Yes. Mercury is well-known to cause cancer and it raises cholesterol. I believe the primary cause of high cholesterol in the U.S. is mercury toxicity.

In the interim, here is an excellent, natural way to lower cholesterol:

Cholesterol-Reg

Also, yes, there are special ways to detect mercury but current standard hospital tests are useless.

Unfortunately, this is a bit complicated and I would highly recommend getting this book which explains it fully and in terms that can be easily understood:

Hair Test Interpretation: Finding Hidden Toxicities by Dr. Andrew Cutler

Hope this helps.