About 2 weeks ago I noticed some seepage about 4 feet(up the bank)from the shore. The seepage appeared to have an oily film on top of it. There was no smell associated with this liquid and it was a small spot about 4 inches wide and 10 inches long. This was noticed during a wet period when we seemed to be getting an inch or more of rain a week. I have a few areas where the ground stays muddy for 4 or 5 days after a rain. No rain for over a week and no more seepage. Yesterday while walking around the .75 acre pond I noticed a sewage type smell on the opposite side from where I originally noticed the seepage. It also seemed that there was a bluish-grayish tint to the water. This smell and coloration was pretty much confined to a 30' section of shoreline. Not sure how far out from shore it extended as it was dusk last night when I saw/smelled this. The leach field is at least 200 feet away from the pond and the ground slopes away from the pond.
I am already concerned, bordering on panic. What can I do? What should I do?

The leach field is higher then the pond by about 10 feet and as stated earlier is at least 200 feet away from the pond.

PETA, People Eating Tasty Animals