Might check PBS if they have a log accessible concerning the material of the show. If not, I'd just narrow it to a concise catchy headline on your E-mail header..
Something like,
On PBS/Senator Kit Bond Smacked down Durbin for Nazi Slur
Give the details you have. Their choice if they want to follow up. Maybe shop it to a few blogs and hope one bites willing to do the research.
That would be my approach. Thanks.