Soils in older areas of cities are highly contaminated by lead, due largely to past use of lead additives in gasoline, the use of lead in exterior paints, and industrial lead sources. Soils are not passive repositories and periodic re-suspension of fine lead contaminated soil dust particulates (or aerosols) may create seasonal variations of lead exposure for urban dwellers. Atmospheric soil and lead aerosol data from the Interagency Monitoring of Protected Visual Environments (IMPROVE) database were obtained for Pittsburgh, Detroit, Chicago, and Birmingham (Alabama), USA. The temporal variations of atmospheric soil and lead aerosols in these four US cities were examined to determine whether re-suspended lead contaminated urban soil was the dominant source of atmospheric lead. Soil and lead-in-air concentrations were examined to ascertain whether lead aerosols follow seasonal patterns with highest concentrations during the summer and/or autumn. Atmospheric soil and lead aerosol concentrations on weekends and Federal holidays were compared to weekdays to evaluate the possibility that automotive turbulence results in re-suspension of lead contaminated urban soil. The results show that the natural logs of atmospheric soil and lead aerosols were associated in Pittsburgh from April 2004 to July 2005 (R²=0.31, p <0.01), Detroit from November 2003 to July 2005 (R²=0.49, p <0.01), Chicago from November 2003 to August 2005 (R²=0.32, p <0.01), and Birmingham from May 2004 to December 2006 (R²=0.47, p <0.01). Atmospheric soil and lead aerosols followed seasonal patterns with highest concentrations during the summer and/or autumn. Atmospheric soil and lead aerosols are 3.15 and 3.12 times higher, respectively, during weekdays than weekends and Federal Government holidays, suggesting that automotive traffic turbulence plays a significant role in re-suspension of contaminated roadside soils and dusts. To decrease urban atmospheric Pb concentrations, subsequent Pb-rich dust deposition and penetration into homes, and its consequent deleterious effect in childhood Pb levels, it is necessary to remediate and or isolate urban soils contaminated with Pb. While the US Federal Government has enacted legislation covering clean air and clean water, there is no universal clean soil act, although there are several standards pertaining to acceptable values. These guidelines are inconsistent across the US and in light of the evidence, they need to be harmonized and re-evaluated so as to develop a unified strategy to mitigate an unnecessary and preventable exposure pathway.
|Number of pages||1|
|Publication status||Published - 2012|
|Event||Goldschmidt Conference (22nd : 2012) - Montreal, Canada|
Duration: 24 Jun 2012 → 29 Jun 2012