Traces of bug found in Dublin reservoir

A MINUTE quantity of the water-borne pathogen cryptosporidium was detected in Dublin’s water supply last month. Dublin City Council confirmed yesterday that a sample taken from the Stillorgan reservoir in south Dublin tested positive for “small levels” of the bug on February 13th.

However, the council said the finding did not automatically mean there was a problem with the water system.

As part of a follow-up protocol to check whether there was an actual problem with water quality, further samples were taken which found no evidence of cryptosporidium contamination.

The council said it had notified the Health Service Executive and the Environmental Protection Agency of the findings.

The original contaminated sample was also sent to an external laboratory for “typing” to identify the origin of the contamination, but the levels of the bug were too small to be of any use.

Dublin city engineer Michael Phillips said because Stillorgan reservoir was an open-air facility there was a risk of contaminants being dumped into the reservoir. “However, it should be reiterated that there is no issue with the Dublin supply, and water is safe to drink.”

He said it was not uncommon to find minute traces of cryptosporidium in the water system, noting that there were five such finds in Dublin last year and three in January this year.

In 2007 a large-scale outbreak of cryptosporidium in Galway resulted in up to 250 people becoming ill and the water supply to the city being shut down for five months. The outbreak was linked to untreated sewage getting into Lough Corrib, from where drinking water is sourced.

Cryptosporidium usually enters water systems via human and animal waste. Ingestion of the bug by humans can cause abdominal cramping and diarrhoea. However, in immuno-compromised individuals the symptoms can be more severe and even fatal.