GEOCHEMISTRY: Postdiluvian Pb

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Science  24 Nov 2006:
Vol. 314, Issue 5803, pp. 1218d-1219d
DOI: 10.1126/science.314.5803.1218d

Lead contamination of exposed soils in residential areas is a strong concern because of the danger that ingestion of the heavy metal can pose to children's health. One promising remediation strategy is the addition of a clean soil layer to the surface. Before Hurricane Katrina in August 2005, Mielke et al. had undertaken a study in which they were monitoring soil lead levels at 25 contaminated New Orleans properties after treatment with 15 cm of clean alluvium drawn from the Mississippi River. They now report the impact of flooding caused by the hurricane on these lead levels. Although erosion and soil mixing might have been expected to substantially elevate surface lead levels, the authors found that the general increase on the flooded properties was relatively small, and consistent with a steady but slow rise observed in the series of measurements before the hurricane. Median lead levels were reduced from 1051 to 6 mg/kg by the treatment, subsequently rose to 10 mg/kg before the flooding, and were elevated after the hurricane to 16 mg/kg. The authors attribute this steady rise to resuspension and deposition of lead-bearing dust across the city. — JSY

Environ. Sci. Technol. 40, 10.1021/es061294c (2006).

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