Hi Logan! Sorry; but recommend throw the poison treated log away. No matter of rinsing is going to make that safe again.

Next time, shake as much dirt and stuff off wood piece as you can and bag it. Then when home, rinse in water, and bake for 1 hour at 250F in oven. Following that, turn off oven and let it wood pice slowly cool overnight inside the oven.

Any remaining ants, eggs, molds, bacteria, etc. will be dead and then you can use safely. Wood piece might mold over when vivarium is fresh; but it will go away as molds consume any organics. Good luck !