Entitled, “Evidence for inhibition of cholinesterases in insect and mammalian nervous systems by the insect repellent deet,” and published in BioMed Central (BMC) Biology, the study utilized toxicological, biochemical and electrophysiological techniques to show that DEET is not simply a behavior-modifying chemical, but that it also inhibits cholinesterase activity in both insect and mammalian neuronal preparations. The researchers examined DEET’s effects on mosquitoes, cockroach nerves, mouse muscles, and enzymes purified from fruit flies and humans. Applications of DEET slowed or halted the actions of the enzyme acetylcholinesterase. This enzyme is crucial for regulating nerve impulses in both insects and mammals, and once its functions are disrupted, neuromuscular paralysis, leading to death by asphyxiation result. In humans, symptoms include headache, exhaustion and mental confusion together with blurred vision, salivation, chest tightness, and muscle twitching and abdominal cramps.

The study also investigated the consequences of DEET interactions with carbamate insecticides on the cholinergic system, and found that DEET has the capacity to strengthen the toxicity of carbamates, a class of insecticides known to block acetylcholinesterase.

The results are consistent with previous studies, says Mohammed Abou-Donia, PhD, of the Duke University Medical Center in Durham, N.C, who was not involved in the new work. “DEET is a good chemical for protection against insects,” Dr. Abou-Donia says. “But prolonged exposure results in neurological damage, and this is enhanced by other chemicals and medications.”

In light of these recent findings, SC Johnson, manufacturer of a variety of DEET repellent products released a statement claiming that such concerns were “unfounded.” However, this is not the first study that has highlighted the adverse impacts associated with DEET and its use with other pesticides. Several studies done by a team of Duke University researchers suggest that DEET, in conjunction with permethrin-impregnated clothing, may be linked to Gulf War Syndrome.

DEET (N,N-diethyl-meta-toluamide) is commonly used as an insect repellent but its use has become highly controversial. Scientists have raised concerns about the use of DEET and seizures among children, even though the U.S. Environmental Protection Agency (EPA) claims that there is not enough information to implicate DEET with these incidents. DEET is quickly absorbed through the skin and has caused adverse effects including severe skin reactions including large blisters and burning sensations. Laboratory studies have found that DEET can cause neurological damage, including brain damage in children. DEET was originally developed for military use in 1946 and was then registered for use on the general public in 1957. According to the EPA, more than one third of the U.S. population uses DEET-containing products every year.

However, safer alternatives to DEET include citronella and other essential oils, like oil of lemon eucalyptus which has been recommended as an efficacious alternative by the Center for Disease Control and prevention (CDC). For more information on safer methods to protect yourself from mosquitoes and other insects, please visit Beyond Pesticides’ fact sheet on mosquito repellents.

In a letter addressed to Coalition Against Bayer Dangers, Bayer said: “We plan to stop the sale of the substance endosulfan by the end of 2010 in all the countries where it is still legally available.” The letter, signed by Bayer CropScience’s head of investor relations, Judith Nestmann, said endosulfan would be replaced by alternatives “with a significantly better risk profile”.

Bayer’s decision comes after years of global campaigning by the PAN Network and its partners and allies against this persistent pesticide, which is linked to autism, birth defects and male reproductive harm, as well as deaths and acute injuries to farmers through direct contact. It is banned in over 60 countries including those in the European Union. In the United States endosulfan is used primarily on cotton in the state of California and tomatoes in Florida. Several lawsuits and legal petitions have been filed by groups, including Beyond Pesticides, concerned about the chemical’s health effects.

In this latest action, in 16 centers around the world, people exchanged their conventional undies for a free pair of organic underwear, and signaled their commitment to cotton production without the use of endosulfan. The conventional undies were sent to Bayer’s HQ with a demand that it ceases to distribute endosulfan.

