Lead is a kind of chemical element, chemical symbol mensa, chemical symbol is the Pb (Latin), the Plumbum 207.2 atomic weight, atomic number for 82. Lead is all stable chemical element of atomic number.Lead as heavy silvery blue, it is toxic, a group of metal extensibility. 327.502 melting, boiling 17.4 degrees c, g / 11.3437 density, hardness is 1.5 cm ^ 3, texture is soft, tensile strength is small.Lead is one of the earliest use of humans, 3000 BC metal from ore, humans will already lead smelting in. Lead in the content of 0.0016% crust, main mineral is galena. Lead in nature have four stable isotopes: lead 204, 206, 207, 208, and more than 20 kinds of radioactive isotopes.Metal lead in the air, water and carbon dioxide by oxygen, its surface oxidation generating protection film will soon, In heating, can quickly lead with oxygen, sulfur compounds, halogen, Lead and cold, cold sulfuric acid, with little effect to heat or strong sulfuric acid, reaction, Lead and dilute nitric acid reaction, but not with strong nitric acid reaction, Lead to slow in alkaline solution is strong.Lead is mainly used to produce lead battery, Lead alloys can be used to cast type, make soldering, Lead is also used to manufacture radioactive radiation, X-ray protective equipment, Lead and compounds are bigger toxicity of human body, and in the human body. Lead used in building materials, lead acid battery, as bullets and shells, soldering, trophies and some alloys are lead.Lead in the crust is in the nature of content, there is a natural lead. But because contain lead things together, melting and low (ep), lead in ancient times was used by people.Galena until today (PbS) is the main source of extracting lead people. In ancient times, people had accidentally put into bonfires, galena it burned into oxide, and then by the reduction of carbon, formed a metal lead.In the British museum boasts more than worshipped in Egypt, mosques, found the paste 3000 BC. In the Iraqi city of ur excavation sites and other cities of materials, not only find all sorts of 4,000 years BC, and metal objects of ancient Persian use text clay board type fellowship records. These records, B.C., already from ore 23.5 extract large iron, copper, silver and lead. In 1792 before 1750 BC - HanMuLaBi reign of emperor, has large production of lead. Yin and burial in China are also found in the attic, come late shang and amraphel, etc.Han Chinese in Yin to the amount of lead in the bronze has the tendency of increase. The increase in bronze lead in liquid alloy liquidity plays an important role in improving their grain, make casting.However, the ancient respectively to lead and tin and not very clear. Roma said lead to black lead, says that later, as it BaiQian element symbols as Pb.Sino-foreign ancient alchemists and LianDan economists to lead and lead some compounds, such as in the view that received zhou yi can tong qi said: "hu powder fire, color bad shots for lead." With today"s chemical formula that is:Pb3O4 + 2C -- - 3Pb + 2CO2Until 16 centuries ago, graphite in pencil, made in Europe, from the Greek, Roman times, people is in the hands of QianTiao stick on paper writing, it"s a pencil. "today" name. In the middle ages, to lead the American oil-rich, some churches, houses, especially the roof is built with QianBan lead, because of laziness, chemical corrosion. First use of lead acid made by the method of room also lead the characteristics.Lead element symbols Pb is derived from Latin name plumbum.Lead pollutionIn all known in the toxic substances, the book is the largest lead. On record that lead a water pipe. There are many ways of public contact lead. In recent years, a major concern for the public petroleum products contain lead. Lead-based paint, especially some old lead-based paints, higher, has caused many deaths, so some special formulated the environmental standards in the contents of lead paint should be controlled in 600PPM.Some countries have a high standard, but the market sell when the lead paint posted labels warning users. Food also found the residue, or lead in the air pollution, or lead showers of canned food lead pollution canned food. Another important sources of the lead is lead tube. Decades ago when building houses with lead tube lined pipe, or lead with the natural refrigerator in the summer, has banned lead lining, plastic, or other materials.General safety of drinking water amount is 100 microgram/boundaries, and maximum acceptable level is 50 micrograms/litre. Then further regulation in