ONCE again, Spain holds more blue flags for its beaches and marinas than any other country in the world – a record it has held without interruption for 30 years.
Can Coronavirus survive in sea and pool water and on sand? Scientists reveal findings
10/05/2020
WITH summer looming close on the horizon, residents in Spain keen to get to the beach or use their urbanisation pool as soon as it does, and northern Europe eager to get to Spanish shores for a sunny holiday, a thorough investigation of how the 'new' Coronavirus interacts with sand, sea and chlorinated water is set to be key to finding out whether normality can resume sooner or later.
The National Research Council (CSIC) was commissioned a week ago by the Spanish Institute for Quality in Tourism (ICTE) to carry out an exhaustive study on these hitherto unanswered questions.
It has now revealed its findings, and a lot of it could be good news – although procedures need to be set up to keep everyone as safe as possible.
Talks have been ongoing about what to do, but nothing is official and some of it seems unworkable – 'shifts' for using communal or public pools could be impractical, and setting up metacrylic screens on beaches has been ruled out as bathers between them would literally fry.
Beaches should be open for general use by the time the country enters into 'Phase 3', the final stage of 'recovery', but swimming pool openings have not been confirmed as yet.
Still, the CSIC's 17-page report on whether the SARS-CoV-2 virus can survive in water, on sand, or even in sea breeze, based upon scientific evidence currently available, should help the health authorities come to a decision soon.
The CSIC starts by recalling that the main transmission channels are person-to-person contact, and through the droplets emitted when an infected person coughs or sneezes.
For this reason, it continues to recommend social distancing on beaches and near pools.
The institution has confirmed there is 'no evidence' of the presence of any type of Coronavirus in mains water, but that it is possible for traces of it to survive in waste water.
Sea water
According to the CSIC, there is 'no scientific evidence' that the virus can survive in salty water, and salt has been shown to be 'an effective biocide', or capable of killing off viral particles.
For this reason, it believes the SARS-CoV-2 is unlikely to be present, or in enough quantity, to pose a risk in sea water, and that the probability of its being transmitted this way is 'very limited'.
This said, the virus could reach the sea through waste water pumped into it.
However, if it is treated properly beforehand, its harmful effects are expected to be limited.
Waste water becomes diluted when it is pumped into the sea, and the salt in the water neutralises it, meaning as long as it is treated correctly at the sewage plant, it does not pollute – there is no need to worry that you're swimming in a giant toilet when you go for a dip off the coast.
“Sodium chloride filters have been shown to be highly effective in deactivating the influenza virus, independently of their subtypes and their capacity to be stored in adverse environmental conditions,” says the report.
“This could probably be extrapolated to a wide spectrum of pathogens in the air that cause epidemics and pandemics of respiratory diseases.”
Sea breeze
Given that the SARS-CoV-2 virus enters the human body via others' airborne fluids, scientists researched whether the spray caused by waves breaking and transported in the coastal breeze would be capable of transporting it to humans.
“Neither the World Health Organisation, nor the Center for Disease Control and Prevention in the USA, nor the local health agencies in the USA or in other countries have warned that the virus could propagate itself via coastal or sea breeze,” the report assures.
So, there's no apparent danger of 'breathing it in' just by sitting on the beach.
Beach sand
In theory, sand on beaches could indeed be contaminated by the virus, either through contact with infected bathers, or by waste water.
The CSIC says the transporting of the virus via waste water is 'fairly limited', although it could be deposited on sand through droplets from infected bathers coughing or sneezing, or even through other bodily secretions such as urine, faeces or spit.
As for how long the SARS-CoV-2 virus might survive when deposited on coastal sand, the CSIC says that in principle, the sun's radiation ought to deactivate it, and if the sand reaches a temperature of more than 56ºC – which is rare, even in a high-summer heatwave on the east or south coast, but possible, bearing in mind that air temperatures reported by the Met office are taken from thermometers in the shade, meaning the mercury is typically 10ºC higher in direct sunlight – this should also kill off the virus.
But heat and the sun's radiation vary, due to a number of factors, such as latitude, time of year, the climate on a given day, and so on, meaning it is not possible to give a firm answer in this case.
“The joint action of the salt from the sea, UVB rays and the high temperatures that the sand on the beach can reach, all favour the deactivation of pathogens in general,” says the CSIC.
To this end, it is still not clear how long it takes for the SARS-CoV-2 virus to be extinguished through natural processes on sand.
