[yuye]

Copper is an essential trace element for many living organisms, including humans, meaning you need copper to survive. Generally, copper has low toxicity. (That is, unless you have rare genetic defects such as Wilson's Disease)

Lead is nothing like that. We don't need lead to survive, we shouldn't put lead in our bodies. Lead is also known to accumulate in your body (especially your brain). Avoid lead exposure as much as you can.