Spatial and Temporal Variation of Ground Water Quality in Sand Dune Area of Aomori Prefecture in Japan

Abstract

To develop the best management practice for agricultural land of sand dune area forsustainable crop production and conservation of surrounding environment, ground water qualityis to be evaluated. The objective of the present study was to investigate the spatial andtemporal variation of ground water quality in sand dune area of Tsugaru city in AomoriPrefecture, Japan. Three observation wells were installed with three plastic tubes to collectground water of 2.0 m, 2.5 m and 3.0 m depth. Ground water samples were analysed forelectrical conductivity (EC), pH, concentration of Fe, K, NO3-N, and PO4-P. Soil environmentfrom 0.1 m through 3.0 m was also evaluated. The results showed that EC, pH, and Kconcentration in ground water were decreased with increasing depth throughout theinvestigation period whereas Fe concentration was increased. The ground water of the studyarea was found not suitable for sprinkler irrigation since concentration of Fe was more than 1.5mg L-1. Average concentrations of NO3-N and PO4-P in ground water of the study area were0.029 mg L-1 and 0.062 mg L-1, respectively. Soil environment at the depth of 0.1 m and 0.5 malways showed oxidized condition (oxidation-reduction potential >300 mv). On the other handsoil environment at the depth of 2.5 m and 3.0 m showed reduced condition (oxidation-reductionpotential <300 mv) during the study period. Soil environment at 1.5 m depth was found oxidizedin the month of April, July, September and October, and reduced in the month of May, June,August and November. This might be due to fluctuation of ground water level. Because ofpresence of very low concentration of NO3-N and PO4-P in ground water, there may not be anythreat to human health and environment.