UCSD researchers warn of potential risk to civilians exposed to pesticides
March 10, 2008
A study by researchers at the University of California, San Diego School of Medicine shows there is increasing evidence that high rates of illness in Persian Gulf War Veterans can be explained, in part, by exposure to certain chemicals, including pesticides and nerve agents. Veterans from the 1990-91 conflict have a higher rate of chronic, multi-symptom health problems than either non-deployed personnel or those deployed elsewhere. Symptoms routinely reported by these veterans include fatigue, muscle or joint pain, memory problems, trouble sleeping, rash and breathing problems.
"This evidence suggests that exposure to this certain class of chemical may be linked to elevated risk of health problems," said Beatrice Golomb, M.D., Ph.D., associate professor of medicine at the UC San Diego School of Medicine, whose study will be published in the early online edition of the Proceedings of the National Academy of Sciences (PNAS) the week of March 10.
"Health issues among Gulf War veterans have been a concern for nearly two decades. Now, enough studies have been conducted, and results shared, to be able to say with considerable confidence that there is a link between chemical exposure and chronic, multi-symptom health problems," said Golomb. "Furthermore, the same chemicals affecting Gulf War veterans may be involved in similar cases of unexplained, multi-symptom health problems in the general population."
The study synthesized evidence regarding a class of chemicals known as acetylcholinesterase inhibitors (AChEis) -- including so-called "organophosphates" and "carbamates." These include nerve gas chemicals such as sarin; some military personnel were exposed when demolishing Iraqi munitions. They include common classes of pesticides which were aggressively used in the Gulf to control sand flies and other insects. And they include the nerve gas protection pill "pyridostigmine bromide" or PB. (Note: As a result of an earlier RAND Corporation report by Golomb detailing concerns about using such pills preventatively, military policy has been changed in the US and elsewhere.)
The study linked exposure to each of these chemicals with the chronic, multi-symptom health problems in 25 to 33 percent of returning Gulf War veterans.
"There is evidence that genetics have something to do with how a body handles exposure to these chemicals," said Golomb. "Some people are genetically less able to withstand these toxins and evidence shows that these individuals have higher chance of suffering the effects of exposure." Specifically, illness is linked to lower activity of enzymes that detoxify AChEis, due to genetic variants The enzymes known to be involved are paraoxonase (PON) for OPs, including sarin, and butyrylcholinesterase (BChE) for PB.
Among those service members given PB pills as a preventive measure, those with the mutations that reduced their ability to detoxify the pills were at significantly higher risk of illness, according to Golomb.
Previous studies have shown genetic variants of these enzymes are also associated with increased rates of some neurological diseases, such as amyotrophic lateral sclerosis (ALS) or Lou Gehrig's disease. Golomb says this may explain the elevated levels of ALS seen in Gulf War veterans.
Some of the chemicals linked to these multi-symptom illnesses continue to be used in agriculture, and at homes and offices for pest control in the United States and around the globe. Studies not related to the Gulf War showed that agricultural workers exposed to organophosphate pesticides had 10 times the number of health symptoms as those not exposed.
"Again, genetic variants that hamper defense against these chemicals were linked to higher risk of health problems. These findings carry important implications for current members of the armed forces as well as the general public, suggesting that exposure to these pesticides in any setting may increase risk for impaired neuropsychological function and poor health" said Golomb.
