TOXICITY OF NEWSPRINT DYES TO RAINBOW-TROUT AND ACTIVATED-SLUDGE

Aquatic toxicity effects of dyes used in the manufacture of newsprint and telephone directory-grade papers were studied on luminescent bacte ria, rainbow trout, and activated sludge. The results show that triphe nylmethane dyes, used in tinting newsprint, were more toxic than yello w dyes, which are used in making telephone directory-grade papers. Dat a from Microtox tests agreed with fish toxicity data. The dyes inhibit ed respiration of flora in activated sludge at high concentrations not likely to exist in mill effluents.