08 Nov, 2016
The United Kingdom’s
Royal Agricultural University (RAU) has joined forces with a regional water
company to investigate ways to reduce the occurrence of metaldehyde in drinking
Thames Water, the
water company responsible for supplying London with its drinking water, has
awarded RAU postgraduate student Tom Edwards a Master of Science by Research,
following Tom’s investigation into the use of ‘swales’ as a potential mechanism
to reduce metaldehyde concentrations in watercourses.
Although the Royal
Agricultural University is situated some 100 miles west of London, it is within
the catchment area of the River Thames. Metaldehyde is difficult to remove from
water using current treatment processes, hence the interest shown by Thames
Water in Tom’s research.
designed to collect field run-off in shallow ditches, providing a ‘natural’
water treatment through interaction with soil, bacteria and vegetation.
Previous studies have shown swales’ effectiveness in reducing other pollutants
such as heavy metals and nutrients, but they have remained unproven for plant
The RAU has
established two experimental swale sites, where water is taken from an existing
stream before travelling the length of the swale. Here it makes contact with
soil and root systems which, it is hoped, will effect a reduction in
metaldehyde levels. Water flowing out of the swale returns to the watercourse,
heading downstream where it will be extracted by Thames Water for further
treatment to produce drinking water.