WHEN MY HUSBAND AND I SET OUT to find a nursery school for our daughter, Faith, nearly ten years ago we took the decision seriously. I looked at large parent-run cooperatives and visited small home-based operations. Jeff studied the pink towers and chiming bells at the Montessori school on the hill and considered the wonder balls and wooden fairies at the Waldorf school in the valley. In the end, we chose a nursery school that operated out of a community center close to home. There was a frog pond out front and a play structure out back. The trees were full of chickadees and nuthatches. We had weighed many considerations in the decision-making process, and we all, Faith included, were happy about it.

That is, until I discovered that, like many of its kind, the school’s beloved play structure – with its wooden gangway, turrets, and tunnels — was made out of pressure-treated lumber, which, at the time, contained arsenic, a carcinogen. A bladder carcinogen, in fact. I am a bladder cancer survivor. I am familiar with this particular disease and all the ongoing medical surveillance it requires. So, after a lot of research and discussion, we eventually decided to move our daughter to a different nursery school. The risk of doing nothing just seemed too high.

Seven years later, the Environmental Protection Agency released its final risk assessment for children who regularly contact wood impregnated with chromated copper arsenate. The conclusion: children who play frequently on pressure-treated play sets and decks (we had one of those, too) experience, over their lifetimes, elevated cancer risks. Ergo, our precautionary decision as parents to disenroll our daughter had been a wise one. And yet, because the EPA stopped short of recalling pre-existing play structures and decks when it outlawed arsenic-treated lumber for residential use in 2004, the old play structure at our old nursery school still stands.

ARSENIC, AS IT TURNS OUT, is not only a carcinogen but a developmental neurotoxicant as well – one of a family of substances that impair the growth of the brain in ways that interfere with learning. They take many forms, according to a major review of the evidence published in 2006 in the British medical journal The Lancet. Some of them are heavy metals, such as lead and methylmercury. Some are long-outlawed compounds that still linger among us (PCBs). One common one is used to strip paint, turn crude oil into gasoline, extract natural gas from shale, and suspend pigment in some nail polishes (toluene). Another two hundred chemicals are known to act as neurological poisons in human adults and are likely toxic to the developing brains of infants and children as well — animal studies strongly suggest that any neurotoxic chemical is likely also a neurodevelopmental toxicant – but scientific confirmation awaits.

Current laws do not require the systematic screening of chemicals for their ability to cause brain damage or alter the pathways of brain growth, and only about 20 percent of the three thousand chemicals produced in high volume in the United States have been tested for developmental toxicity of any kind. The Lancet paper is one of the most comprehensive summaries available to date (though the EPA is preparing to release its own list of developmental neurotoxicants in early 2011). Parents struggling to pay tutors, tuition bills, and school taxes — who are, right now, clearing off a spot on the kitchen counter to sit down and offer help with homework — might consider taking a look at this compilation, particularly the review’s central conclusion: “The combined evidence suggests that neurodevelopmental disorders caused by industrial chemicals have created a silent pandemic in modern society.”

In the basket of problems labeled neurodevelopmental disorders are a variety of cognitive and psychomotor disabilities that have different names and changing diagnostic criteria. Mental retardation – increasingly referred to as intellectual disability – is one. Attention deficit disorder, with or without hyperactivity, is another. A third is learning disabilities, itself a basket of discrete disorders that are variously characterized by significant difficulties in listening, speaking, writing, memorizing, reading, or calculating. Dyslexia is a well-known type of reading disability. Its mathematical equivalent is dyscalculia. Within the life-altering category of pervasive developmental disorders is autism – a continuum of problems that is now collectively referred to as autism spectrum disorders.

By pandemic, the authors of The Lancet study mean that learning and developmental disorders are common, cut across all walks of life in all geographic regions, and are ballooning in prevalence. Changing diagnostic criteria, along with the absence of a nationwide registry, makes vexing the work of constructing precise time trends. The estimate most often cited by the medical literature is that developmental disabilities now affect about one in every six U.S. children, and most of these are disabilities of the nervous system. If accurate, this figure means that the number of children with neurodevelopmental disorders now exceeds the number of children with asthma, which is also a problem of pandemic proportion.

