By Philippe Grandjean
This time of the year, parents worry about what the new school year will bring for their children, teachers complain about school budget constraints, and politicians express ambitions that at least 90% of all children complete basic schooling and 50% or more pursue college degrees. We all want our kids to get the best educations that they can, and we want the next generation to be productive and successful to the benefit of society (including ourselves when we get old). Yet the statistics are not encouraging. Even when we invest heavily in education, kids still drop out of school, students fail or change their mind about vocational training or higher education, and even schools themselves are said to fail.
Are we right to blame negative influences in society, or inadequate funding for schools, or bad teachers for these problems, as we often do? Not necessarily. Recent research suggests that we have missed a crucial factor: chemical pollutants. Although it may come as a surprise, we already know the damage to brain development that can be caused by lead, mercury, arsenic, solvents such as toluene, and certain pesticides. They cause what I call chemical brain drain. It is insidious and silent, as it is usually not linked to any medical diagnosis, and it is serious.
Our highly sophisticated brains start out as a tiny strip of cells. After they have begun to multiply, most cells do not remain in the same place, but move to specific locations, where they will attain specialized functions. All told, our brains rely on highly complex steps to happen in a specific fashion, in the correct order and at the right time. If some disruption occurs, brain development will be incomplete or abnormal, and there will be little, if any, opportunity for repair. Thus, chemical damage to a brain during its formation will likely remain throughout the complete lifespan.
Alarming findings of studies on this phenomenon show that developmental delays, cognitive deficits, and neurological dysfunctions occur in children exposed to brain-toxic chemicals during early development. Could chemical brain drain be part of the reason that the education system is not working as well as we had hoped?
The best evidence refers to lead exposure during infancy or early childhood and how it impacts negatively on school performance. A report from Detroit, Michigan last year linked data on blood-lead concentrations to educational assessment scores of over 21,000 students from school grades 3, 5, and 8 from 2008-2010. At increased lead exposures, proficiency in reading, mathematics, and science declined, even at exposure levels below the limit used by the Centers for Disease Control. In Massachusetts elementary schools, elevated blood-lead concentrations adversely impacted student test scores in 3rd and 4th grade throughout the 2000-2009 study period. In Providence, Rhode Island, a study just released showed that increased blood-lead concentrations were associated with lower reading readiness at kindergarten entry. All of these studies adjusted for other factors and suggested that some of the detrimental effects traditionally attributed to poverty or ethnicity may rather be due to lead. These comprehensive data provide solid documentation that lead exposure adversely affects academic performance.
But cognitive skills represent just one aspect of the problem. What about motivation? Disciplinary problems are common in schools — one out of 14 US public school students are suspended each year. In Milwaukee, Wisconsin, children exposed to excess lead were over twice as likely as children with lower exposure levels to be suspended from school. The lead exposures in these studies were not particularly high. Similar levels are prevalent worldwide. However, linkage between school performance and lead exposure is feasible only in the United States, where measurement of the amount of lead in children’s blood is a legal requirement. Even lower exposure levels may not provide much comfort, as the World Health Organization concluded in 2011 that there is no safe limit for lead exposure. The costs to society are substantial. Using data on lifetime income at different IQ scores, economists have calculated the value of lost brain functions. Lead exposure appears to cause worldwide losses worth hundreds of billions of dollars per year.
Chemical brain drain is not just a matter of a few dangerous substances like lead. When I scrutinized the scientific and medical literature, I was able to identify more than 200 industrial chemicals that had caused toxicity to the human brain one way or another. Hundreds of industrial chemicals are present in our blood. Many of them may well attenuate educational achievement.
Unfortunately, our research methods are inefficient tools to obtain the documentation we need to shed more light on chemical drain. It can take decades to gather sufficient evidence on each individual chemical. Our knee jerk demand that scientists provide ironclad and exhaustive proof before governments take action may leave the brainpower of the next generation at serious risk. On the other hand, we are too content to believe that if we invest in education, the problem will be solved.
Having studied brain toxicity for 30 years, I realize that I must speak up. The adverse impacts of chemicals on developing brains demand attention — and the longer we wait to prevent these effects, the longer we put our children in danger. We get only one chance to develop a brain, and brain development therefore needs vigorous protection. As the Massachusetts study concludes, dollars spent on public health policy likely have a high return relative to dollars spent on education policy. As a starting point, we should no longer focus solely on schooling as a determinant of, e.g. PISA test scores and success rates. We need protection against chemical brain drainers to defend our children’s brains far before they even start school.
Philippe Grandjean is author of Only One Chance: How Environmental Pollution Impairs Brain Development – and How to Protect the Brains of the Next Generation. He is a professor and chair of environmental medicine at the University of Southern Denmark and an adjunct professor of environmental health at Harvard School of Public Health. He has spent his career studying how environmental chemicals affect children’s brain development. His studies helped trigger an international response that led to a United Nations convention to control mercury pollution, to be signed this month.