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Category: pesticides

Published on Leave a comment on Early Pesticide Exposure Linked to Poorer Lung Function

 Just a few years ago the type of pesticide (organophosphate, for example chlorpyrifos) looked at in this study was commonly used everywhere - in schools, homes, agriculture. It was easy to buy in stores (e.g., Raid spray), and was considered "safer" than older pesticides. Over time problem after problem has been found with them - with the latest being decreased lung function in children exposed to organophosphates early in life.

Keep in mind that with all current pesticides we know very little about long-term effects, especially on developing fetuses and children, and so we should be very, very careful about using them and avoid unnecessary use. Yes, that means using them for harmless lawn weeds is an unnecessary use. Common lawn weeds can not give a person cancer, birth defects, health problems, or illnesses, but pesticides can. From Medical Xpress:

Weaker breaths in kids linked to early pesticide exposure

Taking a deep breath might be a bit harder for children exposed early in life to a widely used class of pesticides in agriculture, according to a new paper by researchers at the University of California, Berkeley. A new study has linked the levels of organophosphate pesticide metabolites in the urine of 279 children living in California's Salinas Valley with decreased lung function. Each tenfold increase in concentrations of organophosphate metabolites was associated with a 159-milliliter decrease in lung function, or about 8 percent less air, on average, when blowing out a candle. The magnitude of this decrease is similar to a child's secondhand smoke exposure from his or her mother.

"Researchers have described breathing problems in agricultural workers who are exposed to these pesticides, but these new findings are about children who live in an agricultural area where the organophosphates are being used," said study senior author Brenda Eskenazi, a professor of epidemiology and of maternal and child health. "This is the first evidence suggesting that children exposed to organophosphates have poorer lung function."

The children were part of the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a longitudinal study in which the researchers follow children from the time they are in the womb up to adolescence. The researchers collected urine samples five times throughout the children's lives, from age 6 months to 5 years, and measured the levels of organophosphate pesticide metabolites each time. When the children were 7 years old, they were given a spirometry test to measure the amount of air they could exhale.

"The kids in our study with higher pesticide exposure had lower breathing capacity," said study lead author Rachel Raanan, who conducted the research while she was a postdoctoral scholar in Eskenazi's lab. "If the reduced lung function persists into adulthood, it could leave our participants at greater risk of developing respiratory problems like COPD (chronic obstructive pulmonary disease)."

The study did not examine the pathways for the children's exposure to pesticides, but the researchers did recommend that farmworkers remove their work clothes and shoes before entering their homes. They also suggested that when nearby fields are being sprayed with pesticides, children be kept away and, if indoors, windows should be closed. Pesticide exposure can also be reduced by washing fruits and vegetables thoroughly before eating.

The authors noted that although organophosphate pesticides are still widely used, most residential uses of organophosphate pesticides in the United States were phased out in the mid-2000s. In California, use of organophosphates in agriculture has also declined significantly from 6.4 million pounds in 2000, when the study began, to 3.5 million pounds in 2013, the year with the most recent pesticide use data. 

Published on Leave a comment on Which Mosquito Repellents Work?

People spend a lot of effort trying to repel mosquitos  - because the bites are so annoying and because they spread serious diseases. New research looking at different mosquito repellents - both DEET and non-Deet ("natural") products - had interesting results. What was once thought effective in repelling mosquitoes doesn't work at all (vitamin B patch), and what was thought attractive to mosquitoes may actually repel them (floral scents), and the "natural" alternatives may or may not work. Also - the species of mosquito is important (they tested Aedes aegypti and Aedes albopictus), for they found that there was some variation among the 2 species in what they were attracted to or repelled by. Best choices for protection lasting at least 2 hours: DEET repellants, Cutter lemon eucalyptus insect repellent, and Victoria's Secret Bombshell. Best protection lasting 4 hours: DEET repellants, and Cutter lemon eucalyptus insect repellent. This last non-DEET product contained lemon-eucalyptus oil containing p-menthane-3,8-diol. Of course there was an untreated control (an attractive to mosquitoes volunteer's bare hand) in the study for comparison purposes.