By silent, the authors mean that these disorders are subclinical. They don’t announce themselves on an X-ray or in a pathology lab. There is no medical test to herald their increasingly familiar presence among us.

Child neurodevelopmental disorders do, however, leave economic tracks behind. At $77.3 billion per school year, special educational services, according to the most recent accounting, consume 22 percent of U.S. school spending. This is a cost we all pay. According to a 2006 Harvard study, the annual societal cost for mental retardation is $51 billion. For autism, it is $35 billion. The financial burden of autism is particularly cruel for families because affected children typically have special health needs and require more medical care on top of everything else. For a profoundly affected child, annual costs for care can exceed $70,000 — or $3.2 million over the lifetime of a single autistic individual. Tellingly, even in the face of those kinds of financial costs, many of which are shouldered by the family, the demands of caring for an autistic child compel some parents to give up paid work altogether.

Of course, the child whose IQ is diminished by early-life exposure to neurotoxic chemicals but who is not classified with a disorder also incurs economic costs to the family and to the community — but these are not reflected in the estimates above.

LET’S LOOK MORE CLOSELY at the trends. Mental retardation, which affects 2 percent of children (one in every fifty), is one of the only disorders whose incidence is going down – in part as the result of the drop in children’s lead levels over the past two decades.

This drop is dramatic – from an average of thirteen micrograms of lead per deciliter of blood when I was a first grader to less than two today. Clearing lead from the blood and brains of children was made possible by two public policy decisions: the 1977 decision to phase lead out of house paint, where it was used as a pigment, and the 1990 decision to phase lead out of gasoline, where it was used as an antiknock additive. Those accomplishments, carried out over the objections, threats, denials, and obfuscations of the lead industry, are considered triumphs of public health. As well they should be. Lead exposure, at any level, is associated with distractibility, poor language skills, aggressive behavior, and lower overall intelligence. Removing lead from paint and gasoline lowered its levels in soil and house dust, and thereby slashed lead levels in children by a factor of six.

Lead is one of only two chemicals – the other is mercury – that we actually do regulate on the basis of its ability to sabotage brain development in children at background levels. At vanishingly small concentrations – at levels far lower than are required to swell the brain and produce the clinical, physical symptoms of poisoning – lead can paralyze the moving neurons within the growing brain of a child. As a result, the architecture of the brain is subtly altered in ways that compromise later learning. Many children labeled as mentally retarded in years past were, as we now know, actually lead poisoned.

In contrast to mental retardation, the neurological developmental disorders mentioned earlier are on the rise. Four times more prevalent than mental retardation and twice as common in boys than girls, ADHD now affects nearly one in every ten children between the ages of four and seventeen. An estimated 5.4 million children are believed to suffer from ADHD, a condition that affects impulsivity and self-control as well as attention span. (Of these, 2.7 million–nearly 5 percent of all U.S. children–are on medication to control it.) The prevalence of ADHD has been increasing an average of 3 percent a year. (Some, but not all, of the apparent rise in ADHD is fueled by relaxed diagnostic criteria.)

Just ahead of attention problems are learning disabilities, which now affect 10 percent of U.S. children, according to the latest survey of a nationally representative sample. Of course, these are not mutually exclusive problems; some children are challenged both by attention deficits and by a learning disability.

Autism, first given a name in 1943, is a condition that is difficult to quantify, due to the complex nature of the disorder and changes in how it’s been defined over the decades. Children so affected may or may not have intellectual deficits. Indeed, some individuals with the variant called Asperger’s syndrome have keenly developed intellectual skills. Along the spectrum of disorders that carry its name, impaired social interactions is the unifying trait. Other distinguishing features include repetitive behaviors, a narrow range of interests, limited symbolic thinking, an insistence on sameness, and, mostly notably, language deficits. About 40 percent of autistic children do not speak. Others do learn to talk but, often, far later than their peers. And a quarter of autistic children initially develop vocabularies and then, inexplicably, lose them, word by word, sometimes gradually, sometimes overnight.

