Through choices private and public, our children’s future is in our hands

Ag chemicals in food and water are having profound, generational impacts through subtle effects

Posted May 12, 2006: A while back a group of medical researchers in the Seattle area started to measure the concentration of organophosphorus insecticides in the urine of pre-school children. Most children had sizable concentrations well over FDA recommended safe levels. Given what we are learning, I wonder if we scientists really know enough to set a “safe toxic level” for kids confident that it will still seem “safe” in the coming decades.

As in many scientific investigations, a few children were found to be atypical. In this case, their toxic levels were way under the rest of the kids measured. Interviewing the parents of these rare cases, researchers learned that their parents chose certified organic foods for the kids. With this tantalizing lead, the researchers expanded their trial to evaluate equal numbers of children eating conventional and organic diets. Again measuring urine samples, they found a whopping eight-fold increase of organophosphate contamination in the conventional non-organic group compared to the organic children.

These findings point to the importance of how food is produced and how the exposure to synthetic chemistry varies accordingly. Parents worried about their children’s exposure to contaminants can take measures to help protect their brood by lessening and eliminating these unnecessary toxic exposures. Eating organically certified food or food you produce yourself without chemical inputs is a rational protective step with benefits confirmed through rigorous scientific study.

Organophosphorus (also called organophosphate) insecticides were originally developed in Germany during World War II. They act to inhibit acetyl cholinesterase, an enzyme fundamental for nerve transmission in humans, other mammals and insects. It takes a much higher dose to kill a human than to kill a bug, but death by herbicide poisoning is not the only problem. There is robust scientific literature showing the ability of organophosphates to impact human developmental activity at far below lethal doses, due in part to these compounds' tendency to bio-accumulate within animals.

Our regulatory system mostly ignores the long-term effects of agrichemicals as our bodies encounter their residues. Noted University of Wisconsin animal scientist Warren Porter has shown that sub-toxic developmental effects of agrichemicals and mixtures that form synergistic damage are the Achilles Heel of the environmental regulatory system.

Organic farmers and consumers make many decisions to put health first in how to farm and what to eat. Why would we willingly throw the dice with our personal health or that of our family?

Porter points out that humans have the ability to de-toxify synthetic chemical residues only after puberty. This is because a child’s liver lacks key enzymes for this mission. Parents, nutritionists and policymakers need to make food choices realizing that children are much more vulnerable to chemical assault than are adults, and will accumulate toxic substances over a longer timeframe.

Dr. Elizabeth Guillette from the University of Florida has studied the influence of agrichemicals on the development of the Yaqui Indians children in Mexico. She identified within the Yaqui tribe one group which had accepted the introduction of chemical agriculture and has resided in a valley where it is practiced extensively. Another Yaqui group moved up into the surrounding hills to practice traditional lifestyles, avoiding chemical agriculture.

Guillette’s studies identified that the chemically exposed valley children lagged in every measurement of development including coordination, learning and memory. Many of the valley children could not draw the basic elements of a human even at 4 and 5 years old, putting them into a group of people believed to have little or no potential to develop appreciable social skills. The following illustration shows typical examples of the drastic developmental difference associated with valley (chemically exposed) and hill people who were largely unexposed to chemical agriculture.

Atrazine, the most-applied corn herbicide in the U.S., is infamous for washing into our surface and ground water, its persistence for years in our soil and even its ability to invade our atmosphere. Although this chemical is agriculturally banned in Switzerland (where it was discovered and is manufactured), we still apply millions of pounds annually throughout North America.

Scientific studies such as The Rodale Institute Farming Systems Trial regularly show that atrazine is routinely found in water at rates well over the EPA regulatory level. More importantly, research led by Tyrone Hayes at the University of California shows that exposure to even 1/30th of the regulatory dose changes male frogs into hermaphrodites. It is critical to note that ambiguous sexual development in humans is an epidemic in the United States. (You may not be aware of the epidemic in birth defects we are having, but from 1978 to 1993 the rate increased more than 5 times.)