Linda Craig, Director of Pesticide Action Network UK, said, “We are pleased that Bayer has committed to stop selling endosulfan. There are many proven alternatives to its use that do not have the deadly side effects of this pesticide”.

Staff scientist Karl Tupper of PAN North America said “With Bayer stepping out of the picture, this leaves just handful of generic manufactures selling this poison. We call on these companies to put health and the environment ahead of the meager profits they earn pushing this antiquated pesticide, and stop their sales. It’s the only responsible thing to do.”

“Nine countries in West Africa have taken the resolution to ban the use of endosulfan in agriculture because of the serious effects observed on farmers and their families, and on the environment. It is necessary to continue to push for the total ban of this product around the world” indicated Dr. Abou Thiam, regional coordinator of Pesticide Action Network Africa.

At the international level, endosulfan is being scrutinized at the Rotterdam Convention for stricter regulation and at the Stockholm Convention for an international ban due to its adverse effects on human health and the environment. PAN will continue to work to ensure that endosulfan is included in the list of chemicals that are banned globally.

However, progress is obstructed by the Government of India, as Dr. Meriel Watts, Coordinator of PAN Aotearoa New Zealand observes: “In India, the Government itself manufactures endosulfan — it owns Hindustan Insecticides which manufactures endosulfan, and then the Indian Government acts in the international conventions to stop endosulfan’s listing. It has members on both the Stockholm Convention’s POPS Review Committee and the Rotterdam Convention’s Chemical Review Committee. This is a “clear conflict of interest”, she says, “a manufacturer is using its power to veto international agreements on a chemical.”

“Chemicals like endosulfan that are toxic, bioaccumulative and so persistent that they contaminate our bodies, our babies and the environment have no place in agriculture. We are calling on all governments and industries that still use, manufacture or trade in endosulfan to follow Bayer example and cease to profit from this toxic poison,” said Dr. Mariann Lloyd-Smith, Co-Chair of the International POPs Elimination Network.

Last week Beyond Pesticides reported on a new study that found that insecticides, such as endosulfan, used in highly populated agricultural areas of California’s Central Valley affect amphibians that breed in the Sierra Nevada Mountains to the east. The study adds to the increasing evidence that pesticides impact areas and wildlife species that are miles from sources of pesticide application. Earlier this year, two-headed bass found in the Noosa River were at the center of a controversy surrounding pesticide drift from neighboring farms in Queensland, Australia. The pesticides, endosulfan and carbendazim, were implicated in the contamination of the river, which has yielded thousands of chronically deformed fish.

Last month the Center for Biological Diversity notified the U.S. Environmental Protection Agency (EPA) of its intent to file suit against the agency for failing to consider impacts to the polar bear and its Arctic habitat from toxic contamination resulting from pesticide use, including endosulfan, in the U.S that are known to be transported to the Arctic via various atmospheric, oceanic, and biotic pathways. Such pesticides are biomagnified with each step higher in the food web, reaching some of their greatest concentrations in polar bears, the apex predators of the Arctic.

For the more of the latest news and research findings on the chemical, see Beyond Pesticides Daily News Blog on endosulfan.

The study evaluated more than 700 people, including carefully chosen controls, in Fresno, Kent, and Tulare counties. 17 percent reported drinking private well water between 1974 and 1999. Researchers focused on wells’ proximity to agricultural fields sprayed with pesticides, since private wells are not regulated, and many are shallow enough to be contaminated by pesticides seeping into groundwater.

Researchers looked at 26 pesticides and six in particular, “selected for their potential to pollute groundwater or because they are of interest for PD, and to which at least 10% of our population were exposed.” Those are: diazinon, chlorpyrifos, propargite, paraquat, dimethoate, and methomyl.

Propargite exposure was most closely correlated with incidence of PD, with a 90 percent increase in risk. It is still used in California, mostly on nuts, corn, and grapes. Chlorpyrifos, once a common household chemical, was linked to an 87 percent higher risk of PD. While it was banned for residential use in 2001, it is stilled commonly used on California crops. Methomyl also increased risk by 67 percent.

