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Lead (/ l ɛ d /) is a chemical element; it has symbol Pb (from Latin plumbum) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to ...
Why are lead pipes a problem? The EPA has set the maximum contaminant level goal for lead in drinking water at zero because lead is a toxic metal that can be harmful to human health, even at low ...
Why is lead so harmful for babies and young children? The focus on lead exposure for babies and young children is greater because they absorb four to five times as much ingested lead as adults ...
Although lead has been banned from paint since 1978, lead poisoning still occurs. A medical expert explains the signs and symptoms of this public health problem. Why is it important to remove lead ...
Lead shielding refers to the use of lead as a form of radiation protection to shield people or objects from radiation so as to reduce the effective dose. Lead can effectively attenuate certain kinds of radiation because of its high density and high atomic number ; principally, it is effective at stopping gamma rays and x-rays .
Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. [5] Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms.
The FDA recommends a maximum of 0.1 parts per million (ppm) of lead in candy, but many imported types exceed this limit. The lead usually comes from things like lead-based ink used on the ...
It is believed that lead smelting began at least 9,000 years ago, and the oldest known artifact of lead is a statuette found at the temple of Osiris on the site of Abydos dated around 3800 BC. [12] It was recognised as an element by Guyton de Morveau, Lavoisier, Berthollet, and Fourcroy in 1787. [6]