There are many different ways of measuring how toxic something is, so you probably won't get any meaningful replies in a short paragraph or 2 from this forum. For example, how toxic is it to drink directly? Vs how toxic is low-level skin contact for 20 years of exposure? Issues like that....
Roundup is very low on the toxic scales to animals, including humans. It really only acts on green plant material, and _very_ rapidly breaks down in the enviornment. Of all the chemicals out there, Roundup is one of the safest to humans, both for direct contact, and long-term lowlevel concerns, and because it breaks down so rapidly to not stay in the environment.
Some people are starting to question it's effects on the environment: It seems the Roundup itself isn't the issue, but some of the soaps & sticky agents used to make it work better against plants don't break down so fast, and accumulate in waterways, affecting frogs & fish. This is highly speculative at this point, and these additives are basically the same soaps we use everyday. Lots of hollering on both sides of this issue, no real understanding of it. Just trying to present both sides of the issue....
As with all chemicals, follow the label & wear the basic protections - long pants, long sleaves, eye protection, and unlined waterproof gloves. But all in all, Roundup is very, very low on the danger scale.
What I know from my farm chem application courses anyhow.
--->Paul