One strength of the study is its focus on subjects’ proximity to pesticide application. Researchers used California’s pesticide use data to estimate exposure. Pesticide use reporting elsewhere is not widespread, and in some states, has been cut from budgets. Full reporting would make broader research of this kind possible. Although proximity data is helpful in evaluating risk, the researchers did not know what chemicals each subject was exposed to, since private wells are not tested.

“Allowing residues of these hazardous pesticides on imported food gives tacit U.S. approval to foreign countries to use chemicals that are known to be deadly to U.S. migratory birds,” said Dr. Michael Fry, American Bird Conservancy’s Director of Conservation Advocacy. “EPA has an obligation under Executive Order 13186, the Migratory Bird Treaty Act, and the Endangered Species Act to ensure that migratory birds are not harmed.”

Many Latin American countries that currently use these pesticides export coffee, bananas, citrus crops, and other fruits and vegetables to the United States. Agricultural areas — in particular shade coffee farms — provide valuable habitat for migratory birds, and so pesticide use in these areas can pose a significant threat to bird populations.

“The EPA must protect U.S. migratory birds on their wintering grounds by preventing these pesticides from being imported on food products,” says Dr. Fry. “Doing so will encourage the use of safer pesticides and organic farming practices by foreign growers, at least for those crops that are imported into the U.S.”

Chemicals that the American Bird Conservancy is seeking to revoke the import tolerances for include: cadusafos, cyproconazole, diazinon, dithianon, diquat, dimethoate, fenamiphos, mevinphos, methomyl, naled, phorate, terbufos, and dichlorvos.

Fumigation, photo by the LA Times

“We strongly believe that methyl iodide has no role to play in building a secure, viable and healthy agricultural economy in the 21st Century,” said authors Senator Leno and Assemblymember Monning. On August 19, the Assembly Labor and Employment Committee will meet to explore the approval of methyl iodide and the potential impact on workers.

“While I am encouraged at the decision of DPR to pursue the external peer review and public testimony, I still believe it is imperative to devote a special informational hearing by the Assembly Labor and Employment Committee focused on worker health and safety issues related to the potential registration of Methyl Iodide,” said Assemblymember Monning.

“We are pleased that this group of legislators is taking the lead to protect public health. The scientific review of methyl iodide is very important in this case because of the sheer number of hazards it poses–cancer, thyroid disease, miscarriages, and neurotoxicity. This highly politicized process needs a reality check that the scientific review will provide,” said Dr. Susan Kegley, consulting scientist for Pesticide Action Network of North America.

On July 29, responding to concerns that previously planned public and scientific process were subject to cancellation or postponement by the Governor’s office, the Department of Pesticide Regulation (DPR) announced its intentions to proceed with an external scientific review of methyl iodide.

Highly toxic and with application rates of up to 175 pounds per acre, methyl iodide has been controversial from the time US EPA announced its intent to register this chemical for legal use as a pesticide. In 2007, US EPA fast-tracked the registration of methyl iodide (a Proposition 65 carcinogen) for use as a soil fumigant despite serious concerns raised by a group of over 50 eminent scientists, including five Nobel Laureates. These scientists sent a letter of concern to US EPA explaining, “ Because of methyl iodide’s high volatility and water solubility, broad use of this chemical in agriculture will guarantee substantial releases to air, surface waters and groundwater, and will result in exposures for many people. In addition to the potential for increased cancer incidence, US EPA’s own evaluation of the chemical also indicates that methyl iodide causes thyroid toxicity, permanent neurological damage, and fetal losses in experimental animals.” The letter concludes, “It is astonishing that the Office of Pesticide Programs (of US EPA) is working to legalize broadcast releases of one of the more toxic chemicals used in manufacturing into the environment.”

