You can absolutely test for this crap. Contaminated land and remediation is a big business. Soil, groundwater, and air quality testing would be a good start. Perhaps testing some local chicken eggs would be a good idea too.

You'd have to contact an environmental service business, and they'd collect samples, send it to a lab, and then analyse the result. Unfortunately these services are expensive and these businesses won't move on their own free will - usually a government contract will kick things in motion in this scenario. However, you can be damned sure they won't tell you the results or will lie to you if it's a government contract.