The pesticides used outside your home find their way inside

Insects and rodents are pretty smart; at least they look like they know what they’re doing.  When the air starts to get chilly in the morning and evenings, they start to move operations indoors–making our homes, their homes!  Pest control companies report that peak season for their services is the summertime, followed by fall.  However, before you call and sign up for services, you’ll want to do more research on what they use.  Even if they are spraying the outside or foundation of your home, it’s likely that the chemical they use is going to affect your indoor air quality–whether you can smell it or not.

Recently, we posted some natural solutions for deterring spiders from entering your home.  In the article we mentioned that some pesticides and herbicides have endocrine and DNA-disrupting effects in pregnancies and even subsequent generations, even when the offspring had no direct contact with the chemicals.  (Environmentally-Caused Disease Crisis? Pesticide Damage to DNA Found ‘Programmed’ Into Future Generations)  One of the chemicals mentioned in this reference is glyphosate, also known by its brand name RoundUp.  We all know RoundUp is meant to be used outdoors on weeds…so why does it show up in the urine of 93 percent of a group of pregnant women in a Midwest pregnancy clinic?  According to previous studies, the likely primary sources of glyphosate exposure was the diet. For example, the European Food Safety Authority (EFSA) database lists soybeans, corn, barley, lentils, linseed, mustard seed, oats, sorghum, wheat, coffee beans, tea, beet root, and mushroom as crops with glyphosate residues.  In turn, the levels of glyphosate detected in the urine correlated with shorter pregnancies.  

Similarly, the most popular termite control treatment in the US, Termidor, has the active ingredient Fipronil.  A U.S. EPA study conducted between 2005-2006 found fipronil residues (on floor wipes) in approximately 40% of homes studied.  This is because even though Termidor is rated for outdoor use (or in wall voids), it can be easily tracked into the home, and it’s also an active ingredient in the topical flea treatment Frontline for cats and dogs.  Fipronil may alter the normal functioning of the endocrine system and cause adverse reproductive effects and disrupt thyroid function.  Disturbingly, some of the metabolites (breakdown products) of Fipronil are 6-10 times more acutely toxic and persistent than Fipronil itself!  (ChemicalWatch Factsheet: Fipronil)  Another 2009 study measured fipronil, fipronil sulfide, and desulfinyl fipronil concentrations in indoor and outdoor dust from 24 residences in Austin, Texas, where at least one of these three fipronil compounds was detected in every sample. Fipronil accounted for most of the total fipronil (T-fipronil; fipronil+desulfinyl fipronil+fipronil sulfide), followed by desulfinyl fipronil and fipronil sulfide. Nineteen of 24 samples of indoor dust had T-fipronil concentrations less than 270 g/kg; the remaining five had concentrations from 1320 to 14,200 g/kg. All three of the residences with a dog on which a flea-control product containing fipronil was used were among the five residences with elevated fipronil concentrations. (Fipronil and its degradates in indoor and outdoor dust)  If you don’t have a pet that is treated with Frontline, and Fipronil is only supposed to be used outdoors, how does it get inside?  

1. It’s used improperly by the pesticide company. Some products containing fipronil, such as Fipronil-Plus-C, are labeled for indoor use as spot, crack, or void treatments for pests like roaches. They are not intended for broad-surface spraying.

2. It’s tracked inside by humans or pets.

Moving on to another popular insecticide, Pyrethrin is found in the dried flowers of the chrysanthemum cinerariifolium plant, also known as the Dalmatian daisy.  However, retail and commercial pesticides use synthetic pyrethroids, which are designed to be more toxic with longer breakdown times, and are often formulated with synergists, increasing potency and compromising the human body’s ability to detoxify the pesticide.  Many pyrethroids have also been linked to disruption of the endocrine system, which can adversely affect reproduction and sexual development, interfere with the immune system and increase chances of breast cancer. (ChemicalWatch FactSheet: Synthetic Pyrethroids)  In the same study of residues found on floors of American homes, permethrin (a synthetic pyrethroid) was the most common, found in 89% of homes.  This study was conducted on single family homes.  However, urban multiunit housing is considered to have an even higher prevalence of insecticide use due to higher rates of pest infestation.  A previous study showed that rates of surface loading on the kitchen floors of 42 apartments in urban public housing in Boston, Massachusetts showed that these residues were found in magnitude of 3−40 times greater than single family homes! (American Healthy Homes Survey: A National Study of Residential Pesticides Measured from Floor Wipes)  In a 2001 study of surface loadings of insecticides in child care centers in both commercial buildings and residential dwellings, synthetic pyrethroids were the second most common pesticide detected.  