However, while EcoSmart organic insect repellent  worked for 4 hours for Ae. albopictus mosquitoes, it only worked for the first few minutes for Ae. aegypti mosquitoes (so don't buy this product). For years people thought that Avon Skin So Soft worked well as a repellent - well, forget it- not good at all. Other products that did not work: a mosquito skin patch (vitamin B), and Cutter natural insect repellent. These results showed that DEET-free products containing citronella or geraniol did not work. See the original study for the result lists for 10 products for both species of mosquitoes. From Popular Science:

VICTORIA’S SECRET PERFUME WARDS OFF MOSQUITOES, STUDY FINDS

Because mosquitoes carry diseases like malaria and dengue fever, and irritate us, humans do a lot to avoid them. In most places people have to fend for themselves against the pests by sleeping under mosquito nets or using repellant. A number of new repellant formulas have hit the market in recent years, many with questionable efficacy. Researchers at New Mexico State University decided to compare the effectiveness of different repellants and perfumes, according to a study published recently in the Journal of Insect Science.

The Y-shaped tube used in the study.  Rodriguez et al, Journal of Insect Science, 2015

The researchers tested eight commercially available repellents, two fragrances, and a vitamin B patch that reportedly keeps the mosquitoes at bay, on two different species of disease-carrying mosquitoes. To test the efficacy of each, the researchers put a mosquito at the long end of a Y-shaped plastic tube. One of the researchers who is particularly attractive to mosquitoes placed her two hands at the ends of both forked tubes—one hand was untreated, the other treated with the chemical being tested. If the mosquito avoided the tube with the treated hand by staying still or moving towards the untreated hand, the researchers determined that the repellent worked.

The researchers found that, among repellents, those that contained the tried-and-true ingredient DEET were most effective in warding off the mosquitoes. A few others, such as Cutter Lemon Eucalyptus Insect Repellent, worked almost as well, while most of them (including the vitamin patch) didn’t make any difference.

While those findings weren’t unexpected, the researchers were surprised to find that Avon Skin So Soft Bath Oil repelled the mosquitoes for about two hours. Another fragrance, Victoria’s Secret Bombshell perfume, also repelled the mosquitoes and lasted even longer.

That overturned the previous understanding about how mosquitoes interpret scents. “There was some previous literature that said fruity, floral scents attracted mosquitoes, and to not wear those,” said Stacy Rodriguez, a research assistant involved in the study, said in a statement. “It was interesting to see that the mosquitoes weren’t actually attracted to the person that was wearing the Victoria’s Secret perfume – they were repelled by it.”

Published on Leave a comment on Should Pesticides Be Next to the Food?

Why are huge (42+ pound) bags of lawn chemicals being sold with foods in stores? Should stacked bags of pesticides ever be placed next to foods in stores? Is this legal? Why is this happening in warehouse stores that call themselves environmentally conscious and brag about carrying organic foods?

Apparently the store does not recognize that the stacked bags of lawn chemicals (pesticides) are dangerous, that the bags can tear and spill pesticides, or that they always give off an awful chemical odor that can be smelled many aisles away. (This means we are breathing in those chemicals)

Why is it OK to place foods and enormous bags of pesticides in the same shopping cart, perhaps with children next to and handling the bags? (Note: I have personally seen this!) The pesticides should be sold in a separate area (like in Home Depot or Lowe's) or perhaps only in garden center. These pesticide products all say "Keep out of reach of children", to "avoid skin contact", and to "avoid inhaling". They are dangerous and do not belong in food stores.

The following photos were taken by me over the course of several years (2012 to 2015) in two Costco stores in NJ. The bags of "Turf Builder Winterguard Plus Weed Control" contain both fertilizer and pesticides and are commonly known as "Weed and Feed". Pesticides that kill weeds are also known as herbicides, and here the 2 pesticides (the active ingredients) are 2,4-D and mecoprop-p.

The first pesticide (2,4-D) was one of the the two pesticides found in Agent Orange used during the Vietnam War, and is linked to many serious health problems, including cancer in both people and dogs. (Note: scroll down for more information on these 2 pesticides).

Pesticides get into the body through the skin (dermal exposure) or eyes, through the mouth (ingesting it, including residues on foods), or through inhalation. Note that all odors represent an exposure to a chemical.

