Sublethal effects of tetrachloro-1,2-benzoquinone--a component in bleachery effluents from pulp mills--on vertebral...

The effects of tetrachloro-1,2-benzoquinone (TCQ), a component in bleached kraft mill effluents (BKME), on vertebral and physiological parameters were investigated in juvenile fourhorn sculpin, Myoxocephalus quadricornis L. After about 4.5 months of exposure to 0.1 and 0.5 mg TCQ/liter in 7% salinity brackish water, the fish demonstrated vertebral deformities, aberrant mechanical properties of the vertebrae, effects on white and red blood cell counts, enhanced activity of delta-aminolevulinic acid dehydratase in erythrocytes, and increased levels of ascorbic acid in the liver. The effects are discussed in relation to those previously observed in fish exposed to complex BKME in the field and the laboratory.