The WHO guideline value for fluoride in drinking water is 1.5 mg/L. In India, endemic fluorosis is characterized by dental fluorosis at fluoride levels above:

• A 0.5 mg/L
• B 1.0 mg/L
• C 3.0 mg/L
• D 1.5 mg/L ✓

Explanation

Dental fluorosis (mottled enamel) begins to occur when fluoride in drinking water exceeds 1.5 mg/L. Skeletal fluorosis occurs at higher levels (>3 mg/L for prolonged exposure). The optimal level for dental caries prevention without causing fluorosis is 0.5-1.0 mg/L. BIS (Bureau of Indian Standards) specifies 1.0 mg/L as the desirable limit and 1.5 mg/L as the permissible limit in the absence of an alternative source.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.