Olivier Evrard

Atomic Energy and Alternative Energies Commission | CEA · LSCE - Laboratoire des Sciences du Climat et de l'Environnement

Saharan dust outbreaks have profound effects on ecosystems, climate, human health and the cryosphere in Europe. However, the spatial deposition pattern of Saharan dust is poorly known due to a sparse network of ground measurements. Following the extreme dust deposition event of February 2021 across Europe, a citizen science campaign was launched to...

The Ipojuca River is the third most polluted fluvial system in Brazil. Sediment-associated metal fluxes threaten the environmental health in the estuary of this system. However, the sources supplying these particle-bound contaminants have not been determined yet. Sediment source fingerprinting provides a powerful technique to obtain such informatio...

Although Extreme El Niño Events (EENE) have always impacted hydrology in South America, their intensification by global warming and their association with changes in human activities and land cover may lead to the acceleration of sediment transfers in river systems and dam reservoirs. This situation may threaten soil and water resources in a region...

In 2011, the Fukushima Dai-Ichi Nuclear Power Plant (FDNPP) accident released significant quantities of radionuclides into the environment. Japanese authorities decided to progressively reopen the Difficult-To-Return Zone after the decontamination of priority reconstruction zones. These areas include parts of the initially highly contaminated munic...

The current dataset was compiled to study sediment fingerprintings practices, i.e tracer selection and contribution modelling. Colorimetric properties analysed with a portable diffuse reflectance spectrophotometer (Konica Minolta CM-700d) and geochemical contents obtained with an energy dispersive X-ray fluorescence spectrometer (ED-XRF Epsilon 4)...

The current dataset was compiled to investigate the temporal evolution of plutonium concentrations, isotopic ratios and radiocesium activity concentrations in flood sediment deposits collected in the Ukedo and Takase Rivers, draining a part of the Difficult-to-Return Zone, in Fukushima Prefecture, from 2013 to 2020. These radionuclides were release...

Eleven years ago, the Fukushima Dai-Ichi Nuclear Power Plant (FDNPP) accident released significant quantities of radionuclides into the environment[1]. Japanese authorities decided to progressively reopen the difficult-to-return zone without obligatory decontamination. This zone includes the initially highly contaminated municipalities to the north...

Data can be downloaded at https://doi.org/10.5281/zenodo.7056364

Data can be downloaded at https://doi.org/10.5281/zenodo.7056364

Every accident affecting industrial or nuclear facilities emits micrometric fragments of material into the environment [1-3] whose elemental and isotopic compositions are characteristics of the process or event [4]. Accordingly, particle analysis provides a powerful tool to monitor nuclear activities in the framework of the Non Proliferation Treaty...

Every accident affecting industrial or nuclear facilities emits micrometric fragments of material into the environment whose elemental and isotopic compositions are characteristic of the process or event. Particle analysis, mainly implemented in the framework of the Non Proliferation Treaty to detect clandestine nuclear activities, provides a power...

To truly understand the hydrologic and erosive processes that occur at the catchment scale regarding land use and soil management changes, intensive monitoring is required over a long period. Variables such as precipitation, flow rate, and suspended sediment concentration are the fundamentals needed to estimate sediment yield. However, in order to...

The Brazilian semiarid is the most densely populated dry region in the world. Although climate change projections underline the need for the creation of integrated strategies to protect water resources in the semiarid, sediment source apportionment data remain scant for this environment. Accordingly, we evaluated sediment source contributions in on...

Large volumes of radionuclides were deposited on the soils in North-eastern Japan after the accident at the Fukushima Dai-ichi nuclear Power Plant (FDNPP) in March 2011. The village of Iitate, with a population of 6544 inhabitants in early 2011, was located in the main radioactive plume. Its population was evacuated between 2011 and 2017, when the...

High mountain environments are among the most fragile on Earth. Due to anthropogenic disturbances and the exposure to extreme weather events, the rates of soil erosion have recently been accelerating, resulting in ecological degradation and geological hazards. Ecological restoration of mountains and an improved understanding of nature-based solutio...

The detrimental impacts of surface runoff and soil erosion, particularly in cultivated areas, call for the use of distributed runoff and soil erosion models with a view to supporting adapted catchment management strategies. However, runoff model parameterization remains challenging in agricultural catchments due to the high spatial and seasonal var...

