WARSAW, Poland -- Poland is turning to laboratories abroad in a bid to solve the mystery of a massive fish die-off in the Oder River, authorities said Tuesday, while the government pledged to toughen laws against environmental polluters.
Experts in Poland and Germany, which share the lower course of the river, describe the deaths first observed last month as the worst natural disaster in the two countries in many years.
Polish Climate and Environment Minister Anna Moskwa said on Twitter Tuesday that samples were being sent to laboratories in Czechia, where the Oder starts its course, and also to the Netherlands and the U.K. Later Tuesday, her deputy, Malgorzata Golinska said the samples were of the Oder’s water.
Poland's government, which has been accused of responding too slowly to the problem, vowed Tuesday to track down those responsible and was discussing significantly increasing penalties for polluters.
“We are determined to make every person and every establishment responsible for this kind of incident bear the consequences," said Michal Dworczyk, the Polish prime minister’s chief of staff.
For most of its course, the river flows through Poland.
Dead fish in the Oder were first noticed by fishermen in southwestern Poland in late July. Polish firefighters say they have removed almost 100 tons of dead fish so far, while German authorities downstream have put oil barriers on the river to contain the spread of rotting fish.
Some environment experts say climate change could be to blame, as due to the low summer river level fish would have come closer to toxins potentially resting on the riverbed.
Golinska from the climate and environment ministry said that toxic substances but also unfavorable changes to the environment are being analyzed as the potential cause.
A marine expert at Poland’s Academy of Sciences, Jacek Piskozub, said it would be worse if climate change were behind the disaster because it’s much harder to address than any case of incidental pollution.