Recommended reading
Only One Chance: How Environmental Pollution Impairs Brain Development — and How to Protect the Brains of the Next Generation. Philippe Grandjean. New York: Oxford University Press, 2013: 212pp.

Book Review by Hana Nasr and Ana Boischio

Over the past few decades, the number of neurodevelopmental disorders likely associated with chemical exposures, has been on the rise. In his book, Only Once Chance: How Environmental Pollutions Impairs Brain Development — and How to Protect the Brains of the Next Generation, Dr. Philippe Grandjean refers to this phenomenon as "chemical brain drain", described as a silent pandemic in which chemical substances that are released into the environment and into the human bodies through various routes of exposures, can disrupt normal brain development, thus resulting in conundrum of mental and neurodevelopmental health impacts.

As explained in the book, the developing human brain undergoes a highly complex, rapid, and extremely intricate series of growth patterns in the mother's womb and continues to develop throughout an individual's teenage years. The slightest biochemical interference may result in a minute developmental deviation with colossal implications on future mental, neurodevelopmental, and general health.

According to the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) regulation of the European Chemicals Agency (ECHA), there are more than one hundred thousand chemicals that are currently in use. Of this large number, approximately two hundred have been documented as "brain drainers" or toxic to the [adult] brain — most of which are pesticides. Of these two hundred chemicals (presented in the book appendix), about a dozen have been determined to be toxic to the human developing brain (these include lead, methyl mercury, arsenic, PCBs, and toluene). Out of approximately two hundred industrial chemicals presented as "brain drainers", about half are high-volume production chemicals.

Several toxicological events from various regions of the globe are described to debunk the notion that the placenta protects the fetus from industrial chemicals. Examples are provided to acknowledge that hundreds of elements actually circulate through the mother and enter into fetal blood thus, inevitably, having some sort of impact on the fetus' developing brain. Other critical erroneous assumptions were the perception that children are simply "little adults". This notion masks relevant growth events, such as cell formation and proliferation, as well as the higher metabolic and respiratory rates of children.  Additionally, the book delves into and discredits the impression that damage by toxic poisoning is reversible — and that subtle affects can be ignored. As previously mentioned even the most minute biochemical alterations to a developing brain may result in traumatic, irreversible health deficits.  Finally, Dr. Grandjean writes of the Precautionary Principle, and condemns the need for scientific proof [of neurotoxicity] of a chemical to ensure policies that protect the population from that particular chemical. He states that testing each chemical is not only too expensive, but also time consuming, and it is imperative that the next generation be protected from chemicals that are thought to be neurotoxics before this toxicity is proven in the laboratory.

Upon ending the discussion on neurodevelopmental damage, chapters 8 and 9 incorporate societal considerations (economic strain and scientific obstacles, respectively). There is no doubt that with the environmental and health impacts of these toxics, there is also a financial and ethical burden associated. The book addresses economic strain and scientific obstacles, respectively, and also highlights several complications in the interface between science and policy. Also, a point is made regarding the  monetary burdens and deficits — in the billions of dollars — as a result of IQ loss due to neurotoxics. This IQ loss is further emphasized as a result of what Dr. Grandjean refers to as the "triple whammy" of scientific evidence. This concept encompasses the notions that: 1. there is a great lacking of evidence on damage to children's brains (it is available only for a handful of chemicals) 2. the ignorance is further propelled by the fact that testing industrial chemicals for developmental brain toxicity is not mandatory 3. Scientists often express their conclusions in a subtle language, thus underestimating the risks. These three ideas greatly deteriorate the efficacy of the impact of most environmental pollutants on the brain.

In the concluding remarks, a two-part, ten-step strategy is proposed to counter chemical brain drain. The first portion of this strategy is more of an immediate agenda, which includes the prioritization of optimal brain functioning over avoidance of neurological disease and the protection of those who may be extremely vulnerable. It also emphasizes public access to information on neurotoxic exposures and vigorous, immediate chemical control with an emphasis on the promotion of collaborative efforts for the protection of developing brains. The second half of the agenda calls for innovative approaches to research and a higher prioritization for the testing of industrial chemicals. The importance of chemical toxicity testing and a necessity to further understand optimal brain-development is stressed in the book, with the need for international collaboration, a decrease in the demand of scientific proof for the regulation of brain-drainers, and an increase in public safety awareness while safer technologies are developed.

In his attempt to depict the impact of brain-drainers on society, in particular, upcoming generations, Dr. Grandjean highlights the scientific milestones that have led to the realization of this chemical brain-drain phenomenon. He concludes his book with a powerful statement that, "We [as a society] are conducting a massive clinical toxicological trial, and our children and our children's children are the experimental subjects." The vast implications of this statement are, no doubt, quite troubling; not only are we exposing our future generations to neurotoxic substances, but we are also incognizant of the potential depth of destruction these chemicals are capable of producing.

From a societal — as well as an ethical — standpoint, key areas addressed in the book include chemical safety responsibilities among manufacturers and public awareness of environmental toxics — for which efforts on risk communication are needed. For such a science-policy interface, a wide array of institutions, who often have different agenda priorities and competing interests, are at play. 

As depicted in the strategy section, the notion of changing the manner by which risks are currently evaluated and managed is imperative, with emphasis on optimal brain functioning as a key focus of health promotion rather than simply the avoidance of neurological disease. A simpler research topic to tackle would be the idea that the Precautionary Principle should be applied, rather than the demand of scientific proof of causation before a toxic is deemed a neurotoxic. While this, in theory makes logical sense, this concept alters policy-making as we know it, and comprises a complex net of stakeholders, many of which will have a direct interest to negate this principle (i.e. the chemical manufacturing industry).

Though in absolute agreement with the Dr. Grandjean's immediate agenda, as well as his proposition for transformative research, it must be noted that an implementation of this ten-step strategy requires more consideration on several levels and engagement of different sectors. It is clearly evident that brain function is tied to the quality of life (not only that of the individual, but that of society as a whole). After a close analysis of the toxicological paradigms of specific environmental contaminants as well as the proposition of a strategic implementation plan, it is evident that we as a society have merely scraped the tip of an iceberg, and must dedicate immediate effort and collaboration to this topic. It is clear that as scientists, intra/intergovernmental health organizations, and simply as humans seeking a bright future for our younger generations, we must work together in an expansive, all inclusive, effort to address the various subject areas of this dilemma and strive to create narrower, more precise, and ¬¬more focused goals that we can address thus making our only one chance to develop a brain, our best chance.