A recent revision of Japan’s Guidelines for Management of Sanitation, Etc. in Public Bathhouses (Ministry of Health, Labour and Welfare) added an evaluation method using total organic carbon (TOC) to the methods for measurement of the organic content of inlet hot water, original water, and bathtub water used in public bathhouses in addition to the existing method based on potassium permanganate consumption.
At some public baths, hot spring water is used as inlet hot water and bathtub water, but this type of water sometimes contains chlorides, sulfates, and alkali salts originating from the hot spring. Although the measured values obtained in the potassium permanganate consumption test may be affected in some cases if the sample contains oxidizable substances other than organic compounds, TOC measurements are not affected by coexistent substances.
This article introduces an example of evaluation of the organic content in hot spring water used as bathhouse water and water containing bathing agents using a Shimadzu combustion-type TOC analyzer.