Could you mean 2-4D herbicide?Rg
Z the only thing you could have done is spray them with a lot of water as soon as you could... Give them a week and see what happens..Not sure why your worried about the soil?Sounds like its all surrounded by chemicals.....
It's always a guessing game. Better to err on the onservative side IMO.Sorry for your misfortune. Not to rub it in....but I had a ribeye on the Weber with a heaping helping of fresh steamd spinach for dnner. Not much I like better than fresh cut spinach.Rg