Pesticide products contain a number of ingredients – the “active ingredients” that targets the pest (weed or insect), and other ingredients that are just labeled "inert ingredients" or "other ingredients". Any one of them may produce a sickening odor. Odors also may be related to a breakdown product, a warning agent (a smelly substance added to make otherwise odorless products easier to detect), or a chemical added to the formula to hide a bad odor.

Currently, under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), pesticide manufacturers are only required to list the active ingredients in a pesticide, leaving consumers and applicators unaware of the possible toxics present in the inert or "other" ingredients of pesticide products. Pesticide manufacturers argue they cannot release information on inert ingredients because they are trade secrets, and if released, their products could be duplicated. Quite often inert ingredients constitute over 95% of the pesticide product, and can be as toxic as the active ingredients. 

So.... what this means is that just by being able to smell the pesticide-fertilizers, we are being exposed to some chemicals through inhalation. And when this product is placed by foods, one doesn't smell food but instead inhales chemicals, perhaps the pesticides. These huge bags easily leak and spill (unlike small metal containers or cans). Leaking bags also result in shopping carts being contaminated with pesticides, as well as the store floor.

By placing the bags of pesticides next to foods, Costco is also sending the message to customers that the product is "safe", but that is incorrect. Pesticides that are dangerous (toxic) must be registered with the EPA. Harmless things don't have to be registered - toxic chemicals do.

And yes, a few years ago I contacted Costco management about this issue, but their response was to pooh-pooh my concerns, and that I must "be sensitive". And they continued as before. The following are some photos from 2012 to 2015 at 2 Costco warehouse stores.

Next to refrigerated foods

Contains 2,4-D and Mecoprop-p

Next to bakery goods

By the meat

2,4-D (or 2,4-Dichlorophenoxyacetic acid is a systemic herbicide (broadleaf weed-killer). It is linked to several cancers, especially non-Hodgkin's lymphoma and soft tissue sarcoma, and can have other serious health effects including endocrine disruption (disruption of hormones), thyroid effects, neurotoxicity (nervous system damage), and developmental and reproductive effects.

As the post of Oct.19, 2015 indicated, a person's exposure to 2,4-D can be measured in a person's urine. There is much still unknown about what constant low-level exposure to 2,4-D does to a fetus, developing child, or adult of any age.

Of big concern is that the use of 2,4-D is increasing in the USA because of the development of new genetically modified soybean and corn strains that are resistant to 2,4-D. Thus farmers are using increasingly large amounts of 2,4-D on these corn and soybean crops in an attempt to control weeds. And yes, this means consumers are eating more foods with 2,4-D residues. (Note: long-term effects unknown.)

Mecoprop-p is a chlorophenoxy herbicide that is used to control a variety of weeds. It is not as toxic as 2,4-D, but it also has various health effects.

Go to the excellent Beyond Pesticides site  http://www.beyondpesticides.org/ for more information about all sorts of pesticides, resources, up-to-date information on pesticide laws, and more.

Published on Leave a comment on Eat Organic Foods to Lower Pesticide Levels

Several studies have found that when children eat organic foods, especially fruits and vegetables, the amount of pesticides in their bodies declines significantly. Most organophosphorus pesticides have been phased out for residential use, but they are still widely used in agriculture, and so these pesticides are detected in both foods and people.

This latest study looked at 20 children living in urban Oakland, Calif., and 20 in the agricultural community of Salinas, about 100 miles south. The children (between 3 - 6 years of age) ate a conventional diet for four days and an organic diet for seven days and then returned to conventional foods for five days. Their urine was collected daily and analyzed for pesticides, specifically by looking at pesticide metabolites (pesticide breakdown products).

Several classes of pesticides were frequently detected, for they were found in more than 72 percent of their urine samples, and 2,4-D was detected in 90% of samples. Of the six most frequently detected pesticides, two decreased by nearly 50 percent when children were on the organic diet, and levels of the common herbicide 2,4-D fell by 25 percent. Amounts of some pesticides were not significantly lower on the organic diet, but these were pesticides associated with use around homes for pest control, and not on foods (e.g., pyrethroids, diazinon, malathion).

Bottom line: eat as many organic foods as possible to lower pesticide levels in the  body. To further reduce pesticide levels in the body - avoid pesticide use around the home and garden. Instead, use least toxic IPM (Integrated Pest Management) or organic pest control and organic gardening.

