According to new estimates, especially in poorer countries, several million people die every year as a result of high levels of lead exposure. In addition, such contamination led to children suffering neurological damage. In low- and middle-income countries (LMICs), they lose an average of almost six IQ points in their first five years of life, write researchers at the World Bank in the journal The Lancet Planetary Health. The damage would therefore be significantly greater than previously assumed.
The WHO includes lead in its list of ten chemicals that pose a major threat to the health of the general population. The toxic heavy metal accumulates in bones, muscles and the brain. It can damage the cardiovascular system, kidneys and nervous system, among other things. Lead can cause serious and permanent neurological damage, particularly in children.
The two World Bank researchers Bjorn Larsen and Ernesto Sánchez-Triana write that lead contamination has reduced significantly globally since leaded gasoline was gradually banned. However, people can still be exposed to high levels of lead, particularly in low- and middle-income countries. The list of potential sources of lead is long: it includes food, mining, leaded paint, toys, cosmetic products, electronic waste and fertilizers.
How lead gets into the environment is often unclear
The researchers assume that around 5.5 million adults died from lead-related cardiovascular diseases alone in 2019 – primarily in LMICs. The two scientists also estimate that people’s income is twelve percent lower over their entire lives due to the lower intelligence quotient.
Larsen and Sánchez-Triana estimate the economic damage caused by lead contamination around the globe at six trillion US dollars in 2019. According to them, this corresponds to around seven percent of global economic output at that time. More than three quarters (77 percent) of these enormous costs arise as a result of cardiovascular diseases, while the remaining quarter (23 percent) are due to loss of income due to neurological damage.
The researchers emphasize that lead contamination must decrease as quickly as possible. To do this, however, we would need to know better where exactly the lead that people ingest comes from – and how contaminated people in certain regions actually are. Scientists are also calling for effective laws to reduce lead pollution.
The researchers also address weaknesses in their study. It is difficult to accurately estimate the lead concentration in the blood of people around the world. Their calculations are based on models that assume certain lead concentrations in people’s blood depending on the region. Accordingly, the average lead concentration in the blood in emerging and developing countries (46 micrograms per liter) is more than three times higher than in industrialized nations (13 micrograms per liter). For comparison: In a decades-long series of measurements among students in Münster, the lead concentration in the blood per liter fell from a good 77 micrograms in 1985 to less than nine micrograms in 2021.