tap water is acceptable for the largest concentration of lead 50 ug/liter (0.05 mg/litre). In addition, in order to study the influence of lead to human body health, scientists to lead human blood test, as if the concentration of lead first index. Data shows that: if the water nearly 50 ug/litre, so the patient"s blood lead levels in about 30 micrograms/litres. The infant requirements should be more strictly, average blood lead levels or more than 10-15 microgram/litre.Water treatment process of water can join the calcium carbonate in water and keep in alkaline, then to reduce water conveyance pipeline corrosion, this process will bring new risks. But the corrosion problems are complicated, isn"t so, should be solved, but overall purification and expensive.Many chemicals in the residence environment after a period of time for the final may degrade harmless, but cannot lead compounds, once into the environmental degradation long remained the usability. Due to lead in the environment of long-term durability, and many lives have stronger organization of potential toxicity, so the lead has been listed as strong pollutants.Acute poisoning the present study more thoroughly, the symptom is: the stomach, headache, trembling, neurological fidgety, in the most severe cases, could not wake up until the death of personnel. In very low concentrations and lead the chronic health effects: on the brain and nervous system. Scientists found that even the blood lead children maintain acceptable level of concentration, still significantly affect children"s intelligence development and performance. We only lower levels in drinking water can ensure people to lead the total. The popularization and application of the unleaded gasoline to reduce the environment pollution have made of lead, especially reduces the atmospheric particulates lead.Lead and particulates from the urban transportation by the wind to the suburbs, from one province to another, even to other regions, became the effects of pollution. Scientists in north area of Greenland ice on the tip of the region by drill drilling, the year old icicles, top years trying to different levels, determination of lead ice. Results: 1750 in lead to 20 micrograms per ton alone, 1860 for 50 ug/tons. In 1950 to 120 microgram/tons. In 1965 to 210 micrograms per ton. The development of modern industry, the serious pollution worldwide.Toxicology material and environmental behaviortoxicityAcute toxicity: LD5070mg/kg (rat transvenous)Subacute toxicity: 10 mu g/m3, rats contact 30 to 40 days, the red and ALAD (bravery pigment 80% ~ 90%), blood lead levels as high as 150 to 200 mu g / 100 ml. Overt symptoms. 10 mu g/m3, rats inhaled 3-12 months, from the lungs elution down macrophages reduced 60%, poisoning. 0.01 mg/m3, occupational exposure, urinary system pressure changes, death, inflammation, women fetal deaths.Chronic toxicity: long-term exposure to lead and compounds Yi palpitations, will lead to increased erythrocyte, adopted. After the nervous system, lead infringement insomnia, dream, memory drops,, and development for the weary manic, blindness, sane fuzzy, coma, finally died due to cerebral oxygen. Blood lead levels tend to be higher than 2.16 micro Moore/litre, clinical symptoms occur, so many children"s body blood lead levels, although high, but no particular discomfort, mild mental or changes in behaviour is difficult to parents or doctors found. This is why children lead poisoning in foreign countries are called "hidden killer".Cancer: lead the animal experiment of inorganic compounds that may cause cancer. Another according to the document, the lead is a chronic and accumulating poisons, individual sensitivity is not identical, to people lead is a potential carcinogens urinary system.Teratogenic: there is not enough to provide evidence of animal experiment and lead compounds have teratogenic role.Cause mutation: with 1% of pbch3 feed fed mice, cultivating the chromosome fissure - white fracture type, the increase in the number of distortion that individual chromosomes, change involves DNA damage in duplicate.Metabolism and degradation of inorganic lead and environment is very stable, not easy metabolic compounds and degradation. Lead poisoning is accumulating on the human body, inhaled lead in the lungs, 25% of sedimentary water soluble part through the blood. If a person contact air lead 1 muon g/m3, human blood leels of the lead for 1 ~ 2 muon g / 100 ml of blood. From the intake of food and beverage lead approximately 10% is