http://youtube.com/riskbites

How much is too much when it comes to being exposed to something unpleasant? Using examples of fecal contamination on cellphones and cocaine on bank notes, Risk Bites begins to lay the ground for exploring dose-response.

More information on the UK cellphone contamination study: http://www.eurekalert.org/pub_releases/2011-10/lsoh-cou101211.php

It's also worth reading this blog post on cellphone contamination: http://www.mindthesciencegap.org/2012/10/02/right-now-there-may-be-poop-on-your-cell-phone-and-oh-so-much-more/

There are numerous studies looking at cocaine contamination on bank notes - here's a good place to start: http://www.scientificamerican.com/article.cfm?id=cocaine-contaminates-majority-of-american-currency