Over the past two decades, the number of children identified with autism or autism spectrum disorders has increased tenfold. Not all of the upsurge represents a real increase in prevalence. Because the disorder was once blamed on poor parenting, shame and stigma almost surely obscured the true frequency of autism in decades past. In addition, as with ADHD, changing diagnostic criteria that now accept a broader array of signs and symptoms have applied the word autism to children who, in an earlier time, might have been labeled otherwise.

And yet, the ever-longer shadow that autism casts cannot entirely be explained away by changing definitions, greater cultural acceptance, and relaxed diagnostic criteria. An audit of carefully tended records in California suggests that less than half of the apparent increase in autism is due to a more generous application of the label. Even after correcting for evolving diagnostic criteria, excesses remain. The Centers for Disease Control estimate that autism presently affects almost 1 percent of U.S. children overall–about 730,000 individuals–and is four to five times more common in boys than girls. One in every 110 U.S. eight-year-olds now has autism. Among boys only, the rate rises to one in seventy.

Autism is the most swiftly rising developmental disorder, yet no one knows what causes it. Genetic factors clearly contribute – several variations in several genes have been identified as players, and identical twins are more likely than fraternal twins to be dually affected – but the genes involved are many and seem to create predispositions rather than destiny. A dramatic rise in incidence over a short time period certainly points to the potential role of environmental exposures. But what role? And what exposures?

Considerable early investigation focused on the question of whether the preservative thimerosal is linked to autism. Mercury-based thimerosal was used in children’s vaccines until 1999 and is still found in some flu shots. For the majority of cases, the evidence does not point to a vaccine-autism link. As one thorough review of the topic concludes, “There are no reliable data indicating that the administration of vaccines containing thimerosal is a primary cause of autism.” It’s still possible that vaccinations play a role in a subset of autistic children–perhaps those with inborn genetic susceptibilities. But with autism rates still on the rise years after thimerosal was removed from vaccines, the search has shifted to include a much broader array of potential environmental contributors.

There are no answers yet, but there are some clues from the field of pharmacology. When taken by mothers during the first trimester of pregnancy, three drugs–thalidomide, misoprostol, and valproic acid–have been linked to increased risk of autism, as has infection by pregnant mothers with rubella (German measles). These results do not explain the increase in the prevalence of autism – these three compounds are rarely used medicines, and population-wide rubella vaccination has brought the infection rate of German measles far below what it was when I was a child – but they do point to early pregnancy as a window of vulnerability for autism. A 2010 review of the evidence, published in Current Opinion in Pediatrics, thus recommended that future research efforts into the causes of autism seek to identify other environmental exposures–perhaps a common chemical of some kind – to which pregnant women are routinely exposed.

THE VERY THICK BOOK Holt’s Diseases of Infancy and Childhood, copyright 1936, marches through an alphabetical litany of horror — rickets, scarlet fever, syphilis, tetanus, tuberculosis. Flipping through the copy that I found in the used bookstore here in our village, I tried to imagine what my life as a mother might have been like in 1936 – the year that my own mother was six years old. I was about to conclude that my concerns for my children are entirely different ones than those that would have worried my grandmother, until I reached the final pages of the book. Under “Miscellaneous Diseases, Lead Poisoning” is this complaint:

The body seems to be able to repair all damage except that done to the brain. The prognosis of children who recover from the acute symptoms of lead encephalitis is bad . . . most of them are dull or obviously defective. . . . The treatment of lead poisoning is most unsatisfactory. It is obvious then that prevention of exposure is the main line of attack. Parents should be educated to recognize the possible harm of pica [eating things that are not food], paint chewing and other common methods of acquiring lead. In spite of the rather high incidence of cases of lead poisoning there are no laws in this country to prevent the use of lead paint in children’s toys and furniture. In only three states is it necessary to label paint so that one may ascertain that lead is an ingredient.