If registered as a soil fumigant, methyl iodide would be applied primarily in California’s strawberry fields before planting, and as a gas it would drift away from the application site, and expose neighboring residents and farmworkers in nearby fields. Methyl iodide is a threat to air and water supplies and has been linked to very serious illnesses including cancer, miscarriages, thyroid toxicity, and neurological problems.

Take Action: Sign on to Pesticide Action Network of North America’s petition. If you live in California, you can urge Governor Schwarzenegger to allow DPR’s evaluation process to continue as they are designed, for the protection of public health and scientific integrity. For more information and background on organic agriculture and alternatives to toxic pesticides like methyl iodide, visit Beyond Pesticides’ organic program page.

“There is little doubt that antibiotic-resistant diseases are a growing public health menace,” said Rep. Slaughter, a microbiologist with a master’s degree in public health. “From peanut butter to spinach to hot dogs, we all want to make sure the food we feed our families is safe. My legislation will limit the use of antibiotics on our livestock to ensure that we are not inadvertently creating antibiotic- resistant diseases that we can’t fight with modern medicine.”

Antibiotics are an indispensable part of modern medicine, protecting all of us from deadly infections. Unfortunately, over the past several years, the widespread practice of using antibiotics to promote livestock growth and compensate for unsanitary, crowded conditions has led to the emergence of antibiotic-resistant strains of bacteria and other germs, rendering many of our most powerful drugs ineffective.

Supporters of the legislation are optimistic that renewed congressional interest in food safety and a supportive administration will see the legislation signed into law this congress. In his testimony before the committee, Joshua M. Sharfstein, MD, Principal Deputy Commissioner at the Food and Drug Administration, said, “There is clear evidence that the use of antimicrobials in general selects for resistant organisms. To avoid unnecessary development of resistance under conditions of constant exposure to antibiotics, the use of antimicrobials should be limited to those situations where human and animal health are protected. Purposes other than for the advancement of animal or human health should not be considered judicious use. Eliminating these uses will not compromise the safety of food.”

According to estimates by the Union of Concerned Scientists (UCS), 50 million pounds of antibiotics – nearly 70 percent of all antibiotics sold in the U.S. – have been used in food animals for purposes other than treating disease since PAMTA was last introduced two years ago.

In her testimony before the committee, UCS’s Margaret Mellon, Ph.D. explained the clear scientific case connecting antibiotic resistance with the practice of feeding antibiotics to livestock and poultry that are not sick. “Antibiotic resistance is of particular concern in terms of food safety,” said Dr. Mellon. “The CDC has found that half of all human Campylobacter infections are drug resistant as are one in five Salmonella infections. Nearly 100,000 of the Salmonella infections would resist treatment with at least five antibiotics. Salmonella and Campylobacter, the most common sources of food borne illnesses in the United States, account for well over a million resistant infections in this country each year.”

Organic practices already prohibit the use of antibiotics, as well as hormones and other animal drugs in animal feed for the purpose of stimulating the growth or production of livestock. If an antibiotic is used to restore an animal to health, that animal cannot be used for organic production or be sold, labeled or represented as organic.

There is also substantial evidence that the widespread use of antibacterial compounds, such as triclosan and triclosan-containing products, promote the emergence of bacteria resistant to antibiotic medications and antibacterial cleansers. While manufacturers of such products claim that the use of antibacterials will protect your health and that of your family, it may actually contribute to more illnesses.

“Unfortunately, it failed to include contemporary research showing organic strengths, and dismisses areas of organic superiority within its reviewed work, including antioxidant capacity (important for cancer-fighting properties),” states Timothy LaSalle, CEO of the Rodale Institute in the Huffington Post. “The study appears to say absolutely nothing negative about organics, despite valiant attempts by the media to create sensational headlines.”

