'Excellent Waters in Hiroshima': A Review of Pioneering Endeavours of Water-Tasting and Water-Quality

Abstract

Japan, the country of high-Technology, is a clean and tidy nation that has an abundant supply of very high quality water Hiroshima, because of its geography and climate, is endowed with an abundance of fresh-water. Moreover, practically all the good waters of Hiroshima are soft, with the highest recorded hardness of 120 mg/l. Many of these waters from the springs and wells in the granitic terrains of Hiroshima are rich in Radon (Rn). The average concentrations of ²²²Rn Ci/litre of water are in the order of 80 x 10^-10 and the highest recorded concentration is at Onomichi Toraku Station (647.2 x 10^-l0) (pers commn, Prof Ken Sasaki). These Rn-rich waters are traditionally believed to be health-giving and restorative.

In Hiroshima, Prof Ken Sasaki has pioneered water-tasting as an independent branch of science. Currently esoteric, water-tasting makes use of water chemistry, presence of dissolved solutes and minerals in water, and the science of tasting by human palate. Chemical analyses and sensory tests carried out on 82 samples of well, spring, river, and commercial mineral waters showed good correlation for organic matter, total hardness, iron and bicarbonate. Multiple regression analyses using these four chemical constituents produced correlation coefficients of 0.8217 for Hiroshima (n = 47) and 0.8401 for other districts (n = 35) (Sasaki et al 1996). Fuzzy reasoning, when applied to the evaluations of palatable water, where the chemical constituents organic matter, total hardness, iron and bicarbonate formed the four input variables, and sensory test, produced a correlation coefficient of 0.8621 (Iwanaga and Sasaki, 1996).