Hell
Sharon leads the trio to Devil's Acre, which is described with imagery associated with Hell. As Sharon takes them by boat, this is an allusion to Charon in Greek Mythology, who takes souls of the dead across the River Styx to the land of the dead.
Death
When they reach Devil's Acre, they are pursued by vultures, which are heavily associated with death. The imagery of death here represents the threat that the trio face, and the danger that they are in.
Dirtiness
Devil's Acre is described with imagery of dirtiness. The place is rotting, and there is a yellow fog that hangs over the place. Additionally, the people's water and sewage are the same thing. This imagery of dirtiness represents the corruption of the place.
The Coast
The coast is a liminal space which acts as a crossing place between locations. As such, it also represents a transition from good to evil, from safety to danger.