The toxic legacy of lead continues to haunt our world, as revealed by a recent report from The World Bank. While leaded fuel has been phased out, the harmful impacts of lead exposure persist, especially in low- and middle-income countries (LMICs) where contamination is widespread. This article delves into the dangers of lead exposure, its chronic effects, and the staggering toll it takes on global health.
Lead has been recognized as a neurotoxin that can cause severe neurological damage and even death since Ancient Rome. However, it is now understood that even low levels of regular lead exposure can have long-term detrimental effects. Adults exposed to lead may develop cardiovascular disease, while children may experience neuropsychological problems, such as lower IQ scores and increased behavioral issues.
In the 20th century, leaded fuels were the primary source of lead exposure. Recognizing the dangers, the United Nations initiated a campaign to phase out leaded fuels in 2002, and by 2021, they were officially removed from the market. This international effort has significantly reduced blood lead levels worldwide. However, a recent modelling study conducted by environmental specialists Bjorn Larsen and Ernesto Sánchez-Triana reveals that the burden of lead exposure remains alarmingly heavy.
Contrary to previous estimations, Larsen and Sánchez-Triana’s research suggests that lead exposure is deadlier than anticipated. In 2019 alone, it is estimated that 5.5 million adults died from cardiovascular disease associated with lead exposure, a figure six times higher than previously thought. Additionally, the study estimates that 765 million IQ points were lost among children aged 5 or younger as a result of lead exposure. These impacts were most significant in LMICs, where 95 percent of global IQ loss in young children occurred, and 90 percent of cardiovascular disease deaths were concentrated. Furthermore, IQ losses in these countries were nearly 80 percent higher than previously estimated.
The economic cost associated with lead exposure is substantial. In 2019 alone, lead exposure accounted for approximately US$6 trillion, equivalent to around 6.9 percent of global GDP. This staggering amount breaks down into 77 percent attributed to the welfare cost of cardiovascular disease mortality and 23 percent estimated as the present value of future income losses resulting from IQ loss. The study by Larsen and Sánchez-Triana places lead exposure as a significant environmental risk factor, on par with combined PM2.5 ambient and household air pollution, and ahead of unsafe household drinking water, sanitation, and handwashing.
To address this global health crisis, the authors urge nations to take proactive measures. A more comprehensive approach involving national blood lead level measurements is necessary to assess the true scale of the problem. Identifying and eliminating sources of lead exposure is crucial in curbing its detrimental effects. Furthermore, it is imperative to quantify the health effects and costs of other chemicals in a similar manner, ensuring a comprehensive understanding of the risks they pose.
Lead exposure continues to wreak havoc on global health, particularly in LMICs. The insidious nature of this toxic legacy demands urgent attention. The world must unite in the fight against lead exposure, implementing comprehensive measures to reduce its prevalence, mitigate its consequences, and protect future generations from its devastating effects. Only through concerted efforts can we overcome this pressing global health crisis and secure a healthier, lead-free future for all.