Bacterial pathogens in surface waters may threaten human health, especially in developing countries, where untreated surface water is often used for domestic needs. The objective of the long-term multiscale monitoring of Escherichia coli ([E. coli]) concentration in stream water, and that of associated variables (temperature (T), electrical conduct...

Purpose Identifying best practices for sediment fingerprinting or tracing is important to allow the quantification of sediment contributions from catchment sources. Although sediment fingerprinting has been applied with reasonable success, the deployment of this method remains associated with many issues and limitations. Methods Seminars and debat...

Atmospheric nuclear tests (1945-1980) have led to radioactive fallout across the globe. French tests in Polynesia (1966-1974) may influence the signature of fallout in South America in addition to those conducted by USA and former USSR until 1963 in the Northern hemisphere. Here, we compiled the 240Pu/239Pu atom ratios reported for soils of South A...

Purpose Evaluating sediment fingerprinting source apportionments with artificial mixtures is crucial for supporting decision-making and advancing modeling approaches. However, artificial mixtures are rarely incorporated into fingerprinting research and guidelines for model testing are currently lacking. Here, we demonstrate how to test source appor...

Sediment that has deposited after the flood generated by the 2019 typhoon (referred to as Flood Sediment, FS) was collected along two rivers in eastern Fukushima Prefecture, Japan to determine the total and exchangeable radiocesium ($^{137}\mathrm{Cs}$), and acid-extractable potassium (K) contents. Then, these FS parameters were compared with those...

Every industrial facility, industrial and nuclear accident emits micrometric fragments of material in the environment whose elemental and isotopic compositions are characteristics of the process or event. Thus particle analysis is a powerful tool to monitor nuclear activities in the framework of the Non Proliferation Treaty and to assess the exposu...

This publication shows results of a comparison of three techniques for localising radioactive, and U-bearing particles in contrasted samples. Particles are localised by the means of three methods: (1) Fission Tracks (FT), (2) Imaging Plate (IP), and (3) real time autoradiography (BeaQuant®). These techniques were applied to various samples, includi...

Purpose Erosion and its spatial distribution in three agricultural headwater catchments were assessed in the border of the volcanic plateau in Southern Brazil. We analyzed terrain, hydrological processes, and land use infuence to provide a comprehensive assessment of the catchments’ sensitivity to erosion. Methods Topographic attributes were acqu...

The Jacuí Delta drains into Lake Guaíba which is the main source of water for more than two million people in South Brazil and has suffered from pollution with heavy metals and phosphorus. The objective of the current research is to demonstrate how the use of sediment source tracing techniques, in combination with sediment flux monitoring, can impr...

Bacterial pathogens in surface waters may threaten human health, especially in developing countries, where untreated surface water is often used for domestic needs. The objective of the long-term multiscale monitoring of Escherichia coli concentration in stream water, and that of associated variables (temperature, electrical conductance, dissolved...

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Dating recent sediment archives (<150 years) constitutes a prerequisite for environmental and climatic reconstructions. Radiocaesium (137Cs) emitted during thermonuclear bomb testing (1950–1980) and nuclear accidents and the decrease in excess lead-210 (210Pbxs) with depth are often combined to establish sediment core chronology. Although these met...

Land use change in the Southern Grasslands biome with the introduction of exotic, fast-growing forest species is a controversial topic, because of the potential effect on water and soil resources. The aim of this study was to assess the effects of afforesting degraded grassland on streamflow and sedimentation in subtropical headwater catchments. Tw...

Since 1945, a large amount of heterogeneous data has been acquired to survey river sediment quality, especially concerning regulatory metals such as Cd, Cr, Cu, Hg, Ni, Pb, and Zn. Large-scale syntheses are critical to assess the effectiveness of public regulations and the resiliency of the river systems. Accordingly, this data synthesis proposes a...

Dating recent sediment archives (<150 years) constitutes a prerequisite for environmental and climatic reconstructions. Radiocaesium (137Cs) emitted during thermonuclear bomb testing (~1950 ̶ 1980) and nuclear accidents, as well as the decrease of excess lead-210 (210Pbxs) with depth are often combined to establish sediment core chronology. Althoug...

