EFFECT OF NITROGEN LIMITATION ON THE BIODEGRADABILITY AND TOXICITY OFNITROPHENOL AND AMINOPHENOL ISOMERS TO METHANOGENESIS

Citation
Oa. Oconnor et Ly. Young, EFFECT OF NITROGEN LIMITATION ON THE BIODEGRADABILITY AND TOXICITY OFNITROPHENOL AND AMINOPHENOL ISOMERS TO METHANOGENESIS, Archives of environmental contamination and toxicology, 25(2), 1993, pp. 285-291
Citations number
18
Categorie Soggetti
Toxicology,"Environmental Sciences
ISSN journal
00904341
Volume
25
Issue
2
Year of publication
1993
Pages
285 - 291
Database
ISI
SICI code
0090-4341(1993)25:2<285:EONLOT>2.0.ZU;2-P
Abstract
Monosubstituted nitro- and aminophenol isomers exhibited limited biode gradability under methanogenic conditions when supplied as the sole so urce of carbon and energy. This was examined by supplying to the same sediment samples, each isomer of nitro- and aminophenol as a sole sour ce of added carbon under either N-supplemented or N-deprived methanoge nic conditions. The results demonstrated that under N-supplemented con ditions, only 2-NP (NP = nitrophenol), 4-NP and 4-AP (AP = aminophenol ) were stoichiometrically mineralized, 2-AP, 3-AP, and the 3-AP metabo lite formed from 3-NP reduction were persistent over the 51-week incub ation period. In addition, NP isomers inhibited initial rates of metha nogenesis, while all AP amended cultures exhibited no significant inhi bition in the rate of methanogenesis. Under N-deprived conditions, 2-N P, 2-AP and 4-AP were mineralized, while 3-NP, 4-NP and 3-AP were pers istent over the 51-week incubation period. Although all NP isomers wer e still metabolized through the corresponding AP isomer, the deprivati on of nitrogen significantly depressed both the rate and extent of met hanogenesis. In general, nitrogen supplemented cultures produced 25% m ore methane than the nitrogen limited cultures, and the initial rates of methanogenesis were four times greater. While these data showed tha t under N-deprived conditions methanogenesis was inhibited to a greate r extent by these compounds, it also suggests that N-deprived conditio ns may have facilitated the establishment of a 2-AP metabolizing conso rtium.