No reason for concern. Footings are poured in sections all the time. As long as the footings are doweled together and a keyway would have been a good idea.
Are you really a plumber? If you are i will tell you what to doits not a long taper, probobly around 45 degrees or a little more so it shouldtnt be to thin. as far as structual, what am i looking at, the footer actually moving seperatly? seperating at the joint? if it moves, is going to crack my basement wall all the up?
THere is a product made for bonding cold joints, Google NITOBOND, apply the product, as directed, the joint will then be stronger than the surrounding area. G:thumbsup:yes i am actually a plumber. for comfort systems usa in syracuse ny.