Dog bite me in the toe when I walk away from him?

edit

I suggest you hire a trainer to work with you and the dog to help stop the bad behavior, possibly the group you adopted your dog from can provide references. Best of luck

Majority of dogs who got adopted will have some issues. Understandably , they have been traumatized when the owner left them, gave them up or they were found lost and nobody claimed them. It's always good to hire a trainer that specializes in behavior. Good luck.