Excess nitrates from pig farming have polluted the Ahlhorner fish ponds nature reserve

Germany

Hamburg

Bremen

South Oldenburg

Lower Saxony

North Rhine-

Westphalia

100 km

100 miles

Germany

Hamburg

Bremen

South Oldenburg

Lower Saxony

Berlin

Netherlands

North Rhine-

Westphalia

Düsseldorf

100 km

Belgium

100 miles