Over 50,000 papers were searched, and a total of 162 relevant articles were identified that were published over a fifty-year period up to February 29, 2008 and compared the nutrient content of organically and conventionally produced foodstuffs. A total of 55 of the identified papers were of satisfactory quality, and analysis was conducted comparing the content in organically and conventionally produced foods of the 13 most commonly reported nutrient categories. The review was commissioned by the UK Food Standards Agency (FSA).

“The review rejected almost all of the existing studies of comparisons between organic and non-organic nutritional differences. This was because these studies did not meet particular criteria fixed by the London School of Hygiene and Tropical Medicine, which carried out the review,” said Peter Melchett, policy director at the Soil Association, in a response to the study findings. “There are limited studies available on the health benefits of organic versus non-organic food. Without large-scale, longitudinal research it is difficult to come to far-reaching clear conclusions on this, which was acknowledged by the authors of the FSA review.”

The press statement released by LSHTM states, “The researchers found organically and conventionally produced foods to be comparable in their nutrient content. For 10 out of the 13 nutrient categories analyzed, there were no significant differences between production methods in nutrient content. Differences that were detected were most likely to be due to differences in fertilizer use (nitrogen, phosphorus), and ripeness at harvest (acidity), and it is unlikely that consuming these nutrients at the levels reported in organic foods would provide any health benefit.”

“Although the researchers say that the differences between organic and non-organic food are not ‘important’, due to the relatively few studies, they report in their analysis that there are higher levels of beneficial nutrients in organic compared to non-organic foods,” responds Mr. Melchett. “For example, the mean positive difference between the following nutrients, when comparing organic to non-organic food, was found in the FSA study to be: protein 12.7%; beta-carotene 53.6%; flavonoids 38.4%; copper 8.3%; magnesium 7.1%; phosphorous 6%; potassium 2.5%; sodium 8.7%; sulphur 10.5%; zinc 11.3%; and, phenolic compounds 13.2%. The researchers also found higher levels of beneficial polyunsaturated fatty acids in organic meat and dairy products (between 2.1% – 27.8% higher) compared to non-organic meat and dairy.”

The FSA study also failed to include the results of a major European Union-funded study involving 31 research and university institutes and the publication, so far, of more than 100 scientific papers, which ended in April this year. According to the Soil Association, the European Union research program concluded that:
Ӣ Levels of a range of nutritionally desirable compounds (e.g. antioxidants, vitamins, glycosinolates) were shown to be higher in organic crops;
Ӣ Levels of nutritionally undesirable compounds (e.g. mycotoxins, glycoalkaloids, Cadmium and Nickel) were shown to be lower in organic crops; and,
Ӣ Levels of fatty acids, such as CLA and omega 3 were between 10 Р60% higher in organic milk and dairy products, and levels of Vitamin C were up to 90% higher in leafy vegetables and fruits.

A response by The Organic Center (TOC) states that the study, “also ignored the 15 relevant studies that have come out since their February 2008 cut off date that could have changed the outcome of the report. In addition, the FSA analysis actually found that organic food contains more phosphorus, a beneficial nutrient, while conventional food on average contains more nitrogen, which scientists have linked to cancer ”¦ Despite the fact that [the] three categories of nutrients favored organic foods, and none favored conventionally grown foods, the London-based team concluded that there are no nutritional differences between organically and conventionally grown crops.” TOC also argues that the researchers “used data from very old studies assessing nutrient levels in plant varieties that are no longer on the market.”

Another failure of the study is that it did not include a review of the content of contaminants or chemical residues in foods, which makes organic products superior in quality. This past spring, TOC released a new study on how a balanced, organic diet – both before and during pregnancy – can significantly reduce a child’s likelihood of being overweight, obese or developing diabetes, based on a literature review of over 150 scientific studies. The TOC review finds that exposure to pesticides during pregnancy increases the risk of premature birth, low-birth weight, neurological problems and diabetes. Outlining six ways in which a balanced organic diet can contribute to healthy development, the report also examines how enzymes found in organic foods can slow and even reverse aspects of the aging process.

