Nowhere is truly safe, Susan. That's why the detox.
They even use it in the forestry industry, to keep down competing growth in the monocrop they prefer for
wood pulp and paper products.
My much better half's brother-in-law is a forester. I have discussed it with him, and he, along with much of the industry, is content with the two-day half life figure (which is actually the low-end of the measurement; the highest half life estimate is something like 197 days).
Our best hope is to outlast it. It is currently becoming less and less effective as nature catches up and breeds glyphosate-resistant strains, meaning that the mounting costs of increasingly larger applications that are less effective year after year look less appealing to farmers than alternative management practices.
This can either mean more toxic sprays, or management practices more in line with what permaculturalists consider acceptable.
The chemical industry has been freaking out about how rapidly target species have been adapting to their golden child of sprays for a decade already, and lawsuits have been launched regarding the use of an old pesticide from the 70s that vapourises in the summer heat and goes visiting. Their next-generation spray is no where near ready yet, or they'd be talking it up already.
I would guess that the overuse of it as a dessicant, rather than just at "need" to knock down "weed" species, has played a large part in species' rapid adaptation.
I think it important to avoid hysteria. Let's instead get really familiar with
mushroom slurries and growing our own food in our own carefully nurtured soil. If the target weed species can evolve to the point where they can disregard glyphosate, I am sure that fungi will step up to break it down eventually.
-CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein