Children Exposed to Increasing Concentrations of Pyrethroid Insecticides

Washington, DC–(ENEWSPF)–February 10, 2014.  A recent study has found that exposure to pyrethroids is increasing among children and adults. The study also finds that children are still widely exposure to chlorpyrifos, an organophosphate chemical that has been banned for household use for over 12 years. This is not the first study to find high concentrations of pyrethroids in residential, but it may be the first to evaluate correlations between pesticide dust concentration and concentration of pesticides in children’s urine.pregnant-market-coloradjust

The study, Urinary Pyrethroid and Chlorpyrifos Metabolite Concentrations in Northern California Families and Their Relationship to Indoor Residential Insecticide Levels, conducted by researchers at the University of California, Davis, analyzed urine samples from 90 adults, 83 children, and 88 floor wipe samples from participants’ kitchen floors. The participants were 90 northern Californian families who had children born between 2000 and 2005, with the samples collected from 2007-2009.  These samples were analyzed for concentrations of pyrethroids, pyrethroid metabolites, chlorpyrifos, and chlorpyrifos metabolites. The study found pyrethroid metabolites in 63 percent of all urine samples with concentrations twice as high as levels reported in a national 2001-2002 study.

In children, higher concentrations of pyrethroids found in floor wipes were associated with higher urine levels. This suggests that the indoor residential environment is a more important route of exposure to pyrethroids than dietary ingestion for children. Children also often play on the floor and put their hands in their mouths, which could lead to greater exposure from household dust.

The study also finds that levels of a breakdown product of chlorpyrifos are on average 21 percent lower in the children who participated in the new study than in the nationwide study six years earlier. The researchers attribute this decline to the ban of chlopryrifos products inside homes. However, even at lower concentrations, traces were still found in 65 percent of participant’s urine and in 99 percent of floor wipes. As evident from this study, chlorpyrifos does not breakdown in residential setting quickly and has been detected for up to eight years after its use in homes for termites.

Growing concentrations of pyrethroids indoors clearly create an unhealthy environment for children. High levels of pyrethroids may cause significant toxicity and health effects, including acute neurotoxic effects, immunotoxic effects, and endocrine disruption. Pyrethroids are also a possible human carcinogen, with associations seen between exposure and cutaneous melanoma, as well as childhood leukemia. The impacts of chronic low or moderate level of pyrethroid exposure in general and on children have not been well studied.

Chlorpyrifos exposure is also incredibly harmful to children. Exposure to chlorpyrifos has been found to disrupt endocrine regulation, has been associated with negative impacts of the neurodevelopment of children, and can cause cholinesterase inhibition in humans. In agricultural settings, chlorpyrifos vapor may be emitted from treated fields at levels resulting in exposure to children and others who live, work, attend school, or spend time nearby. In some circumstances, these bystanders may be exposed to chlorpyrifos and/or the transformation product chlorpyrifos-oxon at concentrations that could cause adverse effects.

This is not the first study to indicate homes can be a high pesticide exposure setting. A  recent study found that among New Yorkers who were 20 to 59 years old in 2004 the highest exposed group had between two and six times more organophosphates in their urine than the highest exposed group in a national study. They also had between 1.7 and 2.4 times more pyrethroids than the nationwide group. Researchers also sought to identify some of the demographic and cultural characteristics that predict the higher exposures. They found that overall, Hispanics and blacks, older residents, and people who had pesticides professionally applied recently in their home had higher levels of organophosphates.

High concentrations of pyrethroids have also been found in environmental settings.  A 2008 survey found pyrethroid contamination in 100 percent of urban streams sampled in California. Researchers also find pyrethroid residues in California streams at relatively low concentrations (10-20 parts per trillion) in river and creek sediments that are toxic to bottom dwelling fish. Other studies find pyrethroids present in effluent from sewage treatment plants at concentrations just high enough to be toxic to sensitive aquatic organisms.

Most people are unaware that they, or their children, carry chemical compounds in their bodies. Chemical ‘body burden’ refers to the accumulation of synthetic chemicals found in pesticides, cosmetics, industrial solvents, heavy metals in our bodies. For more information, see Beyond Pesticides’ Body Burden entry in the Pesticide Induced Diseases Database (PIDD).

All unattributed positions and opinions in this piece are those of Beyond Pesticides.

Sources: Environmental Health News, http://www.beyondpesticides.org