Metal toxicity

[desertrat]

What makes some metals beneficial to the body such as iron and some others dangerous such as lead?

[Hamish]

The toxicity of metal depend on how they bins to protines and how the body metabolises them. Iron is infact toxic if you take enough of it as is Selenium (which is not a metal) but both are eccensial for life (in humans). Metals like lead, cadmium and mercury tend to block sites for enzymes and neural pathways, they also tend to be sored in fatty tissue in the body and the body does not excreat them so after a while the concentration builds up and the toxic effects become worse and are not easily treated. At the end of the day almost anything can have a toxic effect on the body but how dangerous the material is depends on a) how much you need to have taken to get an effect b) how easily the body can absorbe the material c) how the body deals with a material once it had been absorbed d) what chemical pathways the material disrupts. Hamish