Metaldehyde in the catchment
In preparation for the phasing out of metaldehyde over the next 18 months, consider reducing your reliance on chemical control measures by adopting a wider range of options in your Integrated Pest Management (IPM) programme to control slug numbers. If you need to use chemical control, please use ferric phosphate-based pellets instead of metaldehyde pellets and, as always, follow best practice guidelines. In some areas there are water company funded initiatives available to support you, so contact your local water company to find out more. Please note that contact details can be found at the bottom of this update.
Please see the map and graph below for 12 monitoring locations within the Thames catchment.
Latest Results
Metaldehyde concentrations have remained below the drinking water standard at all 12 sites this week. More prevalent rainfall over the last week has meant that soils will now be approaching saturation in many places across the catchment and therefore any further rainfall in the coming weeks could readily mobilise recent metaldehyde applications via runoff. If you need to make any further slug pellet applications this autumn please consider water protection, and as always, follow best practice guidelines (www.getpelletwise.co.uk).
Focus on… Wey at Weybridge
The River Wey joins the River Thames at Weybridge. Just before it’s confluence with the River Thames, water samples are collected and analysed for metaldehyde. Metaldehyde concentrations have exceeded the drinking water standard 14 times since monitoring began in 2010, with a maximum concentration of 0.479µg/l in autumn 2012. In autumn 2016, 2017, and so far this season, concentrations have remained below the drinking water standard. A peak of 0.078µg/l was recorded in May 2018 following rainfall. It is possible that a lack of dilution due to low river levels had a part to play in the result observed.
To find out more please contact:
Affinity Water: Q2F0Y2htZW50TWFuYWdlbWVudEBhZmZpbml0eXdhdGVyLmNvLnVr, SES Water: Y2F0Y2htZW50QHNlc3dhdGVyLmNvLnVr, South East Water: Y2F0Y2htZW50QHNvdXRoZWFzdHdhdGVyLmNvLnVr or Thames Water: Y2F0Y2htZW50Lm1hbmFnZW1lbnRAdGhhbWVzd2F0ZXIuY28udWs=