Types of Mercury and Its Toxins

There are three different kinds of mercury and mercury poisoning; it just depends on how you are exposed to it. The first kind is metal mercury which is what you find in thermometers which is why they say if it breaks in your mouth its dangerous. The second kind of mercury is Mercury salts, which can be found around industrial environment where someone would breathe it in hurting the kidneys rather then the nervous system like metal mercury effects. Thirdly there is organic mercury, which is found in food. This happens from chemical plants releasing the mercury into the water where it then gets into the fish. Mercury is toxic because it harms parts of the body with the main parts being the kidneys and the brain especially the nervous system. 

 http://www.nlm.nih.gov/medlineplus/ency/article/002476.htm
 http://www.epa.gov/hg/effects.htm