Lead phosphates

Monoammonium and diammonium phosphates are produced on a large scale as fertilizers. During the 1970s, these materials, produced from economical wet-process phosphoric acid, became the world s leading phosphate fertilizers. 

Phosphorus fin t discovered in a mineral by J. G. Gahn (pyroinorphitc, a lead phosphate) subsequently found in the much more abundant apatite by T. Bergman and J. L Proust. 

We have no proof that lead causes cancer in humans. Kidney tumors have developed in rats and mice given large doses of lead. The animal studies have been criticized because of the very high doses used, among other things. The results of high-dose studies should not be used to predict whether lead may cause cancer in humans. The Department of Health and Human Services (DHHS) has determined that lead acetate and lead phosphate may reasonably be expected to be... 

Discarded commercial chemical products, off-species, container residues, and spill residues hazardous waste codes P110, (tetraethyl lead), U144 (lead acetate), U145 (lead phosphate), and U146 (lead subacetate)... 

Balo J, Bajtai A, Szenda B. 1965. [ Experimental adenomas of the kidney produced by chronic administration of lead phosphate.] Magyar Onkol 9 144-151. (Hungarian)... 

NTP. 1998. Eighth report on carcinogens. 1998 summary. Lead acetate and lead phosphate. U S. Department of Health and Human Services. Public Health Service. National Toxicology Program. 

Ruby MV, Davis A, Nicholson A. 1994. In situ formation of lead phosphates in soils as a method to immobilize lead. Environ Sci Technol 28 646-654. 

Holzbecker and Ryan [825] determined these elements in seawater by neutron activation analysis after coprecipitation with lead phosphate. Lead phosphate gives no intense activities on irradiation, so it is a suitable matrix for trace metal determinations by neutron activation analysis. Precipitation of lead phosphate also brings down quantitatively the insoluble phosphates of silver (I), cadmium (II), chromium (III), copper (II), manganese (II), thorium (IV), uranium (VI), and zirconium (IV). Detection limits for each of these are given, and thorium and uranium determinations are described in detail. Gamma activity from 204Pb makes a useful internal standard to correct for geometry differences between samples, which for the lowest detection limits are counted close to the detector. 

There are several reports that certain lead compounds, including lead acetate and lead phosphate, administered to animals in high doses are carcinogenic, primarily producing renal tumors.(Note Those salts demonstrating carcinogenicity in animals are soluble, whereas human beings are primarily exposed to insoluble metallic lead and lead oxide.)... 

Sauve, S., McBride, M. Hendershot, W. 1998. Lead phosphate solubility in water and soil suspensions. Environmental Science Technology, 32, 388-393. 

The extremely low solubility of lead phosphate in water (about 6 x 10 15m) again suggests potentiometric analysis. Selig57,59 determined micro amounts of phosphate by precipitation with lead perchlorate in aqueous medium. The sample was buffered at pH 8.25-8.75 and a lead-selective electrode was used to establish the end-point. The detection limit is about 10 pg of phosphorus. Anions which form insoluble lead salts, such as molybdate, tungstate or chromate, interfere with the procedure. Similar direct potentiometric titrations of phosphate by precipitation as insoluble salts of lanthanum(III), copper(II) or cadmium(II) are suggested, the corresponding ion-selective electrodes being used to detect the end-point. 

J. N. Ryan, Enhanced Dissolution of Cinnabar (Mercuric Sulfide) by Dissolved Organic Malta Isolated from the Florida Everglades, Environ. Sci Technol 1998, 32, 3305 S. Sauvd, M. McBride, and W. Hendershot, Lead Phosphate Solubility in Water and Soil Suspensions, Environ. Sci Technol 1998,32, 388. 

Phosphate. Lead phosphate. CAS 7446-27-7. PbitPOj) . white precipitate. by reaction of soluble lead salt solution and sodium phosphate solution. 

The early workers on phosphorus prepared that element from urine which normally contains ammonium and sodium phosphates. Thus, R. Boyle1 evaporated the urine to a syrupy consistency, and distilled the product either alone or admixed with sand or charcoal. The carbon produced by the decomposition of the organic matter in the urine, or added to it in the form of charcoal, decomposes the ammonium phosphate, without affecting the sodium phosphate. A. S. Marggraf mixed the cone, urine with lead chloride and charcoal powder, and heated the mass until it became pulverulent. The ammonium and sodium phosphates were converted into lead phosphate, and on distillation, the carbon liberated the phosphorus from the lead phosphate. G. A. Giobert mixed the unevaporated urine with lead nitrate or acetate washed the precipitated mixture of lead phosphate and sulphate mixed the precipitate with charcoal and distilled the dried product. 

W. Ipatieff and W. Nikolaieff observed the formation of phosphine when white phosphorus is heated with hydrogen in a sealed tube at 360° and when water-gas at 400 atm. press, acts on lead phosphate. J. Brossler said that if white phosphorus be added to a mixture of zinc and dil. sulphuric acid, in a short time, spontaneously inflammable phosphine will be produced and if a cone. soln. of alkali hydroxide and zinc be mixed with yellow phosphorus, the spontaneously inflammable gas will be given off at about 60° if the temp, be below 20°, the gas evolved is not spontaneously inflammable. H. Davy, and L. Dusart showed that the gas obtained by the action of zinc and dil. acids on yellow phosphorus contains phosphine, although J. B. A. Dumas questioned the fact. D. Vitali observed that the presence of mercuric chloride retards the formation of phosphine. J. Brossler obtained phosphine by the action of hydrochloric acid and a few drops of nitric acid on tin in the presence of yellow phosphorus. The formation of phosphine during the action of ammonia, and of water on yellow phosphorus has been indicated in connection with the chemical reactions of phosphorus. 

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