SIGNIFICANT numbers of drinking water supplies in the Republic are "bacteriologically unfit for human consumption", according to a report published, today by the Environmental Protection Agency.
Although the report concludes - that the overall quality of drinking water is satisfactory, it says "many problem supplies - mainly group water schemes and other privately organised projects - "remain to be dealt with".
The EPA is required by legislation to produce an annual report for the Minister for the Environment on drinking water. The latest report, relating to 1994, monitors compliance with EU regulations which cover all supplies, apart from bottled water.
It found that the water quality monitoring carried out by most local authorities went beyond what was required and said they were to be complimented on "this positive approach". But in some cases "the extent of monitoring is minimal and at times inadequate for conformity with the regulations".
In these instances, the apparent absence of breaches "reflects an inadequate analytical base rather than inherent excellence of water quality", the EPA said. Nonetheless, it detected a "definite trend towards more complete surveillance of drinking water quality throughout the country".
A total of 14,200 samples were taken in 1994, 8 per cent more than the previous year, and these were analysed to determine compliance with a range of 53 bacteriological, chemical and physical parameters, ranging from the presence of aluminium or heavy metals to aesthetic issues such as colour and taste.
As expected, the EPA found the highest quality in public water supplies, although there were "many instances" where even these were infected by coliform bacteria (mainly non faecal). This was largely due to contamination of the distribution network rather than the omission of disinfectants.
Referring to the relatively high, level (12.8 per cent) of breaches' involving coliforms, it said was not surprising given the widespread nature of agriculture.
Many group water schemes were liable to from improperly sited septic tanks or slurry pits and it was clear that these may pose "serious risks to the health of the consumer unless precautionary measures are taken" - such as use of chlorine to disinfect the water supply.
The primary aim of chlorination was to render drinking - free of harmful micro which posed the threat of the EPA said. The report chlorine and fluoride were over used to treat water proper care in dosing the with these chemicals surely be possible".
"Stricter control of all existing chlorination facilities would bring about a substantial improvement in drinking water quality" - on the one hand, by, eliminating coliform bacteria while, on the other, ensuring that chlorine levels were not so high as to cause "odour and taste problems".
Many of the breaches of water quality in 1994 were "marginal" and reflected naturally occurring local conditions; for example, there was "excessive colour in peatland areas and excessive iron or manganese in mineral rich areas. The report said these did not pose a health risk.
Although there was a "significant drop" of 2.5 per cent in the number of breaches involving aluminium in 1994, compared to 1993, the report concedes that this remains a problem. There were also higher, numbers of breaches for ammonium, manganese, pH and turbidity, all indicating "diminished quality".
"In the case of some supplies, notably where persistently high nitrates are a problem, the provision of an alternative source may be the only practical means of resolving quality problems," it says, adding that this matter of "some urgency" was being addressed by a capital works programme, now under way.
