The “Sarg As & Cld” project addresses the environmental impacts of Sargassum (Sar) piling up along shorelines or inland, in link with arsenic (As), a very toxic trace element naturally present in Sar, and chlordecone (CLD), known to accumulate in Sar washing ashore in places that connect with rivers flowing from banana plantation areas. The first task will be to develop analytical techniques for quantifying the various physico-chemical forms of As in Sar and in the leachates produced by dripping and rain falling on piles. The speciation of As in the soils below these piles will also be studied. The second task will be to determine the toxicity of these Sar leachates for test organisms, mainly representative of local wildlife (freshwater crustaceans and oysters from mangroves). Both As and CLD will be studied, whether separately or simultaneously present, to investigate possible synergic effects. The third task will be to develop a cost-effective, environmentally friendly process for removing As from Sar leachates. Laboratory development will be followed by a field trial in actual natural conditions. Activated carbon will be tested for CLD sorption. Treated leachates will be used in task 2. The fourth task will focus on the social acceptability of Sar stockpilings, investigating how the population feels about the management of the Sar washing ashore and especially about the real and assumed dangers of As and CLD, and assessing the inclinations of the population to come out in protest against Sar stockpiling. All results will be disseminated to the scientific community and stakeholders through task 5. The project is coordinated by the BRGM (Scientific and technical centre in Orléans, France, and its local Guadeloupe agency) with partners from the Universities of the Antilles, French Guiana, Orléans and TAMUG (USA), and the ADERA/UT2A association. The “Conservatoire National du Littoral, Guadeloupe” is the end-user associated with the project.

When a liquid droplet is placed on a solid surface with a temperature significantly higher than the boiling point of the liquid, the droplet hovers above the surface on a thin layer of its own vapor, a phenomenon known as the Leidenfrost effect. While this effect is highly undesirable in certain cooling applications due to the reduced energy transfer between the solid and evaporating liquid caused by the poor heat conductivity of the vapor, it can be of significant interest in various processes where avoiding contact with the surface is advantageous. The LeidenForce project aims to comprehensively study the Leidenfrost effect and propose novel applications, either to mitigate its adverse effects or leverage its advantages. LeidenForce intends to (i) shift the fundamental understanding of the transition to the Leidenfrost state, (ii) optimize the heat transfer between the droplet and the substrate, (iii) utilize the isolated droplet to manipulate small amounts of liquid in unconventional scenarios (e.g., on a liquid surface, within a channel), and (iv) harness the vapor film to capture or confine particles using an external electrical field. The practical implications will be leveraged by non-academic institutions involved in aviation (such as AIRBUS), metallurgy (CRM), cryogenics (Air Liquide), and space exploration (Centre Spatial de Liège). In aviation, managing cryogenic fuel is a crucial step toward achieving zero-emission flights. In metallurgy, innovative cooling methods will be developed based on mitigating the Leidenfrost effect. Air Liquide will address cooling issues by introducing particles into the evaporating liquid to modify the Leidenfrost effect. Lastly, at the Centre Spatial de Liège, Leidenfrost droplets will be utilised to delicately clean surfaces by trapping particles within these contactless droplets.