Researchers Find Children Exposed to Pyrethroid Insecticides in the Home

(Beyond Pesticides, September 6, 2006)

According to researchers at Emory University and the Centers for Disease Control and Prevention (CDC), residential pesticide use represents the most important risk factor for children’s exposure to pyrethroid insecticides. The study, A Longitudinal Approach to Assessing Urban and Suburban Children’s Exposure to Pyrethroid Pesticides, is published in the September 2006 issue of Environmental Health Perspectives (Vol. 114, No. 9).

The results are part of a larger study examining the impacts of dietary and residential exposure of children to organophosphate (OP) and synthetic pyrethroid pesticides. With the phaseout of most residential uses of the common OP insecticides, chlorpyrifos and diazinon, home use of pyrethroids has increased. Pesticide products containing synthetic pyrethroids are often described by pest control operators and community mosquito management bureaus as safe as chrysanthemum flowers. While pyrethroids are a synthetic version of an extract from the chrysanthemum plant, they were chemically engineered to be more toxic, take longer to breakdown, and are often formulated with synergists, increasing potency and compromising the human body’s ability to detoxify the pesticide. Pyrethroids may affect neurological development, disrupt hormones, induce cancer, and suppress the immune system.

The authors conducted a longitudinal study to assess the exposure of 23 elementary school age children to pyrethroid pesticides, using urinary pyrethroid metabolites as exposure biomarkers. The 15-consecutive-day sampling period was divided into three phases. During phase 1 (days 1¬ø3) and phase 3 (days 9¬ø15), children consumed their normal conventional diets. During phase 2 (days 4¬ø8), organic food items, including fresh fruits and vegetables, juices, processed fruit or vegetables (e.g., salsa), and wheat- or corn-based items (e.g., pasta, cereal, popcorn, or chips), were substituted for the children’s conventional diet. These food items are routinely reported to contain pesticide residues by the U.S. Department of Agriculture (USDA). During the 15 days, urine samples were analyzed for five common pyrethroid metabolites. The researchers also surveyed the children’s parents for residential pesticide use. Comparing metabolites between dietary phases, the researchers saw no apparent trend. However, seven children in families that reported using pyrethroid pesticides had significantly higher metabolite levels than the other children.

Furthermore, children’s ages appear to be significantly associated with pyrethroid exposure, which is likely attributed to the use of pyrethroids around the premises or in the facilities where older children engaged in outdoor activities. The researchers conclude that an organic diet alone is unlikely to dramatically decrease a child’s exposure to pyrethroids the way it does exposure to OP pesticides. Limiting residential use of pyrethroids and preventing children’s contact with treated areas are essential in reducing children’s exposure to these harmful pesticides.