Rivers of salt: the extent of salinization in European running waters
Abstract
Freshwater salinization is emerging as a widespread but poorly documented challenge across Europe. Using random forest models applied to river-reach scale data, this study provides a continent-wide quantification of salinization and identifies its key drivers. Of the 35 countries with available data, we demonstrate that 28 contained rivers where salinity more than doubled relative to baseline, with increases reaching up to 11,377 µS/cm. Across the European river network, 14% showed salinity increases of up to 100% and a further 26% up to 50%. The analysis revealed previously underreported hotspots, notably catchments in Romania and Hungary. More than 23,000 km of river network, around 2% of the total, exceeded 1 mS/cm, surpassing international standards for aquatic life protection and raising the risk of altered community structure, disrupted ecosystem function, harmful algal blooms, and fish mortality. Salinity exceeded drinking water limits in 1% of the network and irrigation and industrial limits in 3%. Salinization is driven by natural factors, such as evaporation, soil composition, and rock weathering, and by human pressures, highlighting the need for further research and Europe-wide salinization standards aligned with the Water Framework Directive.
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BibTeX
@article{crabot2026rivers,
title = {{Rivers of salt: the extent of salinization in European running waters}},
author = {Julie Crabot and Sandra Mingarelli and David Cunillera Montcusi and Gary Free and Daniel Hernández-Carrasco and Martyn Kelly and Álvaro Javier Moyano-Salcedo and Ralf B. Schäfer and Miguel Cañedo-Argüelles},
journal = {Nature Communications},
year = {2026},
month = nov,
doi = {10.1038/s41467-026-76477-5},
url = {https://hal.science/hal-05854087v1},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Rivers of salt: the extent of salinization in European running waters
AU - Julie Crabot
AU - Sandra Mingarelli
AU - David Cunillera Montcusi
AU - Gary Free
AU - Daniel Hernández-Carrasco
AU - Martyn Kelly
AU - Álvaro Javier Moyano-Salcedo
AU - Ralf B. Schäfer
AU - Miguel Cañedo-Argüelles
PY - 2026
DA - 2026/11/05
JO - Nature Communications
DO - 10.1038/s41467-026-76477-5
UR - https://hal.science/hal-05854087v1
AB - Freshwater salinization is emerging as a widespread but poorly documented challenge across Europe. Using random forest models applied to river-reach scale data, this study provides a continent-wide quantification of salinization and identifies its key drivers. Of the 35 countries with available data, we demonstrate that 28 contained rivers where salinity more than doubled relative to baseline, with increases reaching up to 11,377 µS/cm. Across the European river network, 14% showed salinity increases of up to 100% and a further 26% up to 50%. The analysis revealed previously underreported hotspots, notably catchments in Romania and Hungary. More than 23,000 km of river network, around 2% of the total, exceeded 1 mS/cm, surpassing international standards for aquatic life protection and raising the risk of altered community structure, disrupted ecosystem function, harmful algal blooms, and fish mortality. Salinity exceeded drinking water limits in 1% of the network and irrigation and industrial limits in 3%. Salinization is driven by natural factors, such as evaporation, soil composition, and rock weathering, and by human pressures, highlighting the need for further research and Europe-wide salinization standards aligned with the Water Framework Directive.
SN - 2041-1723
SN - 2041-1723
ER -