Forty years before it was removed from paint, pediatricians had enough evidence of lead’s ability to maim children’s brains – catastrophically and irreversibly – to warrant discussion in a medical textbook. The only cure was understood to be prevention, but in the absence of government action, or even right-to-know legislation, parents were left to serve, as best they could (ineffectively, as we now know), as their own poison-control centers. Stumbling upon this paragraph reminded me that, even though the labels have changed, the evidence for an environmental connection to neurodevelopmental disorders is not exactly news.

Other than a keener appreciation for subtle damage at subclinical levels of exposure, what have we learned since 1936?

There seem to be four big lessons arising from the frontiers of pediatric neurotoxicology. The first is that the developing brain is more vulnerable than the adult brain, and the timing of exposure can determine whether and how severe the damage might be. PCBs, for example, are linked to decrements in remembering. Specifically, they interfere with recall ability and long-term retrieval of memories. They do so, in part, by disrupting the activity of thyroid hormones whose job it is, during development, to direct neurons to their proper places within the brain. The first cells to arrive then help direct the later ones. Thus, for PCBs, the earlier in development the chemically induced disruption, the more aberrant the final architecture in the memory centers of the brain.

The second lesson is that neurotoxicants can act in concert with each other. Prenatal exposure to lead contributes to the risk of ADHD, as does exposure to tobacco smoke. Both together, however, create a higher risk than either one alone. These findings indicate that neurotoxicants need to be regulated as a group rather than one by one.

The third is that elements of a child’s social and nutritional environment can also be toxic to the development of cognition and can magnify the effects of exposure to chemical toxicants. Poverty and family stress are particularly detrimental. Attention deficit disorder is more prevalent among poor children, as are learning disabilities. Children living within dysfunctional families are also at increased risk for a learning disability. (If you have ever wondered, while listening to two people yelling — and one of them is you – if dysfunctional is an applicable label for your own family, know that there are some established criteria. One of them is having a parent who “rarely discusses serious disagreements calmly.” As long as the adverb rarely is part of the definition, I can honestly say that I am not that parent. But, when short on sleep and patience – as when simultaneously confronting quarterly estimated tax payment worksheets and a child who has made sibling annoyance a personal hobby – I have seen the road to that parent. And it’s sobering to realize that more than emotional lives can be wrecked when tempers flare too often and too wildly.)

And fourth, maybe not surprisingly, is that the chemicals designed to act as neurological poisons – the organophosphate pesticides – truly do so. And at levels common among children. Frequently used in fruit and vegetable farming, organophosphate insecticides kill by attacking the nervous systems of insect pests. They have the same effect in humans: organophosphates interfere with the recycling of the neurotransmitter acetylcholine, one of the messaging signals that flow between neurons. Mounting evidence collected among various populations of children – from Harlem neighborhoods to the fields of California’s Central Valley – all suggest that organophosphate exposure affects cognition. For example, a small study of inner-city minority children found connections between organophosphate levels in their umbilical cord blood collected at birth and attention problems at age three. These results were later corroborated by the results of a large study of children selected to serve as a cross-sectional representation of the U.S. population as a whole. Its main finding was this: children with above-average levels of pesticides in their urine were twice as likely to have a diagnosis of ADHD.

The release of this study in spring 2010 triggered intense media coverage and lots of advice-giving to concerned parents. Wash fruits and vegetables well. Opt for organically grown food. Eschew pesticidal lawn chemicals. Avoid organophosphate pesticides when attempting to control insect pests within the home or on the family pet. With these admonitions, I felt I was back in 1936 with Dr. Holt: to prevent lead poisoning, tell parents to stop children from putting things in their mouths.

