Downloading PDFs and Security?

Hello everyone,
I have been downloading a lot of PDFs from marketing firms as a means of trying to gather new information. Now I am wondering if there might be some trojan horses embedded within these pdfs.
Can anyone tell me how I can check? Is downloading pdfs a safe thing to do?
Thank you for your help.

Hi MacLover

I did a quick Google & found these links which might be helpful:

http://security.stackexchange.com/questions/64052/can-a-pdf-file-contain-a-virus
https://www.sans.org/security-resources/malwarefaq/pdf-overview.php
http://www.malwaretracker.com/pdfthreat.php

However, without offence, may I be permitted to comment that OS X Lion is either no longer supported by Apple or soon won't be. In my view, this opens up more potential vulnerabilities than run-of-the-mill PDFs. Just my thoughts.

Ian

Also, I've found that "marketing firms" are among the worst sources possible (short of politicians) for accurate information about ... well, anything.

Thanks everyone.

Don't be too exclusive. You must analyse news or buy The Guardian.