"Look, lad! You see the streak of glowing green off the larboard bow? Them's the bright waters!"
While the lad peered intently at the eerie glow, the old salt continued. "Entire ships have been lost to the Bright, lad, for once you let it surround you, you'll never touch land again!"
Along the sluggish Vanne River, the banks are lined with thick stands of tall bulrushes. These areas of wetland are considered ill-omened by the locals, for they hide the skeletal remains of thousands of grazing animals, washed downriver in a terrible flood decades before.
Adding to the uncanny reputation of the place is the occasional undead cow or goat that lurks there. The product of a necromancer's experiments some years before, these relatively harmless undead wander the area at night, startling livestock as they attempt to graze with them.
Another real world thing. White tea. Can only be picked two days a year, the two days before the flowers blossom. Could be a similiar plant that...is the deadliest poison known, cure known diseases or psychosis, or a potent herb that just tastes awesome.