A bright spot in this area is the finding that folic acid can reduce spina bifida by 75 percent if administered to a mother one month before or after conception. Information is now pointing to nitrates as sources of superoxidants which cause the spinal lesions of spina bifida. Folic acid seems to work as an anti-oxidant antidote to the reactive chemistry causing the lesions. Atrazine and nitrate invade our water system from herbicide and fertilizer use, respectively, in corn. (Both are also common lawn chemicals.)

Even as evidence mounts showing how pesticides impact human health, the industry has yet to own up to the full extent of its responsibility. One measure of this disparity of what we know medically and how we have yet to act in public policy is the fact that many doctors recommend against breast feeding due to the high level of toxins within breast milk.

The acknowledged negative impacts of agri-chemistry are accommodated in current regulations because, regulators say, overall societal benefits outweigh the risks. Unfortunately food consumers, not sufficiently aware of all the dangers of agriculture chemistry, take the risks, while the agrichemical industry derives the profits. We have yet to see an agrichemical interest step forward to clean up any of the contamination to our soil, water or air.

The proliferation of 10,000 registered chemicals which are tested mostly by the chemical industry itself does not guarantee our children’s safety. To the contrary, under the present system it guarantees that our children will have multiple and repeated exposures to known toxic components.

The good news is that more food grown with fewer chemicals is becoming more accessible in North America, week by week. Parents, especially, are seeking out certified organic food and other foods identified as being more healthful. Currently about half of the parents in North Americ—and more than 75 percent of European parents—are opting for organic baby food. While this phase lasts for a short period in a child’s life, it’s an important time and signifies a commitment by parents safeguard their young ones.

Both the Seattle parents who served organic food and the traditional Yaqui who literally took to the hills to avoid agricultural chemicals show the wisdom of being proactive for healthy food. The future of your children—and the farmers who want to raise their food—depends on it.

Annotated References

Cavieres et. al. 2002.Developmental toxicity of a commercial herbicide mixture in mice: I. Effects on embryo implantation and litter size. Environ Health Perspect 110:1081-1085 (2002). [Online 17 September]

A number of epidemiologic studies have linked pesticides with developmental abnormalities. Developmental toxicity in mice was found for common commercial formulation of herbicide containing a mixture of 2,4-dichlorophenoxyacetic acid (2,4-D), mecoprop, dicamba, and inactive ingredients. Pregnant mice were exposed to one of four different doses of the herbicide mixture diluted in their drinking water, either during pre-implantation and organogenesis or only during organogenesis. Litter size, birth weight, and crown-rump length were determined at birth, and pups were allowed to lactate and grow without additional herbicide exposure so that they could be subjected to additional immune, endocrine, and behavioral, studies.The data varied by season but showed an inverted or U-shaped dose-response pattern for reduced fitter size, with the low end of the dose range produced the greatest decrease in the number of live pups born. The decrease in litter size was associated with a decrease in the number of implantation sites, but only at very low and low environmentally relevant doses.

Curl et. al. 2003. Organophosphorus pesticide exposure of urban and suburban pre-school children with organic and conventional diets. Environ. Health Perspectives 111:337-382.

Conventional diets lead to over 8 times the organophosphorus insecticide contamination in the urine than that found in children following mostly organic diets.

Croen et. al. 2001. Maternal exposure to nitrate from drinking water and diet and risk for neural tube defects. American Journal of Epidemiology 153(4).

Groundwater containing nitrate exceeding the current allowable standard of 45 milligrams/liter. was associated with a 4 times higher risk for anencephaly (absence of the brain). Women whose drinking water contained nitrate at levels below the MCL had a higher risk for anencephaly, but only when the water source was groundwater.

Guillette et. al. 1998. An anthropological approach to the evaluation of preschool children exposed to pesticides in Mexico. Environ. Health Perspecitives 106(6):

Yaqui tribemen that avoided agrichemicals had pre-school children with superior coordination, learning and memory than valley tribemen who associated with agriculture chemical production areas.

Hayes et. al. 2002. Hermaphroditic, demasculinized frogs after exposure to the herbicide atrazine at low ecologically relevant doses PNAS. 99 ( 8 ):5476-5480.

