One can also take water and soil samples. There are numerous labs that the samples can be sent to. They can test for hundreds of carcinogens, pesticides, heavy metals, various deadly strains of bacteria and much more. Testing is generally between $80 and $400 depending on what you ask them to test for.

$80-400 per hypothesis or per sample (a.i. one sample covers thousands of known chemicals and pathogens)?

Per sample. One sample a few small containers can be tested for hundreds of things.

I've only ever sent one sample at a time but I could imagine that if one were sending many samples one could negotiate better prices. I've never tried negotiating them down.

There are many non-radioactive carcinogens.

Funny you should say that. Look in the news back in the 90s, about the schools history with radioactive mysteries. :)

Some US states offer free radon test kits!