Media Contact: Kim Edwards, 619-543-6163
(Beyond Pesticides, March 3, 2008) In a five-year study of the Chesapeake Bay, the nation's largest estuary, the U.S. Geological Survey (USGS) found that, "Synthetic organic pesticides and their degradation products have been widely detected at low levels in the watershed, including emerging contaminants such as pharmaceuticals and hormones." The report finds that concentrations of DDT, while still present, have declined since the 1970s when it was phased out. The findings are contained in a report entitled Synthesis of U.S. Geological Survey Science for the Chesapeake Bay Ecosystem and Implications for Environmental Management. The study is a part of the Chesapeake Bay Program (CBP), which is a multi-agency partnership working to restore the Bay ecosystem. According to the report introduction, "In 2005, which represented the mid-point of the Chesapeake 2000 agreement, there was growing concern at all levels of government and by the public that ecological conditions in the Bay and its watershed had not significantly improved. The slow rate of improvement, coupled with the projected human-population increase in the Bay watershed, implied that many desired ecological conditions will not be achieved by 2010. The Government Accountability Office (2005) recommended that the CBP complete efforts for an integrated assessment approach of ecosystem conditions and develop a comprehensive, coordinated implementation strategy. To address these challenges, the CBP partners are writing a strategic implementation plan (SIP) to more accurately define the degree to which restoration goals can be achieved by 2010, and the most effective approach to achieve the goals. The USGS findings and their implications provide critical information that will be used by the CBP partners to prepare the SIP and develop improved management strategies. A major CBP restoration goal is to "Have a "toxics free" Bay to improve conditions for aquatic-dependent wildlife." As a part of this effort, the study seeks to define the occurrence of contaminants in the Bay watershed. Some of the findings include:
Two year earlier, according to Water Quality in the Nation's Streams and Aquifers-Overview of Selected Findings, 1991-2001, released in 2004 as a compendium of 51 USGS reports on the health of major river basins across the country, insecticides such as diazinon and malathion were found in nearly all of the streams that were sampled in urban areas. Streams in agricultural areas were more likely to contain herbicides-especially atrazine, metolachlor, alachlor, and cyanazine.
(Beyond Pesticides, February 19, 2008) Common household chemicals and widespread pollutants are changing male reproductive health and impacting sexual function, development and cancer rates of today's generations and possibly their offspring, according to more than 15 years of research by a Colorado State University expert. For example, one study looking at sperm counts globally from 1940, when chemicals first began to be widely produced, to the 1990s, indicates a 1.15 percent per year decline in sperm counts. These declines may be linked to chemical exposure. Rao Veeramachaneni, BVSc, MScVet, PhD, a biomedical sciences professor in the College of Veterinary Medicine and Biomedical Sciences, has found that chemicals including pesticides, common pollutants in ground water, and chemicals in plastics, make-up and nail polish are on a growing list of culprits causing developmental abnormalities such as impaired sperm quality and impotence. Reproductive health can be compromised if males are exposed at various times in life spanning from in utero up to adulthood.Dr. Veeramachaneni's findings span the globe and are across species lines, from humans to horses, wildlife to frogs. His research, coupled with the collective findings of other experts in the field, indicates a strong link related to pollutants, and incidence of such impacts continues to increase from year to year as chemicals infiltrate the modern world.
"Exposure to these chemicals, particularly during certain windows of time during fetal development, in newborns or as adolescents, can do permanent damage," said Dr. Veeramachaneni, who works in the university's internationally-known Animal Reproduction and Biotechnology Laboratory. "It's been a difficult task to trace the impact of these chemicals because an exposure as a fetus may not be manifested until that fetus becomes an adult. Once exposed, many males develop a condition for life. But when we look at the big picture — at trends over time — research shows lasting effects of chemicals since their popularity after World War II."
Some of these chemicals can survive in the environment for 30 to 40 years, and the chances for exposure are high because the chemicals have permeated our world. For example, the U.S. Environmental Protection Agency says that about one-third of the nation's lakes and one quarter of its rivers are polluted. There is also evidence that exposure today to some of these chemicals can affect the reproductive health of this generation as well as the future health of offspring of those exposed. The incidence of testicular cancer in young men 15 to 35 years old has increased three to four fold over the past 50 years, particularly in the Western world.
These chemicals affect the body through several channels. They attach to receptors in the body that help hormones carry out their functions and either block actual hormones from attaching or mimic the expression of the real hormones, causing confusion in the male body. In addition, some interfere with the body's natural production of hormones.
A pattern emerges when comparing the explosion of the world's use of chemicals, including pesticides and herbicides, and the steadily increasing incidence of testicular cancer, reproductive system abnormalities and impotence.
Phthalates, which are used in a variety of products including cosmetics, upholstery, pharmaceuticals and medical tubing, and also are found in drinking water and air. The chemicals can be found in body fluids of people who have been exposed, including in urine, blood and breast milk. Presence in breast milk can pass exposure on to an infant.
