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Ammonium

Annual ammonium concentrations decreased by 10.93 µg/l per year (-2.6% per year) on average over the period 1992-2020 (Figure 1b). Significantly decreasing concentrations were observed at 74% of the sites, with an additional 4% of the sites showing a marginal decrease. No change has been observed at 20% of the river monitoring sites. A significant increase was evident at 1% of the sites.