This dataset is a subset of the "WFD Classification Status Cycle 2" product. It contains summary data for the element ammonia for river water bodies, as used in the classification for Ecological status for the water framework directive (WFD). The ammonia classification dataset is an element of the physico-chemical group or element set and is used to consider particular phyisco-chemical conditions. Ammonia is hazardous due to its toxic and sub-lethal impacts on fish and macro-invertebrates. It is a decay product of nitrogenous organic wastes and of the breakdown of animal and vegetable wastes. Classifications are derived from spot sampling monitoring data, the results of which are calculated into percentiles and assessed against two different environmental quality standards (EQS), which are derived from site typology. Site classifications for ammonia use categories of High, Good, Moderate, Poor, and Bad. Attribution statement: © Environment Agency copyright and/or database right 2016. All rights reserved.