In a series of studies funded by the Environmental Protection Agency, Dr. Veeramachaneni's laboratory found that exposing tadpoles to dibutyl phthalate, one form of phthalate, drastically slows their growth and reproductive development. At varying doses, tadpoles lagged weeks behind non-exposed frogs in developing legs and entering adulthood. More significant, however, was the impact on their ability to reproduce; one effect of the chemicals is particularly notable on their mating calls. Those exposed to chemicals had calls that were weaker and shorter. Images of the larynx, the voice box, showed that it was significantly underdeveloped. Without a competitive mating call, the frogs will not be able to reproduce successfully.
DDT and other pesticides have been linked to testicular cancer in humans and animals. Reflecting human trends in the U.S. and abroad, in collaboration with medical scientists at University of Pretoria, South Africa, Dr. Veeramachaneni has found instances of testicular cancer in wildlife in Africa, potentially tied to the increasing renewed use of DDT to fight malaria-carrying mosquitoes. His research showed that DDT causes precancerous lesions in the testis. Dr. Veeramachaneni also documented cancerous lesions in the testes of infertile domestic horses and wild deer, and is working on a possible connection to ubiquitous pollutants.
The incidences of hypospadias and cryptorchidism are increasing. While figures indicating the increase vary by population, the Centers for Disease Control and Prevention cites a marked twofold increase in the last 25 to 30 years, now impacting almost one per 100 males born. Hypospadias can affect urination and sexual function. Dr. Veeramachaneni's laboratory has found that exposure to some chemicals such as phthalates causes hypospadias and cryptorchidism.
Historical studies show that the quality of sperm in humans has decreased rapidly in the last 50 years. With the assistance of research associate Carol Moeller, Dr. Veeramachaneni's electron microscopic studies show that sperm quality is affected by malformations of structures that are needed for fertilization of the egg or two or more sperm attached to each other following exposure to a variety of so-called innocuous chemicals.
Erectile dysfunction is reported in one-third of the U.S. male population. It also is being linked to chemicals in the environment. Vinclozolin, a fungicide commonly used in agriculture, can contaminate food and water supplies. In laboratory tests, Veeramachaneni and his research associate, Jennifer Palmer, found that some male offspring of animals exposed to vinclozolin during pregnancy displayed a complete lack of interest in females.
Other researchers have made similar findings. For instance, Cecilia Berg, Ph.D., a researcher in environmental toxicology, found frogs to be more sensitive to hormone-disturbing environmental pollutants. Recent studies by Tyrone Hayes, Ph.D. at the University of California have demonstrated that atrazine is an endocrine disruptor that chemically castrates and feminizes male amphibians. In addition to hermaphroditic deformities in frogs, pseudo-hermaphrodite polar bears with penis-like stumps, panthers with atrophied testicles, and intersex fish have all been documented as the probable result of endocrine-disrupting chemicals in the environment. Many scientists believe that wildlife provides early warnings of effects produced by endocrine disruptors, which may as yet be unobserved in humans.
Source: Colorado State University
(Beyond Pesticides, February 20, 2008) Pesticides that run off agricultural land and mix in rivers and streams combine to have a greater than expected toxic effect on the salmon nervous system, according to researcher Nathaniel Scholz, PhD, a zoologist with the National Oceanic and Atmospheric Administration (NOAA) in Seattle.
Dr. Scholz, who presented his findings at the symposium entitled From Kitchen Sinks to Ocean Basins: Emerging Chemical Contaminants and Human Health, which was organized by NOAA and hosted at the American Association for the Advancement of Science (AAAS) Annual Meeting, had previously looked at the effects of individual pesticides. However, to get a more realistic idea of exposure, combinations of several pesticides were used and juvenile salmon exposed to them two at a time. The results surprised Dr. Scholz and his team. The total impact observed from combined pesticides was greater than the sum of the individual pesticides, demonstrating a synergistic effect. Some pesticides that were not deadly when tested in individual trials killed all salmon exposed to combinations. A mixture of the pesticides diazinon and malathion, exhibited the greatest synergistic effect and killed all the salmon exposed to them, even at the lowest concentrations.
"It was eye opening," Dr. Scholz said. "We're seeing relatively dramatic departures" from what happens with each pesticide by itself. "The real world is usually more complex, and exposures to mixtures of chemicals can be more of the rule than the exception."