Rivers, lakes and wells
Inhabitants of inland towns and villages who are too far from the beach to cool off in summer often have a local public chiringuito, or lido, they can use, or sometimes inland beaches are set up on the shores of rivers and lakes with safe bathing areas. For this reason, the CSIC took samples of water from these, and also from wells – and the conclusions they reached are less favourable.
“Viral particles continue to be temporarily infectious in natural freshwater environments,” the report says.
“Stringent precaution measures should be taken in these areas.
“In particular, special attention should be paid to small wells of non-saline stagnant water, which may be frequented by a high number of bathers, and which could give rise to a possible accumulation of the virus.
“We do not recommend the use of these areas for recreational purposes.”
Swimming pools
Once again, the CSIC cites the USA's Center for Disease Control's findings that there is 'no evidence that the virus causing Covid-19 can be transmitted to persons via water in swimming pools, jacuzzis, spas, or purpose-built leisure and play areas involving water', which would include, for example, water parks.
To guarantee this, though, the CSIC insists it is crucial to ensure chlorine levels are maintained according to those set by law.
These, says the CSIC, stipulate a 'free-circulating chlorine-water ratio of 1-3mg per litre', which 'would be sufficient to deactivate the virus and, therefore, sufficient to prevent contamination risks whilst bathing'.
Maintaining these levels, however, means constant monitoring 'at all times during pool use' to 'guarantee the necessary anti-microbial capacity'.
Pools with on-site maintenance staff, such as public facilities, may 'feasibly' be monitored to this extent, says the CSIC, but otherwise, 'the essential measures need to be taken' to ensure 'permanent and constant disinfection'.
And the problem in this scenario is that chlorine levels do not remain constant throughout the day, reveals Salvador Mauri, managing director of SCP Pool España – part of PoolCorp, the world's largest distributor of swimming pool equipment and products – since chlorine becomes diluted as it acts on the water.
Factors such as water temperature and 'organic material from bathers' – unavoidable substances, such as sweat and dead skin particles – gradually deactivate the chlorine and leave 'chloromines' in the water, Mauri explains.
Chloromines are derivatives of ammonia and organic amines, chemical compounds containing these along with chlorine, often used to clean drinking water – but in the quantity they appear in swimming pool water after chlorine comes into contact with high temperatures and with dirt from bathers, they cause irritation to eyes, skin, and mucous membranes.
Mauri says two methods of chlorinating public, private and communal pools are normally used – one is an automatic dosing with sodium hypochlorite, which is basically bleach; the other is by using ordinary salt dissolved in water which is converted into chlorine using salt electrolysis systems, which is generally considered to be healthier, easier and cheaper, and is becoming increasingly popular in Spain.
In either case, they diminish rapidly.
“You could have, at 09.00 in the morning, 3mg chlorine per litre of water, but if it's a really hot day and you have lots of bathers, by 11.00, it's all evaporated and there's none left. The more bathers and the higher the temperature, the faster the chlorine acts, and as it does so, it reduces.
“For this reason, you need to check the water an absolute minimum of four times a day – when opening, closing, and twice in between.
“The problem is that chlorine levels are measured using optical systems, which are very simple, but do not give you an exact measure,” Mauri reveals.
“To maintain a pure level of chlorine in the water, governments and experts recommend using automatic control systems – a type of 'robot' which analyses the water constantly and, if it detects a fall in 'available' chlorine, it activates immediately to add more. Once the level of disinfection is sufficient, it stops, so it never adds more chlorine than is safe.
“These systems have been available for over 20 years, but largely due to not knowing they exist, they are not found in all communal and public pools.”
Indoor swimming pools, spas, steam-rooms, saunas
The CSIC says the recommendations and findings for outdoor pools also apply to indoor ones and to jacuzzis and spa water circuits, including in relation to chlorine levels.
For saunas and steam rooms, the report states: “Available scientific information regarding the survival of the virus in different environmental conditions is scarce, but indicates a reduced survival level of SARS-CoV-2 at high temperatures.”
Steam-rooms and saunas tend to be between 40ºC and 60ºC, which the CSIC considers may be enough to limit the amount of time viral pathogens could remain active in these.
But to be safe, they strongly recommend following the same stringent cleaning procedures as anywhere else where people gather, on all surfaces – wood, metal, tiled floors and so on – and disinfecting regularly.
Generally, though, the researchers advise against disinfecting the ground in natural environments – such as grass or sand – in the same way as in built-up areas and buildings, so as not to damage ecosystems.
Any disinfecting of beach sand or riverbanks should be in a way which is 'kind to the environment', the CSIC concludes.