This sort of public health approach – surround kids with brain poisons and enlist mothers and fathers to serve as security detail — is surely as failure-prone with pesticides as it was with lead paint. Following all the popular advice, I do feed my children organic food, and my pesticide-free “freedom lawn” lets a thousand flowers bloom.

But Faith and her brother, Elijah, do not live solely within the bubble of my kitchen and property lines. They occupy a much bigger ecological niche, and I cannot verify the agricultural origin of every food item served at every birthday party, summer camp, sleepover, recital, and library summer reading program event. I can’t ensure that every backyard soccer field, every patch of lawn, and every pet in every neighborhood home they run in and out of are free of organophosphates.

Nor can I stop the wind from blowing. Even if I home-schooled my children and confined them to the premises, their bodies are connected to the rest of the world through the medium of air. Our house exists within a village community that is ringed by dairy farms and cornfields. The chemicals sprayed in those fields, on the neighbors’ lawns, and on the driving range and putting greens of the village golf course can easily drift into our yard. And every study of pesticide drift indicates that they almost certainly do — just as every study of lead indicates that, sooner or later, lead molecules exit painted walls and windowsills and seed themselves into soil and dust. The average four-year-old performs 9.5 “hand-to-mouth interactions” per hour. If lead – or pesticide – is in the dust or on the pet or inside the food, it’s in the kid.

I am a conscientious parent. I am not a HEPA filter.

If organophosphate pesticides are damaging children’s brains at background levels of exposure and above, they should be abolished. After decades of dithering, abolition was the decision we ultimately made with lead paint. It worked. Educating parents to prevent the problem on their own did not work.

Those who argue that abolition for organophosphates is unrealistic need to explain how realistic it is to run a high-quality public school system when more than 9 percent of children can’t pay attention and one dollar of every four must be directed to special educational services.

In response to the publication of the study linking organophosphates to increases in ADHD, the EPA released a statement that summarized its work to phase out a limited set of organophosphate pesticides. I doubt that I was the only parent less than comforted to learn that the amount of organophosphates used on foods favored by children (e.g., apple juice and grapes) has declined by half – from 28 million pounds in the mid-1990s to 12 million pounds in 2004. My reaction to this news was along the lines of, 12 million pounds of known brain poisons with suspected links to ADHD are sprayed on foods commonly eaten by kids? Every year? That’s insane.

EXPOSURE TO AIR POLLUTION – whether indoors or out – also harms children’s cognitive development. Specifically, it reduces intelligence. Thus, the combustion of fossil fuels not only creates a climate problem, it renders our children less able to solve it — or any other problem.

Polycyclic aromatic hydrocarbons (PAHs) – the sooty chemicals released from tailpipes and power plants – are the leading culprit. In studies of young laboratory animals, PAHs behave as neurodevelopmental toxicants, and they appear to have the same effects in children – although the mechanism by which they impede brain growth is not yet known. As part of their series of long-term studies, researchers at the Columbia Center for Children’s Environmental Health demonstrated in 2006 that three-year-olds who had higher levels of exposures to PAHs during pregnancy – as measured by their levels in umbilical cord blood – scored lower on cognitive tests when compared to less exposed counterparts.

Subsequent studies in New York City and in Krakow, Poland, revealed similar findings. In both countries, five-year-olds exposed to above-average levels of PAHs scored, on average, about four points lower on standardized tests of reasoning ability and intelligence.

Research conducted in China before and after a coal-fired power plant was shuttered reveals similar results – but with a happy twist: Two-year-olds with elevated prenatal exposures to PAHs showed poorer neurobehavioral development when compared to less exposed toddlers. However, after the power plant shut down two years later, concentrations of PAHs in umbilical cord blood declined, and the neurodevelopmental scores among an identical cohort of toddlers improved. Mothers who got pregnant after the coal plant closed had smarter children.