There’s no question that these pesticides are effective at killing insects, and can stick around a long time in soil (and food) due to their chemical structure and synergist additives.  However, this means that, even though most are meant to be applied outdoors, they also stick around a long time when they find their way indoors.  Children are at particular health risk given their more frequent contact with flooring, as well as hand to mouth activity.  The question is, do homeowners (especially those with children) consider the pesticides they use to be possibly more dangerous than the insects they are repelling?  For sure, homes in certain climates need to be protected from termites, or they will be prematurely destroyed.  Likewise, in multiunit housing, pest treatments are more frequent to keep insects such as ants and cockroaches from taking over, to protect most of the tenants from other tenants that don't have sanitary practices.  

Thankfully, though, there are a lot of ways that you can reduce your and your children' s exposure to pesticides.  For the full recommendations, check out this helpful pamphlet: Reducing Residential Indoor Exposure to Pesticides: a Toolkit for Practitioners

• Prevention is the best medicine: stop “taking them home” and “tracking them in”.

• “Take home” means taking the pesticides in the home on your hands and clothing.  In order to intercept this, if you are a farmer or use pesticides outside, you’ll need to plan ahead and have a place outside the home to take off your clothing and don clean clothing (taking an outdoor shower would be ideal!)  Designating an area of your garage or workshop for this is a good idea.  

• “Take home” also includes removing gloves (try not to touch the outside as you do so) and wash your hands with soap and water before going inside.

• “Tracking in” pesticides is probably the most common way to bring them inside.  Even city dwellers who don’t apply pesticides themselves, do this when they walk through the park or walk their dogs.  So, taking off your shoes at the entrance of your home is the best practice.  If you have a pet this is a lot more difficult, as bathing pets doesn’t happen as frequently as we like (!), so try to keep pets and children away from treated turf or garden. Wash exposed pets frequently in the first week after lawn or garden treatment.

• Remain indoors with windows closed when the neighborhood is being sprayed. 

• Your number one weapon in removing residues contained in dust, is a HEPA vacuum.  Use it regularly on bare floors, and with a rotating brush attachment on carpets.  Steam cleaning carpets also helps: in a study of 10 farmworker homes, steam cleaning the carpets essentially reduced the amounts to non-detectable levels. (Effectiveness of cleaning practices in removing pesticides from home environments)

• Wet cleaning can also be effective in removing residues, but it depends on the surface (porous, semi-porous or non-porous) and the chemical.  For example, according to the National Pesticide Information Center (NPIC), linoleum is a “semi-porous” surface and one study found that double mopping with detergent, followed by a rinse on a linoleum floor had no effect on the level of pesticide residue in a cotton swab test, presumably because the pesticide had absorbed into the surface. (Cleaning Up After Indoor Pesticide Misuse)  In extreme cases of mis- or overapplication of pesticides inside the home, sometimes “sealing them in” with polyurethane on hard surfaces like flooring, is the only way to prevent continuous exposure to them.  This page on cleaning using non-toxic cleaners/techniques is a great resource.  

• If you or someone else in the family is asthmatic or chemically sensitive, be very cautious when using pesticides.  For example, some pet shampoos contain pyrethrins, and there have been at least two case reports of known asthmatics who died shortly after treating their dog with a pyrethrin-based pet shampoo to treat ticks. Both cases were asymptomatic at the time of exposure but died of severe acute asthmatic attacks. (Reducing Residential Indoor Exposure to Pesticides: a Toolkit for Practitioners)

• Integrated pest management (IPM) is based on the concept that pests can be controlled by removing their basic survival elements: air, moisture, food, and shelter. IPM is a combination of measures to prevent, manage, and treat pest infestations and consists of several elements, such as closing entryways, removing food sources, monitoring pest populations, and using the least toxic pesticides or mode of delivery. It is important that the elements be practiced together to reach a maximum effect.  Less toxic pesticides or modes include traps and gels, which are not easily transferred to pets and humans.

Dr. Paul Winchester, the pediatrician who researched pesticides in pregnant mothers in the first part of this article, brought up an ancient expression in comparison to this modern health crisis:  “Even in the Bible, there is the saying, ‘the sins of the father are visited upon his offspring.’  Well, it turns out that they are.”

Photo by Annie Spratt on Unsplash