Why is barium toxic while magnesium and calcium are not, and how does this affect its industrial handling?

Why is barium toxic while magnesium and calcium are not, and how does this affect its industrial handling?
Barium's toxicity profile is distinct among alkaline earth metals. While magnesium, calcium, and strontium chlorides show rat oral LD50 values around 2,250-2,800 mg/kg, barium chloride is far more toxic at roughly 86 mg/kg. The barium ion interferes with calcium and potassium metabolism, causing arrhythmias, tremors, and paralysis. However, not all barium compounds are equally hazardous. Barium sulfate is practically insoluble and safe enough for medical use as an X-ray contrast agent, while barium carbonate dissolves in stomach acid and is used in rat poison. This solubility-toxicity relationship is critical for downstream buyers. In industrial settings, the main exposure risks come from soluble barium salts and dust inhalation, not from the metal itself or insoluble sulfate. China's barium salt producers, particularly those making carbonates and chlorides, must manage these hazards under tightening environmental and occupational safety regulations, which adds to production costs and influences regional supply dynamics.