Children absorb poisons in various ways - Toxic Exposure

Give an infant a stuffed teddy bear and before long he or she will be nibbling on its ears, nose, and feet. After all, biting, tasting, and touching are all part of the maturation process. Yet, as children begin to explore their surroundings, they inevitably come in contact with a wide array of potentially harmful substances--from paints to pesticides--that can be swallowed, inhaled, and even absorbed through the skin. Although the accumulation of hazardous chemicals in the body can have harmful effects on development and behavior, determining the amount of toxic exposure in a child is still largely a matter of guesswork.

"We've been working in the area of exposure analysis for about 10 years," notes James Leckie, a professor in the School of Engineering, Stanford (Calif.) University. One technique developed by Leckie and his research team is to videotape individual children at home--a method designed to document and quantify a child's real life exposure to pesticide residues. "We videotape kids for periods of up to eight hours to see what they touch and to determine their hand-to-mouth activity. By applying software we have developed, we [ascertain] each child's dermal contact behavior on a second by second basis. Using this information allows us to estimate the amount of chemicals that are transferred to their skin or their mouth."

Leckie cautions that children are exposed to harmful particles while crawling and playing in household dust or tracked-in soil. He states that, unlike adults, children are far more sensitive to low concentrations of toxic chemicals because of their developing organs, as well as high metabolism and skin-surface-area-to-body-weight ratio. "In a growing body, cellular membranes are expanding. As a result, toxic chemicals readily pass through those membranes," Leckie observes. "Also, biochemical pathways in children are not complete yet and can be easily damaged. This damage is often manifested in slow learning and ... development."

Rural residents are particularly at risk. "Because they are among the most poorly paid and least protected in the United States workforce today, many farm workers and their families live in conditions which expose them chronically to toxic agrochemicals," Leckie laments. "But virtually all regulations for controlling chemicals in the U.S. have used adult white males as the control target. We're now realizing that was the worst possible choice. You really want the most vulnerable populations: children and pregnant women."

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