Dr. Scholz said the findings, which are in review for publication, mean that the Environmental Protection Agency (EPA) may be underestimating the hazards pesticides pose to salmon. It also indicates that combinations of pesticides found on fruits and vegetables may also pose an unknown and unexpected risk for people.
Pesticides sprayed on agricultural crops are widespread in streams in the Northwest and half of the waters sampled by the U.S. Geological Survey contain six or more pesticides. Pesticides found in salmon watersheds were at concentrations at or above levels set to protect fish and other aquatic life. The pesticides used in Dr. Scholz's study include the organophosphates malathion, chlopyrifos and diazion, among others. Organophosphates are neurotoxic and kill cells by inhibiting acetylcholinesterase, an enzyme that helps neurons communicate. This in turn harms the ability of salmon to feed. Diazinon also reduces sperm production in male salmon even at extremely low levels.
In a 2002 order, a U.S. District Court in Seattle found that the federal government had failed to protect threatened species of salmon and 26 other endangered species from toxic pesticides. The judge ordered EPA to consult with the National Marine Fisheries Service (NMFS) to identify permanent measures needed to protect the salmon and others from pesticides. Despite the ruling, federal agencies have been negligent in their efforts to protect declining salmon populations. In November 2007, fishing and environmental groups seeking to force the federal government to uphold the five-year-old rule once again filed a lawsuit (See Daily News Blog of November 7, 2007).
(Beyond Pesticides, January 31, 2008) A study to be published in the February 2008 issue of Environmental Health Perspectives finds that children who eat a conventional diet of food produced with chemical-intensive practices carry residues of organophosate pesticides that are reduced or eliminated when they switch to an organic diet. The study is entitled "Dietary Intake and Its Contribution to Longitudinal Organophosphorus Pesticide Exposure in Urban/Suburban Children" (Chensheng Lu, Dana B. Barr, Melanie A. Pearson, and Lance A. Waller) and includes authors from Rollins School of Public Health, Emory University, and the National Center for Environmental Health, Centers for Disease Control and Prevention.According to the authors, "The objective of this article is to present the data of assessing young urban/suburban children's longitudinal exposure to OP [organophosphate] pesticides in a group [of] young children participating in the Children Pesticide Exposure Study (CPES). The results from this study identify not only the predominant source of OP pesticide exposure but also the profile of exposures in children that are vital in formulating the strategies, both from the regulatory policy and personal behavior change perspectives, in reducing children's exposures to OP pesticides."
The study design included 23 children, male and female, from the Seattle area, ages 3-11 years who only consumed conventional diets and were recruited for a one-year study conducted in 2003-2004. Of the 23, 19 completed the study. Children switched to organic diets for five consecutive days in the summer and fall sampling seasons. The authors measured specific urinary metabolites for malathion, chlorpyrifos and other OP pesticides in urine samples collected twice daily for a period of 7, 12, or 15 consecutive days during each of the four seasons. According to the authors, "By substituting organic fresh fruits and vegetables for corresponding conventional food items, the median urinary metabolite concentrations were reduced to non-detected or close to non-detected levels for malathion and chlorpyrifos at the end of 5-day organic diet intervention period in both summer and fall seasons. We also observed a seasonal effect on the OP urinary metabolite concentrations, and this seasonality is correspondent to the consumption of fresh produce throughout the year." And, "Considering the lack of residential use of OP pesticides among the families of CPES-WA children, consumption of conventional diets is likely to be the sole contributing factor to the seasonality effect of pesticide exposures."
The authors point out that few studies evaluate the longitudinal exposure to pesticides that all children experience. According to the authors, "Most of the studies published in the literature have either targeted children living in agricultural environments or have used a cross-sectional design with spot sample collection."
The authors raise concerns about inadequate attention being given by regulators to chronic low-level exposures to pesticides, such as those found in their study. They point out that, "Using spot biomarkers [one-time measurement of urinary metabolites] of OP pesticide exposure to examine the link between adverse health outcomes and cumulative OP pesticide exposure is obviously an inadequate approach."
Corresponding author: Chensheng Lu, Department of Environmental and
Occupational Health, Rollins School of Public Health, Emory University, 1518
Clifton Road, NE, Atlanta, GA 30322, (404)727-2131, (404)727-8744 (fax), clu2@sph.emory.edu.
