Are you 99.999999% sure that picking up that penny won't kill you? You need a reason for every 9 (if you're ambivalent between using seven 9s and using nine 9s, you should use seven; the number of 9s is never arbitrary), and by the time you come up with eight reasons to pick up the penny, you'll have wasted several cents' worth of time. If you can reduce the probability of harm that far, I applaud you.

What? No. I don't need to spend several cents worth of time thinking of reasons sufficient to get your permission to pick up a penny. I have absolutely no reason to even privilege the hypothesis that picking up a penny kill me. If I did, and if I felt the desire to think of reasons why not to be concerned about that I would probably start with reasons why the act of picking up a penny could extend my life. Perhaps the benefits of cerebellar stimulation or enhancing environmental awareness through penny grabbing biofeedback.

If I had a penny, I'd drop it. In fact, I drop 5c pieces as a matter of course (the smallest denomination of Australian currency, worth more than a penny but not accepted by most vending machines). That may technically count as littering but I haven't been fined yet. Even so, this particular argument against penny picking is bogus.