![]() ![]() It also enters the human body through consumption of contaminated fruits, and vegetables. From contaminate soil and water, lead can enter the food chain and effect animals. Lead can persist in our environment, especially organic soil and can remain there for hundreds of years. About 100 mg/m 3 of airborne lead concentration is considered dangerous to health and life. Inhalation of lead is the second most common pathway of lead toxicity, and lead from automobiles and cigarette smoking can cause severe toxic effects on the human body. Lead dust from furniture or window sill painted with lead can enter the body via hand to mouth contact. Lead toxicity is primarily caused by the ingestion of lead-based paints, in toys, or in home. Lead is known to interfere with many biologically significant enzymes, including enzyme of heme synthesis pathway. Lead exposure during pregnancy can cause miscarriage and can lead to delay in puberty in girls. Lead toxicity is specially alarming for children as it can lead to lifelong neurological disorders, and behavioral challenges. Lead has the ability to cross the blood-brain barrier and cause damage to brain and other organs. It can accumulate in bones and soft tissues and damages the neurons and nervous system. Its toxicity was recognized in the late 19 th century. Lead is used to detect aldehydes, and organic acids (Oddy test).Lead is used in lead batteries and various supercapacitors are being used to in US, Australia and Japan in various megawatt scale applications.Lead alloys with copper, including bronze and brass are used to make components of machinery.Lead is used to make sculptures and statues.And is part of gutters, roofing material, cladding etc., to reinforce the structure. It is widely used in construction industry.Lead is used to cover underwater cables as it is resistant to corrosion.It is used in weight belts used by scuba divers to counteract their buoyancy. ![]() It is still used in various industries where its toxic effects are minimal for the environment and humans. Lead toxicity has led to major decline in its uses since mid-1980s.Lead can also form bonds with other lead molecule and can acquire unique arrangement, such as rings, chain and polyhedral structures. The common oxidation state of lead in compounds is +2. Lead frequently form stable covalent bonds as compared ionic bonding. It belongs to the post-transition metal group in the periodic table. Lead has the atomic number of 82, which is considered as the highest among all stable naturally occurring elements. it is malleable and has a low melting point. Lead is soft but is significantly denser than other metals. It tarnishes to dark gray color when exposed to air. Lead is a silver colored metal with a tint of blue. The largest deposits of lead are found in Australia, Russia, China, US, and Ireland. There are various impurities in lead minerals and ores, including tin, arsenic, gold, silver and copper. The most common mineral of lead is galena (PbS). It is primarily present in combined form with sulfur and is rarely found in elemental or metallic form. It is considered as the 38 th most abundant element on Earth. Lead is an abundant metal and is present around 14 ppm in the Earth’s crust. The word lead has been derived from Old English word lead. The origin of name of lead is intertwined with tin, as olovo translates to lead in Czech, while it translate to tin in Russian language. The name plumbum, was given to the metal and the English word plumbing was originated from this Latin word. Civilizations of Indus valley and Ancient Greece used lead to make amulets, glasses, ornaments, glazes and sinkers in fishing net. Lead was used as a currency in Ancient Chinese courts. The use of lead decreased with the fall of the Roman Umpire. It was widely used to make water pipes by the Romans and named it as plumbum nigrum (black lead). Lead is a prehistoric metal and was used by people of ancient Rome and Western Asia around 7000 BCE. It is the heaviest stable element and is resistant to corrosion. Lead has been known since old ages and its use has been largely limited due to its high toxicity. ![]()
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