Lead is a neurotoxin that accumulates in delicate tissues and bones; it damages the nervous system and interferes with the perform of organic enzymes, inflicting neurological issues, corresponding to mind harm and behavioral issues. Within the late nineteenth century, lead’s toxicity was acknowledged extensively, though a lot of well-educated historic Greek and Roman writers have been conscious of this truth and even knew among the signs of lead poisoning. Lead additionally impacts basic well being, cardiovascular, and renal techniques.
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Bodily properties[edit]
In complete, 43 lead isotopes have been synthesized, with mass numbers 178–220.[33] Lead-205 is probably the most steady radioisotope, with a half-life of round 1.73×107 years.[j] The second-most steady is lead-202, which has a half-life of about 52,500 years, longer than any of the pure hint radioisotopes.[33]
Chemistry[edit]
These compounds are comparatively steady: tetraethyllead solely begins to decompose if heated[91] or if uncovered to daylight or ultraviolet gentle.[92][k] With sodium steel, lead readily types an equimolar alloy that reacts with alkyl halides to type organometallic compounds corresponding to tetraethyllead.[93] The oxidizing nature of many organolead compounds is usefully exploited: lead tetraacetate is a crucial laboratory reagent for oxidation in natural synthesis.[94] Tetraethyllead, as soon as added to gasoline, was produced in bigger portions than some other organometallic compound.[89] Plumbane could also be obtained in a response between metallic lead and atomic hydrogen.[90] Two easy derivatives, tetramethyllead and tetraethyllead, are the best-known organolead compounds. For a lot of natural compounds, a lead analog doesn’t exist.[90]
Origin and incidence[edit]
Typical background concentrations of lead don’t exceed 0.1 μg/m3 within the environment; 100 mg/kg in soil; 4 mg/kg in vegetation and 5 μg/L in freshwater and seawater.[114]
Etymology[edit]
The identify of the chemical aspect shouldn’t be associated to the verb of the identical spelling, which is derived from Proto-Germanic *laidijan- (‘to steer’).[119]
Historical past[edit]
From 1960 to 1990, lead output within the Western Bloc grew by about 31%.[186] The share of the world’s lead manufacturing by the Jap Bloc elevated from 10% to 30%, from 1950 to 1990, with the Soviet Union being the world’s largest producer in the course of the mid-Nineteen Seventies and the Nineteen Eighties, and China beginning main lead manufacturing within the late Twentieth century.[187] Not like the European communist international locations, China was largely unindustrialized by the mid-Twentieth century; in 2004, China surpassed Australia as the biggest producer of lead.[188] As was the case throughout European industrialization, lead has had a unfavorable impact on well being in China.[189]
Manufacturing[edit]
Of the sources of lead for recycling, lead–acid batteries are crucial; lead pipe, sheet, and cable sheathing are additionally vital.[193]