What are the lessons to be learned from the pollution incident last week on the River Martin in Cork while nutrient enrichment, or eutrophication, was giving a green tinge to the Lakes of Killarney? Mr Aidan Barry, chief officer of the South Western Regional Fisheries Board, says the lesson is that time is running out for our environment.
Either we make a stand now so as not to lose what we have, or Ireland's environmental reputation will no longer be credible. The River Martin incident was a case in point. Three years ago, farm effluent was allowed to seep into the river, a tributary of the Lee, and 10,000 trout and salmon parr were killed.
Two years before there was another fish kill. But the river had been recovering and the irony is that just three weeks before the latest incident, in which 100,000 fish were killed, the fishery board conducted tests to determine the health of fish life in the river. It was satisfied that recovery was under way.
Now, all has been laid waste because pig slurry was allowed get into the Martin. In addition, if the ESB had not released hundreds of thousands of gallons of water from its reservoir at Inniscarra in the Lee Valley, to dilute the pollution, Cork might have been without water supplies.
There is a sense of deja vu about this. And what's the connection between the destruction over intervals of a 10-mile stretch of the Martin and the greening of the Lakes of Killarney?
And this phenomenon also brings with it a sense of deja vu. It happens in Cork every summer when the Lee turns peagreen. This is the result of chemicals spread on high land outside the city and it is estimated that if fertiliser spreading stopped right now, it would take 15 years for the chemical build-up to dissipate.
The connection between the Cork and Kerry incidents, Mr Barry says, is that we are letting things slip. For instance, tourists in Blarney last week saw fish floating belly-up before their coaches moved on to Killarney where signs informed them of lake pollution there too.
The greening effect does not grab headlines in the way that fish kills do but it is the most potentially damaging factor environmentally, Mr Barry says.
Salmon and trout have inhabited our rivers and lakes for 10,000 years, but if the nutrient enrichment continues at its present rate, caused in the main by phosphates introduced to the land by farmers, it might take only 20 years to decimate the stocks.
And Mr Barry has some sobering statistics to prove the point.
There has been a fundamental change in Irish agriculture since the 1950s. Mr Barry argues that the move to silage and fertiliser use has had its effect. There are four classes of water pollution: `A', `B', `C', and `D'. `A' represents unpolluted water; `B' slightly polluted; `C' moderately polluted; and `D' seriously polluted. From 1978 to 1990, 77.5 per cent of our waterways were unpolluted; the slightly polluted figure stood at 12 per cent; the moderately polluted at 9.5 per cent; and the seriously polluted at 1 per cent.
Then, from 1991 to 1994, the unpolluted category dropped by 6 per cent while the slightly moderately polluted categories rose by 16.8 per cent and 11.4 per cent respectively. This trend has continued for some time, according to Mr Barry.
The gradual increase in nutrient enrichment incidents has to be assessed and a co-ordinated action plan put in place, he says.
Phosphates are the root cause of the problem, and Mr Barry estimates that 80 per cent comes from the agri-sector. Household detergents and industrial sources account for the remainder.
In 1950, 20,000 tonnes of phosphates were spread on the land annually, says Mr Barry. Now, the figure is 67,000 tonnes. The agri-sector puts twice what is required onto the land each year and the same production output could be achieved with half the amount of phosphates, he says. Phosphate deposits are now more than 10 times what they were in the 1950s and the "export" to water of phosphates is more than five times higher than it was in the 1950s.
The need now, Mr Barry says, is to inform farmers that fertiliser levels can be reduced without affecting production. Mr Barry claims that a conservative saving, if phosphate levels were reduced, would be about £25 million a year. The answer, he believes, is for farmers to have their soil tested so as to determine their particular requirements, and then spread accordingly. This would cost about £20.
Also, if there was a new tax on compound fertilisers, he believes, significant revenue could be raised which might subsidise a national soil-testing programme.
Finally, this thought. In Mr Barry's region there are some 700 miles of rivers and lakes. In the first four months of this year alone, pollution affected 25 miles of waterway. Should this rate continue, then within 15 to 20 years, the entire 700 miles will be similarly affected, says Mr Barry. It is up to the authorities to ensure that no further serious damage is done.