Metaldehyde

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Metaldehyde is the active ingredient in most slug pellets available to the commercial and domestic markets. During times of high rainfall, metaldehyde can be washed into watercourses and is detected in rivers at concentrations exceeding the drinking water standard.

Did you know?

The Drinking Water Regulations state that pesticides in drinking water must not exceed a standard of 0.1 µg/l. This is the equivalent of 1 grain of wheat in 390 tonnes. This is not a health or environment based standard, but it is a legal requirement that all water companies must meet.

Metaldehyde is not well removed by existing water treatment processes which were designed to remove other pesticides.

Therefore, catchment management is a more sustainable way of protecting drinking water sources from metaldehyde.

We began a catchment management project to reduce water pollution from metaldehyde in 2010. The projects that we are currently involved with include:

Product substitution

Encouraging farmers to use slug pellets that contain ferric phosphate instead of metaldehyde.

Hotspot trials

Risk mapping of fields (slope, soil, proximity to water).

Encouraging farmers to use an alternative product (ferric phosphate) on fields identified as high risk.

In collaboration with the MSG.

Payment for Ecosystem Services

Paying farmers for providing clean water.

Allowing the farmer to decide how to achieve this.

Swales trial

Researching if drainage mitigation measures on fields (swales), can reduce runoff containing pesticides from entering the watercourse.

Abstraction management

Using modelling software (Metpred) to predict when high metaldehyde concentrations are likely to occur and stopping abstraction when condition allow.

Further catchment activities

We are represented on a number of catchment management steering groups. These groups aim to raise awareness and reduce diffuse pollution from a variety of sources in the catchment.