The U.S. Public Health Service (USPHS) Drinking Water Standards of 1946 are currently being re‐examined in preparation for revision incorporating new knowledge acquired in the subsequent years. In establishing limits on concentrations of certain metals in drinking water, one of the several factors that must be considered is taste threshold. The technical literature is, unfortunately, lacking in such data. The study reported here was undertaken to provide taste threshold data on copper, iron, manganese, and zinc for consideration in the revised standard. The results of the study are summarized in 5 per cent and 50 per cent points on the cumulative frequency distributions of taste threshold concentrations are shown for each metal.

This is the first of three articles on the effect of fish poisons on water supplies. Parts 2 and 3, to be published in later issues of the Journal, will deal with odor problems and a field study, respectively. This article discusses the removal of toxic materials from the water supply source, particularly related to fish management practices. Managers of fisheries sometimes find it necessary to remove an entire fish population from a body of water to eliminate stunted populations or coarse fish, and to enable restocking with fry or fingerlings of suitable species for recreational sport fishing. Much work has been done on the development of suitable piscicides. Cost, ease of application, safety, and effectiveness in destroying fish populations are the major considerations in the selection of a compound. The deliberate addition of a fish toxicant to a water supply source requires careful appraisal of its effect on water quality and safety, including the following: toxicity of active agents to humans, other mammals, and to fish in household aquariums; effects of fish poison formulations and components on water treatment processes and, conversely, the effects of treatment on these compounds; tastes and odors produced by the components of the formulations; and, effects on water quality that may result from decomposing fish. Activated carbon treatment is discussed as far as its effectiveness in removing small amounts of organic material, along with the effectiveness of chlorine in removing known amounts of fish poisons, and the use of chlorine dioxide for removing taste and odor problems.

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This article discusses the effectiveness of water treatment processes in coping with relatively small concentrations of pesticides in raw water. Duplicate pilot water treatment plants at the Taft Center were used to evaluate the effectiveness of conventional and auxiliary treatment processes. The methods and procedures used included: the chromatographic method; solubility and incidental loss; coagulation and filtration; chlorine; potassium permanganate; ozone; powdered activated carbon; and, granular activated carbon.