So many reply, much wow!
I thank everyone for the input.
I did however phrase it incorrectly, as Henry Jabel pointed out, the tools are actually a copper and tin mix(still +-90% copper) but that would make them bronze.
So even though I can see how 100% copper tools would be quite silly, I wonder if the the liberation of copper particles wouldn't be waaay less than expected because of the tensile strength the tin adds, thus stopping the copper from being present in the soil in such quantities that it actually starts affecting soil organisms negatively.
Anyway, I think this is an interesting subject, even though it might not make the biggest difference in the bigger scheme of things.
Also, less backache has always been a good thing in my book!
A splendid day to you all