Registration Dossier

Administrative data

Endpoint:
biodegradation in soil
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Published study considered acceptable for assessment

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Bacterial cometabolic degradation of chlorinated paraffins
Author:
Omori T, Kimura T and Kodama T
Year:
1987
Bibliographic source:
Applied Microbiol. Biotechnol. 25: 553-557.
Reference Type:
secondary source
Title:
Unnamed
Year:
2000

Materials and methods

Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
The degradation of Toyoparax 265 (a C12 chlorinated paraffin; 63% chlorination) was assessed by monitoring the release of chloride ion using a mixed bacterial culture isolated from soil.
GLP compliance:
not specified
Test type:
laboratory

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Toyoparax 265
- Substance type: technical product
- Physical state: no data
- Analytical purity: no data
- Composition of test material, percentage of components: C12 chlorinated paraffin (63% chlorinated; C12H18Cl8 )
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
no data
Radiolabelling:
no

Study design

Oxygen conditions:
aerobic
Soil classification:
not specified
Details on soil characteristics:
no data
Duration of test (contact time)
Soil No.:
#1
Duration:
ca. 48 h
Initial test substance concentration
Soil No.:
#1
Initial conc.:
ca. 180 other: mg chlorine/1.2 L solution
Based on:
test mat.
Parameter followed for biodegradation estimation:
other: chloride ion release
Experimental conditions
Soil No.:
#1
Temp.:
30oC
Details on experimental conditions:
Bacterial strains were isolated from soil using an enrichment culture containing n-hexadecane as the sole carbon source. The cometabolic biodegradation experiments were carried out with Toyoparax 265 (designated soil sample No. #1), with a concentration equivalent to 180 mg Cl/l.2 L solution) using a mixed bacterial inoculum (containing strains HK-3, HK-6, HK-8 and HK-10) incubated at 30oC for 48 hours.

Results and discussion

% Degradation
Soil No.:
#1
% Degr.:
21
Parameter:
other: chloride release
Sampling time:
36 h
Transformation products:
not specified
Details on transformation products:
no data
Details on results:
Around 21% dechlorination of the test material was seen, with 32 µg/mL chloride being released
Results with reference substance:
The 4 bacterial strains (HK-3, HK-6, HK-8 and HK-10), grown on n-hexadecane, dechlorinated 1,10-dichlorodecane, 1-chlorobutane, 3-chlorobutyric acid and (for HK-10) 2-chloropropionic acid.

Applicant's summary and conclusion

Conclusions:
Significant dechlorination of Toyoparax 265 (a C12 chlorinated paraffin; 63% chlorination) in a cometabolic process has been demonstrated. Around 21% dechlorination was seen after 36 hours with a co-culture of four soil derived bacteria in the presence n-hexadecane.
Executive summary:

Co-metabolic degradation studies were carried out with Toyoparax 265 (a C12 chlorinated paraffin; 63% chlorination), at a concentration of chloride equivalent to 180 mg/1.2 L solution, using a mixed bacterial inoculum (strains HK-3, HK-6, HK-8 and HK-10) at 30oC for 48 hours. The bacteria were isolated from soil using an enrichment culture containing n-hexadecane as sole carbon source.

Significant degradation was detected, with approx. 21% of the chloride being released after 36 hours, at which time bacterial growth and release of chloride ceased.