In 2008, a comprehensive review of 97 published studies comparing the nutritional quality of organic and conventional foods shows that organic plant-based foods (fruits, vegetables, grains) contain higher levels of eight of 11 nutrients studied, including significantly greater concentrations of the health-promoting polyphenols and antioxidants. The team of scientists from the University of Florida and Washington State University concludes that organically grown plant-based foods are 25% more nutrient dense, on average, and hence deliver more essential nutrients per serving or calorie consumed. The findings are published in TOC report, “New Evidence Confirms the Nutritional Superiority of Plant-based Organic Foods.” In response to the FSA study, TOC has published a comparison between the two studies, click here.

Consumers purchase organic products because organic farming and food systems are holistic, are produced to work with nature rather than to rely on inputs such as chemical pesticides and fertilizers, have higher standards for the welfare of animals, and do not allow routine use of antibiotics. Organic farming also protects the farmworkers and their families from chemicals that have been shown to cause a myriad of chronic health effects, such as cancer, endocrine disruption and a series of degenerative diseases like Parkinson’s disease.

In a report released yesterday, the group calls on federal, state and local government to accelerate research into what threats pesticide contamination may pose to the bay, and to step up efforts to reduce such toxic pollution.

“The thing that alarms us the most are the endocrine disruptors and the findings that have come out about intersex fish and frogs with reproductive problems,” said Robert SanGeorge, director of the Pesticides and the Chesapeake Bay Watershed Project. Endocrine disruptors are chemicals that mimic the natural hormones in humans or animals and can disrupt their growth and reproduction.

The project is a partnership between the Maryland Pesticides Network and the Johns Hopkins Center for a Livable Future. The group’s warning and recommendations are the product of a two-year study, in consultation with scientists, public health experts, government officials, watermen, environmentalists, farmers and pest management industries.

The report comes as federal and state governments attempt to jump-start the 26-year-old effort to restore the bay. The multi-state bay campaign has focused mainly on reducing nutrient pollution from sewage, farm and lawn fertilizer, power plants and vehicles. But the report argues that not enough attention is being paid to the potential harm being done by pesticides, primarily herbicides that wash off farm fields but also the many household products with a plethora of chemical ingredients that are washed down sewers.

“There’s no smoking gun,” Mr. SanGeorge says, acknowledging the lack of conclusive research showing toxic chemicals in the bay and its tributaries are harming fish and wildlife and bay grasses. But he points to studies suggesting problems and “enormous data gaps” that need to be filled.

Researchers suspect pesticides in the Potomac, for instance, may be causing the development of “intersex” fish, with both male and female reproductive organs. They have yet to find clear evidence of such a link however. Likewise, researchers have raised concerns about the impact on frogs and fish of low levels of the weed-killer atrazine found in water samples across the bay region. That connection also is still being studied and debated.

“We know there are some gaps in the data and our understanding of the effects,” said Greg Allen, a scientist in the U.S. Environmental Protection Agency’s Chesapeake Bay office. One area deserving further study, he suggested, is the impact on spawning fish and frogs in springtime, when herbicides freshly applied to farm fields at planting time tend to show up in greater concentrations in nearby streams.

While officials have gone to great lengths to figure the amounts of nutrient pollution entering the bay from all sources, there are no similar catalogs of pesticide use in the region. The report urges required reporting of some uses, but largely calls for voluntary measures and incentives to encourage less use of pesticides and potentially toxic chemicals.

Jeff Lape, director of EPA’s bay program office, acknowledged the report and said in an email that government agencies would continue to work “to promote sensible alternatives and other options that will reduce the input of pesticides to the bay.”

A finding of “limited or suggestive evidence of an association” means that the evidence indicates there could be a link between exposure to a chemical and increased risk for a particular health effect, though conflicting results from studies, problems with how the studies were conducted, or other confounding factors limit the certainty of the evidence. Until now, the cumulative evidence had been inadequate to draw conclusions about whether these two conditions may be associated with veterans’ exposures to herbicides or TCDD.

