Automobiles lead paint

Que Hee SS. 1994. Availability of elements in leaded/unleaded automobile exhausts, a leaded paint, a soil, and some mixtures. Arch Environ Contain Toxicol 27 145-153. 

Leaded gasoline has long been banned in the United States and some other countries, but not before millions of tons of lead poured into the air for 60 years from the exhausts of trucks and automobiles. The lead from those exhausts settled on everything around us, particularly in our soil. Lead has also entered soil from underground leaded gas storage tanks, industrial operations that produce lead grindings, and lead paint waste. 

Over the past 30 years, many lead-based products have disappeared from use or the use has been greatly diminished. These products include lead-based paints, lead-based anti-knock compounds for automobiles, lead glazes for pottery, lead sealants for wine battles, solder for sealing the seams of steel cans, automobile body solder, solders for potable water systems, solder for sealing copper radiators, chemical tank linings, lead pipes, lead-based metal bearings, lead sealants such as for drain pipes, power and electrical cable sheathing, and ammunition. 

Substitution of one material by another will be prompted by such considerations as relative price or availability, technical developments or (particularly for lead) by environmental or health concerns. Lead has faced competition from other materials for many years. The earliest example of large-scale market losses due to substitution came in the 1920s, when lead paints faced sustained pressure from newly-emerging zinc and other metallic paints. However, this trend was disguised by an overall expansion in consumption, based on the development of new fields of application. For lead, these losses were more than compensated, certainly after the Second World War, by expanding automobile demand for SU batteries and lead-based anti-knock petrol additives. 

The manufacture of fertilizers was discussed in Chapter 14. Phosphate rock is digested with sulfuric acid to convert CaC03 into a more soluble form that contains a higher percentage of phosphorus. Sulfuric acid is used as a catalyst in alkylation reactions, petroleum refining, manufacture of detergents, paints, dyes, and fibers, and other processes. It is also used as the electrolyte in the lead-acid battery that is used in automobiles. Sulfuric acid is an enormously important chemical commodity that it would be hard to do without. 

Molybdenum orange is a solid solution of lead molybdate, lead chromate and often lead sulfate. It is used as a pigment in paints, plastics and printing inks. The pigment is used for red hues in automobile and appliance paints. 

In some industrial processes, exposure to HDI may occur in the presence of its hydrolysis products, namely 1,6-hexamethyleneaminoisocyanate and HDA, both of which may also cause adverse respiratory effects (Beard and Noe 1981). In a study to evaluate isocyanate exposures of automobile repair workers involved in welding activities, which could lead to pyrolysis of HDI polymer-based paint, the atmospheric concentration ranges of HDI, 1,6-hexamethyleneaminoisocyanate, and HDA were found to be 0.18-1.3 mg/m (0.027-0.20 ppm), <0.004-0.24 mg/m (<0.0006-0.036 ppm), and <0.004-0.10 mg/m (<0.0006-0.015 ppm), respectively, 25 cm from the source (Sharping et al. 1988). Concentrations of 1,6-hexamethyleneamino-isocyanate and HDA were on the order of 15% of the HDI concentrations. 

Bismuth vanadate pigments are used in the manufacture of lead-free, weather resistant, brilliant yellow colors for automobile finishes and industrial paints. They are suitable for the pigmentation of solvent-containing paints, water-based paints, powder coatings, and coil-coating systems. It can be mixed with other pigments... 

BSWL. pagle-Pidier] Basic silteate white lead pigment, heat stabilizer for idastics rust-inhibitive pigment in the automobile industry us in industrial or maintenance paints. 

Inhalation and ingestion (of water, food, paint, soil and/or dust) are the primary routes of human exposure to lead (OECD, 1993). Percutaneous absorption is minimal in humans. The absorption of lead from air to blood involves two processes the deposition of airborne particles in the respiratory tract and the absorption and clearance from the respiratory tract into the circulation. The respiratory deposition of airborne lead is in the range of 30-50% and varies with particle size, chemical speciation, solubility in body fluids and ventilation rate. Higher deposition rates may occur with larger particles, but this deposition takes place in the upper respiratory tract. The smaller particles of inhaled lead (generated by automobile exhaust) are almost (>90%) completely absorbed after deposition in the lower respiratory tract (WHO, 1995). 

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