While metaldehyde exceedences of the legal limit of 0.1µ/l in drinking water have fallen dramatically since 2012, according to Drinking Water Inspectorate figures, significant academic research and collaboration with farmers aimed at reducing the risk of it entering water courses continues.
Speaking at an Institute for Agri-Food Research and Innovation (IAFRI) metaldehyde conference held at Fera, near York, John Haley, of UK Water Industry Research (UKWIR) said: “2012 was a bad year for the industry. There is a very much improved trend since 2012 in terms of annual [metaldehyde] means. They are coming down quite nicely or have we just been lucky?”
Mr Haley said metaldehyde is very difficult to detect but if there was a low cost test that could be performed quickly and detect when levels could lead to non-compliance, water companies could temporarily stop abstracting from affected sources. However, research funding would be needed to develop such a test, he added.
Professor James Moir, based at the University of York is carrying out research which he hopes will lead to a rapid cheap diagnostic test for metaldehyde. He has identified a shared gene cluster in microbes that can degrade metaldehyde which is absent in the same species that cannot.
“We are exploring the biochemical basis of metaldehyde degradation with a view to development of diagnostic tools for metaldehyde,” he said.
An unexpected discovery from another University of York researcher, Professor Colin Brown was that rainwater contains low levels of metaldehyde. “It was a chance finding when we collected rainwater from a roof,” he said.
Rainwater from other sites was analysed and metaldehyde found. “It is not likely that arable use is the source,” says Prof Moir who has yet to discover where the metaldehyde in rainwater is coming from. However, he said it was not present in high enough concentrations in rainwater to cause drinking water exceedences.