Restoration should fix damage from mercury, he can't think why it wouldn't. 

(He avoids suggesting a quick human-subject test to be sure.)

He does happen to know that bubble-of-air spells make air, rather than pure oxygen; pure oxygen has been isolated and he has a secret technique for doing so which he'd be willing to share with this project for half its proceeds.

Restoration should fix damage from mercury, he can't think why it wouldn't. 

(He avoids suggesting a quick human-subject test to be sure.)

He does happen to know that bubble-of-air spells make air, rather than pure oxygen; pure oxygen has been isolated and he has a secret technique for doing so, as well as one for measuring temperature, which he'd be willing to share with this project for half its proceeds.