(Beyond Pesticides, January 30, 2008) A survey of 31 Australian strawberry growers conducted by a consumer watchdog revealed that almost all conventionally grown strawberries contained residues of pesticides. Several samples of the strawberries tested contained pesticide residues that exceeded the legal limit, and some even tested positive for pesticides banned for use on strawberries.Tests revealed that that 17 of the 27 samples of conventionally grown strawberries registered residues of at least two types of pesticide or fungicide. Four samples had traces of four different chemicals on the skin that had penetrated the fruit's flesh as well.
Choice, the chemical watchdog group that commissioned the survey, described the findings as alarming and calls on the Australian Government to remedy years of neglect over pesticide regulation, and to require independent, mandatory testing of all fruits and vegetables.
"Analysis shows strawberries are more likely to have pesticide
residues than other fresh fruit, and washing does not necessarily remove them,"
said Choice spokesman Christopher Zinn.
"Strawberries contain lots of
nutrients but unfortunately they also tend to contain residues of pesticide…
[T]here are some concerns about long-term exposure to a mixture of different
pesticides."
Jo Immig, the coordinator of National Toxics Network Inc, said the findings showed that the regulation of pesticides in Australia had fallen woefully behind. "The results … should alarm customers, and in particular parents of small children, who are at far greater risk of damage from pesticide exposures," she said.
Australian strawberries are not the only ones to have recorded significant amounts of pesticide residues. In 2007, the United States Department of Agriculture's (USDA) Pesticide Data Program released its latest annual summary detailing pesticide residues in the U.S. food supply. In fruits and vegetables, 73 percent of fresh and 61 percent of processed produce had detectable residues. On strawberries, at least 30 different pesticide resides were detected, along with 31 in grapes, 36 in apples, and 43 in lettuce. The California Department of Pesticide Regulation (DPR) also reported 2006 pesticide use statistics, which showed strawberry growers had increased their reliance on the highly toxic, ozone depleting fumigant methyl bromide (See Daily News http://www.beyondpesticides.org/dailynewsblog/?p=239)
Studies have shown pesticide residues are higher in children that are fed conventional versus organic foods, and that an effective way to reduce a child's exposure to pesticide residues on food is to change their diet to organic. Children with organic diets contain significantly less metabolites of toxic pesticides in their blood and urine.
TAKE ACTION: Buy organic foods for yourself and your family whenever possible. If organic foods are not easily accessible to you due to cost or distribution, consider buying organic for the foods you eat the most. To make sure your food is organic, look for the USDA Organic label.
Source: The Sydney Morning Herald
Mercer Island children tested in yearlong study
Wednesday, January 30, 2008 Last updated 12:59 a.m.
By ANDREW SCHNEIDER
P-I SENIOR CORRESPONDENT
Seattle Post Intelligencer
Government promises to rid the nation's food supply of brain-damaging pesticides aren't doing the job, according to the results of a yearlong study that carefully monitored the diets of a group of local children.
The peer-reviewed study found that the urine and saliva of children eating a variety of conventional foods from area groceries contained biological markers of organophosphates, the family of pesticides spawned by the creation of nerve gas agents in World War II.
When the same children ate organic fruits, vegetables and juices, signs of pesticides were not found.
"The transformation is extremely rapid," said Chensheng Lu, the principal author of the study published online in the current issue of Environmental Health Perspectives.
"Once you switch from conventional food to organic, the pesticides (malathion and chlorpyrifos) that we can measure in the urine disappears. The level returns immediately when you go back to the conventional diets," said Lu, a professor at Emory University's School of Public Health and a leading authority on pesticides and children.
Within eight to 36 hours of the children switching to organic food,
The subjects for his testing were 21 children, ages 3 to 11, from two elementary schools and a Montessori preschool on Mercer Island.
The community has double the median national income, but the wealth of Mercer Island made no difference in the outcome, he said.
"We are confident that if we did the same study in poor communities, we would get the same results," he said. The study is being repeated in Georgia.
The study has not yet linked the pesticide levels to specific foods, but other studies have shown peaches, apples, sweet bell peppers, nectarines, strawberries and cherries are among those that most frequently have detectable levels of pesticides.
