Final answer:
Excessive amounts of fluoride in drinking water may cause discoloration of the teeth.
Step-by-step explanation:
Excessive amounts of fluoride in drinking water may cause discoloration of the teeth. Fluoride is often added to drinking water to prevent tooth decay and strengthen teeth. However, when fluoride levels are too high, it can lead to dental fluorosis, which is a cosmetic condition that causes white or brown stains on the teeth. This is more common in areas with naturally high levels of fluoride in the groundwater. It's important to regulate fluoride levels in drinking water to avoid this issue.