He describes his method as leading discussion back to the 'trunk' of the problem tree rather than chattering about peripheral twigs and leaves. Our laboratory has identified a toxin that plays a far more destructive role,' and so on. That's the sort of thing that happens with questions about the leaves of the environmental tree. But, if one begins with the trunk or branches, the answers become clearer and more consistent. No, it is artificially manufactured by man.
All scientists agree on that.
It is stable and persistent. On that they all agree, as well. Yes it does. No, since the complexity of eco-systems is essentially limitless. Nevertheless, it is known that all such substances have limits, often very low, which cannot be exceeded.