WISE TO KEEP YOUR ‘RUBBER’ DUCKIES CLEAN
Because of my interest in quackery, I collect ducks. Only the inanimate variety, of course. So naturally I was drawn to recent headlines in numerous newspapers and blogs along the lines of “Your cute rubber duck may be a haven for bacteria,” and “Rubber duckies not as squeaky clean as you might think.” I was pretty sure they would not really be talking about rubber ducks since the ubiquitous yellow duckies are made either of polyvinyl chloride (PVC) or polyethylene. Indeed, the scientific paper that was referenced in the articles entitled “Ugly ducklings — the dark side of plastic materials in contact with potable water,” and clearly did not deal with “rubber ducks.”
Originally, way back in the middle of the 19th century, after Charles Goodyear’s discovery of vulcanized rubber, bath toys made of rubber did make an appearance. They weren’t very popular, because they did not float. Then, sometime in the 1950s, manufacturers replaced rubber with polyvinyl chloride, and the rest, as they say is history. Ducks made of PVC are buoyant, are easily dyed, and can be made squishy by the incorporation of plasticizers. Some of these, the phthalates, are controversial because of their hormone-like properties.
The popularity of the yellow ducks really took off in 1970 when Ernie on Sesame Street sang about his playmate, the “rubber duckie” that made “bath time lots of fun” and was his “very best friend.” That “best friend” is on the verge of being shunned because of the findings by Swiss researchers that the popular bath toys can become contaminated with bacteria on the inside and can potentially cause infections by squirting out contaminated water.
What prompted scientists to carry out the autopsies on the poor duckies that revealed the presence of biofilms on their insides? Taking up the scalpel seemed justified because a number of parents had been blogging about discoloured water being squirted out of bath toys, and a couple of papers in the scientific literature had already suggested that bath toys can be subject to bacterial contamination. In one case, an outbreak of infection in a pediatric hospital was linked to shared bath toys.
“A city for microbes,” is the way a biofilm has been described. That “city” is constructed of microbial cells glued to each other and bound to a surface by a mix of polysaccharides, proteins and nucleic acids exuded by the cells. The formation of biofilms is facilitated by warm, moist environments, such as found in showers, sewage pipes, catheters and, as we now have learned, the insides of bath toys. Just to be clear, not all the bath toys examined were ducks. There were alligators, mice, elephants, starfish, boats and footballs, so duckies are not the only creatures that should stand accused of crimes in the bathtub. Although real rubber duckies can still be found, the toys in this study were all plastic. I know this because the paper actually included colour photos of the subjects. Believe me, I know my ducks, and these are all PVC or polyethylene.
The Swiss researchers gathered 19 used bath toys and also purchased brand new ones that were bathed every second day over a period of 11 weeks, half in clean water and half in water that had been used for bathing. All of the toys developed biofilms, with the dirty water controls showing the most bacterial cells per square centimetre of surface. Soap residues, skin secretions and chemicals leaching out of the plastic are believed to acts as nutrients for microbes, leading to the formation of biofilms.
What are we to make of all this? Remember that we do not live in a sterile environment, and that we are exposed to numerous microorganisms all the time. And such exposure is not necessarily a problem. After all, there is much discussion these days in scientific circles about our microbiome, and how exposure to microbes early in life may train the immune system to react only to real dangers and thereby reduce allergies that are basically a result of immune reactions to substances that do not actually pose a risk.
I don’t think that duckies should be banished from the bathroom, but they should be kept clean. Many can be given a bath in dilute bleach or even be put in a dishwasher. Remember also that the “problem” occurs when water gets inside. There are many ducks that are totally sealed. You may not be able to use them as water pistols, but you don’t have to worry about biofilms. And as far as the notorious phthalates leaching out, and possibly affecting babies, well that worry is also gone. The problematic phthalates have been replaced by other plasticizers.
As far as my duckies go, they never go near water. They sit on my shelves quietly serving as a constant reminder of the need to silence the quacks.