Infant Risks from Pesticides
Pesticides in Baby Food: Infant Risks from Pesticides
Any parent knows that infants and children are generally more vulnerable to toxic substances. That is why parents do not give adult doses of drugs to their children. The EPA, in contrast, allows infants and children to eat adult approved doses of pesticides that have not been evaluated in terms of their safety for infants and young children.
Infants and children react differently than adults to many drugs and toxic substances. In many cases they suffer far more serious damage as a result. Aspirin can cause Reyes syndrome (a condition that kills 80 percent of its victims) in children and teenagers, but it does not cause this condition in adults. Lead causes permanent loss of mental capacity when infants and children are exposed at levels of little consequence to adults.
Phenobarbital, a sedative in adults, produces hyperactivity in most children. Ritalin, a sedative in children, produces hyperactivity in most adults. Infants under six months of age suffer methemo-globanemia, or blue baby syndrome, from nitrate exposure at levels that are safe for older children and adults. Radiation treatment for brain cancer in children under four can cause major cognitive problems later in life, but causes almost no effect if performed after age eight. There are many other examples.
In spite of this evidence, the EPA evaluates the safety of most pesticides using protocols that require testing only sexually mature animals. These tests provide little information relevant to infant or fetal exposure to pesticides. For example, unlike human exposure, which begins in the womb and continues through infancy to adulthood, EPA required cancer studies expose only sexually mature animals to a pesticide. Conversely, the EPA requires that reproductive studies expose animals to pesticides in the womb, but then do not examine the impact of this exposure on the reproductive health of successive generations.
A faster and different metabolism, and rapid growth and development are the basic reasons for an infant's increased vulnerability to any toxic substance, including pesticides. After birth the most pronounced period of growth is the first year of life, during which the human infant triples in weight. Different organs grow at different rates as the infant matures, creating a roulette of infant organ susceptibility.
The brain of a newborn child grows rapidly and is particularly sensitive to toxic substances. At birth, the human brain weighs about one third an adult brain, compared to the infant body which weighs about 4 percent of an adult body. This relatively large brain grows rapidly in the newborn child, achieving 50 percent of its adult weight by 6 months of age, with 75 percent of all brain cells present by age 2 (Snodgrass 1992, NRC 1993). In contrast, 50 percent of adult weight in the liver, heart and kidneys is not reached until age nine (NRC 1993).
In general, but not always, rapid development will increase the risk of cancer from toxic exposure. While the issue is complex, the NAS Committee on Pesticides in the Diets of Infants and Children concluded that in the absence of other factors, "direct carcinogens are more potent in rapidly growing animals" (NRC 1993 pp. 29), adding that, "Infants and children are subject to rapid tissue growth and development, which will have an impact on cancer risk" (NRC 1993 pp. 22). The incidence of childhood brain cancer and childhood leukemia has increased 33 percent since 1973 (Reis et al. 1993). Cancer now kills more children under age 14 than any other disease.
A major study with the carcinogens N-nitrosodiethylamine and N-nitrosodimethylamine found a seven fold increase in cancer rates when animals were exposed starting in infancy, as compared to exposure only during adulthood (Peto 1992). A 1992 review of data on 22 chemicals from separate studies that began dosing animals in utero, in infancy and in adulthood concluded that exposure early in life increases the rate of cancer in the exposed population and that these cancers generally occur earlier in life (McConnell 1992).
But cancer is only one cause for concern. Several organ systems, including the nervous, immune, reproductive, and endocrine systems, which are not fully developed at birth may "demonstrate particular sensitivity during the postnatal period" (NRC 1993 pp. 43).
Nervous System Toxicity
The nervous system of the infant and young child is extraordinarily sensitive to some toxins. Infants and toddlers, for example, are far more sensitive than adults to the immediate and long term effects of lead. Many pesticides found in baby food are toxic to the nervous system, but the EPA has not evaluated their ultimate toxic effect on children.
The most common neurotoxic pesticides are the organophosphate and carbamate insecticides which inhibit the normal function of the nervous system enzyme, acetylcholinesterase. According to the NAS, "... emerging data suggest that neurologic and behavioral effects may result from low-level chronic exposure to some organophosphate and carbamate pesticides" (NRC 1993 pp. 64). Current safety standards, the Academy observed, are no guarantee of protection for children:
"The data strongly suggest that exposure to neurotoxic compounds at levels believed to be safe for adults could result in permanent loss of brain function if it occurred during the prenatal or early childhood period of brain development. This information is particularly relevant to dietary exposure to pesticides, since policies that established safe levels of exposure to neurotoxic pesticides for adults could not be assumed to adequately protect a child less than four years of age," (NRC 1993 p. 61).
Reproductive and Hormonal Disorders
The reproductive system is also vulnerable to the toxic effects of pesticides. Evidence is mounting that exposure to chemical pollutants and pesticides in the womb or in early childhood can interfere with normal sexual development and may be contributing to declining male reproductive health in the industrialized world (Carlson et al. 1992, Colborn et al. 1993, Gray et al. 1992, Hileman 1994, Lancet 1995, Reir et al. 1993, Soto et al. 1994, Topari et al. 1995, Sharpe et al. 1993).
Every day, people are exposed to chemicals that mimic the female hormone estrogen and or otherwise may disrupt the human hormone system. The severity and consequences of this exposure are not known nor are they being systematically studied. We do know, however, that several currently used pesticides commonly found in food mimic the female hormone estrogen, and others clearly interfere with normal hormone function. In addition, recent work shows that the effect of estrogenic pesticides is additive, and that exposure to estrogenic mixtures at low levels can cause an effect produced by a single chemical, only when administered at a higher dose (Soto 1994).
A mother's lifelong exposure to estrogens is the best indicator of exposure and risk to the child, particularly for estrogens that accumulate in the body. For chemicals that do not accumulate in the mother, however, childhood exposure appears to be the key. According to a recent editorial in the British medical journal, The Lancet, "The various facets of declining male reproductive health seem to have a common origin in childhood, and defects that may be induced in the current birth cohort by xeno-oestrogens [estrogens from sources other than the human body] or other compounds may not become apparent for a further 20 - 40 years," (Lancet 1995).
Infants and children suffer disproportionately from additional flaws in the current regulatory process.
- Pesticides are regulated in isolation as though no one is exposed to more than one pesticide at a time.
- Additive effects of pesticides consumed in combination are not considered. Multiple routes of exposure (food, water, household use) are ignored.
- Pesticides continue to be allowed in food based on toxicity data that is often incomplete or out of date.
According to the National Academy of Sciences, infants are unlikely to be more than 10 times more sensitive to any single pesticide than an adult. There are 275 pesticides allowed on food, however, and 102 of these were detected by the FDA from 1990 through 1992, on just twenty two different fruits and vegetables (Wiles et al. 1993).
Notably, the Academy committee concluded that it is the additive effect of simultaneous exposure to pesticides causing the same toxic effect that presents the real world risk to infants and children. There are no standards to protect infants, children or anyone else from multiple pesticides in food (or from other sources). The EPA has just begun to consider the additive effects of certain groups of pesticides. The special additive adverse effects that these combined exposures may have on the young, however, are not being studied.