Emissions from lead paints

We characterize lead paint reservoirs in terms of decades, in contrast to lead emissions to the atmosphere where the emissions are associated with air lead changes that are on the order of hours or days in duration. A second contrasting element is that of the namre and extent of lead dispersal via various pathways. While the atmosphere (scaled as to specific areas or regions) is the common conduit for lead from emission sources, lead paint in each of the millions of U.S. residential units that contain it provides microscale risk across a macroscale of distribution. 

House dust. Houses are enclosed spaces and tend to accumulate dust from the outside. There are also internal sources of house dust. The concentration ratio [MJhouse dust/[M]soil has a mean of 0.33 (standard deviation = 0.09) for the ten elements Mn, Fe, La, Sm, Hf, Th, V, Al, Sc and Ce suggesting that around 33% of house dust is soil (93). The concentration ratio for the two surface dusts, [M]house dust/[M]street dust is >1 for the elements Cu, Co, As, Sb, Zn, Cd, Au, Cl and C suggesting these elements also have an internal component. All of these elements, as well as Pb and Br, are enriched in house dust relative to their concentrations in soil. Lead and bromine originate mainly from outside the house, and probably from street dust and motor vehicle emissions and, in the case of lead, from paint. When the concentrations of lead in house dust are very high this generally signifies an internal source of lead paint, especially in older houses. 

Respirable particulate or gaseous forms of lead may be inhaled. Sources include cigarette smoke vehicle exhaust emissions from municipal waste incinerators, iron and steel plants, smelting and refining operations, lead acid battery manufacturing facilities, and sandblasting and burning of surfaces coated with lead paint. Particulate air emissions may eventually deposit and contaminate the soil. 

EXPOSURE ROUTES leaded gasoline combustion combustion of solid waste, coal, and oils emissions from iron and steel production lead smelters tobacco smoke food and soil lead-based paints flaking paint paint chips weathered paint powder drinking water pipes, solder, and fixtures lead smelting and refining industries steel and iron factories gasoline stations battery manufacturing plants... 

Lead poisoning is referred to as an environmental disease because it is caused by exposure to lead in our daily surroundings. Although we cannot see, taste, or smell it, lead is everywhere in our environment. It is not just in the obvious places, such as the emissions from a lead smelter or the peeling paint in an old house, but also in our air, water, soil, and dust. 

Although we no longer use leaded gasoline, our soil has been contaminated from decades of exposure to emissions from cars and trucks burning leaded fuel. Lead is also added to the soil from paint that falls or is scraped from houses and other structures and equipment painted with lead-based paint. In some cases, industrial emissions and pesticides are also present. The net result is large quantities of lead in our soil. For a more detailed discussion of lead in soil and how to protect your family from it, see Chapter 14. 

Even if a child is never exposed to a single large dose of lead, all of the tiny amounts a child is exposed to can add up to trouble. For instance, the average child living in a town near a smelter may have a blood-lead level of 8 micrograms per deciliter from exposure to emissions. A relatively small exposure to lead paint, therefore, will bring his or her blood lead level over the threshold of concern of 10 micrograms per deciliter. Likewise, a child who drinks lead-contaminated water will be much more likely to suffer toxic effects if exposed later to lead-contaminated soil or dust. 

When viewing theie concentrations, one point worthy of note is that lead levels in deposited urban dusts sampled in 1928, before the widespread use of leaded petrol, showed concentrations very similar to those found today in street dusts [11]. Presumably the far greater emissions of smoke from coal combustion and the use of high-lead paints had a substantial influence upon lead deposition. 

The 1974—1975 Silver Valley study data are summarized in Table 23.1. Data are presented as they were gathered in 1974, before emission control systems were restored. Geometric mean PbB values varied with distance of child residences from the smelter emission points but varied only moderately with age of the children. Unlike other Pb exposure scenarios, those based on smelter emissions indicated that excessive exposures persisted into later years. The Silver Valley findings are consistent with findings elsewhere (Neri et al., 1978). Urban children exposed to lead paint more typically show peak PbB values at 2—3 years of age followed by a marked decline. In Area I, with homes within 1 mile of the facility, PbB varied from 75 p.g/dl... 

Lead inhalation can occur when particle sizes are below 10 pm (micrometers) in diameter, as is the case with fiunes and line dust (World Health Organization 2010). Lead-polluted air results from lead smelter emissions and car emissions in countries that still use leaded gasoUne. Lead fiunes are also produced when heat guns are used to remove lead-based paint. 

Lead-based paiat ra buildings, interiors and exteriors Lead food cans Lead gasoline and dust Lead water pipes Soil Oil, coal, combustion and solid waste Metal refining, smelting, and manufacturing processes emissions Emissions from alkyl lead manufacturers Lead battery manufacturers and recyclers Portland cement manufactnring Painted surfaces weathering... 

Mielke etal. (1983) found that lead as well as cadmium, copper, nickel, and zinc were concentrated and ubiquitous in garden soil in the Baltimore, Maryland inner city. The authors noted that elevated soil levels did not appear to be related to painted surfaces weathering in the inner city and concluded that emissions from vehicular traffic was likely a major source of the elevated soil lead levels. Mielke et al. (1989) confirmed the contribution of leaded gasoline emissions to urban soil by studying soil lead levels in four cities in Miimesota. On the basis of that research, the authors concluded ... 

One of the important factors in determining the contribution of lead in soil and dust to lead levels in children is bioavailability (Chaney, 1989). Factors influencing how much lead in soil and dust ingested by children may be absorbed into the blood stream include the physical and chemical properties of the lead, particle size, and the nutritional status of the particular child. Lead from leaded gasoline emissions are predominately small particles and therefore readily bioavailable to children (Chaney, 1989). The bioavailability of lead in paint varies with particle size and the type of lead compound present in the paint (e.g., lead carbonate, lead sulfate). 

Use of some biomass feedstocks can increase potential environmental risks. Municipal solid waste can contain toxic materials that can produce dioxins and other poisons in the flue gas, and these should not be burned without special emission controls. Demolition wood can contain lead from paint, other heavy metals, creosote, and halides used in presen a-tive treatments. Sewage sludge has a high amount of sulfur, and sulfur dioxide emission can increase if sewage sludge is used as a feedstock. 

Results For the St. Louis data, the target transformation analysis results for the fine fraction without July Uth and 5th are given in table 6. The presence of a motor vehicle source, a sulfur source, a soil or flyash source, a titanium source, and a zinc source are indicated. The sulfur, titanium and zinc factors were determined from the simple initial test vectors for those elements. The concentration of sulfur was not related to any other elements and represents a secondary sulfate aerosol resulting from the conversion of primary sulfur oxide emissions. Titanium was found to be associated with sulfur, calcium, iron, and barium. Rheingrover ( jt) identified the source of titanium as a paint-pigment factory located to the south of station 112. The zinc factor, associated with the elements chlorine, potassium, iron and lead, is attributed to refuse incinerator emissions. This factor could also represent particles from zinc and/or lead smelters, though a high chlorine concentration is usually associated with particles from refuse incinerators ( ). The sulfur concentration in the refined sulfate factor is consistent with that of ammonium sulfate. The calculated lead concentration in the motor vehicle factor of ten percent and a lead to bromine ratio of about 0.28 are typical of values reported in the literature (25). The concentration of lead in... 

---