Efficacy of subsurface denitrification to attenuate nitrate in shallow groundwaters

Our preliminary results indicate occurrence of complete ‘benign’ denitrification in the reducing shallow groundwater sites with lower dissolved oxygen (DO) contents (DO < 1mg L-1), as compared with the oxidizing shallow groundwater sites (less-reducing) with higher DO contents (DO > 1mg L-). This study is continued with further monitoring and experiments for examination of processes and regulatory factors driving subsurface denitrification in shallow groundwaters in the Manawatu and Rangitikei River catchments.