Anthropogenic legacy of potassium-40 in French large rivers reconstructed from sediment cores.

Environmental imprint of inorganic fertilizer uses was assessed over the last hundred years at the downstream part of large French rivers (Loire, Moselle, Rhine, Rhone, Meuse and Seine rivers) based on Potassium-40 (K) activity concentration data sets acquired from soil monitoring (1980-2022) and from sediment coes collected from 2020 to 2022 to reconstruct the temporal trajectories of K activity concentrations since the beginning of the last century. Cultivated soils were significantly enriched in K compared to non-cultivated ones in the 1980s and 1990s when they turned back to the contents of non-cultivated soils during the following decades. In riverine sediments, all the rivers displayed close K temporal trajectories with peaking K contents in fine grain size sediments in the 1980s.

Temporal trajectories of artificial radiocaesium Cs in French rivers over the nuclear era reconstructed from sediment cores.

Cs is a long-lived man-made radionuclide introduced in the environment worldwide at the early beginning of the nuclear Era during atmospheric nuclear testing's followed by the civil use of nuclear energy. Atmospheric fallout deposition of this major artificial radionuclide was reconstructed at the scale of French large river basins since 1945, and trajectories in French nuclearized rivers were established using sediment coring. Our results show that Cs contents in sediments of the studied rivers display a large spatial and temporal variability in response to the various anthropogenic pressures exerted on their catchment.

Contrasting platinum trajectories in three major French rivers using dated sediment cores (1910-2021): From geochemical baseline to emerging source signals.

Platinum (Pt) is a Technology Critical Element (TCE) which, since the 1990s, has been mainly used in the industry in catalytic converters for automobile emission control. Previous studies have shown Pt contamination of road-side sediments and surface sediments in urban rivers and lakes but few of them have addressed temporal variations. The present work presents historical Pt concentration trends in Cs-dated sediment cores from floodplains or secondary channels at the outlets of three major French watersheds (Loire, Rhone, and Seine Rivers) covering the past ∼110 years, i.

Temporal evolution of plastic additive contents over the last decades in two major European rivers (Rhone and Rhine) from sediment cores analyses.

Although global plastic distribution is at the heart of 21st century environmental concerns, little information is available concerning how organic plastic additives contaminate freshwater sediments, which are often subject to strong anthropogenic pressure. Here, sediment core samples were collected in the Rhone and the Rhine watersheds (France), dated using Cs and Pb methods and analysed for nine phthalates (PAEs) and seven organophosphate esters (OPEs). The distribution of these organic contaminants was used to establish a chronological archive of plastic additive pollution from 1860 (Rhine) and 1930 (Rhone) until today.

Deciphering sources of U contamination using isotope ratio signatures in the Loire River sediments: Exploring the relevance of U/U and stable Pb isotope ratios.

A broad range of contaminants has been recorded in sediments of the Loire River over the last century. Among a variety of anthropogenic activities of this nuclearized watershed, extraction of uranium and associated activities during more than 50 years as well as operation of several nuclear power plants led to industrial discharges, which could persist for decades in sedimentary archives of the Loire River. Highlighting and identifying the origin of radionuclides that transited during the last decades and were recorded in the sediments is challenging due to i) the low concentrations which are often close or below the detection limits of routine environmental surveys and ii) the mixing of different sources.