Lead compound production toxicity

PbEu (anti-knock agents), radiation and sound shields, in paints, high quality glass. World production 1980 4 0 megatonnes. Lead compounds are toxic and hazardous to health. 

The protection of the environment implies the elimination of lead compounds, first of all because of their individual toxicities and second because these derivatives or their products of decomposition poison catalytic converter catalysts. 

The most important class of stabilisers are the lead compounds which form lead chloride on reaction with hydrogen chloride evolved during decomposition. As a class the lead compounds give rise to products of varying opacity, are toxic and turn black in the presence of certain sulphur-containing compounds but are good heat stabilisers. 

This review describes factors concerning the safety and environmental effects of organic germanium, tin and lead compounds. The factors involve the production and use of the elements, alkylation, degradation, toxicity, health effect assessment and so on. 

The major organolead compounds found in the environment are the tetraalkyllead compounds and their di- and trialkyl decomposition products. Elevated levels of tetraalkyl-leads have two possible sources either (i) anthropogenic leaded petroleum inputs or (ii) environmental methylation of natural lead compounds. While the former is well established, the latter is the subject of some controversy in the literature. Interest in the environmental methylation process derives from the increased toxicity of methyllead compounds compared to their inorganic analogs. 

Modem petrol contains small amounts of additives to inhibit this knocking. Leaded petrol, for example, contains the organometallic compound lead tetraethyl, PbEt. Although PbEQ is excellent at stopping knocking, the lead by-products are toxic. In fact, most EU countries now ban PbEt. ... 

The results of a comparative metabolism study of an aryl-sulfenyl derivative of carbofuran [2,2-dimethy1-2,3-dihydro-benzofuranyl-7 -methyl-N-(2-toluenesulfenyl)carbamate] in the house fly and white mouse Indicated the selective action of this compound to be a consequence of different metabolic pathways in insects and mammals (12). The arylsulfenyl group on the carbamate moiety allows the mammal to carry out metabolic reactions leading to less toxic products which are rapidly conjugated, while the toxic parent methylcarbamate is formed in the insect. 

The selection of a lead compound and the development of a synthetic pathway for its preparation (see Chapters 10 and 11) is not the only consideration at the start of an investigation. Researchers must also devise suitable in vivo and in vitro tests to assess the activity and toxicity of the compounds produced. There is no point in carrying out an expensive synthetic procedure if at the end of the day it is impossible to test the product. 

Like all organic lead compounds, tetraethyllead is very toxic. It can enter the body through skin, lungs or digestive tract thus, the production and use of tetraethyllead requires airproof equipment, overalls and gas masks. 

Practical use of organolead compounds will be hardly extended due to their high toxicity and the possibility of sustainable pollution of the environment by the lead compounds. In this connection it must be indicated that the production of tetraethyllead, which achieved 270,000 tons by 1964 only in the USA, started to be reduced at the end of the 20th century. 

The Roman aristocracy had greater access to lead vessels and cosmetics containing lead compounds. It is believed that their life expectancy may have been as low as 25 years because of lead poisoning. In the body, lead accumulates in bones and the central nervous system. The production of hemoglobin is inhibited by lead because it binds to the enzymes that catalyze the reaction. High levels of lead cause anemia, kidney disfunction, and brain damage to occur, and the accumulation of lead interferes with proper development of the brain in children. Because of their toxicity, lead and its compounds are used much less today as paints or glazes than they were in earlier times. 

SAFETY PROFILE Poison by intravenous and intraperitoneal routes. Moderately toxic by ingestion. Experimental teratogenic and reproductive effects. Questionable carcinogen. Probably a severe eye, skin, and mucous membrane irritant. Mutation data reported. A powerful oxidizer. Explodes on contact with red-hot carbon, cyclopentadienylsodium (at 100-130°C), potassium acetate + heat. Reacts violently with ammonium thiocyanate, carbon, lead hypophosphite. When heated to decomposition it emits very toxic fumes of Pb and NOx. Used as a mordant, a chemical reagent, and in production of matches and pyrotechnics. See also LEAD COMPOUNDS and NITRATES. 

SAFETY PROFILE Human poison by an unspecified route. Experimental poison by ingestion, intraperitoneal, intravenous, subcutaneous, and parenteral routes. Moderately toxic by inhalation and skin contact. Experimental teratogenic and reproductive effects. Questionable carcinogen with experimental carcinogenic data. Mutation data reported. Lead compounds are particularly toxic to the central nervous system. It is a solvent for fatty materials and has some solvent action on rubber as well. The fact that it is a lipoid solvent makes it an industrial hazard because it can cause intoxication not only by inhalation but also by absorption through the skin. Decomposes when exposed to sunlight or allowed to evaporate forms triethyl lead, which is also a poisonous compound, as one of its decomposition products. May cause elemental lead intoxication by coming in contact with the skin. 

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