A potentially toxic algal bloom was found on Lough Guitane in the Killarney Valley last week. The lake supplies water to Kerry's principal towns, Tralee and Killarney, as well as to areas such as Castleisland near the Limerick border and Castlemaine in mid-Kerry.
The area supplied has a resident population of more than 60,000 people. Hundreds of thousands of visiting tourists also rely on water from Lough Guitane.
This is the third year in succession an algal bloom, taken as evidence of increased enrichment of the reservoir-lake, has been found. Scientists in the environment section of Kerry Co Council have expressed concern about water quality in the lake and have sounded warnings about agricultural and housing development along its shores and hinterland.
"It was a very short-lived algal bloom. It did not develop. We have been monitoring the lake closely," Mr David Lenihan, senior executive chemist, said.
Conservation groups such as the Killarney Nature Conservation Group have campaigned for controls on the growth of housing near the lake. They have also sought protective fencing to prevent animals from falling into the reservoir.