Information subsystem of total hardness (Ca + Mg) as a database for studying its influence on human health.

Dalmatia (Southern Croatia) belongs to the Dinaric karst region. The permeability of karst soil allows a great quantity of dissolved organic and toxic matter rendering it hygienically unsafe. The hinterland of the Dinaric karst region is relatively scarcely populated since the largest agglomeration of population and industry is in the coastal zones. Hence, most of the surface flow have preserved their natural characteristics. The water supply authorities and health care institutions are especially interested in observing and monitoring water quality. A relational database has been developed for carrying out chemical analyses expressed by total hardness (Ca + Mg) since it is necessary to organize and integrate a large number of analytical and ecological health-data. The database can serve as a methodological platform for the study of environmental factors influencing human health. The prototype database consists of data obtained by investigations which have been conducted by the Water Examination Department of the Public Health Institute, Split-Dalmatian County (Croatia) and the University of Split Medical School. The database currently contains more than 3000 data.