Pathogens: Researchers find tons of dangerous germs in rubber ducks
The colorful squeaky duck is a must in many bathrooms. Many a child would not like to go into the tub without the toys. But dangers lurk in the plastic animals. Researchers found tons of germs in the bath toy, some of which can trigger dangerous infections.
Diverse bacterial cultures in rubber ducks
For many children they make bathing a pleasure: small yellow ducks or sometimes a poison green crocodile. However, a recent study has shown that bath toys are often full of dangerous germs. The researchers from Switzerland and the USA found fungi and bacteria in the plastic toys, which could sometimes cause ear, eye and intestinal infections in the children. In addition to the plastic material, the bathers themselves help to ensure that diverse bacterial cultures can grow up in the ducklings.
Children often splash brown broth on their faces
It is usually warm and humid in bathrooms. These are ideal conditions for the growth of biofilms from bacteria and fungi, for example on shower curtains or behind boxes.
This applies in particular to rubber ducks and other toys that are used when bathing. Because inside the soft little animals, lush carpets of bacteria and fungi can grow.
When a child squeezes their toys together, it is not uncommon for a brown broth to spurt out of it.
A group of researchers from Eawag (Swiss Federal Institute for Water Supply, Wastewater Treatment and Water Protection), the Swiss Federal Institute of Technology (ETH) Zurich and Illinois University (USA) have now investigated which factors promote this growth and which types of microorganisms are present .
The results were recently published in the specialist journal "NPJ Biofilms and Microbiomes".
Potentially pathogenic bacteria in 80 percent of the ducklings
The scientists have used bathing toys and characterized the biofilms of bacteria and fungi on the inside, Eawag reports.
At the same time, tests were also carried out with new rubber ducks. For eleven weeks, the researchers exposed these to conditions that would be realistic in a household - some as a control group only in clean drinking water and some in the bathing water used, including factors such as soap residues, dirt and sweat, but also bacteria from the human body.
Then all ducklings were cut open in the laboratory and examined. "The results do not sound appetizing," says the message. Between five million and 75 million cells per square centimeter bustled on the plastic surfaces.
Especially in the bath ducks used under real conditions but also between the control groups there were big differences in the composition of the biofilm communities.
Various fungi were found on 60 percent of the control ducks used in real life and on all control ducks used in dirty water.
In 80 percent of all ducklings, the researchers found representatives of potentially disease-causing bacteria, including Legionella or the stick bacteria Pseudomonas aeruginosa known as stubborn hospital germs.
Bathers also bring dirt into the tub
Then the scientists investigated the causes of the abundant biofilms: first, they examined the tap water. As a rule, this has such low nutrient concentrations that bacteria can only grow minimally.
But the ducklings themselves offer a source of nutrients. Because from the soft plastic material - often low quality polymers - a lot of organic carbon is released.
When bathing, other important nutrients such as nitrogen and phosphorus, but also additional bacteria, get into the tub, for example from the body of the bathers, through brought dirt or from care products such as shampoos and creams.
In this country too, unlawful high amounts of various pollutants were found in water toys such as rubber ducks in the past.
For example, TÜV Rheinland reported findings of so-called phthalate plasticizers, which, according to the experts, are suspected of "having a hormonal effect and being carcinogenic".
In addition, some products had too high levels of toxic polycyclic aromatic hydrocarbons (PAHs), which were also suspected of causing cancer.
Germs can cause inflammation and infections
The main author of the current study, microbiologist Lisa Neu, deals with her doctoral thesis - not only on the example of rubber ducks - with how biofilms form on plastic and how the materials influence microbial processes in drinking water.
Her supervisor, Frederik Hammes, is not astonished by the results: "There are many forums and blogs on the internet about dirty rubber ducks, they have hardly been examined scientifically."
The toys are extremely exciting research objects, "because they form the interface between drinking water, plastics, external pollution and vulnerable end users," says Hammes.
With the vulnerable or sensitive users, the expert responds to the (small) children who like to splash themselves with the broth from the ducklings.
"This can strengthen the immune system. Then it's positive, ”says the researcher,“ but it can also lead to eye and ear infections or gastrointestinal infections. ”
So better no more bath ducks in the tub? Extensive cleaning after each use? Or, as recommended on the Internet, stop spraying fun and seal the hole before the first use?
Hammes sees another way: Stricter regulations for the polymers used for the ducklings.
In the end, that also worked for problematic chemicals, and now the release of the carbon would have to be taken into account, as is already done today in the tests for plastic drinking water pipes. (ad)