It can take awhile with bronze equipment. A huntsman bow (42 piercing) with fire arrows (11 pierce +22 fire DOT). The abomination has 800 health is 75% resistant to piercing but takes 1.5 times damage from fire. Each fire arrow would then inflict 13 damage from piercing and 33 damage from fire and it would take 18 fire arrows to kill one.

With bronze gear its hard to tank an abomination (but you could dodge and swing) and the torch would be fast but the DOT doesn't stack. A bronze mace will do 17.5 damage per swing with resistances figured in so it would take 46 whacks to kill one with that.

You can get enough iron from one crypt to craft enough iron gear to survive the swamp and 2 or 3 more good ones will give you all most all pieces of the iron armor fully upgraded. This will happen long before you can kill enough abominations to complete a fully upgraded Root set.