Heavy Metals Surge in Mekong: Arsenic Levels Exceed Safety Limits

Tests carried out in early 2026 by Thai authorities in Chiang Mai and Chiang Rai detected arsenic concentrations above international safety thresholds at all 23 monitoring sites along the Mekong and its tributaries. The river now carries arsenic, lead, cadmium and manganese that have settled in sediments, entered fish stocks and accumulated in staple crops such as rice, garlic and soybeans. The contamination has already entered global supply chains, posing health risks far beyond the immediate river basin.