Sir, - In his interesting and timely series of articles on water Kevin O'Sullivan quotes Mr J. Burke, Chairman of the Trout Anglers Federation of Ireland (The Irish Times, September 22nd) who repreats a misrepresentation of the role of the Environmental Protection Agency (EPA) in examining the water quality of Lough Leane.In Ireland the statutory responsibility for maintaining good water quality rests primarily with the local authorities, which normally carry out the appropriate monitoring. The central and regional fisheries boards carry out additional monitoring of water quality for their own purposes, as do the OPW and the ESB at a limited number of locations. The EPA carries out monitoring on an agency basis for some localauthorities and also where there are perceived gaps in the information or as part of special-interest studies. The main role of the EPA in this part is to collect the available data from the various State bodies and to publish overviews of the water quality in the State.With reference to Lough Leane in Killarney the facts are as follows:The EPA does not carry out any monitoring of the water quality of Lough Leane. The data used in the national reports have been obtained from the OPW and, since 1992, from Kerry County Council.The most recent assessment of the lake by the EPA, covering the period 1990-94, classified the open-water area of the lake as being in a mesotrophic condition compatible with such uses of the lake as game fishery and recreation. Ross Bay in Lough Leane was classified as being in a more enriched condition. The EPA has never stated that Lough Leane was in a pristine condition, nor have we published any information in regard to its condition in 1996.The level of monitoring being carried out by the OPW and Kerry County Council is satisfactory in terms of its frequency and extent.A comparison of the 1994 data for the lake with those from the early 1980s shows that the water quality of Lough Leane has improved over the past decade. This improvement can be attributed in considerable measure to the operation of phosphorus removal facilities at the Killarney Sewage Treatment Works.Lough Leane has a rapid water renewal rate, less than 50 days during periods of very high inflow. Thus it is possible, given an increased input of nutrients, for a deterioration in water quality, similar to that being measured in the lake at the moment, to set in over a short period. By the same token, if the sources of the nutrients fuelling the present excessive algal growth in the lake are stopped, the recovery in the lakes quality will be rapid.The EPA would be concerned if, in the light of these facts, the Trout Anglers Federation still had "no faith whatsoever in the EPA" or felt that we were "not telling the truth". - Yours, etc.,Jim Bowman,Environmental ProtectionAgency,(Regional Inspectorate),Pottery Road,Dun Laoghaire,Co Dublin.