The concurrent decline of soil lead and children’s blood lead in New Orleans

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.

New Approaches to Identifying and Reducing the Global Burden of Disease From Pollution

“…The problem is that soil metal concentrations are highly heterogeneous at the small scale because of multiple sources (house paint, automobile exhaust and debris, particulate matter from utilities, industrial sources, etc. ), and barring the identification of particular emission sources and sinks, these metal hot spots prove exceedingly difficult to pinpoint (Filippelli et al, 2015;Laidlaw et al, 2017;Mielke et al, 2019;Zahran et al, 2013). Indeed, we often need to resort to spatial distribution of metal-poisoning children to map back to potential sources ( Figure 3).…”

Bioavailable soil Pb minimized by in situ transformation to plumbojarosite

“…A recent United Nations Children's Fund ( 1 ) report highlights the global epidemic of lead (Pb) poisoning where one in three children (∼800 million globally) have blood lead levels above the US Centers for Disease Control and Prevention reference value for elevated blood Pb (5 µg/dL) and over 900,000 premature deaths per year are attributed to lead exposure. Exposure of children to Pb has profound and long-lasting health effects ( 2 , 3 ). Historical release of Pb into the environment has resulted in widespread and persistent contamination of urban soil and dust with this toxic metal ( 4 – 6 ).…”

“…Historical release of Pb into the environment has resulted in widespread and persistent contamination of urban soil and dust with this toxic metal ( 4 – 6 ). Although Pb levels in some media (e.g., air and food) have declined in recent decades ( 7 , 8 ) soil and dust Pb levels remain elevated ( 3 ). As a consequence, Pb in soil and dust is a significant source of Pb exposure in 1–6-y-old children ( 9 ).…”

Geospatial approach to investigate spatial clustering and hotspots of blood lead levels in children within Kabwe, Zambia

“…While the physiological mechanisms for Pb dose–response may be similar for all children (Mielke et al, 2019), there are varied exposure pathways. The blood lead levels (BLL) are related to Pb soil contamination (Matte et al, 1991) and social economic factors (Mielke et al, 2019).…”