Nitrate

Natural mineral water contains calcium, magnesium, sodium, potassium as well as nitrate.

The stain on the lab coat is due to silver nitrate.

Mercuric nitrate is an ionic compound.

Silver nitrate solution added to an aqueous solution of salvarsan acidified with dilute nitric acid yields a dark-yellow precipitate which rapidly becomes black.

The doctor may advise cautery, a method that burns the blood vessel with electric current, silver nitrate or a laser.

Nitrates are most commonly used in fertilizers, especially sodium and potassium nitrates. Numerous water wells have had to be abandoned because of the lack of a way to deal with the problem.

The underground water which feeds Britain's springs and rivers and provides a third of its drinking water is becoming seriously polluted with nitrates, causing a threat to wildlife and landing consumers with a big purification bill.

The pinkness of bacon – or cooked ham, or salami – is a sign that it has been treated with chemicals, more specifically with nitrates and nitrites.