The analysis, published in Environmental Science and Pollution Research, suggests that despite a general improvement in European river quality in recent years, the pace is insufficient to meet the environmental objectives set for 2030. The study examined data from 2015 to 2021.
Organic pollution decreased in 14 out of 18 countries studied, and phosphate concentrations fell in 11 out of 16. However, only Slovenia maintains a trajectory fully compatible with the 2030 goals. Finland, Estonia, Ireland, Italy, and Denmark also show a favorable situation but need to maintain or strengthen their management policies.
María Pachés, the study's lead author, emphasizes the importance of analyzing not only the current state of rivers but also the speed of improvement to ensure objectives are met.
Belgium, Bulgaria, Lithuania, Romania, Sweden, and Spain are among the countries facing the greatest challenges. In Spain's case, the organic pollution load remains high, and phosphate concentrations increased between 2015 and 2021. "This trend moves us away from the 2030 environmental goals and highlights the need to strengthen actions aimed at controlling nutrient inputs into riverine ecosystems," explains Remedios Martínez, an IIAMA-UPV researcher.
To reach these conclusions, the team developed the Human Pressure on River Ecosystems (HPRE) indicator, a methodology that assesses human pressure on river ecosystems using Eurostat data. This indicator combines biochemical oxygen demand (related to organic pollution) and phosphate concentration (associated with eutrophication).
The researchers attribute the improvements detected in many countries to advances in wastewater collection and treatment and to regulations aimed at reducing nutrient discharges. Nevertheless, they stress that measures will need to be intensified across much of Europe, including controlling urban, industrial, and agricultural runoff, and harmonizing monitoring systems.
The HPRE indicator helps identify territories under greater pressure, evaluate policies, and guide investments. However, it is considered a diagnostic tool that should be complemented with biological and hydromorphological variables for a comprehensive ecological assessment.
