[PaulKersey]

A DROP of mercury in one backyard will have a negligble effect, a whole nation dumping mercury in their backyards is a public health issue.

Don't be silly. Different drops spread over different backyards will have no effect whatever. 

Do you also oppose peeing in the woods on environmental grounds? Have you ever BEEN in the woods?

[Tony Niar Brain]

Different drops spread over different backyards will have no effect whatever.
If you insist, fine, it has no effect what-so-ever.

Do you also oppose peeing in the woods on environmental grounds? Have you ever BEEN in the woods?
Yes, as a devoted environmentalist, I am against any and all peeing in the woods. That goes for bears and deer and squirrels as well; I hear they have lots of them in the woods, and they simply must cease this offensive behavior. So there.