PIVOTS is a set of seven scientific platforms which are unique in France. They were set up in the Centre-Val de Loire region in 2016. The programme draws on both laboratory research and field experiments in order to better diagnose contamination and clean up pollution in the environment. This will enable us to sustainably manage our natural resources – soil, subsurface, water and air.
PRIME: Platform for remediation and innovation in environmental metrology
In France, over 7,200 sites are polluted with heavy metals: lead, copper, chrome, hydrocarbons, or organochlorine compounds, such as pesticides or solvents. Managing the sites and the polluted soil is a major environmental issue, but it is also a health and economic issue. The PRIME initiative, which is part of the PIVOTS programme, aims to identify and quantify pollutants in soil and underground water, to predict their impact on our environment, and to create solutions for remediation. What makes PRIME unique is that it works on multiple scales, enabling a global approach, closely linking lab and field, and enriching experimentation with modelling. The submetric columns, ranging from 20 cm to 1 metre, are used in the lab to carefully study the physical, biological and chemical changes in pollutants. The data gathered at this scale are used to interpret more complex observations carried out via vaster systems. The metric columns provide a smaller scale and controlled model of a polluted zone from the surface soil down to the groundwater. They allow us to characterize the exchanges between environments, such as the root systems and the groundwater, in great depth. The Labbio system enables us to study the migration of and changes to pollutants from soil to underground water as a function of surface conditions. The Trinappe system allows us to study the interaction between the different zones of groundwater. In this unit, water circulates from surface to the depths, but it can also rise to simulate a water-table rise. This innovative system is a unique tool for gathering data on phenomena that are difficult to study in real life. These different systems have sensors which measure flows of pollutants that have been stabilized, transformed or washed. These are ideal places for developing new quantification technology. The multi-metric system was designed to reproduce polluted sites or soil under controlled conditions and at a scale similar to that of the real world. It is thus an ideal system for developing diagnostic tools and remediation techniques. This tool can also verify digital models. This unit is a vast experimental reservoir. It is about 150 m3 in volume and has double walls to regulate the reservoir's temperature. The hood above the reservoir allows for experimentation with plants and helps control potential flows of volatile pollutants. The reservoir's walls feature holes that can be fitted with sensors and provide access to various depths inside the reservoir, all along the unit. The system's configuration allows the reservoir to be split into up to 4 modules filled with different materials, water, sand, polluted or unpolluted soil, mining residues, sediments, etc., in order to conduct simultaneous experiments. These modules are formed by walls and dividers made of alloy, which resists corrosive pollutants, or of polypropylene, which can be used with electrical geophysical methods. The modularity and unique traits of the unit make it a one-of-a-kind system in Europe. As well as these systems, the PRIME initiative brings together expert teams from BRGM, who are ready to work with public and private partners on innovation and development, from design to execution and promotion, in the Centre region, in France and abroad, in order to better understand and preserve our environment.
O-ZNS: the observatory of transfers in the non-saturated zone
Groundwater tables are our drinking-water reserves. They are often contaminated, by nitrates, for example, mainly of agricultural origin and emerging pollutants such as endocrine disruptors. Today we still don't understand the mechanisms that work beneath us, like the processes of water transfer in subsoil to the groundwater table, and especially the behavior and the fate of the elements that water takes with it. To respond to these issues, the Institute of Earth Sciences in Orléans has launched the O-ZNS program, which observes the unsaturated zone. This research project aims to identify how these pollutants penetrate the unsaturated zone from the surface to the groundwater table. The unsaturated zone contains water and air, and there the pollutants are likely to transform. The transfer of pollutants is subject to interactions, especially with water, gases, and minerals. The roots and micro-organisms also play an important role in the fate of farming pollutants. It's firstly groundwork for the O-ZNS team. This one was set up on an agricultural plot in Beauce to carry out the research. O-ZNS has a tool which is large-scale and unique in Europe with the construction in 2021 of an access well in the unsaturated zone. These exceptional dimensions that are 20 m deep and have a 4-m diameter are a great technological and scientific challenge pointed to O-ZNS's aims.
DECAP: detecting and eliminating micropollutants in water
Pesticides, medicines, heavy metals, household products, human activity generates a large amount of chemical substances in the environment, notably in water. These pollutants are not always treated correctly in water-treatment plants. They are present in too small quantities to be treated by traditional methods.
It has to be said that in water, at very low concentrations, there is a large number of micropollutants that we need to detect as they might be dangerous, even in low concentration. In order to detect them we need to develop sensorsfor each micropollutant. They have to be treated, so processes need to be developed.
Detecting and treating these micropollutants is the work of Decap, a platform which is part of the Pivots programme, a unique group of 7 scientific platforms dedicated to preserving the environment. Pivots is situated in the Centre-Val-de-Loire region. Decap laboratories concentrate on ten or so substances present in the region. The aim is to find low-cost solutions which can be applied on a large scale.
If we offer a sensor that is too expensive, but detects everything, it's of no interest. No company will produce it. The goal is to have low-cost sensors which can be produced on a large scale and deployed on a large scale. We create our sensors from scratch. We work on the material. Mainly sensors made from carbon. Why? It's a question of cost.
Next we work on modifying the surface. We make the sensors functional so they detect certain pollutants.
The surface of the sensor is grafted: chemical groups are implanted which will recognise and detect the specific pollutant. This grafting makes the sensor sensitive, as the pollutant is concentrated on the surface of the sensor, but also selective, as it only detects the pollutant key which matches the lock.
The aim is to put our sensors in watercourses so that we will have a network of intelligent sensors across all our watercourses so we can offer real-time detection with a single operator running everything, and in case of pollution, they can take the necessary action to stop the pollution of the watercourse for example.
Once detected, the pollution must be cleared, another one of Decap's activities.
We develop advanced oxidation processes which will create types which will react effectively with the micropollutant. We will generate hydroxyl radicals, OH radicals, which will be more reactive with the micropollutant than chlorine, which you find traditionally in cleaning and degradation processes. We will pair up the processes at ICMN and GREMI in order to find the best processes, the ones most effective for treating micropollutants, and be able to generate types which are not toxic downstream and which can be treated in conventional water-treatment plants.
Researchers at Decap continue to develop new techniques to make more effective sensors and to detect new substances.
PRAT: impact of gaseous and particulate pollutants on health, climate and the environment
According to the World Health Organization, air pollution is responsible for killing seven million people a year and harming billions more. Many air pollutants are potent greenhouse gases, agents of climatic change, which are predicted to devastate the global economy and disproportionately affect the world's most vulnerable people. Industry, transport, heating, cooking, agriculture: the sources of indoor and outdoor air pollution are many, which makes studying its effects challenging.
Via the PIVOTS environmental research programme, the Centre Val de Loire region, located in France, is equipped with a platform called PRAT, which analyses polluting substances in the air and studies their development.
The chamber is filled with purified air matching the temperature and pressure of the atmosphere. The researchers then introduce a gaseous or suspended particulate pollutant together with the ingredients for its transformation. This pollutant is then broken down by the same chemical cycles found in the atmosphere or is destroyed directly by the sun's rays. The analysis of the results in the laboratory situated below the chamber shows how quickly the pollutant disappears and what changes it undergoes. A pollutant can undergo many such changes. And it is only by studying these processes that we can understand its impact on our health and our planet.