Factors Affecting Nitrate Distribution in Shallow 6 Groundwater under a Beef Farm in South Eastern Ireland

18 Groundwater contamination was characterised using a methodology which combines 19 shallow groundwater geochemistry data from 17 piezometers over a 2 yr period in a 20 statistical framework and hydrogeological techniques. Nitrate-N (NO3-N) 21 contaminant mass flux was calculated across three control planes (rows of 22 piezometers) in six isolated plots. Results showed natural attenuation occurs on site 23 although the method does not directly differentiate between dilution and 24 denitrification. It was further investigated whether NO3-N concentration in shallow 25 groundwater (<5 m below ground level) generated from an agricultural point source 26 on a 4.2 ha site on a beef farm in SE Ireland could be predicted from saturated 27 hydraulic conductivity (Ksat) measurements, ground elevation (m Above Ordnance 28 Datum), elevation of groundwater sampling (screen opening interval) (m AOD) and 29