Coal extinguishes intelligence by a second route: through its release of mercury into the atmosphere, which then finds its way into the brain cells of children through the medium of fish. From the earth to the air to the water to the dinner table. And so into blood and neurons.

When coal is extracted from its Carboniferous tunnels and burned in power plants, the mercury it contains vaporizes. Once airborne, the newly liberated metal can wander the skies for up to a year, traveling thousands of miles. Eventually, it falls with raindrops and snowflakes back to the Earth’s surface. (Urban smog encourages this homecoming.) Bacteria then convert mercury into the potent – and persistent – brain poison methylmercury. Concentrating as it moves through the food chain, methylmercury can magnify its powers many times in aquatic systems, where food chains are long. Our main source of exposure, then, is seafood — especially large, predatory fish.

When consumed by a pregnant woman or a young child, fish ushers molecules of methlymercury into a developing body and into a developing brain. Here it can cause many kinds of damage. Methylmercury stunts the growth of baby glial cells, disrupts the transmission of dopamine, and damages cells in the hippocampus – a sea horse–shaped structure that serves as an office of memory. Altogether, prenatal exposure to methylmercury is associated with loss of IQ, learning disabilities, forgetfulness, attention deficits, as well as balance and coordination problems.

In 2003, the Centers for Disease Control quantified the problem: one of every twelve U.S. women of reproductive age has blood mercury levels above that known to be safe. Accordingly, every year, more than 300,000 infants are born at risk for mercury-induced cognitive impairment. In a 2005 study, no doubt designed to reach the ears of politicians deaf to all but financial impacts, researchers at Mount Sinai School of Medicine’s Center for Children’s Health and Environment put a price on these findings. Noting that the diminishment of IQ leads to reduced economic productivity, these authors estimated the societal cost associated with mercury emissions from U.S. power plants at about $1.3 billion a year from loss of intelligence alone. (The burning of coal is not the only industrial practice driving the creation of methylmercury, but it is the single biggest one.) Coal is not cheap.

In August 2009, the U.S. Geological Survey released the results of a comprehensive study that sampled fish taken from streams across the nation – including the isolated and the pristine. Mercury was found in every single fish. The year before the study was released, all fifty states had issued advisories warning the public – especially women of reproductive age and their children – to limit their consumption of particular types of freshwater fish caught in local waters. Mercury was the reason for 80 percent of these advisories. Some ocean fish, including tuna, are also sufficiently contaminated to trigger recommendations for consumption limits. Indeed, tuna, all by itself, contributes more than one-third of the total methylmercury exposure from seafood.

Tuna salad: the new lead paint.

Divorcing women and children from fish is, of course, an imperfect solution to the problem of mercury contamination, as it deprives them of the considerable health benefits that also come from eating fish. A better solution would be to divorce ourselves from coal – and pursue a full-bore affair with renewable energy.

BECAUSE WE LIVE on a climate-altered planet, as journalist Bill McKibben reminds us, it’s no longer possible to distinguish, even in the weather, the hand of nature from the hand of industrial pollution. A prolonged drought, a massive snowstorm, a powerful hurricane: these phenomena could be part of the natural order, or they could be a consequence of two centuries of intensive fossil fuel combustion. From here on out, we’ll never know.

Similarly, we live in chemically altered bodies now and think with chemically altered brains. It’s no longer possible to discern, in our children, what part of their temperaments or cognitive quirks is innate and what part is derived from the cumulative impact of chemical exposures. Is a rush-ahead, chaotic, unfocused style the sign of a cheerfully unconcerned personality? Or a symptom of a subtle brain disorganization triggered by prenatal exposure to pesticides?

The child who still can’t decode a clock face by age ten: a normal variation? Or the result of mildly elevated blood leads at age one? And is the ongoing difficulty with telling time somehow related to the ongoing confusion about how to add fractions with unlike denominators? Or is the source of the latter problem the math curriculum at school?

