Prenatal Exposure to Widely Used Pesticide Ingredient Linked to Childhood Cough

(Beyond Pesticides, September 12, 2012) Expectant mothers exposed to the pesticide additive piperonyl butoxide (PBO), widely used in synthetic prethroid insecticides and those ending in “thrin” (popular in mosquito spray programs), during pregnancy pass to their children a heightened risk of noninfectious cough at ages 5 and 6, according to researchers at the Columbia Center for Children’s Environmental Health (CCCEH). These findings support the premise that children’s respiratory system is susceptible to damage from toxic exposures during the prenatal period.

Researchers outfitted 224 expectant mothers with air monitors during their third trimester of pregnancy and measured the levels of PBO and permethrin in the air around them. Then, once the children were 5 and 6, the same two chemicals were measured from air samples collected inside their home. Results showed that children exposed to PBO in the womb were at increased odds of reporting cough unrelated to cold or flu. Researchers found no correlation between prenatal or childhood exposure to permethrin, however they pointed out that this may be because PBO is easier to measure in air samples than permethrin. Coauthor of the study, “Prenatal exposure to pesticide ingredient piperonyl butoxide and childhood cough in an urban cohort,” Dr. Rachel Miller, indicates “these exposures may be a factor in a very common problem for children‚ cough.”

PBO is a highly toxic substance that can cause a range of short- and long-term effects, including cancer and adverse impacts on liver function and the nervous system, is one of the most commonly used synergists in pesticide products. Synergists are chemicals added to pesticide formulations to enhance the toxicity of the active ingredients. PBO is frequently used, especially in aerosol products and mosquito sprays, to increase the potency of pyrethrin and synthetic pyrethroids, as well as other types of insecticides. Products generally contain between five to ten times as much PBO as the pesticide product’s active ingredient.

Permethrin belongs to the chemical class of synthetic pyrethroid pesticides, which are chemically formulated versions of the natural-based pesticide pyrethrum, made from extracts from plants in the chrysanthemum family. Due in part to the prevalent myth that it is “natural,” synthetic pyrethroids are a widely used class of insecticides. Unfortunately, they have not been widely evaluated for developmental toxicity, despite the fact that they are designed to be more toxic and longer lasting than pyrethrum, and therefore more potent to insects and pose elevated risks to humans. Permethrin is a possible human carcinogen and endocrine disruptor, and exposure can cause immunotoxicity, and reproductive effects.

Beyond Pesticides has long documented the increased risk pesticides pose to young children and pregnant mothers. Numerous studies have reported birth defects and developmental problems when fetuses and infants are exposed to pesticides. This current research follows a 2011 study that links high levels of prenatal exposure to pyrethroid pesticides containing PBO with a threefold increase in developmental disabilities compared to children with lower exposure levels. Philip Landrigan, M.D., pediatrics professor at New York’s Mount Sinai School of Medicine indicates that those levels are similar to the intelligence loss caused by lead. A study in June found the chemical naphthalene, an active ingredient in mothballs and a common air pollutant, is linked to chromosomal aberrations in children that put them at increased risk of cancer as adults.

Given such compelling research on the risks associated with childhood exposure to pesticides, it is concerning how prevalent and persistent pesticides are in our living environment, and particularly in our homes. In 2008, researchers at Columbia’s CCCEH found PBO in 75% of homes occupied by pregnant women in inner-city New York. A 2009 study from the U.S Environmental Protection Agency (EPA) and U.S Department of Housing and Urban Development (HUD) found the pesticide permethrin in 89% of the 500 homes randomly selected for sampling. Another study conducted by the School of Medicine at The University of Texas San Antonio earlier this year found at least five pesticides in the air of 60% of 29 homes occupied by pregnant Hispanic women. Just earlier this week, results from 11 Oregon schools whose drinking water was tested for pesticides revealed a myriad of different chemicals in various combinations at each school.

In order to reduce exposure to these chemicals, expectant mothers should choose organic foods. Families should also stop using pesticides in and around the home and advocate banning cosmetic pesticides in their communities. For more information on what you can do, see our materials for new parents with tips on food choices and safer pest management, specifically designed for new moms and dads.

Source (including photo credit): Columbia Mailman School of Public Health Press Release