German studies on health effects of inorganic drinking water constituents

The influence of drinking water quality on mortality and morbidity of various diseases has been studied for more than 20 years. From these diseases, those of the cardiovascular system have been playing a special role. Better and more specified information on the differences in the composition of drinking water may essentially contribute to a solution of the problem of association between water quality and the incidence of diseases. In more than 600 water supply areas in the Federal Republic of Germany the composition of the drinking water has been analyzed. From these data, areas of different water quality are to be selected for additional investigations of the problem of health relevance of drinking water quality. So far, the following constituents of drinking water have been measured: Na, Ca, Mg, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn, SO4, PO4, NO3, NO2, Cl, F, I, etc. The methods of analysis used were atomic absorption spectrometry, plasma emission spectrometry, and ion chromatography. Additionally, more than 19 000 data on drinking water in accordance with standard analytic procedures under the Drinking Water Regulations are available in a comprehensive data bank (BIBIDAT). There have been studies establishing associations between water hardness and cardiovascular diseases but also studies which do not confirm this association or even present converse results. Also water constituents like magnesium, cadmium, etc. have been associated with cardiovascular diseases. Some investigations have shown correlations between e.g. the concentration of fluoride in drinking water and caries or iodide and goitre.