The phrase 'plastic barrel' is correct and usable in written English.
You can use it in a variety of contexts. For example, "The children used a plastic barrel as a makeshift raft on the lake."
Hidden deep in the brush outside was a plastic barrel filled with guns.
Take the Hippo Roller, a South African invention, which in essence is a plastic barrel with a handle.
An ancient television sat on a plastic barrel, and bedding and clothes were stacked along one wall.
I put on rubber gloves and carefully untwist the lid of the blue plastic barrel that holds the comfrey solution.
A couple of minutes after taking the lid off our blue plastic barrel the air was humming with expectant bluebottles.
The system included a plastic barrel for holding the wastewater and a foam plate for holding the plant.
But most go into plastic barrels filled with pickling brine.
On it, two workers mix a livid-yellow potion in huge plastic barrels.
Blue plastic barrels and dock segments and huge unidentifiable objects — pieces of ships?
Human waste at base camp is now managed well, and removed in plastic barrels.
They were identifiable by blue plastic barrels outside their doors, in which neighbors deposited water, food, and firewood.
