Body Burden — The Pollution in Newborns
A benchmark investigation of industrial chemicals, pollutants and pesticides in umbilical cord blood, July 14, 2005
Not long ago scientists thought that the placenta shielded cord blood — and the developing baby — from most chemicals and pollutants in the environment. But now we know that at this critical time when organs, vessels, membranes and systems are knit together from single cells to finished form in a span of weeks, the umbilical cord carries not only the building blocks of life, but also a steady stream of industrial chemicals, pollutants and pesticides that cross the placenta as readily as residues from cigarettes and alcohol.
Chemical exposures in the womb or during infancy can be dramatically more harmful than exposures later in life. Substantial scientific evidence demonstrates that children face amplified risks from their body burden of pollution; the findings are particularly strong for many of the chemicals found in this study, including mercury, PCBs and dioxins. Children's vulnerability derives from both rapid development and incomplete defense systems:
A developing child's chemical exposures are greater pound-for-pound than those of adults. An immature, porous blood-brain barrier allows greater chemical exposures to the developing brain. Children have lower levels of some chemical-binding proteins, allowing more of a chemical to reach "target organs." A baby's organs and systems are rapidly developing, and thus are often more vulnerable to damage from chemical exposure. Systems that detoxify and excrete industrial chemicals are not fully developed. The longer future life span of a child compared to an adult allows more time for adverse effects to arise.
Ottawa plans to snuff out flame retardants
This new research has found that flame retardants have an ability to mimic thyroid hormones; it is thought that by following that hormonal route, the chemical plays havoc in laboratory animals, where exposures have been linked to hyperactivity, impaired learning and decreased sperm counts.
Researchers are finding that flame retardants don't obey traditional rules of toxicology, shedding light on the novel ways that some chemicals may still hold dangers, even though they aren't outright poisonous or don't trigger cancer.
The traditional mantra of toxicologists has been that the dose makes the poison, or that exposures have to be large to have an effect, with larger exposures packing more punch than smaller ones.
In experiments with rodents, effects have been noted on the offspring of rats given only one exposure of 60 parts per billion, an amount that a few decades ago scientists would have dismissed as too low to have an impact. To get an idea of the amount involved, a part per billion equals a single drop of water in a gasoline tanker truck.
The study of 130 mothers and their children in California's Central Valley revealed that a natural enzyme in the human body that breaks down toxicants, including commonly used pesticides, varies to such a degree that some of the population's youngest members may be virtually defenseless against some chemicals.
From: Public Library of Science, a peer reviewed Medical Journal
Excerpts of article:
Over the past three decades, researchers have found that remarkably low-level exposures to these toxins are linked with less overt symptoms of toxicity—intellectual impairments, behavioral problems, spontaneous abortions, or preterm births
The developing fetus and young child is particularly vulnerable to certain environmental toxins [46,47,48,49,50]. Critical neurodevelopmental processes occur in the human central nervous system during fetal development and in the first three years of life. These processes include cortical functional differentiation, synaptogenesis, myelination, and programmed apoptosis .
Children's exposure to environmental toxins is insidious. Environmental toxins covertly enter a child's body transplacentally during fetal development or by direct ingestion of house dust, soil, and breastmilk and other dietary sources during early childhood
Exposures to environmental toxins have been linked with higher rates of mental retardation, intellectual impairment, and behavioral problems, such as conduct disorder and attention deficit hyperactivity disorder
From a scientific standpoint, data from epidemiologic studies represent the “gold standard” for detecting subtle effects of environmental toxins on humans. But epidemiological studies are expensive to mount, difficult to execute, and take years to complete. …
More importantly, if society continues to rely on epidemiologic studies to evaluate the toxicity of chemicals only after they are marketed, many children will first be harmed.
Children must be better protected from both new and existing chemicals that are known or possible toxins .
If there is any lesson from our experience with environmental toxins, it is that we need to identify environmental chemicals that are toxic before they are marketed or widely disseminated. [We already know the chemicals to flameproof beds are acutely toxic]
It is time to acknowledge that the existing requirements for toxicity testing and regulations are inadequate to safeguard pregnant women and children. Until a formal regulatory system is developed to effectively screen and identify new and existing chemicals that are toxic to pregnant women and children, we are left to await the next epidemic to warn us about an environmental disaster. Unfortunately, by then we will have once again fouled our nest .