EU countries: Denmark, Germany, Finland, France, Sweden, UK. Accession countries: Bulgaria, Estonia, Hungary, Latvia, Lithuania, Poland, Slovak Republic, Slovenia. Background or natural concentrations of ammonium in rivers will vary across Europe and from river type to river type. The figure above gives a level that might be considered to be at the lower level of the ranges reported to be representative of ?background. concentrations. Ammonium exerts a demand on oxygen in water as it is transformed to oxidised forms of nitrogen. In addition it is toxic to aquatic life at certain concentrations in relation to water temperature, salinity and pH.
