instant ocean here
always had it always will.
as for the contaminant thing, it is hard to say where the safe zone is and that will definitely depend upon region, no doubt.
It does carry farther than most would think, while ina current(like a river outlet). BUT safe here may be 500 ft and there it may be 5 miles.
each area will be different. However, I would never use hand collected for this reason, and no matter how far out you go, you should not collect from near the surface, but deep water for reasons of contaminants.And i really doubt that in the gulf stream he is collecting sand, unless it is from an isle. Secondly going that far out is only done by big game fisherman or those in pursuit of something special, most charters run inshore to 20 miles.Those who run further are normally targeting fish that I think should be protected(but we wont go there, that is not the meaning of this thread or discussion), so in either case I would not respect anyone going out that far who is not doing so for research or diving AND i can assure you no one is runnig 100+ miles jsut for water. for that cost you could buy an RO/DI unit and enough sand for 6 months in most tanks(not including nanos, that would be even longer)