There are a total of 6 BLAST Soda Cans available on Halo 2 Anniversary MP maps. It is recommended that you use a Sniper Rifle to destroy them, and they are easily done in Custom Games.
On Bloodline, this can can be found when standing in between the 3 rock formation close to the blue base. Will in the middle of the formation, look to the far cliff side, and you'll see a small "opening" where the can is hiding. It can also be seen in the video below.
] - Bloodline