Google the active ingredient in your herbicide. Search for that products half life and or environmental fate.
This should be a great place to start and will answer your questions.
Ornamental Insect Control
Bermuda and Zoysia sodding
Seasonal annual and perennial color enhancements
"The ARC was built by a amateur. The Titanic was built by professionals!"
Arkansas State Plant Board Certified Sec. 4 & 5 -Commercial Applicator.