@edgarblythe,
The garden landscaping use of industrial strength vinegar (20% dilution) is considered safe according to the label. I use Green Gobbler brand which was available on Amazon. It won’t put the water source at risk. I’m not at our upstate NY location where irs located but I looked it up just now.
It’s 4 x stronger than table vinegar. It is considered safe and doesn’t use any glyophosphate or toxic chemicals. Though, it’s not cheap, it saves a lot of time and effort and rashes. I hate getting poisoned or poison ivy. It ruins my day.