Two Nations Act as Millions of Fish Die in Rhine; Two Nations Act as Millions of Fish Die in Rhine
millions of fish die as pollutant spreads for 5th day in Rhine River in W Ger and Netherlands; Ger waterworks set up special testing facilities to guard against contamination of water supplies; Dutch health authorities identify chem as insecticide that poses little danger to humans; warnings against pollution, efforts to find its source and theories concerning its emanation discussed; authorities in Netherlands work energetically to head off potential natl emergency; Dutch agency says chem is being blocked near Dordrecht by incoming tide; Brit lab plots probable drift of poisoned water; illus; map