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 asssessment.

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:
Appl. Microbiol. Biotechnol. 25:553-557.
Reference Type:
publication
Title:
Unnamed
Year:
2005

Materials and methods

Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
The degradation of a C14.5 and a C15.4 chlorinated paraffin (43.5 and 50% Cl, respectively) was assessed by monitoring the release of the chloride ion using a mixed bacterial inoculum 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 145 and 150
- Substance type: technical products
- Analytical purity: no data
- Impurities (identity and concentrations): No details on presence/absence of a stabiliser
- Composition of test material, percentage of components: C14.5H26.6Cl4.4 (43.5% chlorinated; Toyoparax 145) and C15.4H25.4Cl5.6 (50% chlorinated; Toyoparax 150)
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)open allclose all
Soil No.:
#1
Duration:
ca. 48 h
Soil No.:
#2
Duration:
ca. 48 h
Initial test substance concentrationopen allclose all
Soil No.:
#1
Initial conc.:
ca. 180 other: mg chlorine/1.2 L solution
Based on:
other: Chlorine content of C14.5 (43.5% chlorinated)
Soil No.:
#2
Initial conc.:
ca. 180 other: mg chlorine/1.2 L solution
Based on:
other: Chlorine content of C15.5 (50% chlorinated)
Parameter followed for biodegradation estimation:
other: Amount of chloride ion released
Experimental conditionsopen allclose all
Soil No.:
#1
Temp.:
30oC
Soil No.:
#2
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 the C14.5 (43.5% Cl) and C15.5 (50%) chlorinated paraffins (designated soil sample No. 1# and 2#), 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

% Degradationopen allclose all
Soil No.:
#1
% Degr.:
ca. 57
Parameter:
other: chloride released
Sampling time:
36 h
Soil No.:
#2
% Degr.:
ca. 51
Parameter:
other: chloride released
Sampling time:
36 h
Transformation products:
not specified
Details on transformation products:
No data
Evaporation of parent compound:
not specified
Volatile metabolites:
not specified
Residues:
not specified
Details on results:
Both showed significant degradation, with 77 mg/l and 85 mg/l of chloride being released from the 50% and 43.5% chlorinated paraffins respectively. As the starting concentration was 180 mg Cl/1.2 L solution, about 51 to 57% of the chlorine present was released during the degradation.
Results with reference substance:
Four 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, to a lesser extent, 2-chloropropionic acid.

Applicant's summary and conclusion

Conclusions:
The biodegradation of a C14.5 and a C15.4 chlorinated paraffin (43.5 and 50% chlorinated) was assessed by monitoring the release of chloride using a mixed bacterial inoculum isolated from soil. About 57 and 51% of the chlorine was removed from these chlorinated paraffins, respectively, after 36 hours.
Executive summary:

Cometabolic biodegradation experiments were carried out with Toyoparax 145 and 150 (a C14.5 and a C15.4 chlorinated paraffin; 43.5% and 50% chlorinated) at a concentration equivalent to 180 mg Cl/1.2 L solution, using a mixed bacterial inoculum (containing strains HK-3, HK-6, HK-8 and HK-10) incubated at 30oC for 48 hours. Bacterial strains were isolated from soil (no further details on soil characteristics given in paper) using an enrichment culture containing n-hexadecane as the sole carbon source.

Both showed significant degradation, with 77 mg/L and 85 mg/L of chloride being released from the 50% and 43% chlorinated paraffins, respectively, after 36 hours. As the starting concentration was 180 mg Cl/1.2 L solution, about 51 and 57% of the chlorine present was released during the degradation, respectively. These findings suggest the potential for biodegredation appears to increase with decreasing chlorine content.