Re: from where can we get wrong level of mercury?
Your questions are too complex and controversial to answer in this setting. I suggest that you check out the youtube videos by Boyd Haley, former chair of the chem dept at the U of KY. For example
https://www.youtube.com/watch?v=LnfBhdT7uU0
Haley reminds us that this is a retention toxicity. Certain vulnerable parts of the body hold onto it rather tightly. Two places that come to mind are the brain and a hormone receptor involved in stress response. Therefore no one is surprised when Hg toxic folks have a foggy brain, poor mood and don't handle stress well!
This is one thing it does to the brain--video from U of Calgary.
http://www.youtube.com/watch?v=GDnfeIwd0wI
I chose Cutler's detox protocol for my heavy metal problem. This is one man's experience with Hg and Cutler detox. He is a physicist.
https://www.youtube.com/watch?v=wE_bjZ4kdJI
This woman got worse after she had dental work done.
http://health.groups.yahoo.com/group/frequent-dose-chelation/message/111235
For some the cause is mysterious but they fortunately guessed right about the solution.
http://howirecovered.com/meet-patti-who-recovered-from-mercury-poisoning/
My situation was similar to Patti's. My hair, urine and porphyrins tests were negative but long-time symptoms HMs that I were exposed to in my family's business for decades.
Good luck. It is not easy to figure out what is going on and you should not expect a doctor to magically figure out how much Hg is stuck in your brain. Dr Mark Hyman writes in his book, The UltraMind Solution, that he went to TEN other doctors before someone figured out that heavy metals were a major contributing factor in his CFS, etc.
http://drhyman.com/blog/2010/05/20/mercury-get-this-poison-out-of-your-body/
While I am very grateful to Dr Hyman for helping to tip me off about heavy metals, I chose Cutler's detox protocol. It seemed to be the safest effective method and my functional medicine doctor was not opposed to it.
Joe