High concentrations of fluoride and boron in drinking water wells in the Muenster region - Results of a preliminary investigation

In 1998, two cases of severe dental fluorosis in schoolchildren occurred in the Muenster region. These cases took place in one household, where fluori dated toothpaste, fluoridated salt, and fluoride tablets were consumed. Fur thermore, the family used drinking water from its private well only. Analys es of the well water ordered by local health officials revealed very high a mounts of fluoride, boron, and other electrolytes. This unusual combination of high amounts of fluoride and boron could also be found in the water of a great number of other private wells that are the only source for drinking water in this rural region of the Muensterland. Anthropogenic sources coul d be excluded. Because of this, the results of the water samples were colla ted to the specific geological situation in this area. In the Muenster regi on there are marl layers of the chalk era covered with quarternary sediment s. The quarternary sediments are up to 10 to 20 metres thick and they usual ly conduct the groundwater. The marl contains high concentrations of fluori de and boron. In some places the groundwater has contact with these layers. To check the amount of fluoride and boron in the groundwater, indicator va lues were sought, which can give a hint of high contents of these trace ele ments. In this study the conductivity and acidity were identified as possib le indicators of a high amount of fluoride and boron in the drinking water in this specific region. To work economically and efficiently, the drinking water should be checked for fluoride and boron on a regular basis only whe n these values are extraordinarily high. In the case of high concentrations , especially of fluoride, in the drinking water the persons concerned shoul d be informed about their potential health risk, giving them the opportunit y to optimise the total daily intake of fluoride.