(ORDO NEWS) — According to American scientists, past lead exposure continues to affect the health and well-being of our contemporaries in ways we don’t yet fully understand.
Lead is a heavy metal and a toxic chemical element that has cumulative properties and adversely affects the body, accumulates in marine sediments and fresh water.
In the 20s of the last century, the Americans were the first to decide to add it (or rather, tetraethyl lead) as an additive to gasoline: before that, the fuel had a low octane number , that is, it had a bad effect on the operation and survivability of the engine and its operation.
The toxicity of lead was known, however, apparently, at first it was considered that there would be no great harm due to the low content. However, in 1996, the United States was the first to ban the use of this toxic and carcinogenic organometallic compound in gasoline, and European countries and Russia at the beginning of the 21st century.
The world is still reaping the benefits: in developed countries, the historic use of lead in paint, pipes and gasoline has left water, soil, and homes enriched with this element.
As shown by a new study by scientists from Florida State University and Duke University in North Carolina (USA), lead exposure affects not only the basic systems of the body, weakens the immune system, disrupts metabolism, provokes the development of cancer, and so on.
Among other things, mainly inhaling it with exhaust gases in the past lowered the IQ of living Americans by a total of 824 million points.
According to its authors, from the late 1960s to the early 1980s, the average blood lead level in the United States was three to five times higher than the reference value today (three and a half micrograms of lead per deciliter of blood – a reason to hike to the doctor).
That is, millions of current adults, at least in the US, were exposed to high levels of lead as children. This, according to previous animal studies and epidemiological data, disrupts the development of the brain, bones, and cardiovascular system, and ultimately affects cognition, fine motor skills, and emotional regulation.
The scientists used data from the United States Census, statistics on lead exposure from vehicle emissions, and a national survey on the topic conducted by the Centers for Disease Control and Prevention from 1976 to 2016.
They estimated the number of Americans as of 2015 who were born no later than 1996 and were exposed to various levels of lead before, during, and after the leaded gasoline era.
The analysis showed that out of 318 million people, only 131 million had blood levels of this element below five micrograms per deciliter in childhood.
Nearly 100 million 31% of the population had more than ten micrograms per deciliter of blood, double the 2015 norm. About ten million people living in 2015 had 25 micrograms of lead per deciliter of blood (seven times the normal limit) as children.
“Early childhood lead exposure varied significantly across cohorts. Its level was relatively low in people born in the 1940s, increased sharply in middle-aged residents and decreased sharply in younger people, ”the researchers note.
Thus, the level of lead of more than five micrograms per deciliter of blood in childhood was detected in 90% of Americans born in 1951-1955, in 99% of those born in 1956-1960, in 97% of people born from 1961 to 1965, and for all those born in 1971-1975.
For comparison: a similar indicator was found only in 6% of children born from 2001 to 2005, 3% born in 2006-2010, and only 1% of those born in 2011-2015.
“People born between 1951 and 1980 had particularly high blood levels of this element during childhood. For example, in about 78% and 73% of children born from 1966 to 1970 and from 1971 to 1975, it exceeded 15 micrograms per deciliter of blood, ”the scientists add.
According to them, in 2030, at least 43% of US residents will have blood lead levels above five micrograms per deciliter (in childhood), and 23% – from ten micrograms per deciliter and above. Over time, the rate will continue to decline.
In terms of cognitive decline due to exposure to a toxic element, in 2015 the US population lost 824,097,690 IQ points – about 2.6 points per person.
“Lead-related cognitive deficits were greatest for the 1966-1970 cohort (population: about 20.8 million), with an average IQ drop of 5.9 per person. The cohort from 1961 to 1965 – minus 4.8 points, from 1971 to 1975 – minus 5.7 points, ”write the authors of the work.
In addition, over 7% of Americans born in the 1966-1970s and 1971-1975s (nearly three million children combined) had lead levels above 30 micrograms per deciliter of blood, and their cognitive abilities were below average, often in the diagnosable mental retardation range (IQ <70).
“Our projections are that the loss of IQ points due to childhood lead exposure will be similar in the future: by 2030, the IQ of the population will therefore decrease by 709,054,633 points, which corresponds to 2.03 IQ points per person,” the study emphasizes. .
It may seem that nothing terrible will happen, but at the individual level, even a relatively minor deficit in cognitive abilities can greatly affect a person’s life, health, well-being and professional achievements.
Scientists are confident that pronounced early childhood lead exposure will remain a hallmark of the United States population for the next few decades.
In addition, even recent blood levels of this element are abnormal. For example, the UN Children’s Fund estimates that 800 million children in the world today are exposed to lead, mainly due to insufficient regulation of enterprises in developing countries.
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