From Medical Xpress: Organic produce means reduced pesticides in kids, study shows

New research out of the Center for Environmental Research and Children's Health at UC Berkeley shows that switching from conventional to organic fruits and vegetables, even for just a few days, significantly reduces pesticide levels in children's bodies.

Twenty children in Oakland, California and 20 in Salinas, California, all 3 to 6 years old, had their urine tested for 16 days during the study. For the first four, they ate conventional produce, for the next seven their diet was organic, and then conventional for the last five. The levels of several pesticides that showed up in daily testing dropped by one-quarter to one-half during the organic stretch.

Excerpts from the original study from Environmental Health Perspectives: Effect of Organic Diet Intervention on Pesticide Exposures in Young Children Living in Low-Income Urban and Agricultural Communities

Recent organic diet intervention studies suggest that diet is a significant source of pesticide exposure in young children....We aimed to determine whether consuming an organic diet reduced urinary pesticide metabolite concentrations in 40 Mexican-American children, 3–6 years of age, living in California urban and agricultural communities. In 2006, we collected urine samples over 16 consecutive days from children who consumed conventionally grown food for 4 days, organic food for 7 days, and then conventionally grown food for 5 days. We measured 23 metabolites, reflecting potential exposure to organophosphorous (OP), pyrethroid, and other pesticides used in homes and agriculture.

For six metabolites with detection frequencies > 50%, adjusted geometric mean concentrations during the organic phase were generally lower for all children, and were significant for total dialkylphosphates (DAPs) and dimethyl DAPs (DMs; metabolites of OP insecticides) and 2,4-D (2,4-dichlorophenoxyacetic acid, a herbicide), with reductions of 40%, 49%, and 25%, respectively (p < 0.01). Chemical-specific metabolite concentrations for several OP pesticides, pyrethroids, and herbicides were either infrequently detected and/or not significantly affected by diet.

Although most residential uses of many organophosphorus (OP) pesticides, including chlorpyrifos and diazinon, have been phased out since the mid-2000s due to potential health risks to children, they have continued to be used in agriculture [U.S. Environmental Protection Agency (EPA) 2000, 2001]. The use of OP pesticides in agriculture could result in ingestion of residues in food, and recent studies suggest that dietary intake of produce and juices may account for a significant proportion of OP pesticide exposure in young children (Lu et al. 2006b, 2008; Morgan et al. 2005; Smith-Spangler et al. 2012; Wilson et al. 2003). Some of the best evidence supporting these findings includes results from diet intervention studies where significant reductions in excreted urinary pesticide metabolites were observed in young children when they consumed an organic diet (Lu et al. 2006b, 2008)....The lower urinary pesticide metabolite concentrations found in children eating organic diets is consistent with food residue monitoring data that has shown lower pesticide residue levels in organic versus conventionally grown food [Baker et al. 2002; U.S. Department of Agriculture (USDA) 2008].

Other factors associated with children’s cumulative pesticide exposures include socioeconomic status and location of residence. For example, low-income children may experience higher exposures to pesticides, particularly pyrethroids, because of poor housing quality and associated pest infestations and home pesticide use (Bradman et al. 2005a; Quirós-Alcalá et al. 2011; Whyatt et al. 2002). Children living in agricultural areas, compared with children living in non-agricultural suburban areas, are exposed to higher ambient and residential contamination from drift or volatilization from nearby agricultural applications and take-home residue by farmworking parents (Bradman et al. 2011; Harnly et al. 2009;Lu et al. 2000; Quirós-Alcalá et al. 2011).

Our finding that an organic diet was not associated with a significant reduction in pyrethroid metabolite (3-PBA) excretion for all children is not surprising given that these pesticides are primarily used in and around homes and not commonly applied to food crops; the finding is also consistent with Lu et al. (2006a), who reported that residential use is a more significant pyrethroid exposure factor for children than a conventional diet. 

Several studies indicate that dietary intake is a potential route of exposure for herbicides.....Overall, these studies indicate that 2,4-D may be present in food and support our finding that the lower levels observed in our population during the organic diet phase were attributable to lower dietary exposure.

