Oily water on my property

When water pools up on my new property, I see an oily surface in some parts.  Can that be natural, or does it necessarily mean that there is some contamination that I need to address?

I moved here about 6 months ago.  I'd like to build a small pond, but if there is some kind of oil leak, then certainly that would need to be addressed first.  There is no obvious source of oil like a car repair shop next door or anything.

Thanks!

Can you give us a bit of history on your property? And a rough location? Is the oil sheen quite localized?

I have seen that before, maybe a water test will help but I THINK its from particular plants

There are two main sources of oily film on water: hydrogen sulfide and iron bacteria. Here's your trick for being able to tell the difference: stir the water with a stick. ... If the oily film breaks up when you stir it, it's probably due caused by an iron oxide mineral.

I have the same problem.

In my case it's probably due to iron oxide because the water from some of my sources has a high iron content.

Unfortunately I don't know much about the history of this property or the area.  I'll contact the previous owner and see what I can find out.  

I'm in north Georgia (the US State, not the former soviet "republic").  The sheen is pretty much everywhere there is standing water.

It's very common in water with decomposing vegetation in, nothing to worry about at all.

A hydrocarbon sheen usually has a "rainbow" of colours. I'm not seeing that in the photo. Even if it was, a small amount of hydrocarbon isn't much of a concern IMO. Natural bacteria will take care of it. I would poke around with a shovel and see if more appears -- in the good ol' days, people were casual with oil changes, and would also toss used filters in ponds and sloughs to deter mosquitoes.

A sheen from plant decomposition is a new concept to me. Very interesting!

On a similar previous post on permies, someone suggested that I do a "stick test" where you pass a stick through the slick.  If it immediately closes up the way it was, then it is some oil/petroleum product.  But if it cracks and stays apart, it is iron oxide/bacteria.  My test was definitely the latter.  It cracked like dry desert ground and stayed apart.  I guess that's good news?  

I have the same thing on a natural spring on my property, gotta clean the dead leaves and stuff out of it. on my place its 1/2 way up a small, 1000' mountain there was never any development or anything like it there. its just wild forest

I would say it's good news. Hydrocarbons don't act that way.

Todd Markey wrote:When water pools up on my new property, I see an oily surface in some parts.  Can that be natural, or does it necessarily mean that there is some contamination that I need to address?

I'll ditto what others have said, and I believe it appears to be microbial activity, or what can often be referred to as a microbial bloom. It is more common in ponds, but surface sheens can appear in short lived puddles too. I believe only a water analysis can correctly identify this sheen as a chemical/petroleum residue.

Another option: I think soaking up some sheen in a paper towel or thin, white cotton cloth and letting it dry would also indicate hydrocarbon residue quite clearly.