GENERAL CONSIDERATIONS OF MINERAL INTAKE FROM WATER

The initial undertaking of the first Safe Drinking Water Committee (SDWC) was the identification of substances and their concentrations in the nation's water supply that might pose risks to the public health and, therefore, require the setting of limits. The committee's report, Drinking Water and Health (National Academy of Sciences, 1977) contained gaps for which data were not available or were just emerging at the time the report was written. In other cases, the data were not reviewed in depth because the specific substances were not considered pertinent to the initial charge of the committee, i.e., identification of adverse consequences of various substances in water.

One such area was that of nutrients, known to be essential or strongly suspected as being necessary for optimal health of humans and animals. While a few of the nutrients, notably the trace elements, were reviewed in the first report, the coverage was generally toxicological. The committee examined them as sources of potential risk to human populations.

In view of these considerations, the second Safe Drinking Water Committee established a Subcommittee on Nutrition and charged it with the responsibility of reviewing this area by selecting elements of interest and evaluating the effects of their presence in water. In this report, the subcommittee has examined the concentrations of nutrients in drinking water and the contribution of these concentrations to the observed intake and optimal nutrient requirements of human populations. It studied the benefits of the presence of an element in water and, in cases in which symptoms of both deficiency and toxicity are known to occur, adverse effects. This is a departure from most of the studies of the SDWC conducted previously or in progress, which were or are limited to adverse effects. The subcommittee chose to tide this review The Contribution of Drinking Water to Mineral Nutrition in Humans, focusing on the positive effects of suites of elements that are known or assumed to interact in the environment or in biological systems.