In summary, consistent with other studies, urinary 2,4-D and two measures of OP pesticide exposure (total DMs and total DAP metabolites) were lower in children eating an organic diet. Other frequently detected metabolites for pyrethroids, diethyl OP pesticides, and the herbicide metolachlor were not significantly lower during the organic diet phase. Further, several compound-specific herbicide and OP pesticide metabolites had low detection frequencies, indicating that diet was not an important exposure source for these pesticides (e.g., diazinon, malathion) in this population. Last, independent of diet, most frequently detected metabolites were generally higher in Salinas compared with Oakland children, with DMs and metolachlor at or near significance (p = 0.06 and 0.03, respectively), suggesting additional sources of pesticide exposure for children living in agricultural communities.

Published on Leave a comment on Dogs, Weed Killers, and Malignant Lymphoma

Research as long ago as 1991 found that households with dogs that developed malignant lymphoma applied 2,4-D herbicides (weedkillers) to their lawns more frequently than households where the dogs did not develop malignant lymphoma.

In addition, the risk of canine malignant lymphoma rose much higher with four or more yearly applications of 2,4-D. This finding that exposure to certain lawn chemicals by dogs increases the risk of the dogs developing canine malignant lymphoma was confirmed in a 2012 study .

The following excerpts from an article geared toward students nicely explains a recent study that looked at the exposure that dogs have to lawn pesticides, specifically looking at 2,4-D, MCPP, and dicamba (commonly used weed-killers or herbicides). The study looked at exposure of pet dogs to 2.4-D by measuring it in the dog's urine, and also looked at how long the herbicides come off the grass where it had been applied.

They found widespread detection of lawn chemicals in the urine of pet dogs, that lawn chemicals were commonly detected on both treated and "untreated" lawns (probably due to "drift"), that the lawn chemicals persisted on grass for at least 48 hours after application, and that the chemicals can persist longer on grass under certain environmental conditions (e.g., dry brown grass).

Finally, the researchers said that dogs may serve as sentinels for human exposures (think of them as canaries in the mine) - if they are exposed to this degree, then humans must also be highly exposed. Dogs get malignant lymphomas after a short latency period, while for humans it is years longer to develop cancer. NOTE: weed-killers are herbicides, a type of pesticide.

My question is: why are people still applying pesticides to their lawns when there are links between pesticides and cancers? Is the weed-free lawn more important than health?

From Science News for Students: Weed killers may go from plant to pooch

Many people treat their lawns with weed killers — also known as herbicides — to rid themselves of unwanted plants, such as dandelions. Most people know to keep small children away from the grass after it’s been sprayed. That’s because these chemicals can be dangerous if children touched the treated lawn and then put their hands to their mouths. New data show that herbicides also can end up in dogs. The evidence: It comes out the other end in the animals’ urine.  ...continue reading "Dogs, Weed Killers, and Malignant Lymphoma"

Published on Leave a comment on Home Pesticide Use Linked to Childhood Cancer

Children exposed to insecticides (pesticides) at home have an increased risk of developing leukemia or lymphoma, a new review finds.The analysis, of 16 studies done since the 1990s, found that children exposed to indoor insecticides had an elevated risk of developing the blood cancers. There was also a weaker link between exposure to weed killers and the risk of leukemia.

There is also evidence from studies linking pesticides with neurological consequences, such as lower IQ and attention deficit hyperactivity disorder. Note: insecticides and weed-killers (herbicides) are both pesticides. The article also gives some non-chemical approaches to treating pests with non-chemical means.

From CNN: Report: Pesticide exposure linked to childhood cancer and lower IQ

Pesticide use in homes may increase the risk of children developing leukemia or lymphoma, a new report suggests. Researchers combined data from 16 earlier studies that had compared pesticide exposure between children who developed leukemia or lymphoma and those who did not. These studies estimated the level of insecticides and herbicides both inside the home and in the yard and outdoor residential space.

