Dr. Anne Marie Mahon:

We are currently intensifying our investigations on land and we are taking some sediment cores on sites that have been land-spread with sewage sludge for 20 years to see what the vertical profile of the microplastics would be. We hope that we will get an idea from that as to whether the microplastics will be mobilised after a rain event, therefore increasing the risk to local, nearby watercourses or whether they would be transported vertically and perhaps enter the groundwater. Either way, it is not ideal.