Artificial radionuclides including radiocesium (134Cs and 137Cs) and radiosilver (110mAg) were released into the environment following the Fukushima Dai-ichi nuclear power plant accident in March 2011. These particle-bound substances deposited on soils of north-eastern Japan, located predominantly within a ∼3000 km2 radioactive fallout plume and dr...

No-till (NT) is a soil management system designed to protect soil resources from water erosion and provide numerous benefits compared to conventional tillage through the increase of organic matter inputs into the soil. However, NT in isolation is not sufficient to control erosion processes caused by an excessive production of surface runoff. This s...

Dating recent sediment archives (<150 years) constitutes a prerequisite for environmental and climatic reconstructions. Radiocaesium (137Cs) emitted during thermonuclear bombs testing (~1950-1980) and nuclear accidents (1986 and 2011) was generally used for identifying sediment sources or for establishing sediment core chronology based on discrete...

Although sediment yield reflects a catchment’s erosive processes, material transfer from hillslopes to rivers depends on a series of phenomena occurring on variable and continuous range of scales. Physically based, distributed models can be used to evaluate erosion’s spatial variability within a catchment and to identify hotspots. Sediment fingerpr...

The Fukushima Dai-Ichi Nuclear Power Plant (FDNPP) accident that occurred in March 2011 released significant quantities of radionuclides into the environment. Ten years after the accident, questions still remain, particularly about the processes that led to the partial core meltdown of reactors 1 and 3. So far, some answers have been provided by th...

Brazil is one of the largest consumers of pesticides in the world, and these chemicals present a high contamination risk for the country’s water bodies. The mechanisms of mobilization and transport of pesticides from cropland to river systems are controlled by runoff and erosion processes occurring at the catchment scale. In addition to the excessi...

Artificial radionuclides including radiocesium (134Cs and 137Cs) and radiosilver (110mAg) were released into the environment following the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011. These particle-bound substances deposited on soils of Northeastern Japan located predominantly within a ~3000 km2 radioactive fallout plume and drai...

Bacterial pathogens in surface waters threaten human health. The health risk is especially high in developing countries where sanitation systems are often lacking or deficient. Considering twelve flash-flood events sampled from 2011 to 2015 at the outlet of a 60-ha tropical montane headwater catchment in Northern Lao PDR, and using Escherichia coli...

Intensification of agricultural practices during the second half of the 20th century has accelerated of soil erosion around the world. Although this phenomenon has been widely investigated through a combination of monitoring or modelling at short timescales (<10 years), few records are available for reconstructing the trajectory of soil erosion dur...

In recent years, several sediment fingerprinting studies have used ultraviolet–visible (UV–Vis), near-infrared (NIR) and middle-infrared (MIR) spectroscopy as a low cost, non-destructive and fast alternative to obtain tracer properties to estimate sediment source contributions. For this purpose, partial last square regression (PLSR) has often been...

No‐till (NT) is a conservation system that improves the hydrological regime of agricultural slopes by providing greater surface protection and benefits to the physical and hydrological properties of soils. However, the isolated use of NT is not enough to control runoff and its associated degradation processes. Therefore, this study aimed to evaluat...

Owing to the rapid expansion of agriculture in South America in recent decades, soil erosion and fine sediment supply to river networks, which lead to deleterious on-site and off-site environmental impacts, are exacerbated in intensively cultivated catchments. Measuring soil inventories of bomb-derived fallout radiocesium (¹³⁷Cs) bound to fine part...

The widespread use of pesticides in agriculture during the last several decades has contaminated soils and different Critical Zone (CZ) compartments, defined as the area extended from the top of the vegetation canopy to the groundwater table, and it integrates interactions of the atmosphere, lithosphere, biosphere, and hydrosphere. However, the lon...

The source dynamics of total and dissolved material in riverine systems are being affected by anthropogenic activities resulting in the degradation of waterways worldwide. Identifying the main sources of total and dissolved material is thus central to the management of increasingly scarce water resources. Here, we utilize data generated from water...

The Fukushima nuclear accident in March 2011 generated a 3000 km 2 plume of soils heavily contaminated with 137 Cs. Decontamination was completed early in 2019. Typhoon Hagibis was the first extreme event that occurred in the region after decontamination. Its impact on sediment sources and sediment 137 Cs contamination was investigated through the...

