Q & A

Metaldehyde and the issues involved

Metaldehyde is a selective molluscicide widely established for use by growers to provide slug and snail control over a wide range of crops. Applied as an edible, granular bait containing a small amount of active ingredient, it has been used for slug control for over 50 years, playing a key role in pest control strategies for arable farmers and UK agriculture as a whole.

New monitoring programmes and risk assessments introduced by water companies late in 2007 identified the active ingredient occurring in rivers and streams at certain times of the year.

Expert advice is that, at levels being detected, there are no health or environmental risks, but the issues pose a serious problem for water companies in terms of regulatory compliance with drinking water standards.

Even using existing advanced water treatment processes the compound, that has a very slow rate of breakdown in water, is very difficult to effectively remove.

Previous testing has shown metaldehyde levels closely correlating with peak slug pellet application periods on farms. Water companies are continuing to monitor raw and treated waters for metaldehyde, looking for significant reductions, in particular as the main slug pellet application time begins.

Experts have concluded that the most appropriate and sustainable solution to deliver a reduction in metaldehyde levels detected is to stop the active ingredient entering the water catchments in the first place - hence the industry 'Get Pelletwise' campaign.

The 2009/10 water company results demonstrated that raw water analysis saw a significant reduction in the levels of metaldehyde being detected compared to 2008/09. However, the weather conditions experienced during the year’s slug pelleting period will have had a part to play, contributing significantly to a reduction in pellet use.

< back to General and Specific questions