How widespread are mutagens?

Question

Are mutagens found anywhere conceivable? For example if I got stung by a bee, could that cause a mutation and change my DNA? What about smelling foul odors?

Answer 1

No.  And getting bitten by a spider won't do it either, not even a radioactive one.  ;-)   Smells won't hurt you by themselves, although if something is caustic enough it could certainly damage the lining of your nasopharynx.

Technically, anything that causes damage to cells could conceivably act as a mutagen.  Usually they are either chemicals or ionizing radiation, and they work in different ways--some actually get into the cell and interfere directly with the DNA, some cause cells to react and produce either faulty DNA or compounds that are dangerous to DNA.  Some examples on the chemical side would be bromine and some of its compounds (which is why you have to be careful handling them), or for radiation, sunlight (which is why sunburns can lead to skin cancer) and X-rays (which is why radiologists and techs wear lead aprons).  A lot of effort goes into keeping the genome in good repair, so anything that interferes with that can cause mutations.

One thing that's important to remember is that even though mutations are usually thought of as bad (or directly carcinogenic), they aren't always.  Something that's called a mutagen is probably also a carcinogen in general usage, though.