How do I keep my son's ipod from receiving my email?

My 9-year-old son has an iPod, and it's the only Apple product I own, so I know little about the details of setting it up. However, I just realized that he has full access to my email on it, presumably because I set it up with my own email. How can I prevent this from being the case? I've tried fooling around with some settings, but I can't seem to get my email account off his iPod.