Measuring the harm
Lu is quick to point out that there is no certainty that the pesticides measured in this group of children would cause any adverse health outcomes. However, he added that a recent animal study demonstrated that persistent cognitive impairment occurred in rats after chronic dietary exposure to chlorpyrifos.
Death or serious health problems have been documented in thousands of cases in which there were high-level exposures to malathion and chlorpyrifos. But a link between neurological impairments and repeated low-level exposure is far more difficult to determine.
"There's a large underpinning of animal research for organophosphate pesticides, and particularly for chlorpyrifos, that points to bad outcomes in terms of effects on brain development and behavior," Dr. Theodore Slotkin, a professor of pharmacology and cancer biology at Duke University in North Carolina, said in the April 2006 Environmental Health Perspectives.
Lu says more research must be done into the harm these pesticides may do to children, even at the low levels found on food.
"In animal and a few human studies, we know chlorpyrifos inhibits an enzyme that transmits a signal in the brain so the body can function properly. Unfortunately, that's all we know."
Not many chemicals, including pharmaceutical products, were designed specifically to kill mammals, which was genesis of organophosphates.
"It is appropriate to assume that if we -- human beings -- are exposed to (this class of) pesticides, even though it's a low-level exposure on a daily basis, there are going to be some health concerns down the road," said Lu, who is on the Environmental Protection Agency's pesticide advisory panel.
The EPA says it eliminated the use of organophosphates on many crops and imposed numerous restrictions on the remaining organophosphate pesticide uses.
Congressional concern that children were being harmed by excessive to pesticides led to the unanimous passage of the Food Quality Act. At its heart was a requirement that by 2006, the EPA complete comprehensive reassessment of the 9,721 pesticides permitted for use determine the safe level of pesticide residues permitted for all
"As a result, the amount of these pesticides used on undergone) a 57 percent reduction," said Jonathan Shradar, spokesman.
But that's not nearly enough to prevent birth defects and neurological problems, said Chuck Benbrook, chief scientist of the Organic Center, a nationwide, nonprofit, food research organization.
"The pesticide limits that EPA permits are far, far too high to say they're safe. And, the reduction that EPA cites in the U.S. has been accompanied by a steady increase in pesticide-contaminated imported foods, which are capturing a growing share of the market," he said.
Yet the EPA continues to insist that "dietary exposures from eating
crops treated with chlorpyrifos are below the level of concern for
the
That statement is "not supported by science," Benbrook said.
"Given the almost daily reminders that children are suffering from an array of behavioral, learning, neurological problems, doesn't it make sense to eliminate exposures to chemicals known to trigger such outcomes like chlorpyrifos?" he asked.
What to do
While the gut reaction of some parents might be to limit the consumption of fresh produce or switch completely to organic food, Lu cautions not to make the wrong decision.
"It is vital for children to consume significantly more fresh fruits and vegetables than is commonly the case today," he says, citing such problems as juvenile diabetes and obesity.
"Nor is our purpose to promote the consumption of organic food, although our data clearly demonstrate that food grown organically contains far less pesticide residues."
Lu says an all-organic diet is not necessary. He has two sons, 10 and 13, and he estimates that about 60 percent of his family's diet is organic.
"Consumers," he says, "should be encouraged to buy produce direct from the farmers they know. These need not be just organic farmers, but conventional growers who minimize their use of pesticides."
Understanding how fruits and vegetables grow can help guide the consumer, he says.
For example, organic strawberries probably are worth the money because they are a tender-fleshed fruit grown close to the dirt, so more pesticides are needed to fight insects and bugs from the soil. He adds apples and spinach to his list.
"It may also be money-smart to choose conventionally grown broccoli because it has a web of leaves surrounding the florets, resulting in lower levels of pesticide residue," Lu says.
He is greatly concerned about one finding from the study.
"Overall pesticide (marker) levels in urine samples were even higher in the winter months, suggesting children may have consumed fruits and vegetables that are imported. The government needs to ensure that imported food comply with the standards we impose on domestic produce," he said.
Dangerous science
Chlorpyrifos, made by Dow Chemical Co., is one of the most widely used organophosphate insecticides in the United States and, many believe, the world.
