Acid River
From Tardis Wiki, the free Doctor Who reference
The Acid River was a river on Skaro in and around which Zeg and the Dalek Emperor once battled.
The Dalek Emperor thought that the sulphuric acid would destroy Zeg, so led him to the river, which Zeg fell into. However, as his casing was made of metalert, the acid could not hurt him, and he emerged unharmed. (COMIC: Duel of the Daleks)