Ecotoxicity characterization of dinitrotoluenes and some of their reduced metabolites.
In the present study, the toxic effects of 2,4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT) and a selection of their respective metabolites were examined and compared to 2,4,6-trinitrotoluene (TNT) using the 15-min Microtox (Vibrio fischen) and 96-h freshwater green alga (Selenastrum capricomutum) growth inhibition tests. All of the compounds tested were less toxic than TNT. Using the Microtox assay, 2,6-DNT was more toxic than 2,4-DNT and the order of toxicity for 2,6-DNT and its metabolites was: 2,6-DNT > or = 2A-6NT >> 2,6-DAT; whereas that for 2,4-DNT was: 4A-2NT > 2A-4NT > 2,4-DNT > 2,4-DAT. For the algal test, 2,4-DNT was more toxic than 2,6-DNT and the order of toxicity for 2,4-DNT and its metabolites was: 2,4-DNT > 2,4-DAT approximately equal to 4A-2NT = 2A-4NT. The order of toxicity for 2,6-DNT and its reduced metabolites using the algal test was very similar to the Microtox bioassay. These results demonstrate that the reduced metabolites of 2,6-DNT tested in this study were less toxic than that of the parent compound, but certain partially reduced metabolites of 2,4-DNT can be more toxic than the parent molecule. These data put into question the general hypothesis that reductive metabolism of nitro-aromatics is associated with a sequential detoxification process.
Dodard
S G
SG
Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada.
Renoux
A Y
AY
Hawari
J
J
Ampleman
G
G
Thiboutot
S
S
Sunahara
G I
GI
D001673:Biodegradation, Environmental; D000460:Chlorophyta / Q000187:drug effects; D004136:Dinitrobenzenes / Q000378:metabolism / Q000633:toxicity*; D018675:Toxicity Tests / Q000379:methods; D014733:Vibrio / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D004136:Dinitrobenzenes; D014874:Water Pollutants, Chemical