The growing public concern about environmental matters has prompted widespread discussion in the media. Unfortunately much of this public debate has been characterized more by ardour than by information, and often the wildest speculations are pro mulgated with the same appearance of veracity as hard scientific facts. It is an important, and often neglected, duty of scientific societies to make sure that the public is properly informed regard ing the technical aspects of matters of public interest, and to assure that policy decisions of governmental and other agencies are made with due regard...