Mass Fish Die-Off at Polish Reservoir

A freshwater ecological disaster has occurred at the Pirchowice Reservoir in southwestern Poland. Engineering operations to drain the reservoir, combined with prolonged extreme heat, led to a sharp drop in dissolved oxygen levels in the water. This resulted in a massive fish kill, with large numbers of dead fish floating on the surface and emitting a foul odor. Nutrients such as nitrogen and phosphorus carried by agricultural runoff into the reservoir, and the high temperatures accelerated eutrophication, causing the water quality to continue to deteriorate.