Is synthetic grease more earth-friendly than non-synthetic grease? I ask because, after spending an hour reading "which grease should I use?' threads, I've narrowed my purchase options to these three:

Sta-Lube CRC SL3121 Marine Boat Trailer and 4 x 4 Wheel Bearing Grease
Evinrude Johnson OMC Triple Guard Grease
Peak Synthetic Marine Grease

If the price is roughly equal (which it is) and all three brands work equally well for hubs and headsets and the like (which I hope), then for me the only remaining question is, if a bit of this grease oozes off my bike and onto the pavement and into a stream, what harm does it do? Yes, it's a tiny dab of grease. But still, it adds up! So I'd like to use the most benign/least harmful grease.

Any thoughts? Facts? Recommendations? I skimmed an EPA document called "Environmentally Acceptable Lubricants" but it was inconclusive and also boring.

I could post this question on the Mechanics forum but I wanted to start with C&V because I'm loyal to C&V. Thanks!