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Metaldehyde Stewardship message evolves – more constraint or opportunity?

Metaldehyde has been in the headlines since 2007 when it was first detected in raw water supplies at a level that presented serious difficulties for the water companies in meeting their statutory drinking water standard for pesticides of 0.1 parts per billion.

Metaldehyde has been in the headlines since 2007 when it was first detected in raw water supplies at a level that presented serious difficulties for the water companies in meeting their statutory drinking water standard for pesticides of 0.1 parts per billion.

The campaign to ‘Get Pelletwise’ has been high profile and done much to raise standards and awareness across the agri-supply chain by providing guidance and information, says Metaldehyde Stewardship Group’s (MSG) Simon McMunn.

Yet instances of metaldehyde peaks, which exceed the set drinking water standards, are still occurring at detection points in catchments across the country – a situation not helped by several seasons of high slug pressure and record rainfall. So are we any further along in solving the problems posed by metaldehyde?

Significant progress has been made. “When the issues with metaldehyde first came to light, little was known about how it was getting into water. We now know that it is by a predominantly diffuse pathway – run off from fields and field drains – that it is reaching rivers and reservoirs,” explains Mr McMunn.

Historically there haven’t been strong links between the agricultural and water industries. “The collaborative approach is groundbreaking and has made excellent progress. Many industry stakeholders are working together to understand the problems each industry faces and trying to jointly find a solution,” adds Mr McMunn.

Stewardship guidelines are now well established and ‘best practice’ adopted by agronomists and growers using metaldehyde, but there is a finite time left to show we can manage metaldehyde through a voluntary approach, emphasises Mr McMunn.

The metaldehyde stewardship message has consequently evolved with a focus on heightened targeting and, alongside existing guidelines, the concentrated effort has been on enhancing stewardship in the highest risk catchments. Growers within four pilot areas are now being asked to either rely on cultural controls or use an alternative active ingredient for slug control.

“The four pilot catchment studies, introduced in 2014, are in different regions and have been developed by the water companies in conjunction with the MSG and supported by others in the industry including our regulators,” explains Simon Eyre, Source Protection Manager at Anglian Water. The pilot studies are expected to run for an initial two year period.

“The pilots are targeting selected water catchments in an attempt to show we can manage the metaldehyde problem by asking growers not to apply metaldehyde to their higher risk fields and to use an alternative product or approach instead,” explains Mr Eyre. Within the pilots, risk levels have been identified on a field-by-field basis according to soil type, topography and proximity to a watercourse.

 “The scheme is voluntary but growers involved in the pilot project in the catchments feeding our Pitsford Reservoir were very engaged in the meeting we held recently with them. Some growers have already switched from metaldehyde to ferric phosphate but there is also some nervousness amongst those who have no or little experience with ferric phosphate, especially where they are growing oilseed rape,” he adds.  

In order to reassure farmers, Anglian Water have commissioned ADAS to conduct field trials in the catchment using ferric phosphate to gather further independent evidence for slug control using ferric phosphate and to share the results with growers in the catchment.
The problem for the water industry remains that metaldehyde cannot be removed with current treatment practices in order to meet drinking water standards, explains Mr Eyre.

Anglian Water has recently hosted growers at a water treatment plant as part of Catchment Sensitive Farming’s ‘Lincolnshire on Tap’ initiative. “We are keen to build closer relationships with the farming community and show growers what it is we do with the water draining from their land in order to make it wholesome for public supply. We also explain where the water goes after leaving the treatment works and some of the problems we are facing maintaining water resources,” comments Mr Eyre. “It’s education on both sides and we are learning about farming, the industry’s legislation, pressures and pests.

We don’t want farmers to lose metaldehyde from their armoury and now we need to show our regulators, the Drinking Water Inspectorate (DWI), that a voluntary approach can work. It is only in the last five years that we have started looking at a catchment approach to managing water quality,” explains Mr Eyre. ” If we can’t show this approach working by 2018, then the DWI will expect a different solution to the problems posed by metaldehyde.”

On the plus side, if catchment management can be shown as an effective way of keeping metaldehyde within acceptable limits for drinking water standards, then the scheme will be rolled out countrywide across the eighty priority water catchment areas and metaldehyde will still be available as an important tool for slug management in situations where conditions favour its use without compromising water quality.

In the meantime, the threat still looms of potentially losing metaldehyde, the most widely used active for slug control. With the imminent withdrawal from sale of methiocarb in September, it is in the whole industry’s interest to maintain choice in the options for slug control. So what is the current position of metaldehyde with the regulators?

“Metaldehyde manufacturers are currently going through the process of submitting updated product information as part of the review process under EC directive 1107/2009 for re-registration of products,” explains Mr McMunn.

Re-registration of pesticides marks the transition to regulation under European Community legislation (from national regulation) and involves updating product dossiers which are then assessed according to the EC harmonised standards.  As part of this process, any new information about an active since its first inclusion as an approved substance is submitted along with updated risk assessments.

 “The usage guidelines jointly advocated by the manufacturers of metaldehyde, that together form the MSG, are not currently a statutory obligation for growers but it is probable actual label changes will occur as a result of the re-registration process,” comments Mr McMunn.

“It’s critical for the future of metaldehyde for growers in the pilot catchments to engage in the scheme and to help make catchment management work,” stresses Mr McMunn. “The regulators for both industries will be observing the progress. We have a tremendous opportunity to prove we can cooperate with the water industry, and all stakeholders, to take responsibility for the way our agronomic decisions can impact water resourcing and quality.”