More than 400 common disinfectants currently in use could be made safer for people and the environment and could better fight the COVID-19 virus with the simple application of UVC light, according to a new study from the University of Waterloo.
Benzalkonium chloride (BAK) is the most common active ingredient in many disinfectants routinely used in hospitals, households and food processing plants to protect against a wide range of viruses and bacteria – including all strains of SARS-CoV-2, the coronavirus that causes COVID-19 – but its toxicity means it cannot be used in high concentrations. It also means that products containing BAK are harmful to humans and the environment.
Waterloo researchers found that the chemical’s toxicity could be fully neutralized using ultraviolet light (UVC) when tested in cultured human corneal cells.
“Our results show that a disinfection procedure using BAK followed by UVC radiation can minimize the harmful effect of BAK residues on humans and the environment,” said Dr. David McCanna of the Department of Optometry and Waterloo vision science. “Such a procedure also has great potential to maximize the effectiveness of disinfection using two different antimicrobial mechanisms.
“As the pandemic continues, our findings are particularly important as they provide another method to make our hospitals, food, homes and environment safer.”
Although it is an important ingredient for the effectiveness of a disinfectant, BAK is a severe irritant to human skin and eyes. The high toxicity of the chemical limits the ability to use products with high concentrations of BAK to better protect against harmful viruses and bacteria. High levels of BAK residues are also harmful to the environment, being particularly toxic to fish, aquatic invertebrates and birds.
After exposing a solution of BAK to UV-C germicidal lamps, they applied the solution to cultured human corneal cells for five minutes and analyzed the metabolic activity and viability of the cells. BAK solutions were completely neutralized by UVC because the solutions no longer damaged cultured human corneal epithelial cells.
“Due to concerns about the spread of COVID-19, people are using products containing BAK as an active ingredient more than ever before,” said former Waterloo student and lead author Dr Manlong Xu, currently a clinical researcher at the department of the University of Alberta. of ophthalmology and visual sciences.
“For many industries, there is a demand to improve the efficiency of standard disinfection procedures, while keeping in mind any potential negative impact on the environment.”
The Neutralization of Eye and Skin Irritating Benzalkonium Chloride Using UVC Light Study, authored by Dr McCanna of Waterloo Faculty of Science and Dr Jacob Sivak and Dr Xu was recently published in the review Skin and eye toxicology.
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