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IN THE PLAYGROUND Exposure to lead can result in aggressive behavior.
3.8-point drop in IQ in 5-year-olds. This drop is comparable to the effects of lead, the discovery of which, in the 1970s, eventually triggered a massive public health response in the form of laws removing lead from automobile gasoline, restricting it in household paint, and, to this day, requiring lead tests in children in many parts of the country. Now that the Harlem children are older, the team is examining whether the ill effects of fetal and cumulative exposures play out in other ways—poor academic performance, impaired social skills, anxiety and depression, and self-destructive behavior. On the day I visited the center this fall, a mom—let’s call her Michelle—and her 14-year-old son came in for a couple of hours of assessments. They were both greeted by a tremendous hug from Diurka Maria Diaz, a researcher and counselor who has followed the families from the beginning. “You’re taller than I am now!” she teased the boy. Hefty, dressed in black pants and a black sweatshirt, he towered over his toddler sister. She is also in the study, which continues to recruit new participants who likely have different exposomes. While Michelle’s placenta absorbed chlorpyrifos during her son’s gestation, it probably absorbed replacement pesticides during her daughter’s. The replacements come from a class of chemicals known as pyrethroids, whose neurodevelopmental effects remain largely unstudied. Diaz, who is known to the families as Didi, exudes warmth and charisma as well as concern for the challenges faced by kids in the study. “It’s hard to be a 14-year-old,” she says. “Many of these kids are overweight, many are depressed. We’ve referred about 40 percent for counseling.” Furthermore, she says, a remarkable 70 percent of children under the age of 3 have developmental delays that qualify
them for New York City’s early intervention services. Such delays are typically attributed to growing up in impoverished environments with relatively low parental involvement, low mental stimulation, and pervasive psychological stress. Perera’s team, though, is convinced that fetal environmental exposures play a role and that their effects may be aggravated when combined with maternal stress, as well as when combined with one another. “In the past, we took a reductionist approach,” Perera says, “a single exposure, a single effect. But now we think that pollution interacts with nutritional and social susceptibility factors. We’re making heroic attempts to measure these. We’re building the exposome.”
T
he environmental trail of brain damage extends
far back in history. Accounts of lead toxicity date to the Greek physician Nicander of Colophon in 200 B.C. In more recent times, a French physician in 1848 described ill-tempered infants who’d been sucking on lead soldiers. More examples of damaged childhoods came to light after twentieth-century commercial and industrial exposures. A cheap, arsenic-laced stabilizer was added to powdered milk in Japan during the spring of 1955, causing sickness, epilepsy, or lowered IQ in more than 12,000 victims, most of them infants. (Studies of nerve cells in a Petri dish suggest that arsenic inhibits cell growth and, in the developing brain, reduces the branching of dendrites—the structures of neurons that send and receive signals.) Also in the 1950s, a factory in Minamata, Japan, began releasing mercury into the local bay, ultimately causing severe physical and cognitive problems in children whose mothers ate contaminated fish while pregnant. winter 2013/2014
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