Ischemic heart disease – a condition characterized by reduced blood supply to the heart, which can lead to heart attack and stroke – is the foremost cause of death among people in industrialized countries. Major risk factors include buildup of cholesterol in the arteries, age, smoking, high blood pressure, and diabetes. The committee that wrote the report reviewed several studies investigating TCDD exposure and heart disease, many of which showed that higher TCDD exposure correlated with greater incidence of disease. The studies had weaknesses; for instance, it is difficult to adjust entirely for the impact of smoking, age, weight, and other common risk factors. But based on the preponderance of the evidence as well as biologic data beginning to show how TCDD can cause this toxic effect, the committee concludes that the evidence suggests that veterans exposed to defoliants contaminated with TCDD during the war may face a higher risk for developing ischemic heart disease.

The committee’s conclusion that there may be a relationship between Parkinson’s disease and Agent Orange exposure stems from its review of 16 studies that looked at herbicide exposures among people with Parkinson’s disease or Parkinson’s-like symptoms. The finding was bolstered by several studies that have identified exposure to certain compounds similar to those in the herbicides used in the war as potential risk factors for the development of Parkinson’s. The committee’s review was hampered by the lack of studies investigating the occurrence of Parkinson’s disease in Vietnam veterans specifically and the lack of animal studies testing the chemical components of Agent Orange for their potential to cause Parkinson’s-like symptoms. The report strongly recommends that studies examining the relationship between Parkinson’s incidence and exposures in the veteran population be performed. Parkinson’s disease affects approximately 1 percent of people over age 60 – some 5 million people worldwide.

In response to a request for clarification by the U.S. Department of Veterans Affairs, the committee also affirmed that hairy cell leukemia is in the same category as chronic lymphocytic leukemia (CLL) and lymphomas. Previous reviews in the series found sufficient evidence to state that there is an association between herbicide exposure and increased risk for CLL and lymphomas.

The report presents scientific data only and does not suggest or intend to imply policy decisions that the U.S. Department of Veterans Affairs might make. Also, the findings relate to exposures and outcomes in broad populations; researchers’ abilities to pinpoint the health risks faced by any individual veteran are hindered by inadequate information about military personnel’s exposure levels during service in Vietnam.

U.S. forces sprayed Agent Orange and other defoliants over parts of southern Vietnam and surrounding areas from 1962 to 1970. Most large-scale sprayings were conducted from airplanes and helicopters, but herbicides were also dispersed from boats and ground vehicles and by soldiers wearing back-mounted equipment. TCDD has remained in the environment to the present, being recently found to accumulate in Greenland sharks.

Agent Orange has been found in increase risk of other diseases, including prostate cancer. Parkinson’s disease has been linked to pesticide exposure numerous times. For more information read Beyond Pesticides’ report “Pesticides Trigger Parkinson’s Disease,” a review of published toxicological and epidemiological studies that link exposure to pesticides.

Researchers, in the study entitled, “Pediatric Acute Lymphoblastic Leukemia and Exposure to Pesticides,” caution that these findings, which do not establish a cause-and-effect relationship, suggest an association between pesticide exposure and development of childhood ALL.

“In our study, we compared urine samples from children with ALL and their mothers with healthy children and their moms. We found elevated levels of common household pesticides more often in the mother-child pairs affected by cancer,” says the study’s lead investigator, Offie Soldin, Ph.D., an epidemiologist at Lombardi. Dr. Soldin cautions, “We shouldn’t assume that pesticides caused these cancers, but our findings certainly support the need for more robust research in this area.” Previous studies have found that exposures to certain pesticides increases the risk of developing certain cancers and degenerative diseases.

