Yellowish Tinted rain water

So I had seen a couple threads on GLP about yellowish tinted water falling at different places around the country. We got hit with a pretty gnarly storm here last night and I took the opportunity to set up a jar outside to capture some rain. It's been a record dry season here in Florida so it was one of the few chances we've had.

Anyways, I made sure to set the jar up away from the house so it didn't get polluted by run off from the roof and sure enough, it's got a very very faint, almost imperceptible yellow hue to it. Anyone else performing experiments like this? It would be interesting to see if others are experiencing this too. What could it be? Fallout from the Nuke reactor in Japan?