This paper discusses the Brazilian National Council legislation (Resolutions 357/2005 and 397/2008) standards for ammonia composts in water and effluents. Standards indicated by resolutions are compared to those from previous Conama Resolution 20/1986 and with North American standards. It is concluded that the new ammonia limit concentrations, from Resolution 357/2005 for water bodies and industrial effluents and the elimination of effluent concentration limits for sanitary effluents, by Resolution 397/2008, represent an advance over previous Brazilian standards by considering the pH influence on the distribution and toxicity of ammonia composts, increasing the maximum total ammonia concentration for industrial effluents and eliminating maximum total concentration limits for sanitary effluents. However, the Resolution 357/2005 does not take into account temperature influence on these distribution and toxicity.
ammonia; Conama Resolution 357/2005; Conama Resolution 397/2008