The researchers concluded that children who had been exposed to insecticides indoors were 47% more likely to have leukemia and 43% more likely to have lymphoma. Although leukemia and lymphoma are rare -- leukemia affects about five in 100,000 children in the United States -- they are among the common types of childhood cancers. "Childhood cancers are increasing year by year in this country....  ...continue reading "Home Pesticide Use Linked to Childhood Cancer"

Published on

A recent report found that when a person is exposed to a little bit (or low doses) of a lot of different commonly encountered chemicals, than the combinations over time may cause changes that increase the risk of cancer (they may initiate cancer). Think about it - we are not exposed to just one chemical at a time (which is how chemicals are tested), but to mixtures or a "chemical soup". It is almost impossible to avoid them. As one of the researchers said: "We urgently need to focus more resources to research the effect of low dose exposure to mixtures of chemicals in the food we eat, air we breathe and water we drink." Testing mixtures of chemicals is currently not required by law.

The effects may be synergistic  - an enhanced effect that is more than the sum of the individual chemicals. And some chemicals may have bigger effects at smaller doses (typical of endocrine or hormone disruptors), than at larger doses - which is not how chemicals are typically viewed (typical view: the more you are exposed to a chemical, the greater the effect). A global task force of 174 scientists looked at 85 common everyday chemicals (at everyday low doses), and 50 were found to support cancer-related mechanisms (processes essential to cancer development). Examples of problematic chemicals that are common in everyday life: triclosan (in many soaps and personal care products), bisphenol A (in many plastics, including can linings), and atrazine (common herbicide or weedkiller). From the LA Times:

Combinations of 'safe' chemicals may increase cancer risk, study suggests

Lots of chemicals are considered safe in low doses. But what happens when you ingest a little bit of a lot of different chemicals over time? In some cases, these combinations may conspire to increase your risk of cancer, according to a new report. “Many [chemicals] have the possibility, when they are combined, to cause the initiation of cancer,” said Hemad Yasaei, a cancer biologist at Brunel University in England, one of the authors of the report. “They could have a synergistic or enhanced effect.”

This is not the way regulators typically think about cancer risk when they evaluate a compound’s safety.Normally, they test an individual chemical on laboratory animals, exposing them to progressively smaller amounts until it no longer causes malignant tumors to grow. Then they take that dose, determine the equivalent for humans, and apply what is called a “margin of safety” by declaring that some small fraction of that low dose is safe for people.

The big assumption driving the margin of safety is that a smaller amount of a chemical is less dangerous than a larger amount. (Think of the familiar axiom, “The dose makes the poison.”) But that’s not true for all chemicals, experts say. Some chemicals, such as those that mimic hormones, may actually be more dangerous at lower doses because the human body is exquisitely attuned to respond to minute amounts of natural hormones such as estrogen and testosterone.

And regulators haven’t required testing of mixtures of chemicals at all...Leroy Lowe, president of Canadian nonprofit Getting to Know Cancer and leader of the report published this week by the journal Carcinogenesis. The new report raises questions about whether this approach is adequate...Humans are exposed to about 80,000 man-made chemicals over their lifetimes, experts say. These chemicals are in the foods we eat, the water we drink and the air we breathe. "We live in a chemical soup,” said toxicologist Linda Birnbaum, director of the National Institute of Environmental Health Sciences, who was not involved in the new study.

The research team — a coalition of 174 researchers from 28 countries — set out to determine whether mixtures of these chemicals, at the very tiny concentrations found in the environment, could plausibly trigger the formation of cancerous tumors. They focused on 85 particular chemicals that were impossible to avoid in modern life, that were likely to disturb biological function and were not thought to pose cancer risks at the very low doses that people tend to ingest them.

The researchers scoured the scientific literature to understand how each of these chemicals could affect 10 important processes that are essential to cancer development. Among them: tumor-promoting inflammation, resistance to cell death and the formation of new blood vessels to feed malignant cells. In addition, they categorized whether each of the chemicals exerted biological effects at very low doses to which humans are ubiquitously exposed. (These doses are so small that they tend to be measured in parts per million or parts per billion.)
Of the 85 chemicals researchers examined, 50 were found to affect cancer-causing processes in the body, even at very low doses.

These 50 everyday chemicals included bisphenol A (used in manufacturing plastics), triclosan (often found in hand sanitizer and anti-bacterial soap) and atrazine (a commonly used herbicide). Since each of these chemicals affects different processes that could lead to cancer — bisphenol A makes cells less sensitive to signals to stop reproducing, for example, while atrazine encourages inflammation — it’s plausible that consuming mixtures of these chemicals is riskier than consuming any one individually.