The study was conducted between January 2005 and January 2008 with volunteer participants from Lombardi and Children’s National Medical Center who live in the Washington metropolitan area. It included 41 pairs of children with ALL and their mothers (cases), and 41 pairs of healthy children and their mothers (controls). For comparison purposes, the case pairs were matched with control pairs by age, sex and county of residence. Previous studies in agricultural areas of the country have suggested a relationship between pesticides and childhood cancers, but researchers say this is the first study conducted in a large, metropolitan area.

Urine samples were collected from all child-mother pairs and analyzed by the Centers for Disease Control and Prevention to look for evidence of organophosphates (OP), the chemical name of some household pesticides. The body breaks down OP into metabolites which can be tracked in urine samples. The researchers say pesticides were detected in the urine of more than half of the participants, but levels of two common OP metobolites, diethylthiophosphate (DETP) and diethyldithiophosphate (DEDTP), were higher in the children with ALL compared to the control children (p<0.03 and p<0.05). As a part of the study, the mothers completed a questionnaire to collect information about the family’s exposure to pesticides, their medical history, home and neighborhood characteristics, diet, and history of smoke exposure. More case mothers (33 percent) than controls (14 percent) reported using insecticides in the home (p<0.02), however there was no correlation found between high levels of the OP metabolites in urine and reported use of pesticides. “We know pesticides — sprays, strips, or ”˜bombs,’ are found in at least 85 percent of households, but obviously not all the children in these homes develop cancer. What this study suggests is an association between pesticide exposure and the development of childhood ALL, but this isn’t a cause-and-effect finding,” Dr. Soldin explains. “Future research would help us understand the exact role of pesticides in the development of cancer. We hypothesize that prenatal exposure coupled with genetic susceptibility or an additional environmental insult after birth could be to blame.”

Children are more vulnerable to the negative effects of pesticide exposures. EPA concurs that children take in more pesticides relative to body weight than adults and have developing organ systems that are more vulnerable and less able to detoxify toxic chemicals. The National Academy of Sciences reports that children are more susceptible to chemicals than adults and estimates that 50% of lifetime pesticide exposure occurs during the first five years of life. For more information, read our factsheet, “Children and Pesticides Don’t Mix.” Select studies on pesticides and children’s health can be found here.

The researchers designed their study to determine the consequences of simultaneous exposure to multiple “antiandrogens.” An antiandrogen, or androgen antagonist, is any of a group of hormone receptor antagonist compounds that are capable of preventing or inhibiting the biologic effects of androgens, male sex hormones, on normally responsive tissues in the body. Disrupting the action of androgens during gestation, certain chemicals present in food, consumer products and the environment can induce irreversible malformations of sex organs among male offspring.

The team investigated the effects of mixtures of a widely used plasticizer, di(2-ethylhexyl) phthalate (DEHP), used in medical devices such as IV bags and tubing, beauty products, PVC toys, vinyl shower curtains, car seats, wallpaper and more; two fungicides present in food, vinclozolin and prochloraz; and, a pharmaceutical, finasteride, on landmarks of male sexual development in rats. These chemicals were chosen because they disrupt androgen action according to differing mechanisms of action.

According to the study results, combined exposure on malformations of external sex organs was synergistic, and the observed responses were greater than would be predicted from the toxicities of the individual chemicals. In relation to other hallmarks of disrupted male sexual development, including changes in anogenital distance, retained nipples, and sex organ weights, the combined effects were dose additive. When the four chemicals were combined at doses equal to no-observed-adverse effect levels estimated for nipple retention, significant reductions in anogenital distance were observed in male offspring.

The authors believe that current methods of chemical risk assessment “may lead to considerable underestimations of risks associated with exposures to chemicals that disrupt male sexual differentiation.”

For more information on pesticide synergy, see our article, “Synergy: The Big Unknowns of Pesticide Exposure,” published in our Winter 2004 issue of Pesticides and You. For information on individual pesticide health effects, see the Pesticide Gateway.