“Natural” insect sprays may be as dangerous to children as lead paint
By Ian Wishart
Insect spray dispensers have become ubiquitous in homes around New Zealand and Australia – we all use them, and ads from various manufacturers saturate our TV screens, particularly over summer.
We’re told the cans contain “natural pyrethrins” – a chemical found in chrysanthemum plants – that help send flies and other insects scurrying for fresh air outside the home.
For the most part, these automatic spray dispensers work well, but like all things that seem too good to be true, researchers in the United States have just discovered a major fly in the ointment, so to speak – many of the dispensers contain a chemical that is as damaging to children’s mental development as licking lead paint on a regular basis.
The first major research study into the safety of automatic spray dispensers has just been completed by scientists at Columbia University. They tested hundreds of pregnant women who had automatic spray dispensers in their homes, and then tested the long term outcomes on their babies’ health.
The study included checking for spray dispensing chemicals in the blood and umbilical blood of the mothers. The women were also given an air-sampling back-pack to wear for 48 hours in the home during the third trimester of their pregnancies, so that scientists could get an accurate sample of what chemicals were in the air in the homes, and then their children were assessed at age three using standard health and IQ tests.
While the study found the pyrethrins themselves were not associated with any health issues, it seems manufacturers have been adding a chemical called piperonyl butoxide, or PBO, to the “natural” sprays to give them more punch. What the researchers found astounded them:
“While the results demonstrate that a significant prenatal exposure to permethrin in personal air and/or plasma was not associated with performance scores for the Bayley Mental Developmental Index or the Psychomotor Developmental Index at 36 months, children who were more highly exposed to PBO in personal air samples (≥4.34 ng/m3) scored 3.9 points lower on the Mental Developmental Index than those with lower exposures.
“This drop in IQ points is similar to that observed in response to lead exposure,” lead researcher Megan Horton of Columbia’s Mailman School of Public Health told journalists. “While perhaps not impacting an individual’s overall function, it is educationally meaningful and could shift the distribution of children in the society who would be in need of early intervention services”.
“Prenatal exposure to PBO seems to have an impact on cognitive rather than motor development, which is quite worrisome because mental development scores are more predictive of school readiness,” added Megan Horton. The official conclusion to the study puts it bluntly:
“Prenatal exposure to piperonyl butoxide was negatively associated with 36-month neurodevelopment.”
What does this mean for families? The researchers caution that because it is the first study of its kind in the world, the results are officially “preliminary” – they need to run more studies to confirm their suspicions.
The drop of nearly 4 IQ points in kids whose mothers used automatic insect spray dispensers containing PBO during pregnancy is sharp, but it’s not known if the impact resulted totally from exposure during pregnancy, or whether ongoing use of the sprays in family areas compounded the damage during early childhood.
PBO’s were detected in 75% of the homes tested in the study.
HERS magazine did a brief check of insect spray dispensers at two large NZ hardware chains and found PBO’s were used in all of the brands on the shelves. The only spray that doesn’t appear to contain them is Mortein’s blue refill can range. PBOs are also found in some headlice treatments.