Samples were collected from the mouths of the rivers Elbe, Ebro, Garonne, Loire, Rhone, Rhine, Seine, Thames and the Tiber by some 40 chemists, biologists and physicists from 19 research laboratories.

Samples were collected from the mouths of the rivers Elbe, Ebro, Garonne, Loire, Rhone, Rhine, Seine, Thames and the Tiber by some 40 chemists, biologists and physicists from 19 research laboratories.

Samples were collected from the mouths of the rivers Elbe, Ebro, Garonne, Loire, Rhone, Rhine, Seine, Thames and the Tiber by some 40 chemists, biologists and physicists from 19 research laboratories.

Samples were collected from the mouths of the rivers Elbe, Ebro, Garonne, Loire, Rhone, Rhine, Seine, Thames and the Tiber by some 40 chemists, biologists and physicists from 19 research laboratories.

Samples were collected from the mouths of the rivers Elbe, Ebro, Garonne, Loire, Rhone, Rhine, Seine, Thames and the Tiber by some 40 chemists, biologists and physicists from 19 research laboratories.