Kevin Brigden - senior scientist research lab Greenpeace Science Unit. Waste water samples are tested at the Greenpeace Science Unit at the Exeter University (UK). The samples include waste water from an industrial park and a sewage treatment plant on the Matanza river (better known as the Riachuelo river) in Buenos Aires (Argentina), a textile factory on the canals near Bangkok and from the solid sediments from canals on the Chao Phraya river.