Tuesday 26 June 2007

Lakes contain 20 times cancer toxin limit

IRISH lakes have been found to contain 20 times the recommended World Health Organisation limit of certain cancer-causing toxins — and water purification in this country may not be strong enough to get rid of them.
Researchers from Cork Institute of Technology, backed by the Environmental Protection Agency, studied lake waters and found microcystins which they said can cause “diarrhoea, vomiting, weakness and pallor” and even death in high doses. They can also cause liver cancer, yet are not covered by Irish drinking water regulations, meaning there is no requirement to test for them.
Ambrose Furey, a supervisor of the research, said the tests carried out by the team only related to the water in lakes and reservoirs. Water is treated before it goes from that stage to the tap.
However, he said there is a concern that the level of chlorine currently in Irish waters may be as much as 10 times less than the level necessary to eradicate the toxic microcystins.
The researchers are now hoping to secure funding from the Environmental Protection Agency to spend the next 12 months testing drinking water in every county in Ireland to establish if there is any presence of microcystins in drinking supplies.
They are also advising the Government to begin regulating toxin tests.
“You have to be aware that they are present at certain times of the year and you should test for them,” he said, adding that the bloom is particularly prevalent in summer months.
Mr Furey said water which has evidence of algae blooms which indicate the toxin needs to be tested immediately.
If there are high levels of the toxin in the water it should be left for at least two-to-three weeks and tested again before it is processed for drinking water.
“If you had a larger bloom, the chlorine that exists at the moment would not be enough to decompose the toxin,” he said.
Mr Furey said it also needs to be established how long water is in the reservoir or lake before it is processed, because if it is only there a short time, the chlorine level would have to be higher to rid the drinking water of toxins.
The only study of human drinking water contaminated by microcystins was carried out in China and found that levels of liver cancer there were seven times higher that normal.
Earlier this month, the Irish Government introduced revised regulations which would see local authorities facing prosecution and fines as stiff as €500,000 if they fail to maintain EU drinking water standards.

Stephen Rogers
© Irish Examiner

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