On the Mode of Action of N-Phenyl-2-naphthylamine in Plants

• Published in: Environmental science & technology 2006-10, Vol.40 (19), p.6163-6169
• Main Authors: Altenburger, Rolf, Brack, Werner, Greco, William R, Grote, Matthias, Jung, Klaus, Ovari, Agnes, Riedl, Janet, Schwab, Katrin, Küster, Eberhard
• Format: Article
• Language: English
• Subjects: 2-Naphthylamine - analogs & derivatives; 2-Naphthylamine - toxicity; Aliivibrio fischeri - drug effects; Aliivibrio fischeri - physiology; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Chlorophyta - drug effects; Chlorophyta - physiology; Contaminated sediments; Contamination; Daphnia - drug effects; Daphnia - physiology; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Flowers & plants; Fundamental and applied biological sciences. Psychology; Inhibitor drugs; Photosynthesis - drug effects; Reproduction - drug effects; Toxicity; Zebrafish - physiology
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es060338e

N-phenyl-2-naphthylamine, a sediment contaminant previously identified as a major toxicant of site-specific importance was investigated for its mode of toxic action. From short-term bioassays with daphnids, fish eggs, bacteria, and algae it appears that this compound has specific phytotoxic properties at concentrations below 100 μg/L, which cannot be explained assuming an unspecific narcosis type of action in plants. Also, hydroxy-, nitro-, and methyl-derivatives show clear excess toxicity as compared to baseline toxic effects. Of several plant-specific growth and development processes investigated, only photosynthesis could be demonstrated to be affected at short exposure times and low concentrations. Disturbance of primary photosynthetic reactions such as oxygen evolution and fluorescence quenching, however, becomes only apparent after 2−3 h of exposure, which is in sharp contrast to known specific inhibitors targeting processes such as electron transport or ATP production. This, and concentration-time-effect modeling lead to the suggestion that N-phenyl-2-naphthylamine acts intracellular as a reactive compound in cell membranes producing irreversible, and thus cumulative, damage over time in algae. The effects may become first apparent in membrane-rich compartments such as the algal chloroplast.