Lockdown gardening has been blamed for a rise in the number of breaches of pesticide limits in water supplies last year. They rose from 82 breaches in 2019 to 91 in 2020.

Speaking at a Teagasc Signpost webinar, John Keogh of the Animal and Plant Health Association said there had been an increase in both the number of pesticide exceedances and the number of water supplies affected. This came after a steady and significant decline in exceedances since 2017.

Gylphosate breaches increased to 10 and, while Keogh could not give a definite reason for the increase, he did state: “That may reflect activity in relation to lockdown and people being overly zealous about maintaining hard surfaces.”

MCPA was the most common pesticide exceedance, accounting for 46 of the 91 exceedances in 2020.

MCPA is commonly used for control of rushes and is a common ingredient in lawn weed killer.

To put things into perspective, Keogh also noted that it is important to remember that EU limits for pesticides in drinking water are very safe and they are not health based.

A political decision was taken to basically take a zero-tolerance approach, he noted, which makes the EU’s limits 7,000 times lower than the World Health Organisation’s limits.

EU limits mean that the pesticide cannot exceed 0.1 mg/l or one part in 10bn – the equivalent to one stem in 111,000 hay bales or one baked bean in 21m cans.