It started with a nightmare. Researcher Philippe Grandjean dreamt "that we are polluting the world with chemicals that are negatively affecting brain development, and that those chemicals are damaging the parts of the brain needed to understand what is going on." In other words, a downward spiral.
The scariest part was waking up and realizing that if he didn't do anything, the nightmare could become reality. That's because we are in the midst of a "worldwide silent pandemic of brain damage" that's "not being recorded in medical statistics, and is not part of our medical diagnostic vocabulary," Grandjean said.
The nightmare inspired Grandjean, a doctor and medical epidemiologist at Harvard University, to write a book about the harm caused by industrial pollutants like mercury, lead, pesticides, and others, titled Only One Chance: How Environmental Pollution Impairs Brain Development—and How to Protect the Brains of the Next Generation.
"We seriously need to figure out how to protect the next generation so they will have optimal integrated brain function so that they can be fully capable of dealing with problems of tomorrow," Grandjean said.
One focus of the book is how vulnerable developing brains can be to industrial pollutants, and how early damage can be permanent. "You only have one chance to develop a brain, and that's the brain you have the rest of your life," he said.
Grandjean first got interested in epidemiology in the early 1970s when he heard press reports about widespread poisoning in Minamata, Japan, caused by contamination of seawater with methylmercury. That event created lasting toxicity, leading to mental retardation and numerous developmental problems in children.
In the years since, Grandjean has studied the brain toxicity of mercury and other substances. His work with mercury helped lead to an agreement known as the Minamata Convention on Mercury, formulated earlier this year at a United Nations meeting, which will outlaw certain uses of mercury and help reduce some types of mercury pollution, he said.
But much more needs to be done, Grandjean said. As he mentions in his book, three factors have kept society from taking appropriate action about the risk posed by pollutants: uncertainty, naivety and corruption.
The story of lead pollution illustrates these factors at work. Despite years of knowledge that lead could be toxic at certain concentrations, the metal was first introduced into gasoline in the 1920s to prevent "knocking." At that time, Dr. Robert A. Kehoe, a spokesman for the lead industry, demanded that adequate facts be presented to prove that lead was harmful; otherwise, nothing would be done, Grandjean writes. The influential Kehoe's argument became known as the "show-me rule." Industry used this rational to help keep lead in gasoline for 60 years in the United States, despite ample warnings that lead is highly toxic to the brain even in small doses, Grandjean said.
But evidence accumulated, and by the 1970s and 1980s, several scientists and environmental groups were calling for the removal of lead from gasoline and the reduction of lead pollution. By that time, however, lead had already "damaged brain cells in an entire generation of children, at least, worldwide," Grandjean writes in the book.
Naivety has also helped pave the way for chemical brain drain. For example, it wasn't realized until recently that most industrial pollutants can pass from the mother to the fetus. It was likewise assumed that the blood-brain barrier would offer some protection, which is also not the case with many of these chemicals, like lead and mercury, he added. Also, people wrongly assumed that if you don't get sick or die from a certain exposure, then perhaps it did no harm. But research has shown that often not to be the case.
Corruption has also played a major role. Kehoe, for example, was heavily funded by the lead industries—just one of many "authorities" backed by industry. Corruption has also led to backlash against legitimate scientists. Several prominent researchers who uncovered details about lead toxicity were also harassed and threatened, like researcher Herb Needleman (who was accused of fraud, only to be exonerated after a grueling 10-year investigation).
Kehoe, the defender of leaded gasoline, was himself was also a major proponent of water fluoridation, thanks to backing from the metals industry, Grandjean writes. When researcher Phyllis Mullenix presented data showing that low levels of fluoride can cause neurotoxicity in rats in 1992, she was warned by her supervisor that she was going against the prevailing knowledge of dentists and was "jeopardizing the financial support of [the] entire institution," Grandjean writes. She published her results shortly thereafter and was fired. Mullenix "was probably right that fluoride can under certain conditions be toxic to the brain," Grandjean writes. "She should have been praised rather than fired."
Brain drain is already happening and is a problem of the same magnitude as environmental problems and climate change, Grandjean writes. To fight it, we must demand more information about health risks, more research and more stringent laws, he argues. It will require a "transformation in politics," he writes, as well as placing brains "at the top of our promotion of healthy lifestyles."