More details about this report. From Science Daily: Cocktail of common chemicals may trigger cancer

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Two studies showing detrimental effects on children from pyrethroids in 2 weeks! The June 3 post was about research linking household pyrethroid exposure to ADHD in children and young teens. The second study found that low level childhood exposures to pyrethroid insecticides was linked to lower scores on an IQ test (Wechsler Intelligence Scale for Children - verbal comprehension and working memory) in 6 year old children. The researchers viewed this as evidence that pyrethroid insecticides may "negatively affect neurocognitive development".

Bottom line: even though pyrethroid pesticides are considered safer than many other pesticides, they still can have undesirable effects on humans, especially developing children. To be safe, use least toxic pest control that uses non-toxic, safe "alternative" or "natural" methods rather than just "spraying a chemical". Another possibility is looking for "organic pest control" or"least-toxic Integrated Pest Management" (IPM) that looks to deal with pest problems with non-toxic methods (which may include sealing holes, heat, caulking, trapping, using sticky traps, and even vacuuming up insects). From Science Daily:

Impact of insecticides on the cognitive development of 6-year-old children

Researchers have provided new evidence of neurotoxicity in humans from pyrethroid insecticides, which are found in a wide variety of products and uses. An increase in the urinary levels of two pyrethroid metabolites (3-PBA and cis-DBCA) in children is associated with a significant decrease in their cognitive performances , particularly verbal comprehension and working memory. This study was carried out on nearly 300 mother and child pairs from the PELAGIE cohort (Brittany).

Pyrethroids constitute a family of insecticides widely used in a variety of sectors: agriculture (various crops), veterinary (antiparasitics) and domestic (lice shampoo, mosquito products). Their mode of action involves blocking neurotransmission in insects, leading to paralysis. Because of their efficacy and relative safety for humans and mammals, they have replaced older compounds (organochlorides, organophosphates, carbamate) considered more toxic.

Exposure of children to pyrethroids is common. It is different to adult exposure, due to the closer proximity of children to ground-level dust (which stores pollutants), more frequent hand-to-mouth contact, lice shampoos, etc. In children, pyrethroids are mainly absorbed via the digestive system, but are also absorbed through the skin. They are rapidly metabolised in the liver, and mainly eliminated in the urine as metabolites within 48 hours.

Pregnancy is also an important period of life for the future health of the child. For this reason, the researchers studied the PELAGIE mother-child cohort established between 2002 and 2006, which monitors 3,500 mother-child pairs. This cohort simultaneously considers exposure to pyrethroid insecticides during fetal life and childhood. A total of 287 women, randomly selected from the PELAGIE cohort and contacted successfully on their child's sixth birthday, agreed to participate in this study.

Two psychologists visited them at home. One assessed the child's neurocognitive performances using the WISC scale (verbal comprehension index, VCI, and working memory index, WMI). The other psychologist characterised the family environment and stimuli that might have had a role on the child's intellectual development, collected a urine sample from the child, and collected dust samples. Exposure to pyrethroid insecticides was estimated by measuring levels of five metabolites (3-PBA, 4-F-3-PBA, cis-DCCA, trans-DCCA and cis-DBCA) in urine from the mother (collected between the 6th and 19th weeks of pregnancy) and from the child (collected on his/her 6th birthday).

Results show that an increase in children's urinary levels of two metabolites (3 PBA and cis-DBCA) was associated with a significant decrease in cognitive performances, whereas no association was observed for the other three metabolites (4-F-3-PBA, cis-DCCA and trans-DCCA). With respect to metabolite concentrations during pregnancy, there was no demonstrable association with neurocognitive scores.

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New noteworthy research links commonly used household pyrethroid pesticides to attention deficit hyperactive disorder (ADHD) in children and young teens, especially boys. Ome drawback was that the results were based on a single urine sample.Since pyrethroids are non-persistent and rapidly metabolized, then looking at numerous samples over time would have provided a more accurate assessment of typical long-term exposure. Given how many households use pyrethroid pesticides and that there are seasonal variations in pesticide use, then it wouldn't be surprising if there are times when pyrethroid exposure is higher and so the link to ADHD may even be stronger than seen in this original study.From Medical Xpress:

Study links exposure to common pesticide with ADHD in boys

A new study links a commonly used household pesticide with attention deficit hyperactivity disorder (ADHD) in children and young teens.The study found an association between pyrethroid pesticide exposure and ADHD, particularly in terms of hyperactivity and impulsivity, rather than inattentiveness. The association was stronger in boys than in girls.

