not biodegradable and can accumulate in the environment. Among these heavy metals, lead, cadmium and mercury have attracted most attention due to toxicity issues. Regulatory organisms have strictly defined the concentration limits of these three heavy metals in various types of waters, including drinking water and surface waters. Mobile and portable devices would therefore be a precious tool for on-site analysis of these heavy metals, enabling rapid evaluation of the contamination of water samples. The objective of the proposed project is to develop an analytical device for lead, cadmium and mercury (concentration of free ions and ions complexed to organic matter), which will be designed as a potentially portable and suitable tool for on-site application (development up to Technology Readiness Level 4, laboratory validation). High selectivity and sensitivity will be required in order to allow the analysis of targeted water samples (drinking water or surface waters) with quantification limits below 1 µg L-1 and low interferences (<5%) from other cations or naturally occurring compounds. Several innovations will enable to reach the desired features of our device: Selectivity and sensitivity will mainly stem from the design of fluoroionophores bearing specific electron donating groups (oxygen, sulfur, nitrogen) to provide high affinity for heavy metals. Design of three selective fluoroionophores (one for each targeted metal) based on the same fluorogenic part (in order to have a common optical detection system for the three metals) will be the main challenge of the first part of the work. Fluorescent sensors will be grafted on a 3D-printed microfluidic unit which will be used as a preconcentration module in order to improve sensitivity of conventional liquid-phase fluorescent sensing. Current scientific obstacle for the direct fluorescence reading on a 3D-printed solid surface lies in the very high fluorescence of commercial 3D printing resin, which is due to the resin composition (mainly photoinitiators). Smart formulation of photosensitive 3D printing resins with very low background fluorescence and potential for molecular sensors grafting will be required in order to subsequently print preconcentration units with the adequate fluorescent sensing properties after grafting the fluorescent sensors. Detection and quantification of the fluorescence generated by the presence of metal cations will be then performed thanks to the sensors included in smartphones. Smartphones are indeed portable, widely available, affordable, user-friendly, and therefore well suited to act as an effective platform for on-site detection The targeted optical device will use the camera of a smartphone for light measurements and a dedicated and specially developed application for quantification. Finally, on-site determination of global metal concentrations (including ions complexed to organic matter) will be performed by the design of a portable photo-oxidation microfluidic module which will be used to pretreat the sample before analysis with the previously described device. The scientific challenge of this task will be the development of a portable photo-oxidation module, battery-powered with low tensions power supply (12-24V) but powerful enough to breakdown organic matter in a reasonable time. The final product will include the 3D-printed preconcentration modules grafted with the fluorescent sensors, the optical system for smartphone detection, the portable photo-oxidation module and a set of small peristaltic pumps (for fluids propulsion) controlled by a portable electronic interface. All these components will be integrated together to provide a portable laboratory prototype which can be validated on real samples.

Cloud droplets in the Earth’s atmosphere form on ubiquitous aerosol particles. At present, predictions of cloud droplet size and number concentration derived from aerosol properties are still poor, leading to large uncertainties in the radiation budget and climate projections. Cloud droplet formation on cloud condensation nuclei (CCN activation) is often investigated in closure studies, where the number of activated particles derived from their hygroscopic growth is compared with the one directly measured with a CCN counter. Many of these studies resulted in poor agreement, most probably due to effects related to the organic aerosol fraction: lowered surface tension of the growing droplets compared to pure water due to surface-active substances (or surfactants), solution non-ideality affecting hygroscopic growth due to sparingly soluble organic substances, and co-condensation of semi-volatile organic substances from the gas phase. ORACLE aims to fundamentally improve the understanding of the role organics play in CCN activation through combined experimental and modelling work. The main objectives are: - First, to investigate the evolution of surface tension in a growing solution droplet - Second, to elucidate the effect of co-condensation on particle growth and surface tension. The core of the ORACLE project are tank experiments, where a monodisperse particle population will be equilibrated with an organic vapour over longer time periods at different relative humidity (RH) closely mimicking the atmosphere. The equilibration process will be monitored by measuring the concentration of the semi-volatile species in the gas and the condensed phase. The influence of co-condensation on hygroscopic growth will be assessed by sizing the equilibrated particles at different RH and measuring their CCN activity. To assess the loss of semi-volatile species due to the heating within the commercial CCN counter, an in-house-built continuous-flow thermal-gradient diffusion chamber will be run in parallel. To single out the effect of surface-active species on CCN activation, recently-developed techniques to measure the surface tension of single particles will be optimized and applied to growing droplets. The experiments will be accompanied by thermodynamic and kinetic modelling of surface tension, solution non-ideality and co-condensation effects on CCN activation. These experiments will lead to - an improved theoretical understanding of the contribution of semi-volatile and/or surface-active species to cloud droplet activation for realistic atmospheric conditions; - the proposition of new experimental techniques that are suited to capture contributions of semi-volatile and surface-active species to cloud droplet activation in field experiments; - input for chemical transport and global climate models on how to treat semi-volatility and surface activity of organic species to improve predictions of hygroscopic growth, CCN activation and cloud properties. In the long term, ORACLE will improve our ability to predict the number and sizes of cloud droplets, two parameters paramount to precipitation forecasts in numerical weather prediction models and the climate impact of aerosol particles in future climate projections

Chemical processes in clouds have been suggested to contribute substantially to organic aerosol particle mass since a long time. Recent evidence from the HCCT-2010 field study and the CUMULUS chamber study suggest that this organic mass production can be substantial and depends on the concentration of available organic precursor compounds in the gas phase. However, considerable uncertainties exist, e.g. with regards to the nature of the resulting aerosol particles which might be metastable and loose at least part of their OM content during the cloud droplet evaporation. Hence, PARAMOUNT is aimed at the investigation of cloud processes which are able to process organic constituents and produce organic aerosol particle mass. The project will focus on the multiphase chemistry of very relevant polyfunctional precursors such as polyfunctional carbonyls and acids. With these precursors, a combination of aqueous-phase laboratory and CESAM chamber studies will be undertaken to examine the multiphase cloud processing. The planned aqueous-phase laboratory studies will lay the groundwork with regard to kinetics and mechanism of the multiphase processing of the mentioned compounds. The suggested CESAM chamber experiments, which are central in PARAMOUNT will mainly focus on studying the organic mass production by the chemical in-cloud processing of these compounds one by one, grouped or with mixtures with all of them. The planned chamber studies will use different seeds and oxidant precursors to examine the organic mass production under different environmental and diurnal conditions. The organic mass increases during the cloud episodes will be investigated. Besides the organic mass formation, the partitioning of organic compounds under cloud conditions should be studied to evaluate possible enrichments of organic carbonyl compounds observed during the cloud field campaign HCCT-2010. The organic aerosol fraction will be analysed on-line by two Aerosol Mass Spectrometer instruments and the processing of the interstitial gas phase and the phase partitioning will be investigated by PTR-MS and the use of a mini CVI (counter virtual impactor) followed by offline analysis. Finally, the performed CESAM experiments are being modelled with the complex multiphase chemistry mechanism MCM/CAPRAM. The multiphase modelling will be performed to both validate the mechanism and support the interpretation of the chamber experiments. Overall, the proposed project PARAMOUNT will be a scientific breakthrough for understanding of in-cloud processes clarifying the role of clouds for atmospheric organic aerosol mass production.