Percentage of river stations per country with significant increasing, stable or decreasing total ammonium trend between 1992 and 2006

• Albania
• Austria
• Belgium
• Bosnia and Herzegovina
• Bulgaria
• Denmark
• Estonia
• Finland
• France
• Germany
• Hungary
• Ireland
• Italy
• Latvia
• Lithuania
• Luxembourg
• North Macedonia
• Netherlands
• Norway
• Poland
• Slovenia
• Spain
• United Kingdom

Time series trends have been calculated using only stations that have recorded concentrations for at least seven of the years included in the time series. Sen''s Test then applied to determine statistically significant trends in the data (see Methodology section for further details).