“In many cases, disinfection is not helpful or even harmful”

2023-05-19 15:21:00

KIt sounds complicated at first, but it is quite common in almost every household. American scientists warn against the increased use of so-called quaternary ammonium compounds in disinfectants and other products. Some of these substances can harm aquatic animals and also cause health problems in humans.

Above all, the everyday use of these agents can make the microorganisms that are being fought more resistant through so-called evasive mutations, writes a group led by Carol Kwiatkowski from the Green Science Policy Institute in Berkeley (California, USA). The Study is in the journal „Environmental Science & Technology“ erschienen.

Quaternary ammonium compounds (QAC) are a class of substances with hundreds of substances. What they have in common is a nitrogen atom to which four organic substances are bound. Many of the compounds have antimicrobial effects and – watch out, household! – are therefore used in disinfectants, antibacterial all-purpose cleaners and hygiene wipes.

also read

According to Kwiatkowski and colleagues, the use of this class of substances has risen sharply in the United States since the pandemic. In addition to the corona pandemic, one reason for this is that QAVs, including benzalkonium chloride (BAC), have often replaced other disinfecting active ingredients in liquid soaps and shower gels for several years.

also read

The authors of the study come from academia, government agencies and non-profit organizations. They evaluated more than 200 scientific studies in which the effects of various QAC were examined and summarized the results in their study. “Our review of the research suggests that in many cases, disinfecting with these chemicals is unhelpful or even harmful,” said Courtney Carignan, co-author of Michigan State University in East Lansing, Michigan, in a statement from the Green Science Policy Institute cited.

Too much cleaning makes germs resistant

Quelle: picture alliance / Zoonar

Researchers recommend regular cleaning with soap and water, and disinfecting only when needed and then with safer products.

The studies considered provided evidence that QAC survive the wastewater treatment and thus enter the environment. There they can harm aquatic life, from water flea to fish. Humans can also be affected by health impairments, for example through contact with the skin or by inhaling sprayed disinfectants.

Hypersensitivity and chronic inflammation can develop in people who are frequently exposed to QACs in manufacturing plants, hospitals, or as cleaners. However, intact skin is protected from the penetration of QAV by using a disinfecting soap.

Microorganisms become resistant

More critical are study results that found a decrease in fertility in mice after exposure to QAC. The effect was apparently already known in 1975, which is indicated by a patent specification for the use of QAV as a means of reducing the fertility of dogs and rats, the effectiveness of which has been proven by studies.

In addition, the frequent use of disinfectants, similar to antibiotics, can lead to the development of resistance in the microorganisms being fought. “Antimicrobial resistance was already contributing to millions of deaths per year before the pandemic; overzealous disinfection, especially for products with QACs, threatens to make it worse,” said Erica Hartmann of Northwestern University in Evanston, Illinois, USA, another co-author.

also read

also read

The authors of the study therefore demand that the effects of QAC on humans and the environment be examined more intensively, including combinations of QAC. Among other things, the scientists are demanding from (American) politics that QAVs be included in lists of pollutants of increasing interest for reporting, monitoring, evaluation, etc. Also, QAC should be consistently regulated across different uses and agencies, also recognizing that humans and animals can be exposed to QAC from multiple sources.

Apparently, the trend from the USA has not yet arrived in Germany. In any case, Bernd Glassl from the Cosmetics and Detergents Industry Association is not aware of an increased trend towards the use of quaternary ammonium compounds as active ingredients in disinfectants in Germany. “In 2020 there was a very high demand for disinfectants in Germany, mainly based on ethanol and/or isopropyl alcohol (2-propanol)”, says the head of the household care division.

With increasing knowledge about the transmission of Covid-19, however, this demand had already decreased significantly in 2021.

also read

Christoph Stang from the Federal Environment Agency (UBA) also reports on the observation that alcohol-based disinfectants in particular were increasingly used during the corona pandemic in Germany. Unlike crop protection products, however, biocides were not recorded quantitatively by the end of 2021, “although we have been campaigning for this for many years,” says Stang.

Precise information on the use of QAV biocides is therefore not available. However, QAV are under observation: A UBA research project, in which the effects of using QAV on the environment are being investigated, is already underway.