Structurally Selective Ozonolysis of -Phenylenediamines and Toxicity in Coho Salmon and Rainbow Trout.

The tire-rubber-derived ozonation product of -(1,3-dimethylbutyl)-'-phenyl--phenylenediamine (6PPD), -(1,3-dimethylbutyl)-'-phenyl--phenylenediamine-quinone (6PPD-Q), was recently discovered to cause acute mortality in coho salmon (). -Phenylenediamines (PPDs) with variable side chains distinct from 6PPD have been identified as potential replacement antioxidants, but their toxicities remain unclear under environmentally relevant ozone conditions. We herein tested the multiphase gas-surface ozone reactivity of four select PPDs [6PPD, -isopropyl-'-phenyl--phenylenediamine (IPPD), ,'-diphenyl--phenylenediamine (DPPD), and -phenyl-'-cyclohexyl--phenylenediamine (CPPD)] and evaluated the toxicity of their reaction mixtures in coho salmon, rainbow trout (), and fathead minnow ().