The dangers associated with lead
While the human body needs to consume tiny amounts of many non-organic minerals, lead is not one. So far as we know, lead is of no value to the human body and consumption of lead has devastating consequences for humans--particularly during the early stages of brain development, when it has been widely documented to interfere with neurological development. Furthermore, the neurological impact is permanent and irreversible.
Lead is the heaviest "stable" element, however, it does break down when it interacts with certain other elements--particularly sulfur. Because it is resistant to corrosion and discoloration, it has historically been used in many domestic products including kitchen utensils and water pipes. More recently it has been used to improve the adhesive properties of paint. Although its use was banned in interior paints in 1971, lead is still used in the United States to bind exterior paints. Obviously, in China it is widely used in inferior products because it is cheaper than many other stable minerals.