Novel Policies are Required to Reduce Pediatric Lead Exposure from Legacy Lead (Pb) in Soil and Air

Abstract

In 1925, a U.S. conference on lead (Pb) additives tacitly approved their use in petrol. Over five-decades an exponential increase of air lead occurred from commercial marketing of leaded petrol and the sale of automobiles. The ability to measure microgram quantities of Pb was unavailable to medical researchers until the late 1960s and early 1970s. The clinical application of advanced analytical technology demonstrated that pediatric lead exposure was excessive. Beginning in the mid-1970s, actions were taken to curtail Pb additive and decreases of pediatric lead poisoning coincided with decreased air Pb from leaded petrol use. Exogenous Pb exhaust particles are absorbed through inhalation and ingestion routes of exposure. Exogenous Pb is metabolically mistaken for calcium and stored endogenously in bones, teeth, and other tissues. Endogenous Pb has intergenerational effects. All organs, most notably the nervous system, are affected. Clinical studies indicate that there is no safe level of Pb exposure. A worldwide ban on leaded petrol was achieved on August 30, 2021. Banning leaded petrol corresponded with marked decreases in lead exposure. However, exogenous Pb dust persists in soil as a legacy from the era of leaded petrol. Soil Pb is remobilized into the air. Because of traffic congestion and Pb dust emissions, population centers are of particular concern. An exceedingly strong association exists between soil Pb and blood Pb indicating that at the community-scale Pb dust mitigation is necessary to decrease pediatric Pb exposure. Urban soil Pb and blood Pb studies indicate the risk of excessive exposure from legacy Pb dust in communities is highest where the median soil Pb is ≥ 50 mg/kg. The objective of this article is to demonstrate the practical application of an advanced hand-held analytical instrument to map Pb in children’s playgrounds adjacent to a major traffic corridor. We illustrate soil Pb mapping and then consider mitigation procedures for primary prevention of legacy Pb. Mapping soil Pb provides an informed basis for advising parents and encouraging community mitigation responses for reducing pediatric Pb exposure from legacy Pb dust. The soil health-plant health-animal/human health signaling nexus is compromised by legacy Pb. For the medical pediatric community, the existence of legacy lead requires new policies to address intervention of the soil-air-blood linkages of the Pb exposure pathway.