Learning Hazards

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The Oakland Tribune testing determined that Mikaela also had high levels of phthalates—found in plasticizers in some cosmetics, food containers and building materials—which disrupt hormones. Two varieties of phthalates—dibutyl phthalate (DBP), used in nail polish, and benzyl butyl phthalate (BBP), used in vinyl tiling—have been shown to harm mouse embryos. The CDC found that, among all age groups, chldren had the highest levels of these phthalates. Mikaela's DBP levels, at 89 ppb, put her among the top 10 percent of children, and she had elevated BBP levels too. The Hammond-Holland children are healthy, but Michele is determined to reduce their exposures.

Environmental contaminants can contribute to developmental and behavioral disorders such as attention deficit hyperactivity disorder (ADHD) and mental retardation. The question of possible links to Asperger's Syndrome and autism has also been raised. Unfortunately, "We can't suggest that one type of chemical is going to cause autism and another chemical will cause something else," says Elise Miller.

Recently, thimerosal, a mercury-containing preservative used in some vaccines, has been blamed by some for rising autism rates. But "careful studies have shown no link between thimerosal and autism," Landrigan says. Although the roles contaminants play in autism remain unclear, they are the focus of a new University of California Davis study of 2,000 children.

Are PBDEs the New PCBs?
Banned in 1978, PCBs had been shown to lower the IQ of Japanese children whose mothers ate contaminated rice oil. Studies of pregnant women who consumed PCB-contaminated fish from Lake Michigan showed that their children had smaller head circumferences and other traits associated with reduced IQs. Structurally similar to PCBs, PBDEs may pose similar threats. A 2003 study in Toxicological Sciences found that neonatal mice exposed to deca-BDEs (a PBDE used in television and computer casings) at a critical stage showed permanent damage to brain function. The highest human PBDE levels are equivalent to those at which mice show damage to memory and learning, according to research by toxicologist Tom McDonald, Ph.D., conducted at the California EPA.

Now that PBDEs used in foam are no longer being made in the U.S., blood levels hopefully will drop. As PBDE-treated foam will still be present in furniture until supplies run out, consumers may want to seek PBDE-free varieties (see below).