Photograph 1: A beach in Barcelona
Photograph 2: Pinterest
Photograph 3: Madrid city council
Photograph 4: SCP Pool España
Related Topics
WITH summer looming close on the horizon, residents in Spain keen to get to the beach or use their urbanisation pool as soon as it does, and northern Europe eager to get to Spanish shores for a sunny holiday, a thorough investigation of how the 'new' Coronavirus interacts with sand, sea and chlorinated water is set to be key to finding out whether normality can resume sooner or later.
The National Research Council (CSIC) was commissioned a week ago by the Spanish Institute for Quality in Tourism (ICTE) to carry out an exhaustive study on these hitherto unanswered questions.
It has now revealed its findings, and a lot of it could be good news – although procedures need to be set up to keep everyone as safe as possible.
Talks have been ongoing about what to do, but nothing is official and some of it seems unworkable – 'shifts' for using communal or public pools could be impractical, and setting up metacrylic screens on beaches has been ruled out as bathers between them would literally fry.
Beaches should be open for general use by the time the country enters into 'Phase 3', the final stage of 'recovery', but swimming pool openings have not been confirmed as yet.
Still, the CSIC's 17-page report on whether the SARS-CoV-2 virus can survive in water, on sand, or even in sea breeze, based upon scientific evidence currently available, should help the health authorities come to a decision soon.
The CSIC starts by recalling that the main transmission channels are person-to-person contact, and through the droplets emitted when an infected person coughs or sneezes.
For this reason, it continues to recommend social distancing on beaches and near pools.
The institution has confirmed there is 'no evidence' of the presence of any type of Coronavirus in mains water, but that it is possible for traces of it to survive in waste water.
Sea water
According to the CSIC, there is 'no scientific evidence' that the virus can survive in salty water, and salt has been shown to be 'an effective biocide', or capable of killing off viral particles.
For this reason, it believes the SARS-CoV-2 is unlikely to be present, or in enough quantity, to pose a risk in sea water, and that the probability of its being transmitted this way is 'very limited'.
This said, the virus could reach the sea through waste water pumped into it.
However, if it is treated properly beforehand, its harmful effects are expected to be limited.
Waste water becomes diluted when it is pumped into the sea, and the salt in the water neutralises it, meaning as long as it is treated correctly at the sewage plant, it does not pollute – there is no need to worry that you're swimming in a giant toilet when you go for a dip off the coast.
“Sodium chloride filters have been shown to be highly effective in deactivating the influenza virus, independently of their subtypes and their capacity to be stored in adverse environmental conditions,” says the report.
“This could probably be extrapolated to a wide spectrum of pathogens in the air that cause epidemics and pandemics of respiratory diseases.”
Sea breeze
Given that the SARS-CoV-2 virus enters the human body via others' airborne fluids, scientists researched whether the spray caused by waves breaking and transported in the coastal breeze would be capable of transporting it to humans.
“Neither the World Health Organisation, nor the Center for Disease Control and Prevention in the USA, nor the local health agencies in the USA or in other countries have warned that the virus could propagate itself via coastal or sea breeze,” the report assures.
So, there's no apparent danger of 'breathing it in' just by sitting on the beach.
Beach sand
In theory, sand on beaches could indeed be contaminated by the virus, either through contact with infected bathers, or by waste water.
The CSIC says the transporting of the virus via waste water is 'fairly limited', although it could be deposited on sand through droplets from infected bathers coughing or sneezing, or even through other bodily secretions such as urine, faeces or spit.
As for how long the SARS-CoV-2 virus might survive when deposited on coastal sand, the CSIC says that in principle, the sun's radiation ought to deactivate it, and if the sand reaches a temperature of more than 56ºC – which is rare, even in a high-summer heatwave on the east or south coast, but possible, bearing in mind that air temperatures reported by the Met office are taken from thermometers in the shade, meaning the mercury is typically 10ºC higher in direct sunlight – this should also kill off the virus.
But heat and the sun's radiation vary, due to a number of factors, such as latitude, time of year, the climate on a given day, and so on, meaning it is not possible to give a firm answer in this case.
“The joint action of the salt from the sea, UVB rays and the high temperatures that the sand on the beach can reach, all favour the deactivation of pathogens in general,” says the CSIC.
To this end, it is still not clear how long it takes for the SARS-CoV-2 virus to be extinguished through natural processes on sand.
Rivers, lakes and wells
Inhabitants of inland towns and villages who are too far from the beach to cool off in summer often have a local public chiringuito, or lido, they can use, or sometimes inland beaches are set up on the shores of rivers and lakes with safe bathing areas. For this reason, the CSIC took samples of water from these, and also from wells – and the conclusions they reached are less favourable.
