The group presented results from their salinity levels tests in the Oder and Vistula Rivers that showed that the levels shot up, sometimes off the scale, after the rivers' waters travel through Poland's southern coalmining region of Silesia.

“Our hypothesis is that the source of the high salinity levels are most probably brine waters pumped from Upper Silesia into the Oder and the Vistula,” said the author of the tests and a Greenpeace expert, Leszek Pazderski of Nicolaus Copernicus University in Torun.