NIRE Annual Report 1999

NIRE Annual Report

1999

Transformation of Chrolophenols in Various Environmental Samples

Objectives: Chlorophenols are important intermediates for synthesizing pesticides and dyes in chemical manufacturing industries. Contamination of soil and sediment by these compounds has often been reported and paid more attention these days. Studying biological transformation and degradation of chlorophenols especially under anaerobic conditions, which are common in natural environment and contaminated sites, has been a key issue for predicting fate of environmental contaminants as well as developing more efficient waste treatment means. We have been studying biological transformation rates and pathways of many hazardous chemicals other than chlorophenols for constructing data base for these purposes.

Results: We have been working on transformation of chlorophenols in various microbial consortia obtained from different anaerobic conditions (Table 1) to examine effects of exposure of contaminants and environmental condition on transformation rates and pathways. It could have been found a trend that exposure of microbial consortia to contaminant may have enhanced their transformation rates regardless of types of major biological activity. Exposure to contaminant may also have prevented accumulation of transformation intermediates, maybe because of more diverse transformation pathway (Fig. 1). We are accumulating evidences to make these findings more conclusive.


Fig. 1	Dechlorination pathway of chlorophenols by contaminated sediment is quite diverse (Modified from Masunaga, S., et al., 1996. E.S.T. 30, 1253).

National Institute for Resources and Environment