At the very least, trying to decipher all this is terribly time consuming, expensive, and inconvenient for parents. Parent-teacher conferences. Parent-pediatrician conferences. Educational assessments. After-school appointments with therapy providers. E-mail exchanges with the math tutor. Tears shed at the kitchen table during homework time. All these activities require hours and hours of problem solving, research, advocacy, and — most of all — continued acts of loving patience. Parenting a child with possible attention or learning problems is high-maintenance parenting – just as is parenting a child with asthma and allergies. When you are inside this world, the perceived convenience of the nation’s energy and agricultural systems, both of which rely on low-cost, neurotoxic substances, looks very different.

Even if you are not living inside the world of attention and learning disorders, your child almost certainly is – at school.

As more precious educational resources and instructional time are directed toward accommodating the increasing number of children with special needs, the community of the classroom is profoundly affected. While the results may not always be negative, we should acknowledge that they are real.

To all appearances, Faith and Elijah’s school brings a remarkable combination of compassion and pedagogical skill to the classroom management of children whose minds are wired in alternative ways – whatever the cause. (Once they reached school age, we enrolled Faith and Elijah in the Montessori school on the hill, where Jeff also teaches art.) As a result, my two children have a much greater exposure to – and understanding of – a diversity of learning abilities and disabilities than I did. While hanging around the parking lot during school dismissal recently, I overheard the following conversation:

Child one: So does he have Asperger’s or is he being mean to you?

Child two: Asperger’s.

They nod, shrug, and get on the bus.

And during a potty break at a highway rest stop, while chaperoning a field trip, I was a participant in the following scene involving a boy we’ll call Kenny:

Group of boys to me: Hey, Faith’s mom, can you help Kenny? He’s scared of the toilets.

Indeed, Kenny was frozen to a bench, rocking rhythmically, his eyes squeezed shut.

Group of boys to Kenny: Hey, dude. Faith’s mom is going to stay with you. Don’t freak out.

So I sat with Kenny on a bench outside of a cinder-block men’s room filled with roaring, autoflush toilets while the others took their turns inside. And as I held his hand, I could only marvel at the tender mercies of his ten-year-old comrades. In my elementary school, any boy frightened by toilets – with or without a special needs designation – would have been tormented to within an inch of his life.

AS PARENTS, we can only do so much to protect our children from the brain-disrupting chemicals that lurk in every part of the Earth’s dynamic systems – its water cycles, air currents, and food chains. Faith and Elijah spend their days in a school full of equipment and furniture that no doubt contain brominated flame retardants (which, according to a 2010 study published by the National Institute of Environmental Health Sciences, is linked to lower scores on tests of mental development among children exposed in utero). They ride home on a diesel-powered bus. They fly around town on bicycles – or scooters or skateboards – to flute lessons, piano lessons, the public library, passing by pesticide-treated fields and lawns as they go. And when we lie together in the dark at the end of the day, I sometimes wonder how their brain architecture might have been — might still be — irreversibly altered, even if only slightly, by brain-damaging chemicals that are still allowed to be manufactured and sold, that are constantly pouring out of smokestacks and tailpipes, that are used as ingredients in everything from lipstick to gasoline. I sometimes think about these things when I watch one or the other of them erase a hole through a frustrating homework assignment and start over again.

So don’t give me any more shopping tips or lists of products to avoid. Don’t put neurotoxicants in my furniture and my food and then instruct me to keep my children from breathing or eating them. Instead, give me federal regulations that assess chemicals for their ability to alter brain development and function before they are allowed access to the marketplace. Give me a functioning developmental neurotoxicant screening program, with validated protocols. Give me chemical reform based on precautionary principles. Give me an agricultural system that doesn’t impair our children’s learning abilities or their futures. Give me an energy policy based on wind and sun.

Because I can do the thinking and research associated with making the right school choice for my children. I can help them with multiplication tables and subject-verb agreement. I can pack healthy school lunches. But I can’t place myself between their bodies and the two-hundred-plus identified neurotoxicants that circulate freely through the environment we all inhabit.