Global Distribution of High-Fluoride Regions (High-Risk Areas)

Globally, groundwater fluoride levels exceeding the WHO guideline of 1.5 mg/L are primarily concentrated in an arid-semi-arid belt spanning multiple continents, as well as certain volcanic regions. Key hotspots include:

Asia

China: Home to the world's largest population affected by endemic fluorosis. High-fluoride zones exhibit distinct band-like distributions:

Northern Arid-Semi-Arid Belt: Extending from Northeast China (Heilongjiang, western Jilin), North China (Hebei, Shanxi, Inner Mongolia, Beijing-Tianjin region) to Northwest China (Shaanxi, Gansu, Ningxia, Qinghai, Xinjiang). This area experiences intense evaporation and fluoride ion concentration, constituting the primary zone for drinking water fluorosis.

Southwestern fluoride-rich strata zone: Regions including Yunnan, Guizhou, and Sichuan. Due to fluoride-rich coal-bearing strata and apatite deposits, both coal-burning pollution-type and drinking water-type fluorosis coexist.

Indian Subcontinent: India (particularly Rajasthan, Gujarat, Andhra Pradesh, etc.), Pakistan, and parts of Bangladesh face severe groundwater fluoride contamination.

Central Asia: Many regions in Afghanistan, Iran, Turkey, and other countries.

Africa

East African Rift Valley: Extending from Eritrea, Ethiopia, and Kenya to Tanzania. Volcanic activity and alkaline rocks provide abundant fluoride sources for groundwater.

North Africa and Sahel Region: Certain areas in Morocco, Algeria, Tunisia, Niger, Ghana, and other countries.

Americas

North America: The Great Plains region of the U.S. Midwest (e.g., Texas, Arizona) and the central highlands of Mexico.

South America: The Pampas grasslands of Argentina and northern Chile.

Other Regions

Middle East: Countries such as Saudi Arabia, Jordan, and Syria.

Europe: Certain areas including volcanic regions of Italy (near Mount Vesuvius) and central Spain.