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Environmental fate & pathways

Additional information on environmental fate and behaviour

Administrative data

Endpoint:
additional information on environmental fate and behaviour
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well documented scientifically sound study with sufficient documentation for proper assessment. No data on GLP and no guideline followed.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2004

Materials and methods

Principles of method if other than guideline:
In this study the biodegradation of 3-MCPD was inverstigated using whole-cell baker's yeast (Saccharomyces cerevisiae). Yeast cells were suspended in water, centrifuged and resuspended to form a yeast cream solution. The cream solution was placed in a 250 mL flask containing 3-MCPD. At different time points 3- MCPD was extracted from the reaction medium, analysed and quantified. The percentage degraded was plotted in time. To confirm that the biodegradation of 3-MCPD was due to an enzymatic reaction, the amount of chloride released i nthe reaction medium was compared to the amount of 3-MCPD transformed. For the latter a potentiometric tritration of chloride was performed. Throughout the study the effect of the pH, substrate stereospecificity, substrate concentration and carbon presence (glucose) on the biodegradation of 3-MCPD were also investigated.
GLP compliance:
not specified
Type of study / information:
Information on biodegradation other than in water, sediment and soil.

Test material

Constituent 1
Chemical structure
Reference substance name:
3-chloropropane-1,2-diol
EC Number:
202-492-4
EC Name:
3-chloropropane-1,2-diol
Cas Number:
96-24-2
Molecular formula:
C3H7ClO2
IUPAC Name:
3-chloropropane-1,2-diol
Details on test material:
- Name of test material (as cited in study report): 3-Monochloro-1,2-propanediol (abbreviation used in report: 3-MCPD)
- Analytical purity: Analytical grade
- Source: Aldrich Chemical, Steinheim, Germany

Results and discussion

Any other information on results incl. tables

Effect of pH and substrate concentration:

Maximum biodegradation was seen at pH 8.2, where 45% of 3 -MCPD was converted after 48h, using an initial concentration of 27 mmol/L. For the groups at pH 7.0 and 6.2, this was only 35 and 12%, respectively. In contrast 60% of 3 -MCPD was converted at pH 8.2 after 48h when using a lower initial concencentration (i.e. 7.3 µmol/L).

Effect of carbon presence:

The addition of flucose as carbon source enhanced the 3 -MCPD degradation rate. Thus 68% substrate was transformed after 48h in the presence of glucose, while only 45% could be achieved in the abscence of glucose. Both trials were perfomed at pH 8.2 using an initial concentration of 27 mmol/L.

Effect of eneatiomers:

Results show that the (S)-enantiomer was degraded at a higher rate and percentage in comparison with the (R)-enantiomer. A maximum degradation of 85% was achieved with (S)-3 -MCPD, while only 60% degradation was observed for (R)-3 -MCPD

Chloride titration:

Results indicate that the degradation of 3 -MCPD is due to enzymatic reactions and not to other physicochemical phenomenons such as adsorption for instance.

The results of all assays showed good reproducibility (less than 2% standard deviation)

Applicant's summary and conclusion

Conclusions:
The results in this study suggest that 3-chloro-1,2 propane diol is rapidly biodegradable by baker's yeat (S. cerevisiae). Furthermore the results showed that the pH, presence of a carbon source and stereoisomerism have an influence on the biodegradation rate of 3-MCPD. The maximum biodegradation was seen at a pH 8.2. A higher biodegradation rate was also absorved in the presence of a carbon source and for the (S)-enantiomer.

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