No abstract

Lead (Pb) is extremely toxic and a major cause of chronic diseases worldwide. Pb is associated with health disparities, particularly within low-income populations. In biological systems, Pb mimics calcium and, among other effects, interrupts cell signaling. Furthermore, Pb exposure results in epigenetic changes that affect multigenerational gene expression. Exposure to Pb has decreased through primary prevention, including removal of Pb solder from canned food, regulating lead-based paint, and especially eliminating Pb additives in gasoline. While researchers observe a continuous decline in children’s blood lead (BPb), reservoirs of exposure persist in topsoil, which stores the legacy dust from leaded gasoline and other sources. Our surveys of metropolitan New Orleans reveal that median topsoil Pb in communities (n = 274) decreased 44% from 99 mg/kg to 54 mg/kg (P value of 2.09 × 10−08), with a median depletion rate of ∼2.4 mg⋅kg⋅y−1 over 15 y. From 2000 through 2005 to 2011 through 2016, children’s BPb declined from 3.6 μg/dL to 1.2 μg/dL or 64% (P value of 2.02 × 10−85), a decrease of ∼0.2 μg⋅dL⋅y−1 during a median of 12 y. Here, we explore the decline of children’s BPb by examining a metabolism of cities framework of inputs, transformations, storages, and outputs. Our findings indicate that decreasing Pb in topsoil is an important factor in the continuous decline of children’s BPb. Similar reductions are expected in other major US cities. The most contaminated urban communities, usually inhabited by vulnerable populations, require further reductions of topsoil Pb to fulfill primary prevention for the nation’s children.

No abstract

Power sanding exterior paint is a common practice during repainting of old houses in New Orleans, Louisiana, that triggers lead poisoning and releases more than Pb. In this study we quantified the Pb, zinc, cadmium, manganese, nickel, copper, cobalt, chromium, and vanadium in exterior paint samples collected from New Orleans homes (n = 31). We used interior dust wipes to compare two exterior house-painting projects. House 1 was measured in response to the plight of a family after a paint contractor power sanded all exterior paint from the weatherboards. The Pb content (approximately 130,000 microg Pb/g) was first realized when the family pet died; the children were hospitalized, the family was displaced, and cleanup costs were high. To determine the quantity of dust generated by power sanding and the benefits of reducing Pb-contaminated dust, we tested a case study house (house 2) for Pb (approximately 90,000 microg/g) before the project was started; the house was then dry scraped and the paint chips were collected. Although the hazards of Pb-based paints are well known, there are other problems as well, because other toxic metals exist in old paints. If house 2 had been power sanded to bare wood like house 1, the repainting project would have released as dust about 7.4 kg Pb, 3.5 kg Zn, 9.7 g Cd, 14.8 g Cu, 8.8 g Mn, 1.5 g Ni, 5.4 g Co, 2.4 g Cr, and 0.3 g V. The total tolerable daily intake (TTDI) for a child under 6 years of age is 6 microg Pb from all sources. Converting 7.4 kg Pb to this scale is vexing--more than 1 billion (10(9)) times the TTDI. Also for perspective, the one-time release of 7.4 x 10(9) microg of Pb dust from sanding compares to 50 x 10(9) microg of Pb dust emitted annually per 0.1 mile (0.16 km) from street traffic during the peak use of leaded gasoline. In this paper, we broaden the discussion to include an array of metals in paint and underscore the need and possibilities for curtailing the release of metal dust.