Tests have shown the presence of toxic hydrocarbons in the River Odra, which are not of natural origin but a technological by-product, two opposition MPs said on Monday in Olsztyn, northern Poland.
Donald Tusk, the leader of Poland's main opposition party Civic Platform, has criticised the government for what he regards as its belated reaction to a pollution spill in the River Odra that has killed tonnes of fish.
Polish foreign ministry on Saturday called on Russia to carry out a thorough investigation into the poisoning attempt of Kremlin critic Alexei Navalny, a year after the incident.
The recent poisoning of Russian opposition leader Alexei Navalny should be a warning sign to some Western leaders, PM Mateusz Morawiecki said on Thursday before a sitting of the European Council.
The prime ministers of the Czech Republic, Hungary, Poland and Slovakia, the four countries that make up the regional Visegrad Group (V4), in a joint statement urged Russia to carry out a thorough investigation into the poisoning of Russian opposition leader Alexei Navalny.