Abstract
The water quality of ground waters (spring and deep-well waters) in the Kitatama area of Tokyo was studied once a week during the two-year period 1986-1988. Nitrate nitrogen concentrations in spring water at station N-0 along Kokubunji Cliff ranged from 467 to 653μgat⋅l-1, with high concentrations in winter and low in summer. The secular change of spring water at N-0 during the 13 year period 1976-1988 showed that discharge and chloride ions concentrations tended to decrease, while nitrate nitrogen concentrations tended to increase gradually. In spring waters along Kokubunji Cliff, nitrate nitrogen concentrations showed high values over 800μgat⋅l-1. Nitrate nitrogen concentrations in two deep-well waters were lower (W-1: 353-609μgat⋅l-1, W-2: 143-253μgat⋅l-1) than those in spring water (shallow ground water) along Kokubunji Cliff.
