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COVID-19 in drinking water; is there a risk?

It is becoming clear that COVID-19 spreads through liquid aerosol particles via coughing, sneezing - even breathing.

But do coronavirus particles also present a risk to our drinking water supply?

Drinking Water. Source: wikimedia commons.

While we wait for thousands of current COVID-19 studies to conclude, we can look at the results of previous investigations on the characteristics of similar coronaviruses.

These results show that coronaviruses survive quite well in water, with virus survival rates depending on two main factors – the temperature and the type of water.

A study published in the journal 'Food and Environmental Virology' in 2009 found that human coronavirus 229E (responsible for the common cold) takes up to 10 days to inactivate in tap water at 23°C, but over 100 days in tap water at 4°C.

According to Weather and Climate, Melbourne’s water temperature fluctuates between 13°C in winter and 17°C in summer; with Sydney between 16°C and 21°C, Brisbane between 19°C and 25°C, and Perth between 17°C and 21°C.

So, with most states’ drinking water temperature below 23°C – is there cause for concern?

Not according to the US Centers for Disease Control (CDC) and Environmental Protection Agency (EPA), both releasing statements that “COVID-19 has not been detected in drinking water supplies” – and recommending “drinking and usage to continue as normal”.

This is likely due to dilution effects, whereby virus particles contacting our water supplies are diluted well below the infectious dose (amount of virus required to establish an infection).

Coronavirus Particles. Source: wikimedia commons.

What about other types of water?

Pool water is typically treated with chlorine - a common disinfectant - therefore the water from well-maintained pools should be safe.

Ocean water remains uncontaminated because of its incredible volume and amount of dissolved salts, which have disinfecting properties.

Sewerage is a different story, however. An ongoing study in the Netherlands has detected COVID-19 coronavirus particles in wastewater collected from Amsterdam Airport only days after the first Netherland cases were announced.

Interestingly, the 2009 Food and Environmental Virology journal study found coronavirus 229E deactivated far more quickly in wastewater, decreasing in activity by 99 per cent in two to four days.

While there are no confirmed cases of COVID-19 transmission via wastewater, many diseases are borne from human waste and safe handling practices are required.

Wastewater Treatment. Source: wikimedia commons.

Several water treatment processes have proven to be effective at deactivating coronaviruses; such as oxidation via chlorination, ultraviolet (UV) irradiation, and membrane technologies (ultrafiltration).

However, according to research in California, there are still no water treatment studies that specifically focus on SARS-CoV-2, the strain of coronavirus that causes COVID-19.

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