You are here: Home Blog 2010 July 22 Insecticides on Home Floors:Results from the American Healthy Homes Survey

Insecticides on Home Floors:Results from the American Healthy Homes Survey

by aseligmann — last modified Jul 22, 2010 12:00 AM
Filed Under:

Floors in most American homes are contaminated with insecticides, according to the American Healthy Homes Survey, conducted by the Environmental Protection Agency (EPA) and the Department of Housing and Urban Development (HUD).* The EPA sought to collect nationally representative data on current levels of insecticides that people might be exposed to in their homes. Knowledge of home exposure combined with exposure from other sources such as food, can help EPA assess human health risks, especially for children.*

Floors in most American homes are contaminated with insecticides, according to the American Healthy Homes Survey, conducted by the Environmental Protection Agency (EPA) and the Department of Housing and Urban Development (HUD).* The EPA sought to collect nationally representative data on current levels of insecticides that people might be exposed to in their homes. Knowledge of home exposure combined with exposure from other sources such as food, can help EPA assess human health risks, especially for children.*

Trained field technicians tested samples from 500 residences across the country from June 2005 to March 2006. They collected samples from kitchen floors using isopropanol wetted wipes. The samples showed traces of a variety of insecticides, including chemicals that have long been banned.

The common indoor and outdoor insecticide, permethrin, was detected in 89 percent of homes. Fipronil, used in Frontline flea products and other pest products, showed up on 40 percent of tested floors.

Chlorpyrifos (in Dursban) showed up in 78 percent of homes. This is notable because EPA halted the sale of chlorpyrifos products intended for home use more than three years before the study began. DDT, banned in 1972, was found in 41 percent of homes.

These results are not surprising. EPA estimates for 2000 and 2001 showed that about 78 million U.S households used pesticides, spending almost 1.3 billion dollars.

Pyrethroid insecticides are currently the most popular products for residential pest control. In this study, two natural pyrethrins (found in pyrethrum) were rarely detected in homes (5 percent or lower) reflecting the rapid breakdown of these chemicals. Synthetic pyrethroids, developed to be longer lasting, were detected much more frequently. The top two synthetic pyrethroids were permethrin, found in 89 percent of homes, and cypermethrin in 46 percent. These two chemicals also had the highest average concentrations of all the chemicals tested, probably reflecting accumulation over time.

Researchers also tested for residues of piperonyl butoxide, which is often combined with pyrethrins and some synthetic pyrethroids to improve product effectiveness. Piperonyl butoxide was found in 52 percent of homes while the pyrethroids resmethrin, allethrin, and tetramethrin were found in 4, 7, and 15 percent of homes, respectively. These numbers suggest that piperonyl butoxide breaks down more slowly than these pyrethroids.

Fipronil, a relatively new insecticide, was detected in 40 percent of homes. Residential uses of fipronil include Frontline flea products, roach and ant baits, and the termiticide, Termidor.

Before the adoption of pyrethroids, organophosphate insecticides were commonly used in residential settings. In recent years, the EPA restricted home use of two popular organophosphates, chlorpyrifos and diazinon, to protect children´┐Ż health and the environment.

Although the sale of residential chlorpyrifos products ended in 2001, residues of chlorpyrifos were detected in 78 percent of homes more than three years later. Average concentrations of chlorpyrifos ranked third after permethrin and cypermethrin. Researchers suggested that these elevated levels might be associated with phased out termite treatments but more likely result from the persistence of chlorpyrifos in the indoor environment.

Diazinon was found in 35 percent of homes at low levels. Sales of the very popular diazinon lawn products had ceased only six months before the start of the study. Testing for a third organophosphate that is still used in garden products, malathion, showed contamination inside 15 percent of homes.

The long banned DDT turned up in 41 percent of all homes sampled while chlordane, banned for use as a termiticide in 1988, was found in 74 percent of residences. Average concentrations of both chemicals (geometric mean) were uniformly low. DDT and chlordane belong to the class of chemicals called organochlorines that persist in the environment for many years.

Researchers concluded that the very frequent detections of chlordane, chlorpyrifos, and permethrin suggest that these chemicals are widespread in living areas, showing that popular use, past and present, has an important influence on contamination in homes.

* The American Healthy Homes Survey also looked at lead and allergens, including mold. Survey results for other parts of the study will be published separately.

 


Source:

Stout, D.M. et al. 2009.
merican Healthy Homes Survey: A national study of residential pesticides measured from floor wipes.
Environmental Science and Technology (Article ASAP published online on May 9, 2009 ahead of print) DOI 10.1021/es8030243
Abstract available at: http://pubs.acs.org/doi/abs/10.1021/es8030243