Abstract
Concerning WHO guideline for drinking-water quality (1984), some general matters such as its history, content and meaning were described. The bacteriological items in the guideline, chemical substances playing a main role in the guideline, its relation to animal assays, estimation and safety coefficient of the values in the guideline, and the relationship of its threshold or carcinogenic substances to risk assessment obtained by use of mathematical models were also described. Moreover, after describing inorganic components having an influence on the health, organic components relating to the health (a. selection of organic chemical substances, b. carcinogenic organic subtances), appearance, odor or radioactive materials, the future of the guideline was further mentioned.
