I know soil testing is available, at least in big cities. Not sure about bleach. I used to be a landscape architect in California, and we got soils tested in both areas I worked in. Try your phone book (or I, suppose, google) to find a firm in your area. I just learned how to find phone numbers on line yesterday, instead of 411, says Ms. Dummy. Anyway, we used to mail the samples, if I remember, so you may not need to have the soil testing business right near you..
If you find a few phone numbers, I bet they can tell you if bleach is detectable, or give you ideas for what else it could be.
Also, Farmerman likely knows way more than I do and will likely see your post.
You could pm him if he doesn't. He does farm, but he's also a geologist.