Relationship between water chemistry and human impact on adjacent springs in urban area:Possibility as a teaching material of natural science education in Japanese elementary school

Abstract

Seasonal changes in water chemistry and the influence of human impact on three adjacent springs and rainwater were investigated from 2015 to 2017. Subsequently, the results of this survey were used as teaching materials for science practical classes for elementary school students aged from10 to 11 years old. The water chemistry of the rainwater, the origin of the spring water, had a pH ranging from 4.4 to 5.3, electric conductivity 2 mS m^-1, and dissolved inorganic nitrogen (DIN) 470 μgN L^-1. The spring water in Kinmeisui, a place unaffected by human impact, had a pH ranging from 5.1 to 5.5, electric conductivity 2 mS m^-1, DIN 13 μgN L^-1. In the spring water of Motoyama, a place affected by human impact, the pH ranged from 5.8 to 6.5, electric conductivity 10 mS m^-1, and DIN 2000 μgN L^-1. Environmental parameters of Sugiyama elementary school located in the urban area had a pH ranging from 6.3 to 9.5, electric conductivity 24 mS m^-1, and DIN 5000 μgN L^-1. In the one spring closer to the city center, the water chemistry changed from weakly acidic to neutral and weakly alkaline with high values of electric conductivity and DIN concentration. This clarified that human impact on urban areas significantly affected the quality of the spring water. The science practical education was conducted for fifth-grade students in a Japanese elementary school while learning topics on the rivers and streams. The practice was themed 'A headwater of the urban river from Sugiyama elementary school'. The practice was aimed at answering these questions: First, do rivers start from the spring water on the slope? and second, how does human impact affect the water chemistry of the spring? We introduced topographical analysis using the 3D function of GSI Maps and colourimetric analysis of NO₂^--N concentration by a standard method. The fascinating contents for the students during the practical were the analysis of NO₂^--N concentration, and the spring as the headwater of the urban river, respectively. The students were evaluated based on the aims of this practice, and results showed that springs can be used as a science teaching material. Furthermore, we proposed four future studies to improve the quality of the science teaching materials, namely: the origin of the high concentrations of DIN in spring water located in urban areas, measurement of educational efficiencies, introduction into the subject education, and teaching materials for disaster education.