For years, millions of pounds of the chemical insecticide were used in schools, homes, day care centers and public housing, and studies show that children were often exposed to enormously high doses. Just as the EPA was ready to ban the product, which analysts said would have damaged Dow's overseas sales, the company "voluntarily" removed it from the home market. Yet, with few exceptions, the agricultural uses continued.
The EPA's Web site is a study in contradictions when it comes to chlorpyrifos.
At one section, it "acknowledged the special susceptibility and sensitivity of children to developmental and neurological effects from exposure to chlorpyrifos."
But in another section, the agency reports that infants and children face no risk from eating food crops treated with chlorpyrifos. However, the agency doesn't say how it reached that conclusion. There is no agreement of how much of the neurotoxin is too much.
Benbrook said the EPA has refused orders from Congress to study the cumulative developmental risk to children from low-dose exposures.
"Perhaps we can rest assured that EPA has protected us adults from acute insecticide poisoning risk, but our kids are on their own," Benbrook said.
chart
ABOUT THE STUDY
Chensheng Lu's study was published this month in Environmental Health Perspectives (ehponline.org), a publication of the National Institute of Environmental Health Science. It was funded by the Environmental Protection Agency and used federal laboratories to confirm the accuracy of his findings.
Unlike many previous studies, Lu's team focused on children living in an urban/suburban area who were tested for multiple days in each of the four seasons with urine and saliva sampled twice a day.
The organic produce was sent to the Department of Agriculture lab in Yakima to be tested for pesticides. The Centers for Disease Control and Prevention tested the urine samples and the Food and Drug Administration laboratory is completing its quantification of pesticide residues in samples of the conventional food the children consumed.
The team included scientists from Emory University, the CDC and the University of Washington.
(Beyond Pesticides, January 29, 2008) University of Cambridge scientists say there may be a link between persistent organic pollutants (POPs), including pesticides, and Type 2 Diabetes. The Cambridge scientists are advocating additional research into the little understood links between environmental pollution and adult onset diabetes.
In the most recent edition of the journal Lancet, Oliver Jones, Ph.D., and Julian Griffin, Ph.D., highlight the need to research the possible link between persistent organic pollutants (POPs, a group which includes many pesticides) and insulin resistance, which can lead to adult onset diabetes.
In their commentary, Dr. Jones and Dr. Griffin cite peer reviewed research including that of D. Lee, et al, which demonstrated a very strong relationship between the levels of POPs in blood, particularly organochlorine compounds, and the risk of type 2 diabetes.
"Of course correlation does not automatically imply causation," says Dr. Jones. "But if there is indeed a link, the health implications could be tremendous. At present there is very limited information. Research into adult onset diabetes currently focuses on genetics and obesity; there has been almost no consideration for the possible influence of environmental factors such as pollution."
Interestingly, in the Lee study an association between obesity and diabetes was absent in people with low concentrations of POPs in their blood. In other words, individuals were more at risk of diabetes if they were thin with high levels of POPs in their blood than if they were overweight but with low levels of POPs.
Dr. Jones said, "I think research should be carried out to first test the hypothesis that POPs exposure can cause diabetes, perhaps using cell or tissue cultures, so we know for sure if this can occur. Assuming POPs can have this effect, the next step would be to try and develop a method of treatment for those people who might be affected."
POPs came into prominence as effective pesticides with the
introduction of DDT in the 1940s. However, many of these chemicals, including
DDT, fell out of favor after they were blamed for the declining number of wild
birds and other animals and negative human health effects. As the compounds
biodegrade slowly, they continue to find their way into the food chain and
ultimately into the blood streams of individuals even though many of these
toxins were banned many years ago. Additionally, these compounds can persist in
body fat for very long periods of time following
exposure.
(Beyond Pesticides, January 9, 2008) Triclocarban, an antibacterial compound widely used as an additive to a range of household and personal care products including bar soaps, detergents, body washes, cleansing lotions, and wipes, has been found to have an amplification effect on the activity of natural hormones, which in turn can lead to adverse reproductive and developmental effects.
