The relationship between groundwater quality and landuse was examined on a regional scale for Nobeyama district, Nagano Prefecture which is a large-scale agricultural zone and has a lot of dairy farms in the region. NO3-N, SO42-, Ca2+ and Mg2+ of high concentrations were detected in areas where agricultural activity was high. The concentration of groundwater composition of shallow wells was higher than that of spring water. In particular, high concentrations of NO3-N and SO42- were detected in shallow wells. These show that the effect of human activities for the shallow-well water is stronger than that for the spring water. Many strong correlations were found between the groundwater compositions of the shallow wells, whereas not so many in the spring waters. This suggest that the shallow groundwater quality rapidly reacts to the human impact in limited region. The hexadiagram show that the groundwater has much larger NO3-N and Ca2+ concentrations than the groundwater of the non-polluted control site. The present results indicate that not only NO3-N, Cl-, Ca2+ and Mg2+ but also SO42- could be groundwater composition indicators in an agricultural region like Nobeyama district.
