River Oder mystery after thousands of fish found dead

Scientists are investigating the cause of a “catastrophic” mass death of fish in the River Oder, between Poland and Germany, the Guardian reported. Polish scientists have traced high salt levels, but rejected German claims of mercury pollution, but with both governments suspecting an untraced chemical spillage. German authorities have banned fishing and bathing in the river. Some 2,000 police, 300 firefighters and 200 soldiers have been deployed to remove carcasses.