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Silver (Ag)

Metallic silver is harmless, as it is not reactive. Metallic silver is also used as a food colour, E174.

Soluble silver salts, specially AgNO₃, however, are lethal to adults in concentrations around 2g. Silver compounds can be slowly absorbed by body tissues, with the consequent bluish or blackish skin pigmentation (argiria).

Repeated and prolonged contact with skin may cause allergic dermatitis. Exposure to high concentrations of vapours may cause dizziness, breathing difficulty, headaches or respiratory irritation. Extremely high concentrations may cause drowsiness, staggering, confusion, unconsciousness, coma or death.

May cause stomach discomfort, nausea, vomiting, diarrhoea, and narcosis. Aspiration of material into lungs if swallowed or if vomiting occurs can cause chemical pneumonia which can be fatal.

There are no data on silver toxicity from food, as the concentrations are extremely low.

Sources :http://www.lenntech.com/periodic-chart.htm