Farmers could face a ban on the commonly used rush spray MCPA unless they take more care to follow strict guidelines on how to use it, the Environmental Protection Agency (EPA) has warned.

The grassland herbicide, which can be used to kill rushes, ragwort, docks, thistles and nettles, has been found in drinking water supplies all over Ireland.

The EPA found that 61 water schemes had levels of pesticide exceeding the legal limit in 2015. That was more than double the 28 water schemes reported in 2014. MCPA was the chemical detected in 41 of those 61 breaches.

Preliminary results for 2016 show that pesticides have again breached the legal limit in around 60 water schemes, according to the EPA. There are around 850 water schemes in Ireland.

Senior EPA inspector Darragh Page told the Irish Farmers JournalvMCPA was found in around 80% of the 2016 breaches. “If we keep getting results like that, there is a risk that MCPA could be banned at European level or at Ireland level,” he warned. “That is breaching the Drinking Water Directive set down by the European Commission.”

Page added that Ireland is “already on the Commission’s radar” for the level of trihalomethane (THM) in drinking water, which is not related to agriculture.

Seventy water schemes have been found to have excessive THM levels and, if the Commission pursues the case, Ireland could be fined millions.

The EPA inspector warned that with pesticides found in 60 water schemes for two years in a row, the Commission will be watching closely.

“By and large, MCPA is the most common pesticide found,” he said. “It is used for rushes which grow in marshy areas, which are inevitably near water bodies.

“If it’s not used properly or if it is used at the wrong time and it rains, you can be pretty sure it will end up in the water. The pathway is there for MCPA to easily get into the water supply.”

However, Page said if MCPA guidelines were followed correctly, the EPA is confident the chemical can be kept out of drinking water supplies.

How much MCPA is used?

Department figures show that in 2015, some 3,121,000kg of pesticide active ingredient were put on the market in Ireland. MCPA accounted for 389,216kg or 12% of the total pesticide that year.

If all of that MCPA was used to treat rushes at a rate of 4l/ha, that would be the equivalent of spraying 288,308ha.

Rush spray ban looms

Fears of MCPA ban as chemical found in drinking water

The commonly used rush spray is under threat due to European rules on drinking water.