A study on Quality of Drinking Water

埼玉県越谷市There is a lively discussion on the so-called "tasty drinking water" recently. In order to approach the question of what the tasty drinking water is, we analyzed four types of drinking water. First type of samples were collected from the city water in Hokuriku and Chubu block where the fresh source of water were supplied from near moutain-side. Second type of sampes were collected from the city water in Kanto block where the source of water were supplied through long distance from origin. Third type of samples were the commericialized drinking water which was available to buy at shopping market as today's tasty drinking water. Fourth type of samples were natural water which have been known well as tasty drinking water. As a result of the study, we reached the following results. 1. The Question of city water in each block is different each other in the consumption of potassium permanganate (KMnO4), residual cholrine and the total water hardness. As for the residual chlorine, it is high concerntration in Chiba prefectures paticulary. All water samples from Kanto block (Chiba and Saitama) show higher residual chlorine than the guideline of the tasty drinking water. Generally, high contamination and concentraion above chemicals depends on the polluted sources of water in Kanto block. 2. For the concentration of hydrogenion (PH), part of commercialized drinking water does not accord with quality of drinking water standard stipulated in the City Water Law. And as for the total water hardness and the contamination of potassium permanganate (KMnO4), there is commercialized drinking water that does not satisfy the requirements in the guideline for the tasty drinking water. This shows that the water quality of commercialized drinking water is not necessarily superior to that of city water. 3. As for natural water most of samples have about 55ppm of water hardness, and the comsumption of potassium permanganate (KMnO4) in all samples analized is in conformity with the reguirements in the guideline for the tasty drinking water. Concentration of calcium is higher than commercialized drinking water. Totaly natural water shows high quality for drinking water. 4. It is important for us, which is blessed with comparatively high quality of natural water, to raise our qwareness of the purification of the quality of drinking water by mentioning the water pollution in the sources of water supply rather than acceping commercialized drinking water which is not different from natural water in quality