To validate the sampler, grab samples were collected from a medium-sized river in the South-West of England (SWE), downstream from the city of Bath, as well as from Olifants River in Kruger National Park (South Africa) (figure ). Samples for the UK were collected during June 2019 and samples of South Africa were collected during February 2018. Samples were spiked and extracted on site before being further processed in the lab. UK samples were tested for all three groups of analytes and SA samples were tested only for group A.