Normal safe limit of Fluoride content in drinking water is
**Core Concept**
Fluoride content in drinking water is a crucial public health measure for preventing dental caries, but excessive intake can lead to dental fluorosis and skeletal fluorosis. The World Health Organization (WHO) has established guidelines for optimal fluoride levels in drinking water to balance these benefits and risks.
**Why the Correct Answer is Right**
The recommended safe limit of fluoride content in drinking water is 0.5-1.5 milligrams per liter (mg/L) as set by the WHO. This range allows for the prevention of dental caries while minimizing the risk of dental and skeletal fluorosis. The optimal fluoride concentration in water is typically around 1 mg/L, which is sufficient to provide the benefits of fluoride without causing adverse effects. The fluoride content in water is regulated by the interaction of fluoride ions with the calcium and phosphate ions in saliva and tooth enamel, which helps to prevent the demineralization of tooth enamel and the formation of dental caries.
**Why Each Wrong Option is Incorrect**
**Option A:** There is no scientific evidence to support the claim that a fluoride content of 0.1 mg/L is safe in drinking water. This level is too low to provide any significant benefits in preventing dental caries.
**Option B:** A fluoride content of 2 mg/L in drinking water is considered excessive and can lead to dental fluorosis and skeletal fluorosis. This level is above the recommended safe limit set by the WHO.
**Option C:** A fluoride content of 3 mg/L in drinking water is not a recommended or safe level, as it can cause severe dental and skeletal fluorosis. This level is far above the recommended safe limit set by the WHO.
**Clinical Pearl / High-Yield Fact**
It's essential to note that the optimal fluoride concentration in water can vary depending on the geographical location, climate, and the local diet. Therefore, it's crucial to monitor and adjust the fluoride levels in drinking water to ensure that they remain within the safe limits.
**Correct Answer: C. 1.5 milligrams per liter (mg/L)**