“Viral particles continue to be temporarily infectious in natural freshwater environments,” the report says.
“Stringent precaution measures should be taken in these areas.
“In particular, special attention should be paid to small wells of non-saline stagnant water, which may be frequented by a high number of bathers, and which could give rise to a possible accumulation of the virus.
“We do not recommend the use of these areas for recreational purposes.”
Swimming pools
Once again, the CSIC cites the USA's Center for Disease Control's findings that there is 'no evidence that the virus causing Covid-19 can be transmitted to persons via water in swimming pools, jacuzzis, spas, or purpose-built leisure and play areas involving water', which would include, for example, water parks.
To guarantee this, though, the CSIC insists it is crucial to ensure chlorine levels are maintained according to those set by law.
These, says the CSIC, stipulate a 'free-circulating chlorine-water ratio of 1-3mg per litre', which 'would be sufficient to deactivate the virus and, therefore, sufficient to prevent contamination risks whilst bathing'.
Maintaining these levels, however, means constant monitoring 'at all times during pool use' to 'guarantee the necessary anti-microbial capacity'.
Pools with on-site maintenance staff, such as public facilities, may 'feasibly' be monitored to this extent, says the CSIC, but otherwise, 'the essential measures need to be taken' to ensure 'permanent and constant disinfection'.
And the problem in this scenario is that chlorine levels do not remain constant throughout the day, reveals Salvador Mauri, managing director of SCP Pool España – part of PoolCorp, the world's largest distributor of swimming pool equipment and products – since chlorine becomes diluted as it acts on the water.
Factors such as water temperature and 'organic material from bathers' – unavoidable substances, such as sweat and dead skin particles – gradually deactivate the chlorine and leave 'chloromines' in the water, Mauri explains.
Chloromines are derivatives of ammonia and organic amines, chemical compounds containing these along with chlorine, often used to clean drinking water – but in the quantity they appear in swimming pool water after chlorine comes into contact with high temperatures and with dirt from bathers, they cause irritation to eyes, skin, and mucous membranes.
Mauri says two methods of chlorinating public, private and communal pools are normally used – one is an automatic dosing with sodium hypochlorite, which is basically bleach; the other is by using ordinary salt dissolved in water which is converted into chlorine using salt electrolysis systems, which is generally considered to be healthier, easier and cheaper, and is becoming increasingly popular in Spain.
In either case, they diminish rapidly.
“You could have, at 09.00 in the morning, 3mg chlorine per litre of water, but if it's a really hot day and you have lots of bathers, by 11.00, it's all evaporated and there's none left. The more bathers and the higher the temperature, the faster the chlorine acts, and as it does so, it reduces.
“For this reason, you need to check the water an absolute minimum of four times a day – when opening, closing, and twice in between.
“The problem is that chlorine levels are measured using optical systems, which are very simple, but do not give you an exact measure,” Mauri reveals.
“To maintain a pure level of chlorine in the water, governments and experts recommend using automatic control systems – a type of 'robot' which analyses the water constantly and, if it detects a fall in 'available' chlorine, it activates immediately to add more. Once the level of disinfection is sufficient, it stops, so it never adds more chlorine than is safe.
“These systems have been available for over 20 years, but largely due to not knowing they exist, they are not found in all communal and public pools.”
Indoor swimming pools, spas, steam-rooms, saunas
The CSIC says the recommendations and findings for outdoor pools also apply to indoor ones and to jacuzzis and spa water circuits, including in relation to chlorine levels.
For saunas and steam rooms, the report states: “Available scientific information regarding the survival of the virus in different environmental conditions is scarce, but indicates a reduced survival level of SARS-CoV-2 at high temperatures.”
Steam-rooms and saunas tend to be between 40ºC and 60ºC, which the CSIC considers may be enough to limit the amount of time viral pathogens could remain active in these.
But to be safe, they strongly recommend following the same stringent cleaning procedures as anywhere else where people gather, on all surfaces – wood, metal, tiled floors and so on – and disinfecting regularly.
Generally, though, the researchers advise against disinfecting the ground in natural environments – such as grass or sand – in the same way as in built-up areas and buildings, so as not to damage ecosystems.
Any disinfecting of beach sand or riverbanks should be in a way which is 'kind to the environment', the CSIC concludes.
Photograph 1: A beach in Barcelona
Photograph 2: Pinterest
Photograph 3: Madrid city council
Photograph 4: SCP Pool España
Related Topics
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