Nitrate has been identified as, and remains, a major water quality issue in the UK, and it originates as a diffuse pollutant in all of the major aquifers and many of the minor aquifers of England and Wales. Considerable scientific effort has been devoted to understanding and quantifying the behaviour of nitrogen inputs from normal agricultural practices, and their transport to groundwater.
However, there are other potential sources of nitrate which can affect groundwater. Some of these activities are completely non-agricultural, whilst others are non-arable agricultural, and most are poorly characterised and quantified at present.
Under the Nitrate Directive, review of existing Nitrate Vulnerable Zones (NVZs) and new candidate NVZs will be carried out every four years. Scientifically robust yet relatively simple methods need to be used for establishing a balanced perspective of the
contributions from non-agricultural, non-arable agricultural and arable agricultural activities.