Blog notifications for the admin (like comment moderation, Likes, new subscriptions, etc) are sent to the email address at Settings -> General in the Dashboard.

Personal notifications (like comments on your post, subscription emails, and upgrade renewals) are sent to the email address at Users -> Personal Settings in the Dashboard.

See also > Issues Changing your E-mail Address > http://en.support.wordpress.com/email-address/#issues-changing-your-e-mail-address

Provided you are logged in under the username account that registered the blog you can delete the blog by using these instructions. http://en.support.wordpress.com/delete-site/
Please note that deleted blog URLs are not recycled.
http://en.support.wordpress.com/recycling-blog-names/
You can make the blog private and use it as a test blog and backup blog. http://en.support.wordpress.com/settings/privacy-settings/
You can hide it from dashboard display as well. http://en.support.wordpress.com/my-blogs/#my-blogs-dashboard-visibility