A new study by researchers at ACS ES&T Water reveals that each toilet flush can release thousands of virus particles from infected waste. However, the research team explains that this amount of virus may not always lead to an infection. In comparison, the use of urine-diverting toilets can reduce a person’s exposure to contaminated waste.
Toilets, particularly those of the traditional mix flush type, are known to spray tiny droplets of water and waste into the air, which can spread contagious pathogens, including noroviruses, adenoviruses and human polyomaviruses. The urine-diverting toilet, on the other hand, separates urine from other waste and can potentially reduce the spread of disease.
To understand the potential for spreading disease, the researchers conducted experiments by adding 10 billion surrogate viruses to traditional and urine-diverting toilets in a university restroom. They found that less than 1% of the virus surrogates added to the toilets was released into the air during flushing. Furthermore, the addition of protein, simulating the proteins found in urine, resulted in the traditional toilet releasing tens of times more viruses than the urine-diverting toilet.
The results also showed that a single flush from a traditional toilet could release up to 390 million genome copies of norovirus, while a urine-diverting toilet could release up to 67 million genome copies. Although these levels are within the range of an infectious dose, the researchers explain that it is unlikely for a person to be exposed to all of the particles due to evaporation, settling onto surfaces or inactivation through handwashing.
The study was funded by the University of Michigan, the U.S. National Science Foundation, and a University of Michigan MCubed grant. The next step is to determine a person’s risk of contracting diseases from toilet flushing. The American Chemical Society (ACS) is a non-profit organization chartered by the U.S. Congress with a mission to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and all its people. Find more here.