Will people have to die from drinking polluted water before the Government takes effective action to counter the algal threat in our lakes and rivers ? Large-scale fish kills, and the death of animals from drinking polluted lake water, have already become a sign of industrial development, inadequate sewage treatment and intensive farming practices. And while the need for sustainable development and the eco-auditing of policies is recognised in the current seven-year national plan, strict measures to reduce the enrichment of our lakes and rivers through nitrogen or phosphate run-offs have been sadly lacking. The findings of a three-year study of algal blooms in Irish lakes, commissioned by the Environment Protection Agency, are nothing short of a health warning. As reported by Kevin O'Sullivan in this newspaper, an EU-funded study found twenty per cent of the lakes it surveyed to contain algal blooms caused by cyanobacteria. Cyanobacteria are among the most lethal substances known and can pose a severe threat to drinking water. They have been responsible for many animal deaths and cause acute effects in humans, including skin conditions, vomiting and diarrhoea. Nine types of toxic cyanobacteria were present and causing actual or potential nuisance in 23 lakes, according to the report which identified Caragh Lake in Co Kerry, Iniscarra reservoir in Co Cork and Lough Derg on the Shannon as amongst those affected.
The threat from algal poisoning has probably worsened since the survey was completed in 1998. The report itself commented that because of the small sample "it was considered that the level of toxicity encountered substantially underestimated the true position." It urged that local authorities should routinely test water supplies for their presence and advocated a State-wide monitoring of lakes.
Much of the eutrophication has been caused by the excessive use of phosphate fertilisers and inappropriate slurry spreading by farmers. But the use of phosphates in household detergents has also contributed to the problem. Norway achieved a 40 per cent reduction in phosphate application over eight years by imposing a fertiliser tax. But the Government has failed to give effect to a farm nutrient management scheme, involving VAT charges and rebates, advocated by the Economic and Social Research Institute. And proposals for a tax on household detergents containing phosphates have come to nothing.
Enrichment through excessive phosphate use creates the conditions in which blue-green algae may form a scum on the surface of a water body. And shallow limestone lakes are particularly vulnerable. The situation is particularly worrying from a health point of view because of the poor quality of water already supplied by some rural group water schemes. Two years ago, a report by the Environment Protection Agency found that up to 2,000 of these schemes produced water of an unacceptable quality. And while the Government proposes to spend £420m in improving them over the next seven years - along with massive spending on public sewage works - other actions to tackle the underlying problems of eutrophication and algal blooms remain to be taken. Taxes on phosphates should be introduced immediately.