The pesky cockroach rolled over onto its back, defeated. Its nervous system was completely paralyzed. No longer able to communicate messages through neural pathways, the roach died. Earlier, it had come in contact with the toxic chemical permethrin. Permethrin is present in roach sprays, flea bombs, flea and tick pet shampoos, and other insect control products. If permethrin targets the nervous system of insects, what type of interaction does it have with humans, pets, and the environment? Are there safer ways to combat the pesky roach?
Permethrin is a naturally occurring insecticide derived from chrysanthemum flowers. Pyrethroids are synthetically created chemicals made to mimic permethrin’s ability to kill insects; however, they tend to be more potent and longer lasting in the environment. For simplicity’s sake, we will focus on the pyrethroid class of chemicals, which includes a synthetic version of permethrin.
Humans have a larger and more sophisticated nervous system than insects. While pyrethroids target the human nervous system in the same manner as that of insects, humans can break pyrethroids down much more quickly and effectively than insects. The same holds true for dogs. Cats, on the other hand, have shown particular susceptibility to pyrethroids and are more likely to experience muscle tremors and seizures from high levels of exposure. Consequently, extra care should be taken when using pyrethroids around cats. While pyrethroids often do not enter the water table due to a high degree of bonding to soil substrate, fish that do come in contact with the chemical often face fatal consequences. Concern has also risen over how bees handle the chemical.
Just as different animals face different consequences from pyrethroid exposure, individuals can also be placed on a scale of susceptibility. Each one of us is unique. Due to our distinct mixtures of sensitivities, allergies, and disorders, we will likely have ranging intensities of reaction to chemicals such as pyrethroids. For example, people with nerve damage in their extremities, known as peripheral neuropathy, already have a weakened defense to neurotoxins like pyrethroids and may experience more severe reactions. Consequently, it is difficult to place a blanket statement on whether pyrethroids are safe or not.
The EPA registered permethrin for use in 1979 and re-registered the chemical in 2006. Uncertainty has surrounded whether or not pyrethroids are carcinogenic to humans. The World Health Organization conducted a 1990 meta-analysis on permethrin stating that it was very unlikely to be carcinogenic, whereas a 1991 International Agency for Research on Cancer study was unable to determine whether or not permethrin was carcinogenic. During the 2000s, the EPA has classified permethrin as likely carcinogenic, if consumed.
When you only have one life to live and one family to protect, you can’t afford uncertainty. Anytime you deal with a pesticide, it is imperative to be aware of new updates and regulations on its active ingredients. If a company is trying to sell a product, be sure to use scientific literature to fact check their claims. Technology is constantly changing. When storing chemicals, it is important to mark each bottle with a date of purchase. A general rule is to store chemicals no longer than two years, and then dispose of them properly. Another safety strategy is to investigate less toxic chemicals and natural alternatives, like heat treatments.
The more information you know, the better pest control plan you can make for your unique circumstance. If you feel pesticide companies should have more requirements for informing consumers, consider advocating to reform the Toxic Substances Control Act. The act hasn’t been reformed since its adoption in 1976. You can find out more information from the Environmental Defense Fund here.
No matter what, we hope you find a safe way to deal with that pesky roach. Some have even suggested letting some house geckos lose to deal with the problem (but only if you live in a warm, humid environment)!
Natural Resources Defense Council. http://www.nrdc.org/living/chemicalindex/pyrethroids.asp
National Pesticide Information Center. http://npic.orst.edu/factsheets/PermGen.html
World Health Organization. http://www.tandfonline.com/doi/abs/10.1080/009841097160528
University of Illinois. https://web.extension.illinois.edu/cfiv/homeowners/031025.html
Life Hackery. http://lifehackery.com/2008/07/21/home-2/