The economy. In Roman times, lead sling bullets were amply used, and were effective at a distance of between 100 and 150 meters. Husk mig på denne computer. When freshly cut, lead is silvery with a hint of blue; it tarnishes to a dull gray color when exposed to air. Hjem; Om Pitney Bowes; Kontakt os; Site Map; Pitney Bowes Worldwide; Love & erklæringer The earliest record dates to 1621 in the English Colony of Virginia, fourteen years after its foundation. Elemental abundance figures are estimates and their details may vary from source to source. For example, a firm "...producing quality [lead] garden ornament from our studio in West London for over a century". Lead is soft and malleable, and also has a relatively low melting point. The white faces of women "came to represent their feminine virtue as Japanese women",[163] with lead commonly used in the whitener.[164]. [205] In 1993, the base of the Leaning Tower of Pisa was stabilized with 600 tonnes of lead. [181] As was the case during European industrialization, lead has had a negative effect on health in China. [160] Lead, in the form of Venetian ceruse, was extensively used in cosmetics by Western European aristocracy as whitened faces were regarded as a sign of modesty. Alternatively, as the applied dry paint deteriorates, it peels, is pulverized into dust and then enters the body through hand-to-mouth contact or contaminated food, water, or alcohol. [171] At this time, more (working class) people were exposed to the metal and lead poisoning cases escalated. [87], Lead's per-particle abundance in the Solar System is 0.121 ppb (parts per billion). [113], There is no consensus on the origin of the Proto-Germanic *lauda-. [241] Its prevalence in the human body—at an adult average of 120 mg[u]—is nevertheless exceeded only by zinc (2500 mg) and iron (4000 mg) among the heavy metals. By association, lead was considered the father of all metals. [248] The primary cause of its toxicity is its predilection for interfering with the proper functioning of enzymes. [165] In Australia, the first mine opened by colonists on the continent was a lead mine, in 1841. Only about a third of lead is excreted by a child. [110], Lead is added to copper alloys, such as brass and bronze, to improve machinability and for its lubricating qualities. The latter has become the most common route, though the former is still significant. a direct source is chewing on old painted window sills. [276], Anthropogenic lead includes lead from shot and sinkers. [107][m], The main lead-bearing mineral is galena (PbS), which is mostly found with zinc ores. [290] Lead abatement programs have been mandated by some authorities in properties where young children live. [291], Lead waste, depending on the jurisdiction and the nature of the waste, may be treated as household waste (in order to facilitate lead abatement activities),[292] or potentially hazardous waste requiring specialized treatment or storage. [211] In the past it was often used to balance the wheels of cars; for environmental reasons this use is being phased out in favor of other materials. [188], First, the sulfide concentrate is roasted in air to oxidize the lead sulfide:[189], As the original concentrate was not pure lead sulfide, roasting yields not only the desired lead(II) oxide, but a mixture of oxides, sulfates, and silicates of lead and of the other metals contained in the ore.[190] This impure lead oxide is reduced in a coke-fired blast furnace to the (again, impure) metal:[191], Impurities are mostly arsenic, antimony, bismuth, zinc, copper, silver, and gold. Soil can be contaminated through particulate accumulation from lead in pipes, lead paint, and residual emissions from leaded gasoline. [188] Metallic lead is further obtained from the high-lead (25–40%) slags via submerged fuel combustion or injection, reduction assisted by an electric furnace, or a combination of both. [207], Lead has many uses in the construction industry; lead sheets are used as architectural metals in roofing material, cladding, flashing, gutters and gutter joints, and on roof parapets. Chronic, high-level exposure has been shown to reduce fertility in males. [283] Lead use was further curtailed by the European Union's 2003 Restriction of Hazardous Substances Directive. [85] For many organic compounds, a lead analog does not exist. [204] It is used in scuba diving weight belts to counteract the diver's buoyancy. By mimicking calcium, lead can cross the blood–brain barrier.