Following this guide made this achievement a simple matter (tested and working on PC 11/7/19). Thanks to user Mike31584 who wrote the 360 guide: Solution for Elementalist in Borderlands: The Pre-Sequel (Xbox 360)
There is a Dahl dumpster in Concordia with danger signs on it, to the your left when you spawn in at the fast travel. Simply shoot this dumpster with all 4 elements and achievement unlocked.
This can be done with more than one person shooting the dumpster, only the last person to shoot the dumpster gets the achievement, once the achievement is unlocked by someone you have to exit and reload the city for any additional person to get the achievement.