Lead in Air, Soil, and Blood: Pb Poisoning in a Changing World

Abstract

(1) Background: Leaded petrol became a worldwide vehicle fuel during the 20th century. While leaded petrol was totally banned on 30 August 2021, its lead (Pb) dust legacy remains in the environment as soil Pb. The health impacts of Pb are well known and risks occur when exposures are above zero. The inextricable links between air Pb, soil Pb, and blood Pb are not widely A. Exposure risks continue even after banning leaded petrol and must be explored. (2) Methods: This article evaluates selected examples of temporal measurements of atmospheric Pb and human Pb exposure and the effect of soil Pb on blood Pb. Several search engines were used to find articles on temporal changes in air Pb and human Pb exposures. New Orleans studies provided empirical data on the association between soil Pb and blood Pb. (3) Results: Vehicle Pb emission trends are closely associated with air Pb and blood Pb. Air Pb deposited in soil becomes a reservoir of Pb dust that is known to be remobilized into the atmosphere. (4) Conclusions: The dust from leaded petrol continues to pose major exposure risks to humans. Exogenous sources of Pb in soil and its remobilization into air along with endogenous bone Pb establish the baseline exposure of children and adults. Reducing human exposure to Pb requires novel policies to decrease exogenous contact from the reservoir of Pb in soil and curtailing remobilization of soil Pb into the atmosphere. Mitigating exposure to soil Pb must therefore play a central role in advancing primary prevention.

Keywords: atmospheric Pb; primary Pb prevention; spatiotemporal soil Pb and blood Pb; urban soil Pb.

Figure 2

Blood Pb decreases in two small Swedish cities, Landskrona and Trelleborg. This graph was modified from the published data using WebPlotDigitizer Version 4.5 (Pacifica, CA, USA) and Microsoft Excel Version 16.54 (Microsoft Corporation Redmond, Washington, DC, USA).

Figure 3

Based on the raw data provided in atmospheric Pb and blood Pb in urban and rural communities appear to be out of sync. The main interest is 2000 when China banned leaded petrol. Air Pb dropped precipitously followed by a sharp, although not as steep, decline in blood Pb, a subsequent more gradual decrease, and a flattened response after 2014.

Figure 4

Blood Pb data for 20–29-year-old urban German population compared to the US NHANES (nationally represented data) for the same age group. Compiled from Table 3 in ref. [17] and from NHANES data [18]. The graph was created using Microsoft Excel Version 16.54 (Redmond, WA, USA).

Figure 5

Blood Pb increases and decreases from 1973 to 2005 correspond with increases and decreases in leaded petrol emission ending during 2002 in Australia. Although the leaded petrol emissions continued to decrease, blood Pb stabilized at around 2 µg/dL. Revised and redrawn from [19].

Figure 6

Spatiotemporal declines of soil Pb in New Orleans. The maps of New Orleans were created from a citywide survey of the metropolitan communities (n~5400 soil samples systematically collected across 274 census tracts) [27].

Figure 7

Graph of the median blood Pb (µg/dL) on the y-axis and median soil Pb (mg/kg) on the x-axis. Two surveys of New Orleans over an interval of ~15 years illustrate the concurrent decrease in both blood Pb and soil Pb. The high blood Pb census tracts correspond with high soil Pb. The Fisher’s Exact p-values are <10⁻³⁶. As illustrated in Figure 5, the most contaminated areas are clustered in the inner-city where the highest children’s blood lead values are found. Combination of two different figures and redrawn [27].

Figure 1

Graph comparing the U.S. annual quantities of Pb in paint and gasoline. In the late 1960s and early 1970s, appropriately sensitive analytical instruments became available to measure lead. Failure to include either one or another of the major sources is a disservice to public health. For example, Dr. Henderson’s concern about inhalation is not addressed when lead aerosols from the combustion of leaded petrol are ignored as a major source of lead.