Pb

Lead (Pb) is a chemical element with atomic number 82. Its chemical symbol derives from the Latin plumbum. It is a dense, soft, malleable, bluish-gray metal with poor electrical conductivity relative to many other metals. It has a relatively low melting point for a metal (327.5°C) and a high atomic weight.

Lead occurs naturally in minerals, predominantly galena (PbS). It is produced commercially by mining and concentrating the ore, followed by smelting and refining to obtain metallic lead. In nature it often accompanies silver, zinc, and copper.

Historically important, lead has been used for millennia. Today its largest use is in lead-acid batteries for vehicles; other major uses include radiation shielding, ammunition, and various alloys and solders. Lead was previously common in paints, pipes, and gasoline, but regulatory actions have greatly reduced or eliminated many of these applications. Recycling of lead-containing products remains a significant source of supply.

Lead is highly toxic. In humans, exposure to lead and many of its compounds can harm the nervous system, kidneys, and blood formation, with children and fetuses being particularly vulnerable. Main exposure pathways are inhalation of dust and ingestion of contaminated soil or objects. As a result, many countries regulate lead levels in air, water, paint, and consumer products, and have restrictions on lead in electronics, fuels, and plumbing. Environmental lead persists in soil and sediments and can accumulate in organisms, making remediation challenging.

Lead has several stable isotopes, notably 204Pb, 206Pb, 207Pb, and 208Pb, which are used in geochronology and tracing studies.

Lead compounds are classified by IARC as possibly carcinogenic to humans, reflecting evidence of cancer risk in some studies.