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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Description of key information

Key value for chemical safety assessment

Half-life in freshwater:
40 d
Half-life in freshwater sediment:
21 d

Additional information

DEGDN (10 ppm) in river and pond sediment was completely degraded within 21 days under all combinations of sterile, nonsterile, aerobic and anaerobic conditions. However, no biotransformation products could be identified by HPLC.

Since nonsterile-aerobic treatment of DEGDN-spiked sediments followed a first-order kinetic loss pattern, the sterile -aerobic treatment did not, several proccess, including sterilization of samples, probably contributed to the loss of parent compound. Thus, the data suggest that most DEGDN is nonbiologically removed from river and pond sediments.

The DEGDN undergoes biotransformation by microorganisms in either batch or continuous cultures under aerobic conditions during 6 days. The degradation proceeds via a sequential stepwise hydrolytic cleavage of the nitrate groups resulting in the formation of the partially nitrated parent glycols. The disappearance of the mononitrate esters suggests that they were converted to the corresponding glycols. This hypothesis could not be verified experimentally in this study.