29 September 2015

Green Waste, A Growing Problem

A relatively new, but increasing, bane for geophysicists and metal detectorists alike, is the practice of spreading green waste on fields. Part of the drive for increased recycling in society, which is good, this material comes from our gardens, but is rarely pure. Many households are not too fussed with what they will put in their bins, so plastic and metal will end up in the green waste. Farmers will buy this from the council and then use it to fertilise their fields. The metal component of this will cause problems for magnetometers, producing white noise from thousands of tiny dipoles. For example, this is a Roman settlement :

This is a Roman villa :

Once it's in there, it's there for good. Metal detectorists get it worse, as they are also picking up non-ferrous material. There is even a blog dedicated to the problem.


  1. As Secretary of a metal detecting Group and in involvement in Geophys this is a growing problem which will eventually manifest itself to the general public when it is far too late, Sharp tin and plactics already contaminate some Sussex fields and if it goes on unchecked eventually there will be injuries to people and pets. The contamination does travel in the ground during ploughing, becoming airborne and collecting visible on the edges of fields as an eyesore and a danger to wildlife. If there are tin fragments ignored in the Green Waste process what else - needles ???

  2. I'm busy researching this very problem. You may have seen the paper I wrote with two colleagues http://onlinelibrary.wiley.com/doi/10.1002/arp.1503/abstract
    Please get in touch with me to discuss this further. I'd be extremely interested to hear more about your experiences of geophysics and green waste. Best wishes, Dr James Gerrard, Newcastle University