it's not that the chemicals were made to bond with the soil, it is that they do. as for run off, there are proper precautions one can take to minimize run off the simplest of which is to adhere to the proper applications rates. when chemicals such as herbicides are applied within the correct rate the vast majority of the chemical is taken up by the target plants and never achieves run off status.
most people have no idea of how to calibrate an application device so as to know their exact output. they have not sought the training and therefore have no understanding for distance, time, pressure or volume.
it was a good decision when the full strength chemicals were placed out of reach of joe home owner...
organic is the total solution to the problem...