In the study, published online November 29, 2007 in Endocrinology, researchers from University of California- Davis and Yale University investigated the endocrine disrupting properties of triclocarban and other polychlorinated diphenyl urea compounds by exposing human cells and rats to levels similar to those found in people. Triclocarban was found to have a synergistic interaction with the sex hormone, testosterone- present in both males and females. This interaction produced a positive, amplified biological effect, which is likely to hyperstimulate native sex hormones. This amplification of sex hormone activity occurs at the target cell and can result in developmental defects or decreased reproductive function. Researchers further explained that ovulation and ovarian function in females can be disrupted, while sperm quality can be decreased in males.
The researchers also point out that the results of their study create a new category for endocrine disruptive substances to include "hormone amplifiers or enhancers" rather than simple agonists or antagonists in order to accommodate the synergistic property demonstrated by triclocarban. They also note that since triclocarban has the potential to amplify synthetic compounds, further investigation into its interaction with oral contraceptives and hormone replacement therapy is needed.
Triclocarban, like its cousin triclosan, has been linked to numerous health and environmental effects. When disposed into residential drains and carried to streams and rivers, it kills beneficial organisms in soil and water. Both of these chemicals have been found in breast milk and fish. Triclocarban, along with triclosan, survives treatment at sewage plants and most ends up in waterways and sludge spread on agricultural fields, and may end up on produce. Researchers at the John's Hopkins Bloomberg School of Public Health found that triclocarban was the fifth most frequent contaminant among 96 pharmaceuticals, personal care products and organic wastewater contaminants evaluated and that levels of triclocarban in water resources nationwide are much higher than previously thought.
In 2005, the U.S. Food and Drug Administration led a panel of experts and industry representatives to weigh and analyze different germ killing methods. The panel found "no firm scientific evidence that the flood of antimicrobial products we observe has any discernible benefit over the use of regular soap and water."
TAKE ACTION: You can stay healthy and put pressure on manufacturers to phase out antibacterials by not using products with triclosan or triclocarban. Stay hygienic the most effective way, by using plain soap and water.
Source: Environmental Science and Technology
(Beyond Pesticides, January 4, 2008) A study appearing in the January 2, 2008 issue of the American Journal of Respiratory and Critical Care Medicine has found a correlation between women's exposure to farm pesticides and allergic asthma. The study's lead author, Jane Hoppin, Sc.D., of the National Institute of Environmental Health Sciences, cited the lack of information on the risks incurred when women apply pesticides, saying, "Farm women are an understudied occupational group."
The study evaluated data on 25,814 farm women who are participating in the Agricultural Health Study in Iowa and North Carolina. "This is the largest study of farmers and their families in the world, so it gives us an opportunity to look at diseases that haven't been well characterized," said Dr. Hoppin. The women self-reported their doctor-diagnosed asthma, and the team separated them into subgroups of allergic and non-allergic asthmatics. They also found that more than half of the responders had used or been exposed to pesticides, while 61 percent grew up on a farm.
The resulting data found that use of pesticides increased risk of allergic asthma by almost 50 percent, but not of non-allergic. Where a woman grew up also affected her likelihood to develop allergic asthma. Women who were raised on farms and did not handle pesticides had the lowest risk of asthma. Women who who grew up on a farm and did work with pesticides were more likely to be asthmatic. Women who did not grow up on farms, however, were most likely to develop asthma, due to a little-studied protective affect of growing up in an agricultural setting, which provides an overall reduction in risk.
"Growing up on a farm is such a huge protective effect it's pretty hard to overwhelm it," said Dr. Hoppin. "[But] about 40 percent of women who work on farms don't report spending their childhoods there. It is likely that the association with pesticides is masked in the general population due to a higher baseline rate of asthma."
The study also divided out the different pesticides used by respondents and their correlation to the asthma rate. Malathion, for example, was associated with a 60 percent increase in incidence of allergic asthma. According to the report, "A total of 7 of 16 insecticides, 2 of 11 herbicides, and 1 of 4 fungicides were significantly associated with atopic [allergic] asthma; only permethrin use on crops was associated with nonatopic [non-allergic] asthma," in spite of non-allergic asthma's higher occurrence in adults.
A follow-up study has been planned to better evaluate the link between pesticides and asthma. "We want to characterize the clinical aspects of the disease, as well as lifetime exposures to agents that may either protect against asthma or increase risk," said Dr. Hoppin. "We hope to start the study in 2008."
Sources: Science Daily, U.S. News & World Report, Environmental News Service