Biosensors to make drinking water safer
At the moment, officials monitoring water quality collect samples from reservoirs and bring them back to a laboratory for examination. That means it could be days before they are alerted to dangers such as E.coli and cryptosporidium, a parasite.
‘Rather than cycling to the water works once a week and going back to the lab, we want to be able to identify pathogens continuously with biosensors,’ Professor Paul Hunter from the University of East Anglia's Norwich Medical School in Britain said. ‘We could place a black box up there and cryptosporidium would flash up.’
Prof. Hunter is leading Aquavalens, a five-year EU-funded project launched in February which is trying to figure out ways to better deal with such incidents, and more serious problems. Scientists on the project first want to understand better the biology of threats like E.coli and cryptosporidium. Then they hope to come up with a system to generate an early warning when contaminated water is about to enter the supply.
Global warming
“EU countries generally have good water quality, but around 330 000 cases of water-related disease are reported each year in the World Health Organisation's (WHO) European region, which stretches as far east as Kazakhstan and Kyrgyzstan. Victims suffer symptoms including diarrhoea, vomiting, stomach pains, nausea, headache, and fever. Diarrhoea kills some 39 000 people in this region each year, the WHO said in 2010, though it did not say how many of these deaths were related to drinking water.‘Rather than cycling to the water works once a week and going back to the lab, we want to be able to identify pathogens continuously with biosensors.’
Such incidents might become more common in the future if global warming results in more flooding and encourages water-borne pathogens. Extreme weather is becoming more frequent and intense, affecting the quantity and quality of water resources: the number of extreme events in Europe increased by 65 % between 1998 and 2007, according to the WHO.
On top of that, European countries are placing an increasing burden on their water supplies. The ecological status of more than half of the surface water bodies in Europe is below acceptable levels, said a 2012 report by the European Commission.
Water was not always seen as a potential carrier of disease. Until the first half of the 19th century, cholera was thought to be caused by polluted or otherwise poisoned air. However, British physician John Snow famously found that victims of an 1854 outbreak in the Soho area of London were overwhelmingly people who drank from the same public pump, which accessed water from a well dug close to an old cesspit.
Danger of complacency
One of the biggest dangers is complacency. In July 2000, 344 people fell ill with gastroenteritis at a tourist resort in southern Italy because of contaminated drinking water. In the US, around 200 000 residents of Milwaukee, Wisconsin, fell ill in 1993 from cryptosporidium in drinking water, with most suffering from diarrhoea.
Part of the European Union's good reputation in water could even be a reporting issue, meaning more people may be getting ill than authorities believe. In the 1990s, no contamination incidents were reported in Germany, but after improved monitoring was started, outbreaks began to be found. ‘When countries don't report any, it's because they're not monitoring,’ said Hunter.
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