Atrazine, the most commonly used herbicide in the U.S., can be present at several parts per million in agricultural runoff and can reach 40 parts per billion (ppb) in precipitation. Atrazine altered the sexual development in African clawed frogs (Xenopus laevis). exposed to atrazine (0.01-200 ppb) by immersion throughout larval development. Gonadal histology and laryngeal size at metamorphosis showed atrazine (0.1 ppb) induced hermaphroditism and de-masculinized the larynges of exposed males. De-masculization of human males has been increasing based on health data compiled in the United States and elsewhere.

Rull et. al. Neural Tube Defects and Maternal Residential Proximity to Agricultural Pesticide Applications. American Journal of Epidemiology 2006 163(8):743-753

Residential proximity to applications of agricultural pesticides may be an important source of exposure to agents that have been classified as developmental toxins…. Elevated risks of neural tube defects (NTDs) and anencephaly or spina bifida subtypes were also associated with exposures to chemicals including organophosphorus pesticides and with increasing numbers of pesticides. These results suggest that ambient exposure to certain categories of agricultural pesticides may increase the risk of NTDs. http://aje.oxfordjournals.org/cgi/content/
abstract/163/8/743

Works finding increasing rates of genital abnormalities

Boisen et. al. 2005. Hyposadias. J. Clinical Endrocinology.

This work relates genital abnormality of Follicle Stimulating Hormone in boys more typical of those usually found in females. This information shows an undisputable rise in Denmark rates of male malformation of genitals. Rates of genital abnormalities associate statistically with testicular cancer and endocrine disrupter levels.

Moller, H. 1998. Trends in sex ratio, testicular cancer and male reproductive hazards. APMIS 106:232-239.

Increasing rates of testicular cancer are associated with lower man to women ratio and increase in genital malformations in males. This information points to environmental sources of the changes most likely the prevalence of feminizing and disruptive pseudo hormonal activities of synthetic chemical constituents. Studies on wildlife would support this mechanism for causing these maladies in humans as well.

Paulozzi, L. 1999. International trends in rates of hypospadias. Environmental Health Perspectives 107(4).

Rates point upward in United States and some Northern European countries such as Scandinavia but not necessarily in developing countries.

Skakreback, et. al. 2001. Testicular dysgenesis an increasingly common development disorder with environmental aspects. Human Reproduction 16(5):972-978.

The male disorders now suggested as testicular dysgenesis syndrome include undescended testis, feminization of scrotal anatomy, decreasing sperm count, testicular cancer rates and hormonal aberrations. Feminizing chemical constituents can cause all these symptoms in laboratory animals under control conditions. Information points to these constituents as the prime epidemiological factors in the syndrome.

editors' NOTE: As New Farm Research and Training Manager at The Rodale Institute®, Dr. Paul Hepperly has been a regular contributor to NewFarm.org for some time, providing research updates, op-ed pieces, and white papers on topics like carbon sequestration in organic farming systems. Dr. Paul Hepperly None of those venues do full justice to the range of Paul's experience, however. Paul grew up on a family farm in Illinois and holds a Ph.D. in plant pathology, an M.S. in agronomy and a B.S. in psychology from the University of Illinois at Champaign-Urbana. He has worked for the USDA Agricultural Research Service, in academia, and for a number of private seed companies, including Asgrow, Pioneer, and DeKalb. He has overseen research in Hawaii, Iowa, Puerto Rico, and Chile, and investigated such diverse crops as soybeans, corn, sorghum, sunflowers, ginger, and papaya. He has witnessed the move toward biotech among the traditional plant breeding community and the move toward organics among new wave of upcoming young farmers. Beford coming to the Rodale Institute Paul worked with hill farmers in India to help them overcome problems with ginger root rot in collaboration with Winrock Intermational. Now we've decided to give Paul his own column, in which he can report on agricultural research from around the world and reflect on its relevance to The Rodale Institute's research program and to the progress of sustainable agriculture more generally in light of his own broad perspective. Enjoy.