absorbed. If intake of food every day from 10 mu g, contain blood lead for 6 ~ 18 mu g / 100 ml of blood, these lead compounds can be through a digestive system, which mainly through urine discharge (76%) and intestinal (16%), and the rest is not known by all kinds of ways, such as by sweating, peeling and removal of metabolic product to pass.And the residue accumulation: lead is a kind of accumulating human food intake by poison, and can also lead from polluted air intake of lead, the American lung contain more than Africa, near and far east area is high, it is because of the atmospheric pollution than these areas lead in serious cause. The results from the human anatomy, invades the body"s lead 70% ~ 90% in phosphoric acid PbHPO4 lead (last) attached to the bone deposition and the form of organization, the bones of modern American vendors and 100 times higher than ancient. This part of the content of lead, and gradually increase the lifetime accumulation in the human body tissue, including blood lead to a certain extent (man), and then after early adulthood, almost no longer part will be pa ontaneously external surplus (as described above), showed obvious turnover. Fish to lead strong enrichment.Migration and transformation: according to national research council of Canada, Ottawa in 1978 to lead in the world environment, migration concentration of lead in the sea world mean 0.03 muon g/L, freshwater 0.5 muon g/L. Rural atmosphere around the average levels of 0.1 g/m3, the city through the atmosphere lead concentration range 1 ~ 10 mu g/m3. The soil and rock lead in the bottom 13mg average value/kg. Lead in the world of soil environmental outcomes is: from the air to 15 million tons of soil from the air, sea 25 million tons, transferred from the soil to Marine 41.6y/o tons. Every year from water transfer to the beach for 40 to 60 tons. Due to water, soil, air is the lead to absorb and biological organisms, resulted in the world of plant food vendors in the range of 0.1 ~ mean 1mg/kg (dry weight, food products in the lead) mean for 2.5 mg/kg, fish contain lead 0.2 ~ 0.6 mg average range, part coastal/kg polluted areas crustaceans and molluscs with even more 3000mg up/kg.Lead industrial pollution from mining and smelting, rubber production, dyestuff, printing, ceramics, glass, lead solder, cable and lead tube manufacturing wastewater and waste. In addition, the automobile exhaust is poisonous substances tetraethyl lead. Water pollution by lead Pb0.3 (mg/L) 0.5 ~, inhibit the water from the net effect, 2 ~ 4mg/L, water is a murky.DangerWhen heated, powder in flame or contact will cause burning antioxidant.Combustion (decomposition product)Lead oxideOn-site monitoring methodFour carboxy quinone dipstick colorimetric method of harmful substances in the air, HangShiPing determination methodSpeed measuring instrument, Spectrophotometric method, Anodic stripping voltammetry the environment pollution accident emergency monitoring and disposal technology WanBenTai editorLaboratory monitoring methodMonitoring method source categoryAtomic absorption spectrophotometry GB7475-87MCSO - 4 (were) of sulfonylurea porphyrin spectrophotometric WS/T126-1999 workplaces airHydride atomic absorption spectrophotometry - WS/T127-1999 workplaces airAtomic absorption spectrophotometry GB/T15555.2-95 solid waste leaching solutionGraphite furnace atomic absorption spectrophotometry GB/T17141-1997 soilFlame atomic absorption spectrophotometry GB/T17140-1997 soilFlame atomic absorption spectrophotometry GB/T15264-94 air qualityAtomic absorption spectrophotometry CJ/T101-99 of urban living garbageAtomic absorption spectrophotometry "solid wastes test analysis and evaluation of China environmental monitoring station handbook of solid wasteEnvironmental standardsChina (TJ36-79) in the air of workplace of the maximum allowed harmful material concentration 0.03 mg/m3 / lead smoke], 0.05 mg/m3 / lead dust]China (TJ36-79) residential air harmful substances in the allowable concentration 0.0007 mg/m3 (mean),China (1996) GB3092 - air environmental quality standard season average: 1.50 ug/m3Average annual: 1.00 ug/m3China (1996) GB16297 - comprehensive discharge atmospheric pollutants standard (lead) and (the highest emission concentrations (mg/m3) :0.90 (table 1), 0.70 (table 2.)2 the highest emission rate (kg/h) :Secondary 0.005 ~ 0.39, 3 0.007 ~ 0.60 (table 1)Secondary 0.004 ~ 0.33, 3 0.006 ~ 0.51 (table 2.)3 no organization emissions monitoring concentration limits:0.0060 mg/m3 (table 2), 0.
