i dont know any sites but i have some knoledge for you. i wouldnt worry about the health hazards, filling have a very very low ammout of mercury in them. your body naturally has 10-15mg of mercury in it already. such a small ammout of mercury wont kill you or probably even cause a heath risk at all. there was a british alchemist who was trying to proove the affinity of mercuy and put his toe in mercury, a gold coin in his mouth, and in half an hour the coin was coated in mercury that had traveled through his blood. when you think about that, it had to be a good ammount of mercury to travel through his blood from his toe to his mouth. he did it three times before he died and in those three times i expect that he absorbed almost a couple hundred mg of mercury, way more than what is in your filling.