Elmo wrote:

Duane Bozarth wrote:
PrecisionMachinisT wrote:
...

Back to the oil--always seems to dissappear within a year or so from my
gravel drive, and I find it hard to believe its all being washed away by the
rain...


The area where we drained oil from tractors and trucks from as far back
as the 20s until toughly the 70s or 80s is now covered in grass and is
indistinguishable from that area surrounding it...when I was a kid it
looked like almost like a paved road. It's broken down pretty well.
Not a smart thing to have done, certainly, and I suspect a soil sample
would show some residual, but certainly doesn't appear permanent....

As I understand it, the problem is not so much what it does to the soil that it
leaches through as what it does to the water table when it gets down there.

Certainly where there is either a pathway or the underground aquifers
are surface-replenished, that's an issue. Here the aquifer is not
surface-renewed at any significant rate at all, and while there are
areas where surface contamination can penetrate (abandoned unplugged
oil/gas wells being the prime culprit), there aren't any of those in
this particular location.

Not justifying what was (although common in the time) a poor choice,
simply noting it does appear that a great deal of recovery has occurred
in a relatively short time since the action ceased....