Don’t Lick the DDT Wallpaper | A Day at the Science History Institute
Don’t Lick the Wallpaper! That’s the warning posted near an exhibit of DDT-impregnated wallpaper that used to be sold specifically for the bedrooms of children back in 1946!
Imagine my surprise as I wandered through the Science History Institute on Chestnut Street today and stumbled across a whole gaggle of toxicology related stuff! They have an online catalogue of really cool items too.
DDT is dichlorodiphenyltrichloroethane, an organochlorine molecule developed in 1874 and used as an insecticide in 1939 – the guy that discovered its insecticidal activity won the Nobel Prize in Physiology or Medicine because DDT was demonstrated to be remarkably effective in suppressing malaria and typhus among American servicemen in endemic areas during WWII.
They don’t impregnate children’s wallpaper with DDT anymore – it was banned in 1972 thanks in part to “Silent Spring” by Rachel Carson – a fairly controversial book documenting the persistent and destructive effects of DDT on the environment (there is a first edition volume of the book in the Science History Institute). My guess is that nobody actually got sick by licking the DDT wallpaper (although a human being CAN and WILL ingest DDT if they touch a DDT-impregnated object and then put their fingers in the mouth – like little kids do all the time), but there was some other problem with it. Maybe it had a weird smell or something.
The poster is an advertisement that states “Trimz DDT children’s room wallpaper kills flies, mosquito’s and ants on contact.” and “So convenient, so safe because the DDT is fixed to the paper. It can’t rub off!” and “Tested and commended by Parents Magazine.”
Parents Magazine?! What about the FDA? Who cares about what Parents Magazine has to say?
So suppose a little kid were to start licking the DDT-flavored wallpaper and becomes symptomatic from it? What might we expect to see?
In insects, DDT opens sodium ion channels in neural cells causing them to fire spontaneously, which leads to spasms and eventual death. Mammalian neurons, despite having sodium channels, aren’t affected the same way that insect neurons are. In fact there is very little evidence of severe toxicity of DDT to mammals, although it is classified as “moderately toxic” by the US National Toxicology Program and “moderately hazardous” by WHO.
People are most likely to be exposed to DDT from foods, including meat, fish, and dairy products. DDT can be absorbed by eating, breathing, or touching products contaminated with DDT (which is probably why the DDT wallpaper idea was a bad one). In the body, DDT is converted into several breakdown products called metabolites, including the metabolite dichlorodiphenyldichloroethene (DDE). DDT and DDE are stored in the body’s fatty tissues. In pregnant women, DDT and DDE can be passed to the fetus. Both chemicals are found in breast milk, resulting in exposure to nursing infants.
Acute human exposure data and animal studies reveal that DDT can affect the nervous system, liver and kidney. The real problem, however, is the fact that DDT itself along with the breakdown products (DDE) hang around in the body’s fat for a really long time and that might be a risk factor for the development of cancer. Increased tumor production in the liver and lung has been observed in test animals. An association with pancreatic cancer was suggested in humans in one study.
With the rise of mosquito-born illnesses like Zika and Chikungunya, there has been a call for renewed spraying with DDT despite the clear evidence of harm to birds (it causes their eggshells to become thin and fragile).
Besides the DDT wallpaper there are alot of other cool exhibits at the Science History Institute. Admission is free and you can see all the exhibits in an hour. The Science History Institute is attached to a conference center owned by the DuPont company. The current exhibit highlights the history of chemistry and there is a special exhibit of the Art of Alchemy – lots of beautiful paintings exploring the subject of alchemy.