DUBAI // Swimming pools are being treated with chemicals that could lead to asthma and bladder cancer.
And chlorine used as a disinfectant is too weak to prevent the spread of diseases that can cause severe diarrhoea, especially among children.
When chlorine comes into contact with common pool pollutants such as ammonia and nitrogen compounds, it creates combined chlorine also known as chloramines.
They can be dangerous, said Ian Nicks, a UK independent consultant of swimming pools around the world and a member of the Pool Water Advisory Group.
“High combined chlorine in poor water can contribute to breathing problems and asthma in outdoor pools,” Mr Nicks said. “A high combined level of chlorine could also ultimately result in triggering bladder cancer.”
Most UAE pools are outside and treated with chlorine. But chlorine on its own cannot prevent the growth of some harmful organisms.
“There are some organisms that are adapted and resistant to chlorine, like cryptosporidium and giardia,” said Halim Mirza, the UK manager of Hanovia, a company that provides ultraviolet (UV) technologies to treat water.
They were speaking at a disinfection conference in Dubai last week.
Giardia and cryptosporidium are parasites that can cause intestinal problems including nausea, severe diarrhoea and fatigue.
They are commonly found in water, food, soil and places contaminated with infected human or animal faeces.
“When humans get [crypto-sporidium] in their body, they can act as carriers and deposit it in pools, especially in the under 11-year-olds,” said Mr Nicks.
And because tests for it are rare, it can be a huge issue.
“It was suggested a few years ago that 75 per cent of pools could have unknown faecal releases so cryptosporidium could be present,” he said. “And it’s not a bacteria so it will not respond to chlorine.
“UV will kill cryptosporidium and chlorine-resistant organisms. A lot of UK companies are moving towards UV because of this problem.
“It’s instant. The UV lamp is link-ed and measured by the UV intensity monitor and that’s linked and synchronised with the control system. It works as a supplement [to chlorine or powdered chlorine dioxide].”
But so far, municipalities in the UAE have not adopted the system.
“Whether it’s indoor or outdoor pools, we have a responsibility to disinfect our pools properly,” said Mr Nicks.
Local companies have expressed interest in the new technology.
“We use chlorine but we are interested in UV for our pools,” said Prasanga Vithanage, Le Meridien Hotel’s aquatic sports manager in Dubai. “Powdered chlorine dioxide could also work.”
Although experts agree the system works, alone it is not enough.
“It’s good for disinfecting instantaneously,” said Prof Walid El Shorbagy, director of the water resources programme at the UAE University. “But it doesn’t have residuals, like powdered chlorine dioxide, which are needed to fight any potential contamination from desalination plants, for instance.”
Prof El Shorbagy said the system needed “constant monitoring”.
“It’s good for pools as long as it’s applied to the circulation system continuously,” he said. “It has some strength of disinfection but that disappears some short time after its application.
"It's not constant so depending on the type of bacteria and germs in the water, it has to be monitored."
cmalek@thenational.ae