oily sheen after rains

my partner and i received a whopping 6.5 inches in the last week in norther PA! out camp got washed out and when we returned there was a slick bluish material sitting on the mud in some locations. i've seen it on river beds at times as well. i'd love for someone to tell me it's something natural but i'd prefer to know if i should be cautious about eating my veggies without further testing.

this is in the fracking heartland, but i really don't want to consider the possibilities..

any advice is always appreciated!

Could very well be. Since oils can form a layer one molecule thick on the surface of water, they can go quite a distance from their source, be it a parking lot or a fracking well deep underground. If you are mulching your garden well, and there is a healthy amount of soil fungi, they will take of this problem. If you are concerned about your raw vegetables, just the slightest amount of dish soap in water will take of it, and for the cooked ones, you can parboil them and see if there is any sheen on the water.

If the problem gets worse, PM me for more intensive measures you can take.

I don't think it's likely to be oil: http://pubs.usgs.gov/gip/microbes/intro.html

Generally, red colored standing water, red streaks in the soil, and oily/shiny films are caused by bacteria in anaerobic conditions.