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Pesticides are harmful to developing brains, especially during pregnancy. A number of studies have already found that higher exposure to organophosphate pesticides during pregnancy is linked to poorer cognitive functioning and behavior problems in children. A recent University of California study actually looked at the brain activity in 95 teenagers while they were doing a number of mental tasks. Using advanced brain imaging, they found altered brain activity in those teens who had the highest organophosphate pesticide exposure prenatally. These teenagers live in Salinas Valley, California - an agricultural area with many farms.

The researchers point out that "Over 800 million pounds of pesticide active ingredients are applied in the United States each year, with organophosphates (OPs) the most commonly applied class of insecticides. Exposure to OP pesticides, which are endocrine-disrupting compounds, is widespread in the US population, including among pregnant women and children." [PLEASE NOTE: Conventional farming uses organophosphates. Organic farming does not allow the use of organophosphates.]

The main way people get exposed to organophosphate pesticides is diet - especially pesticide residues on fruits and vegetables. Also, if people live near farms where such pesticides are used, or live with a person who works on a farm. They bring home the pesticides on their clothes. People also breathe breathe in pesticides when they are applied on nearby farms or properties due to pesticide drift.

Chlorpyrifos is one example of an organophosphate pesticide. It is considered so dangerous to the developing fetus and children (lower IQs, neurological effects, behavioral effects) that the EPA was going to ban it in the United States. However, the Trump administration overruled the ban (chemical/pesticide lobbyists at work!). Since then, several states (NY, Hawaii, California) have enacted legislation to ban all use of chlorpyrifos in those states, but it will take several years for the bans to become fully in effect.

From Science Daily: Prenatal pesticide exposure linked to changes in teen's brain activity   ...continue reading "Certain Pesticides Linked to Altered Brain Activity In Teenagers"

 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. 

The researchers of this study looked at proximity to farm fields (how close a pregnant woman lives to a farm) and certain farm pesticides and found a link between exposure to farm pesticides during pregnancy and having a child with autism. But too bad they didn't also include pesticide exposures from homes (for pest control), gardens, and yards which would have given a more accurate measure of total exposure. However, it's a start. From Science Daily:

Association found between maternal exposure to agricultural pesticides and autism

Pregnant women who lived in close proximity to fields and farms where chemical pesticides were applied experienced a two-thirds increased risk of having a child with autism spectrum disorder or other developmental delay, a study by researchers with the UC Davis MIND Institute has found. The associations were stronger when the exposures occurred during the second and third trimesters of the women's pregnancies.

The large, multisite California-based study examined associations between specific classes of pesticides, including organophosphates, pyrethroids and carbamates, applied during the study participants' pregnancies and later diagnoses of autism and developmental delay in their offspring. It is published online in Environmental Health Perspectives. "... the message is very clear: Women who are pregnant should take special care to avoid contact with agricultural chemicals whenever possible."

California is the top agricultural producing state in the nation, grossing $38 billion in revenue from farm crops in 2010. Statewide, approximately 200 million pounds of active pesticides are applied each year, most of it in the Central Valley, north to the Sacramento Valley and south to the Imperial Valley on the California-Mexico border. While pesticides are critical for the modern agriculture industry, certain commonly used pesticides are neurotoxic and may pose threats to brain development during gestation, potentially resulting in developmental delay or autism.

The study was conducted by examining commercial pesticide application using the California Pesticide Use Report and linking the data to the residential addresses of approximately 1,000 participants in the Northern California-based Childhood Risk of Autism from Genetics and the Environment (CHARGE) Study. The study includes families with children between 2 and 5 diagnosed with autism or developmental delay or with typical development. "We mapped where our study participants' lived during pregnancy and around the time of birth. In California, pesticide applicators must report what they're applying, where they're applying it, dates when the applications were made and how much was applied," Hertz-Picciotto said. "What we saw were several classes of pesticides more commonly applied near residences of mothers whose children developed autism or had delayed cognitive or other skills."

Organophosphates applied over the course of pregnancy were associated with an elevated risk of autism spectrum disorder, particularly for chlorpyrifos applications in the second trimester. Pyrethroids were moderately associated with autism spectrum disorder immediately prior to conception and in the third trimester. Carbamates applied during pregnancy were associated with developmental delay.

Exposures to insecticides for those living near agricultural areas may be problematic, especially during gestation, because the developing fetal brain may be more vulnerable than it is in adults. Because these pesticides are neurotoxic, in utero exposures during early development may distort the complex processes of structural development and neuronal signaling, producing alterations to the excitation and inhibition mechanisms that govern mood, learning, social interactions and behavior.