WARSAW, Poland—Laboratory tests following a mass die-off of fish in the Oder River detected high levels of salinity but no mercury poisoning its waters, Poland’s environment minister said Saturday as the mystery continued as to what killed tons of fish in Central Europe.
Anna Moskwa, the minister of climate and environment, said analyses of river samples taken in both Poland and Germany revealed elevated salt levels. Comprehensive toxicology studies are still underway in Poland, she said.
