[chatham]

I think you are right on.
When I was a kid we swam in the Hudson river just off the ferry dock at 125th street.
After a dive while coming to the surface of the water we had to wave our arms wildly to drive off the stuff floating on the surface of the water.
Years later I found out that was the lowest point in the area and the place where all the Raw Sewage was emptied into the River.
I must have had a great immune system.
At that spot they have eracted the biggest Sewer plant I've ever seen.

[CrazyIvan]

Similar story here. Grew up just a few miles from the (then) horribly polluted Mississippi. We all got to be very good water skiers because you wanted to be able to choose WHERE you went back into the water!