Due to concerns about adverse health consequences, the United States Environmental Protection Agency banned the two most commonly used organophosphate (organic compounds containing phosphorus) pesticides from residential use in 2000-2001. The ban led to the increased use of pyrethroid pesticides, which are now the most commonly used pesticides for residential pest control and public health purposes. They also are used increasingly in agriculture.

Pyrethroids have often been considered a safer choice because they are not as acutely toxic as the banned organophosphates. Animal studies, on the other hand, suggested a heightened vulnerability to the effects of pyrethroid exposure on hyperactivity, impulsivity and abnormalities in the dopamine system in male mice. Dopamine is a neurochemical in the brain thought to be involved in many activities, including those that govern ADHD.

The researchers studied data on 687 children between the ages of 8 and 15. The data came from the 2000-2001 National Health and Nutrition Examination Survey (NHANES),...included a diagnostic interview of children's ADHD symptoms and pyrethroid pesticide biomarkers. Pesticide exposure measurements were collected in a random sample of the urine of half the 8-11 year olds and a third of the 12-15 year olds. ADHD was determined by meeting criteria on the Diagnosic Interview Schedule for Children,...

Boys with detectable urinary 3-PBA, a biomarker of exposure to pyrethroids, were three times as likely to have ADHD compared with those without detectable 3-PBA. Hyperactivity and impulsivity increased by 50 percent for every 10-fold increase in 3-PBA levels in boys. Biomarkers were not associated with increased odds of ADHD diagnosis or symptoms in girls.

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An interesting small study of one family shows how quickly one can eliminate many pesticides from the body by switching to an all organic diet. One Swedish family of 2 adults (aged 40 and 39) and 3 children (aged 12, 10, and 3) who had been eating mainly conventional food were studied.

For the study they only ate conventionally grown food for one week and then they switched to an all organic diet for 2 weeks (fruit, vegetables, meat, fish, etc,). Urine was collected every morning from all family members, and a food diary was kept. Common pesticides and their metabolites were analyzed: atrazine, chlorpyrifos, 2.4-D, pyrethroids, MCPA, chlormequat chloride (CCC) etc.

However, the most commonly used pesticide in the world - glyphosate (Roundup) was not looked at. The results showed that pesticide levels were reduced very quickly once they started eating an all organic diet.

The report also mentioned that currently pesticide standards are only for one pesticide at a time, but people have exposure to many pesticides in daily life (foods, their environment, cleaning supplies, etc) - thus people are exposed to a chemical cocktail that we know very little about about - whether looking at short-term or long-term effects. Article (and video link) from The Sydney Morning Herald:

Family eats organic for just two weeks, removes nearly all pesticides from body

A Swedish family has shown just how quickly an organic diet change can rid the body of pesticides. In a fortnight-long experiment, the family of five - parents Anette and Mats, and kids Vendela, Evelina and Charlie - swapped their conventional diet for an organic one and found that just two weeks of eating an organic diet managed to rid their bodies of most traces of pesticides.

The video explaining the experiment, which was conducted by Swedish supermarket Coop and the Swedish Environmental Research Institute, has been viewed more than a million times on YouTube. 

The researchers measured the levels of plant growth regulators chlormequat chloride, mepiquat, 3-PBA and cleaning agent TCP in urine samples taken from each family member before and after their two weeks of organic eating. Before the experiment, middle child Evelina's urine was showing nearly five nanograms of chlormequat chloride per millilitre. After eating only organic foods for two weeks, the chemical was unable to be detected in her sample. The most profound effects were found in toddler Charlie's samples. Despite his urine before the experiment showing high levels of all four of the chemicals, after the experiment none of the substances were detected.

The original 2015 report Coop Sverige AB, Report number U 5080, from the Swedish Environmental Research Institute: Human exposure to pesticides from food: A Pilot Study  ...continue reading "Eat Organic Foods to Quickly Lower the Pesticide Levels In Your Body"