Purpose This review of sediment source fingerprinting assesses the current state-of-the-art, remaining challenges and emerging themes. It combines inputs from international scientists either with track records in the approach or with expertise relevant to progressing the science. Methods Web of Science and Google Scholar were used to review publis...

Le ruissellement est un phénomène épisodique et localisé, donc difficile à mesurer. Il résulte de l'interaction de nombreux facteurs, dont les caractéristiques intrinsèques et de surface du sol, la morphologie du bassin versant, mais également les caractéristiques pluviométriques. Afin d'améliorer la compréhension de la genèse et de la propagation...

Background, aim, and scope The release of trace elements (TE) associated with the development of human activities has accelerated since the nineteenth century, leading to the pollution of river systems. Despite a drastic reduction in industrial inputs in northern Europe, diffuse pollution originating from urban areas still prevents achieving the g...

Soil erosion, runoff and sediment connectivity are strongly impacted by anthropogenic features in lowland agricultural catchments. Among these landscape features, the role played by tile drainage on water and sediment transfers and hillslope-to-river connectivity in drained catchments remains poorly understood. This study quantified water and sedim...

Opencast mining has exacerbated land degradation in New Caledonia, a French archipelago located in the south-west Pacific Ocean. Developed since the 1880s, mining has become the major economic activity in some catchments, which strongly disrupted sediment dynamics. Reconstructing the temporal changes of sediment source contributions is essential to...

Soil erosion on agricultural land is associated with deleterious off-site impacts including the siltation andthe pollution of the receiving water bodies. To better manage this situation, local/regional water agencies needspatially-distributed information to compare the sensitivity to erosion of the areas draining into these water bodiesand supplyin...

Over the last century, human activities have induced significant land-cover changes that have accelerated soil erosion processes around the world. In New Caledonia, a French island located in the south-west Pacific Ocean, open-cast nickel mining has raised many concerns regarding its impact on riverine systems (i.e. hyper-sedimentation, overburden)...

Este livro tem o objetivo de demarcar as ações iniciais do projeto Nexus Pampa o qual adota uma abordagem transdisciplinar e participativa delimitando a bacia do Rio Ibirapuitã como área do estudo. Ao partimos destas premissas podemos explorar fatores ligados à importância da água, da energia e do alimento e suas interrelações, conforme a abordagem...

Solute and particulate elemental concentrations (C) exhibit different responses to changes in discharge (Q), and those relationships are not well understood in subtropical agricultural environments. The objective is to describe the transport processes of different chemical elements during a set of contrasted rainfall events (2011–2015) that occurre...

Free access for 50 days https://authors.elsevier.com/a/1bT~N1Dk5AOy2J An important step in the sediment source fingerprinting approach is the selection of the appropriate tracing parameters to maximize source discrimination. The use of multiple tracing properties may reduce uncertainties and increase discrimination between sources. Accordingly, th...

Global nuclear weapon testing and the Chernobyl accident have released large amounts of radionuclides into the environment. However, to date, the spatial patterns of these fallout sources remain poorly constrained. Fallout radionuclides (137Cs, 239Pu, 240Pu) were measured in soil samples (n = 160) collected at flat, undisturbed grasslands in Wester...

eDNA refers to DNA extracted from an environmental sample with the goal of identifying the occurrence of past or current biological communities in aquatic and terrestrial environments. However, there is currently a lack of knowledge regarding the soil memory effect and its potential impact on lake sediment eDnA records. to investigate this issue, t...

Environmental pollution by polychlorinated biphenyls (PCBs) is a key cause for concern about river quality because of their low degradation rates leading to their accumulation in sediments and living organisms. An original interdisciplinary work was conducted along the four main French rivers (Seine, Rhône, Loire and Garonne rivers), which flow int...

The reconstruction and modelling of contamination trajectories in rivers is a key concern to investigate spatio-temporal impacts of long-term anthropogenic activities. This issue is highly significant for persistent organic pollutants, such as polychlorinated biphenyls (PCBs), known for their toxicity, their low degradation rates and their hydropho...

The ¹⁰Be, ¹³⁷Cs and ²¹⁰Pbxs radionuclide fallout has been used for the last several decades to quantify various soil and geomorphological processes on different time scales. However, a basic assumption of the studies relying on these radionuclides is that they have a strong affinity for soil particles and that their mobility in soil solution and lo...