Natural ground water becomes highly acidic after flowing into old underground mines, where it dissolves heavy metals such as iron and uranium.

Beneficial compounds within the blue-veined cheese were shown to work best in highly acidic environments such as the lining of the stomach.

Has a highly acidic taste; inedible.

These 'extremophiles' can cope with the high temperatures of hot springs and deep sea thermal vents, which are often also highly acidic or abound with sulphur.

Some fruits are highly acidic and mixing them with water and sugars or honey was often necessary to make them palatable.