17 October 2007

Drinking Water Security

Sydney Belly
Sydney Belly”, gastrointestinal illness and diarrhoea is probably as old as Sydney. As long as water and feces are being mashed up the winners are the pathogens. At the moment care facilities for the young and old are being hit by a norovirus (stomach cramps, diarrhoea and vomiting) again.

Crypto in the drinking water
Bugs (“low levels of cryptospo
ridium”) found in Sydney's water supply it was reported yesterday are “not posing any threat to the city's drinking water supply“. A boggling check at Sydney Drinking Water Quality report claims that there are NO Cryptosporidium and Giardia found in the crystal clear water. Going a few days back, this seems to have been the case too.

Cryptosporidium is a parasite resistant to most disinfectants. It is “ spread through feces of infected hosts and causes sometimes severe diarrhea in humans and animals.” Once it gets into the body via water, food or unhygienic pr
actices, the symptoms are usually gastrointestinal illness, diarrhoea and sometimes vomiting. "...It is the most common non-viral cause of diarrhoea worldwide... People can literally die of diarrhoea: they can lose over 13 litres of fluid a day.“

Some Crypto cases: Rapidly growing populations outstrip infrastructure
Galway, the fastest growing city in Ireland is the prototype “where rapid expansion of housing developments has not been matched by infrastructure upgrades...236 laboratory confirmed cases of Cryptosporidium infection had been identified, with at least 40 resulting in hospitalisation...sewage is the major source of contamination.” Many in the tourist industry have “installed their own water filtration systems to reassure guests.”

The cause of the Milwaukee Cryptosporidium epidemic in 1993 was "found to be sewage that passed through the filtration system of one of the city's drinking water plants.” “ 400,000 people became infected and 60 people" (or 100) "died as a result of drinking infected water”.

The 1998 Sydney Water Crisis requiring 3 million residents to 'boil water ' was memorable for residents and visitors. Two small bugs, Cryptosporidium and Giardia led to changes in Sydney Water Corporation. Years on in 2007 the two pathogens are still causing “severe gastrointestinal illness”. In SA too there were “ 228 cases of cryptosporidiosis this year, compared to 52 for the same period last year.” Sewage and water mix in Australia, South Africa and many other places.How many is ok?
In Milwaukee there are no more than one Cryptosporidium oocyst per 10 litres allowed. It is “now a criminal offence in the UK to supply drinking-water that has more than one Cryptosporidium oocyst per 10 litres”. The 1998 Sydney incident "has shown no evidence of any illness that could be attributed to drinking water contamination. Accordingly, law suits claiming for illness among consumers have recently been withdrawn from Australia's high court.

Wait- there is more than Crypto and Giardia
There are other pathogens, but there are chemicals that could have very adverse health effects on humans and animals. “Disinfection by-products (DBPs), endocrine disrupting chemicals, antibiotics, polymers and pesticides”. The question is no longer in a risk-society to aim for not having any harmful substances in the drinking water, but the “Acceptable Daily Intake (ADI) ..which can be ingested for an entire lifetime (70 years) without appreciable health risk” Health and the possible cancer are a matter for probability/statistics. (Micropollutants, pdf)

Balancing burgeoning public needs for safe drinking water with dwindling supplies will be a major challenge for public works managers and regulators in the years to come.”

More on Sydney Water, Health and Pollution
Drinking water security and sewage
Reducing Risks when eating out

The Sydney Water Crisis, Another Lesson in Health Risk Communication Failure, Dr. Steve E.Hrudey (Professor of Environmental Health Sciences in the Department of Public Health Sciences)
Organic Micropollutants in Water, pdf (www.waterquality.crc.org.au)
Galway Cryptosporidium Outbreak, Health Stream Article - Issue 46 - June 2007
Critical processes affecting Cryptosporidium oocyst survival in the environment, King, B.J. and Monis, P.T. (2007) Parasitology, 134 (Pt 3); 309-23.Health Stream Literature Summary - Issue 46 - June 2007
Waterquality, CRC, au
"Cryptosporidium"- tag, ABC

Image: Water sculpture for gathering clouds by Eora

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