The map shows the mean annual concentration of orthophosphates (OP), expressed as milligrams of PO4-P per litre of water, observed in river monitoring stations and reported by EEA member countries via WISE. For most countries the mean annual value is based on observations over the whole year, whereas some countries only collect samples during the growing season (due to ice cover in winter).
High or increased (compared to reference condition) concentration of phosphates represents a risk to normal functioning of river ecosystems, causing eutrophication with potentially excessive growth of benthic algae or other aquatic vegetation, oxygen deficiency in the bottom substrate and reduced biodiversity.
The purpose of the map is to provide an overview of the mean annual value of orthophosphates in rivers across Europe and to enable the user to compare values per country, River Basin District (RBD) or individual monitoring station, depending on the scale of visualisation. Historical data since 1993 can be displayed using the time slider.