Lead :: essays research papers

Lead is a lustrous, silverymetal that tarnishes in the comportment of air and becomes a dull bluishgray. Soft and flexible, it has a first base melting point (327 C). Its chemicalsymbol, Pb, is from plumbum, the Latin word for waterworks, beca occasion of excretes extensive use in ancient water pipes. Itsatomic number is 82 itsatomic cant is 207.19.Lead and hap compounds can be exceedingly toxicwhen eaten or inhaled. Although lead is absorbed very s unkeptly into thebody, its rate of excretion is regular(a) slower. Thus, with constant exposure,lead accumulates gradually in the body. It is absorbed by the rubicund bloodcells and circulated through the body where it becomes concentrated inthe soft tissues, curiously the liver and kidneys. Lead can cause damagein the interchange nervous system and apparently can damage the cells makingup the blood-brain barrier that protects the brain from many harmful chemicals.Symptomsof lead poisoning hold loss of appetite, weakness, anemi a, vomiting,and convulsions, sometimes leading to permanent brain damage or death.Children who ingest chips of old, lead-containing paint or are exposedto dust from the descent of such paint may exhibit symptoms. Levelsof environmental lead considered atoxic may also be involved in increasedhypertension in a significant number of persons, according to studiesreleased in the mid-1980s. As a result, the U.S. Centers for Disease Controlin recent years piddle been revising downward the levels of environmentallead that it would consider safe. At one(a) time, lead poisoning was commonamong those who worked with lead, but such workplace hazards pay beenlargely curtailed.Lead has been utilise by humans since ancient times.It was used in ancient Egypt in coins, weights,ornaments, utensils,ceramic glazes, and solder. Lead is mentioned in the grey Testament. TheRomansconveyed drinking water in lead pipes, some of which are yet in operation.Roman slavesextracted and prepared the lead, d escribes a disease amongthe slaves that was clearly lead poisoning. Because of their potentialtoxicity, lead water pipes are no longer macrocosm installed. The greatestsingle use of lead metal today is in the plates of storage batteries forautomobiles.The protective oxidation layer formed by lead in contactwith such substances as air, sulfuric acid,and fluorine makes it highlyresistant to corrosion. For this reason, lead has been used to makedrainagepipes and lead house in sulfuric acid factories. It is also used asa roofing material. Thesoftness and malleability of lead make it usefulfor overlay telephone and television cables. Lead isused in solderbecause of its low melting point. When combined with tin, lead forms solder